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  • Android: Showing photos runs out of memory

    - by Tom Beech
    I'm using a dialog box to display images in my android project. The first one opens fine, but when I close it and do the process again to show a different one the app falls over with a memory error (it's running on a samsung galaxy s3 - so shouldnt be an issue). Error: 10-24 11:25:45.575: E/dalvikvm-heap(29194): Out of memory on a 31961104-byte allocation. 10-24 11:25:45.580: E/AndroidRuntime(29194): FATAL EXCEPTION: main 10-24 11:25:45.580: E/AndroidRuntime(29194): java.lang.OutOfMemoryError 10-24 11:25:45.580: E/AndroidRuntime(29194): at android.graphics.BitmapFactory.nativeDecodeStream(Native Method) 10-24 11:25:45.580: E/AndroidRuntime(29194): at android.graphics.BitmapFactory.decodeStream(BitmapFactory.java:587) 10-24 11:25:45.580: E/AndroidRuntime(29194): at android.graphics.BitmapFactory.decodeFile(BitmapFactory.java:389) 10-24 11:25:45.580: E/AndroidRuntime(29194): at android.graphics.BitmapFactory.decodeFile(BitmapFactory.java:418) 10-24 11:25:45.580: E/AndroidRuntime(29194): at android.graphics.drawable.Drawable.createFromPath(Drawable.java:882) 10-24 11:25:45.580: E/AndroidRuntime(29194): at android.widget.ImageView.resolveUri(ImageView.java:569) 10-24 11:25:45.580: E/AndroidRuntime(29194): at android.widget.ImageView.setImageURI(ImageView.java:340) 10-24 11:25:45.580: E/AndroidRuntime(29194): at com.directenquiries.assessment.tool.AddAsset.loadPhoto(AddAsset.java:771) 10-24 11:25:45.580: E/AndroidRuntime(29194): at com.directenquiries.assessment.tool.AddAsset$11.onClick(AddAsset.java:748) 10-24 11:25:45.580: E/AndroidRuntime(29194): at com.android.internal.app.AlertController$AlertParams$3.onItemClick(AlertController.java:936) 10-24 11:25:45.580: E/AndroidRuntime(29194): at android.widget.AdapterView.performItemClick(AdapterView.java:292) 10-24 11:25:45.580: E/AndroidRuntime(29194): at android.widget.AbsListView.performItemClick(AbsListView.java:1359) 10-24 11:25:45.580: E/AndroidRuntime(29194): at android.widget.AbsListView$PerformClick.run(AbsListView.java:2988) 10-24 11:25:45.580: E/AndroidRuntime(29194): at android.widget.AbsListView$1.run(AbsListView.java:3783) 10-24 11:25:45.580: E/AndroidRuntime(29194): at android.os.Handler.handleCallback(Handler.java:605) 10-24 11:25:45.580: E/AndroidRuntime(29194): at android.os.Handler.dispatchMessage(Handler.java:92) 10-24 11:25:45.580: E/AndroidRuntime(29194): at android.os.Looper.loop(Looper.java:137) 10-24 11:25:45.580: E/AndroidRuntime(29194): at android.app.ActivityThread.main(ActivityThread.java:4517) 10-24 11:25:45.580: E/AndroidRuntime(29194): at java.lang.reflect.Method.invokeNative(Native Method) 10-24 11:25:45.580: E/AndroidRuntime(29194): at java.lang.reflect.Method.invoke(Method.java:511) 10-24 11:25:45.580: E/AndroidRuntime(29194): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:993) 10-24 11:25:45.580: E/AndroidRuntime(29194): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:760) 10-24 11:25:45.580: E/AndroidRuntime(29194): at dalvik.system.NativeStart.main(Native Method) Loading code: public void loadPhotoList(){ Cursor f = db.rawQuery("select * from stationphotos where StationObjectID = '"+ checkStationObjectID + "'", null); final ArrayList<String> mHelperNames= new ArrayList<String>(); if(f.getCount() != 0) { f.moveToFirst(); f.moveToFirst(); while(!f.isAfterLast()) { mHelperNames.add(f.getString(f.getColumnIndex("FilePath"))); f.moveToNext(); } } f.close(); final String [] nameStrings = new String [mHelperNames.size()]; for(int i=0; i<mHelperNames.size(); i++) nameStrings[i] = mHelperNames.get(i).toString(); AlertDialog.Builder builder = new AlertDialog.Builder(this); builder.setTitle("Select Picture"); builder.setItems(nameStrings, new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int item) { loadPhoto(mHelperNames.get(item).toString()); } }); AlertDialog alert = builder.create(); alert.show(); } public void loadPhoto(String imagepath){ Dialog dialog = new Dialog(this); dialog.setContentView(R.layout.activity_show_image); dialog.setTitle("Image"); dialog.setCancelable(true); ImageView img = (ImageView) dialog.findViewById(R.id.imageView1); img.setImageResource(R.drawable.ico_partial); Uri imgUri = Uri.parse(imagepath); img.setImageURI(imgUri); dialog.show(); }

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  • Severe Tomcat crash has me stumped

    - by Eric Banderhide
    I'm pretty used to crashing my tomcat server. But I don't think I made any changes at all and seem to have broken it completely. Was working one min then not the next. I really hope someone can help here is the Catalina.out: Dec 20, 2012 1:35:56 AM org.apache.catalina.startup.Embedded initDirs SEVERE: Cannot find specified temporary folder at Dec 20, 2012 1:35:57 AM org.apache.catalina.core.AprLifecycleListener init INFO: Loaded APR based Apache Tomcat Native library 1.1.23. Dec 20, 2012 1:35:57 AM org.apache.catalina.core.AprLifecycleListener init INFO: APR capabilities: IPv6 [true], sendfile [true], accept filters [false], random [true]. Dec 20, 2012 1:35:57 AM org.apache.coyote.http11.Http11AprProtocol init INFO: Initializing Coyote HTTP/1.1 on http-8040 Dec 20, 2012 1:35:57 AM org.apache.coyote.ajp.AjpAprProtocol init INFO: Initializing Coyote AJP/1.3 on ajp-8042 Dec 20, 2012 1:35:57 AM org.apache.catalina.startup.Catalina load INFO: Initialization processed in 587 ms Dec 20, 2012 1:35:57 AM org.apache.catalina.core.StandardService start INFO: Starting service Catalina Dec 20, 2012 1:35:57 AM org.apache.catalina.core.StandardEngine start INFO: Starting Servlet Engine: Apache Tomcat/6.0.33 Dec 20, 2012 1:35:57 AM org.apache.catalina.startup.HostConfig deployDirectory INFO: Deploying web application directory docs Dec 20, 2012 1:35:57 AM org.apache.catalina.startup.HostConfig deployDirectory INFO: Deploying web application directory ROOT Dec 20, 2012 1:35:57 AM org.apache.catalina.startup.HostConfig deployDirectory INFO: Deploying web application directory myApp Dec 20, 2012 1:35:57 AM org.apache.catalina.loader.WebappClassLoader validateJarFile INFO: validateJarFile(/lhome/me/tomcat6/webapps/myApp/WEB-INF/lib/javax.servlet.jar) - jar not loaded. See Servlet Spec 2.3, section 9.7.2. Offending class: javax/servlet/Servlet.class Dec 20, 2012 1:35:58 AM org.apache.coyote.http11.Http11AprProtocol start INFO: Starting Coyote HTTP/1.1 on http-8040 Dec 20, 2012 1:35:58 AM org.apache.coyote.ajp.AjpAprProtocol start INFO: Starting Coyote AJP/1.3 on ajp-8042 Dec 20, 2012 1:35:58 AM org.apache.catalina.startup.Catalina start INFO: Server startup in 880 ms Error Reading TLE line 1: java.lang.Exception: TLE line 1 not valid first line Error Creating SGP4 Satellite Dec 20, 2012 1:36:26 AM org.apache.coyote.http11.Http11AprProtocol pause INFO: Pausing Coyote HTTP/1.1 on http-8040 Dec 20, 2012 1:36:26 AM org.apache.coyote.ajp.AjpAprProtocol pause INFO: Pausing Coyote AJP/1.3 on ajp-8042 Dec 20, 2012 1:36:27 AM org.apache.catalina.core.StandardService stop INFO: Stopping service Catalina Dec 20, 2012 1:36:30 AM org.apache.catalina.loader.WebappClassLoader clearReferencesJdbc SEVERE: The web application [/myApp] registered the JDBC driver [com.mysql.jdbc.Driver] but failed to unregister it when the web application was stopped. To prevent a memory leak, the JDBC Driver has been forcibly unregistered. Dec 20, 2012 1:36:30 AM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads SEVERE: The web application [/myApp] is still processing a request that has yet to finish. This is very likely to create a memory leak. You can control the time allowed for requests to finish by using the unloadDelay attribute of the standard Context implementation. Dec 20, 2012 1:36:30 AM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads SEVERE: The web application [/myApp] appears to have started a thread named [Timer-0] but has failed to stop it. This is very likely to create a memory leak. Dec 20, 2012 1:36:30 AM org.apache.coyote.http11.Http11AprProtocol destroy INFO: Stopping Coyote HTTP/1.1 on http-8040 Dec 20, 2012 1:36:30 AM org.apache.coyote.ajp.AjpAprProtocol destroy INFO: Stopping Coyote AJP/1.3 on ajp-8042 Dec 20, 2012 1:37:12 AM org.apache.catalina.startup.Catalina stopServer SEVERE: Catalina.stop: java.net.ConnectException: Connection refused at java.net.PlainSocketImpl.socketConnect(Native Method) at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339) at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200) at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182) at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:391) at java.net.Socket.connect(Socket.java:579) at java.net.Socket.connect(Socket.java:528) at java.net.Socket.<init>(Socket.java:425) at java.net.Socket.<init>(Socket.java:208) at org.apache.catalina.startup.Catalina.stopServer(Catalina.java:422) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:601) at org.apache.catalina.startup.Bootstrap.stopServer(Bootstrap.java:338) at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:416) And I have a new log that has been created, I've never seen it before but it seems to think its something severe. A long one but here it is: Massive Error Log I've never seen before

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  • Android JSon Array is not working with Maplocations class

    - by user1505962
    I am developing a map application in android i have made maplocation class to pass latitude and longitude and using Json Array to fetch data from MYSQl to display in map.But When I run application it crashed unfortunantely here is my log cat 07-07 14:02:26.423: E/AndroidRuntime(366): FATAL EXCEPTION: main 07-07 14:02:26.423: E/AndroidRuntime(366): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.icons.draw.view/com.icons.draw.view.DrawIcons}: android.view.InflateException: Binary XML file line #6: Error inflating class com.icons.draw.view.LocationViewers 07-07 14:02:26.423: E/AndroidRuntime(366): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647) 07-07 14:02:26.423: E/AndroidRuntime(366): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663) 07-07 14:02:26.423: E/AndroidRuntime(366): at android.app.ActivityThread.access$1500(ActivityThread.java:117) 07-07 14:02:26.423: E/AndroidRuntime(366): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931) 07-07 14:02:26.423: E/AndroidRuntime(366): at android.os.Handler.dispatchMessage(Handler.java:99) 07-07 14:02:26.423: E/AndroidRuntime(366): at android.os.Looper.loop(Looper.java:130) 07-07 14:02:26.423: E/AndroidRuntime(366): at android.app.ActivityThread.main(ActivityThread.java:3683) 07-07 14:02:26.423: E/AndroidRuntime(366): at java.lang.reflect.Method.invokeNative(Native Method) 07-07 14:02:26.423: E/AndroidRuntime(366): at java.lang.reflect.Method.invoke(Method.java:507) 07-07 14:02:26.423: E/AndroidRuntime(366): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 07-07 14:02:26.423: E/AndroidRuntime(366): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 07-07 14:02:26.423: E/AndroidRuntime(366): at dalvik.system.NativeStart.main(Native Method) 07-07 14:02:26.423: E/AndroidRuntime(366): Caused by: android.view.InflateException: Binary XML file line #6: Error inflating class com.icons.draw.view.LocationViewers 07-07 14:02:26.423: E/AndroidRuntime(366): at android.view.LayoutInflater.createView(LayoutInflater.java:518) 07-07 14:02:26.423: E/AndroidRuntime(366): at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:570) 07-07 14:02:26.423: E/AndroidRuntime(366): at android.view.LayoutInflater.rInflate(LayoutInflater.java:623) 07-07 14:02:26.423: E/AndroidRuntime(366): at android.view.LayoutInflater.inflate(LayoutInflater.java:408) 07-07 14:02:26.423: E/AndroidRuntime(366): at android.view.LayoutInflater.inflate(LayoutInflater.java:320) 07-07 14:02:26.423: E/AndroidRuntime(366): at android.view.LayoutInflater.inflate(LayoutInflater.java:276) 07-07 14:02:26.423: E/AndroidRuntime(366): at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:207) 07-07 14:02:26.423: E/AndroidRuntime(366): at android.app.Activity.setContentView(Activity.java:1657) 07-07 14:02:26.423: E/AndroidRuntime(366): at com.icons.draw.view.DrawIcons.onCreate(DrawIcons.java:16) 07-07 14:02:26.423: E/AndroidRuntime(366): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 07-07 14:02:26.423: E/AndroidRuntime(366): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611) 07-07 14:02:26.423: E/AndroidRuntime(366): ... 11 more 07-07 14:02:26.423: E/AndroidRuntime(366): Caused by: java.lang.reflect.InvocationTargetException 07-07 14:02:26.423: E/AndroidRuntime(366): at java.lang.reflect.Constructor.constructNative(Native Method) 07-07 14:02:26.423: E/AndroidRuntime(366): at java.lang.reflect.Constructor.newInstance(Constructor.java:415) 07-07 14:02:26.423: E/AndroidRuntime(366): at android.view.LayoutInflater.createView(LayoutInflater.java:505) 07-07 14:02:26.423: E/AndroidRuntime(366): ... 21 more 07-07 14:02:26.423: E/AndroidRuntime(366): Caused by: java.lang.NullPointerException 07-07 14:02:26.423: E/AndroidRuntime(366): at org.json.JSONTokener.nextCleanInternal(JSONTokener.java:112) 07-07 14:02:26.423: E/AndroidRuntime(366): at org.json.JSONTokener.nextValue(JSONTokener.java:90) 07-07 14:02:26.423: E/AndroidRuntime(366): at org.json.JSONArray.<init>(JSONArray.java:87) 07-07 14:02:26.423: E/AndroidRuntime(366): at org.json.JSONArray.<init>(JSONArray.java:103) 07-07 14:02:26.423: E/AndroidRuntime(366): at com.icons.draw.view.LocationViewers.getMapLocations(LocationViewers.java:102) 07-07 14:02:26.423: E/AndroidRuntime(366): at com.icons.draw.view.LocationViewers.init(LocationViewers.java:65) 07-07 14:02:26.423: E/AndroidRuntime(366): at com.icons.draw.view.LocationViewers.<init>(LocationViewers.java:45) 07-07 14:02:26.423: E/AndroidRuntime(366): ... 24 more And Here is My JSOn Array and loop code to make markers double LAT; double LANG; String INFO; public List<MapLocation> getMapLocations() { if (mapLocations == null) { try{ jArray = new JSONArray(result); JSONObject json_data=null; for(int i=0;i<jArray.length();i++){ json_data = jArray.getJSONObject(i); LAT=json_data.getDouble("lat"); LANG=json_data.getDouble("lang"); INFO=json_data.getString("info"); mapLocations = new ArrayList<MapLocation>(); mapLocations.add(new MapLocation(INFO,LAT,LANG)); } } catch(JSONException e1){ Toast.makeText(getContext(), "No Vehicles Found" ,Toast.LENGTH_LONG).show(); } catch (ParseException e1) { e1.printStackTrace(); } } return mapLocations; } Please Help to Remove this error

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  • Expose C++ object to Javascript in Qt

    - by Evans
    Is there any way I can expose a C++ object/function to JavaScript running inside the QtWebKit browser in Qt? It's possible to expose ActionScript objects to JS code running inside the WebKit browser in Adobe AIR - I'm looking for similar functionality in Qt.

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  • how to deal with the position in a c# stream

    - by CapsicumDreams
    The (entire) documentation for the position property on a stream says: When overridden in a derived class, gets or sets the position within the current stream. The Position property does not keep track of the number of bytes from the stream that have been consumed, skipped, or both. That's it. OK, so we're fairly clear on what it doesn't tell us, but I'd really like to know what it in fact does stand for. What is 'the position' for? Why would we want to alter or read it? If we change it - what happens? In a pratical example, I have a a stream that periodically gets written to, and I have a thread that attempts to read from it (ideally ASAP). From reading many SO issues, I reset the position field to zero to start my reading. Once this is done: Does this affect where the writer to this stream is going to attempt to put the data? Do I need to keep track of the last write position myself? (ie if I set the position to zero to read, does the writer begin to overwrite everything from the first byte?) If so, do I need a semaphore/lock around this 'position' field (subclassing, perhaps?) due to my two threads accessing it? If I don't handle this property, does the writer just overflow the buffer? Perhaps I don't understand the Stream itself - I'm regarding it as a FIFO pipe: shove data in at one end, and suck it out at the other. If it's not like this, then do I have to keep copying the data past my last read (ie from position 0x84 on) back to the start of my buffer? I've seriously tried to research all of this for quite some time - but I'm new to .NET. Perhaps the Streams have a long, proud (undocumented) history that everyone else implicitly understands. But for a newcomer, it's like reading the manual to your car, and finding out: The accelerator pedal affects the volume of fuel and air sent to the fuel injectors. It does not affect the volume of the entertainment system, or the air pressure in any of the tires, if fitted. Technically true, but seriously, what we want to know is that if we mash it to the floor you go faster..

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  • Windows XP GUI programming language

    - by bobir
    I need to write a Windows XP/Vista application, main requirements: Just one .exe file, without extra runtime, like Air, .Net; posstibly a couple of dlls. Very small file size. The application is for network centric usage, similar to ICQ or Gtalk clients. Thanks in advance.

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  • sherlock actionbar menu

    - by user1647443
    I am trying to setup a menu programatically and my method gets com.actionbarsherlock.view.Menu menu as a parameter. As I want to change the styling of the menu item I am trying to setup a SpannableString spannable and pass it to add. menu.add(0, MENU_ABOUT, 0, spannable); This is causing a crash only in ICS when I cick that menu item. Any ideas if I am missing something. Thanks Here is the code I am trying and it crashes when I run the app and select "About Application". FYI, I am using SpannableString because I want to add some styling and color to the menu item. The crash does NOT happen if I use a regular string, but then I cant do styling public boolean onCreateOptionsMenu(com.actionbarsherlock.view.Menu menu) { SpannableString spannable = new SpannableString("About Application"); menu.add(0, MENU_ABOUT, 0, spannable); return true; } Here is the stack trace: 09-05 02:25:32.849: E/AndroidRuntime(684): FATAL EXCEPTION: main 09-05 02:25:32.849: E/AndroidRuntime(684): java.lang.IllegalArgumentException: Invalid payload item type 09-05 02:25:32.849: E/AndroidRuntime(684): at android.util.EventLog.writeEvent(Native Method) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.app.Activity.onMenuItemSelected(Activity.java:2501) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.support.v4.app.FragmentActivity.onMenuItemSelected(FragmentActivity.java:351) 09-05 02:25:32.849: E/AndroidRuntime(684): at com.android.internal.policy.impl.PhoneWindow.onMenuItemSelected(PhoneWindow.java:950) 09-05 02:25:32.849: E/AndroidRuntime(684): at com.android.internal.view.menu.MenuBuilder.dispatchMenuItemSelected(MenuBuilder.java:735) 09-05 02:25:32.849: E/AndroidRuntime(684): at com.android.internal.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:149) 09-05 02:25:32.849: E/AndroidRuntime(684): at com.android.internal.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:874) 09-05 02:25:32.849: E/AndroidRuntime(684): at com.android.internal.view.menu.ListMenuPresenter.onItemClick(ListMenuPresenter.java:163) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.widget.AdapterView.performItemClick(AdapterView.java:292) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.widget.AbsListView.performItemClick(AbsListView.java:1058) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.widget.AbsListView$PerformClick.run(AbsListView.java:2514) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.widget.AbsListView.onTouchEvent(AbsListView.java:3180) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.view.View.dispatchTouchEvent(View.java:5541) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:1951) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1712) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:1957) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1726) 09-05 02:25:32.849: E/AndroidRuntime(684): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1860) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.view.View.dispatchPointerEvent(View.java:5721) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.view.ViewRootImpl.deliverPointerEvent(ViewRootImpl.java:2890) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2466) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.view.ViewRootImpl.processInputEvents(ViewRootImpl.java:845) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2475) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.os.Handler.dispatchMessage(Handler.java:99) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.os.Looper.loop(Looper.java:137) 09-05 02:25:32.849: E/AndroidRuntime(684): at android.app.ActivityThread.main(ActivityThread.java:4424) 09-05 02:25:32.849: E/AndroidRuntime(684): at java.lang.reflect.Method.invokeNative(Native Method) 09-05 02:25:32.849: E/AndroidRuntime(684): at java.lang.reflect.Method.invoke(Method.java:511) 09-05 02:25:32.849: E/AndroidRuntime(684): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) 09-05 02:25:32.849: E/AndroidRuntime(684): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551) 09-05 02:25:32.849: E/AndroidRuntime(684): at dalvik.system.NativeStart.main(Native Method) Thanks

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  • Launching an Activity from a Service

    - by nldev
    When I am trying to launch a call activity from a Service, I get a NullPointerException. Here is my code: Intent callIntent = new Intent(Intent.ACTION_CALL); callIntent.setData(Uri.parse("tel:" + number)); callIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK); startActivity(callIntent); I get the exception on the startActivity line. I tried to use getApplication.startActivity and getApplicationContext.startActivity but no luck. Any ideas? edit : Maybe some usefull info: I am trying to create a service that will run on the background and scan sensor data, when a certain signal is given i would like to maken an automated call to a number. edit : full adb error code: 03-31 09:04:10.214: ERROR/AndroidRuntime(1896): Uncaught handler: thread main exiting due to uncaught exception 03-31 09:04:10.226: ERROR/AndroidRuntime(1896): java.lang.RuntimeException: Unable to instantiate service dfz.epilepsiedetector.services.DetectionService: java.lang.NullPointerException 03-31 09:04:10.226: ERROR/AndroidRuntime(1896): at android.app.ActivityThread.handleCreateService(ActivityThread.java:2668) 03-31 09:04:10.226: ERROR/AndroidRuntime(1896): at android.app.ActivityThread.access$3100(ActivityThread.java:116) 03-31 09:04:10.226: ERROR/AndroidRuntime(1896): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1846) 03-31 09:04:10.226: ERROR/AndroidRuntime(1896): at android.os.Handler.dispatchMessage(Handler.java:99) 03-31 09:04:10.226: ERROR/AndroidRuntime(1896): at android.os.Looper.loop(Looper.java:123) 03-31 09:04:10.226: ERROR/AndroidRuntime(1896): at android.app.ActivityThread.main(ActivityThread.java:4203) 03-31 09:04:10.226: ERROR/AndroidRuntime(1896): at java.lang.reflect.Method.invokeNative(Native Method) 03-31 09:04:10.226: ERROR/AndroidRuntime(1896): at java.lang.reflect.Method.invoke(Method.java:521) 03-31 09:04:10.226: ERROR/AndroidRuntime(1896): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:791) 03-31 09:04:10.226: ERROR/AndroidRuntime(1896): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:549) 03-31 09:04:10.226: ERROR/AndroidRuntime(1896): at dalvik.system.NativeStart.main(Native Method) 03-31 09:04:10.226: ERROR/AndroidRuntime(1896): Caused by: java.lang.NullPointerException 03-31 09:04:10.226: ERROR/AndroidRuntime(1896): at android.content.ContextWrapper.getPackageName(ContextWrapper.java:120) 03-31 09:04:10.226: ERROR/AndroidRuntime(1896): at android.content.ComponentName.<init>(ComponentName.java:75) 03-31 09:04:10.226: ERROR/AndroidRuntime(1896): at android.content.Intent.<init>(Intent.java:2302) 03-31 09:04:10.226: ERROR/AndroidRuntime(1896): at dfz.epilepsiedetector.services.DetectionService.<init>(DetectionService.java:35) 03-31 09:04:10.226: ERROR/AndroidRuntime(1896): at java.lang.Class.newInstanceImpl(Native Method) 03-31 09:04:10.226: ERROR/AndroidRuntime(1896): at java.lang.Class.newInstance(Class.java:1472) 03-31 09:04:10.226: ERROR/AndroidRuntime(1896): at android.app.ActivityThread.handleCreateService(ActivityThread.java:2665) edit Trimmed class code: `public class DetectionService extends IntentService implements SensorEventListener { private SensorManager mSensorManager; private Sensor mAccelerometer; private boolean hasSeizure = false; private final int POLLS_PER_SECOND = 10; public DetectionService() { super("EpilepsionDetectionService"); //mSensorManager = (SensorManager)getSystemService(SENSOR_SERVICE); // mAccelerometer = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER); /*Intent callIntent = new Intent(Intent.ACTION_CALL); callIntent.setData(Uri.parse("tel:" + "+31648363944")); callIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);*/ Intent callIntent = new Intent(DetectionService.this, InformationActivity.class); callIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK); getApplication().startActivity(callIntent); //((Activity) getContext()).startActivity(callIntent); }`

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  • missing table in SQLite with specific version of HTC DESIRE HD

    - by William
    My application has a SQLite database in the asset folder. When the user launches my application, the database is created and the tables too. This works fine with a lot of devices (Nexus One, Htc Magic, SGS, X10… and even Htc Desire HD v2.2). My application works with all versions of Android (tested on my device (1.6, 2.2, 2.2.1 Htc Magic) and on the emulator (v1,5 until v2.3). I have just a problem with HTC DESIRE HD v2.2.1 1.72.405.3. The logcat: android.database.sqlite.SQLiteException: no such table: LISTE: , while compiling: select _id from LISTE at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2833) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2854) at android.app.ActivityThread.access$2300(ActivityThread.java:136) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2179) at android.os.Handler.dispatchMessage(Handler.java:99) at android.os.Looper.loop(Looper.java:143) at android.app.ActivityThread.main(ActivityThread.java:5068) at java.lang.reflect.Method.invokeNative(Native Method) at java.lang.reflect.Method.invoke(Method.java:521) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:858) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) at dalvik.system.NativeStart.main(Native Method) Caused by: android.database.sqlite.SQLiteException: no such table: LISTE: , while compiling: select _id from LISTE at android.database.sqlite.SQLiteCompiledSql.native_compile(Native Method) at android.database.sqlite.SQLiteCompiledSql.compile(SQLiteCompiledSql.java:91) at android.database.sqlite.SQLiteCompiledSql.(SQLiteCompiledSql.java:64) at android.database.sqlite.SQLiteProgram.(SQLiteProgram.java:80) at android.database.sqlite.SQLiteQuery.(SQLiteQuery.java:46) at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:53) at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1417) at android.database.sqlite.SQLiteDatabase.rawQuery(SQLiteDatabase.java:1387) ... 11 more My application create the database but it doesn’t copy the tables of the file of the asset folder in data\data\packagename\databases\mydatabase. My code: public void createDataBase() throws IOException{ boolean dbExist = checkDataBase(); if(dbExist){ //do nothing - database already exist }else{ //By calling this method and empty database will be created into the default system path //of your application so we are gonna be able to overwrite that database with our database. this.getReadableDatabase(); try { copyDataBase(); } catch (IOException e) { throw new Error("Error copying database"); } } } private void copyDataBase() throws IOException{ //Open your local db as the input stream InputStream myInput = myContext.getAssets().open(DB_NAME); // Path to the just created empty db String outFileName = DB_PATH + DB_NAME; //Open the empty db as the output stream OutputStream myOutput = new FileOutputStream(outFileName); //transfer bytes from the inputfile to the outputfile byte[] buffer = new byte[1024]; int length; while ((length = myInput.read(buffer))!= -1){ if (length > 0){ myOutput.write(buffer, 0, length); } } //Close the streams myOutput.flush(); myOutput.close(); myInput.close(); } I think that the copydatabase function has a problem but I don't see. This code works fine with all devices except the HTC DESIRE HD v2.2.1 1.72.405.3. What problems might exist here for the HTC Desire with the given version above? How can this be remedied?

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  • redirection follow by post

    - by lucas
    hi, just wonder how those air ticket booking website redirect the user to the airline booking website and then fill up(i suppose doing POST) the required information so that the users will land on the booking page with origin/destination/date selected? Is the technique used is to open up new browser window and do a ajax POST from there? Thanks.

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  • SPAZ to connect to Laconica

    - by Linley
    I installed a local version of Laconica microblogging in my env. Then I downlowaded SPAZ (an AIR client) to try and talk to the Laconica app. I get an authenitcation error. I have put in the appropriate credentials - I think :) But I think that I have to alter the API and base URL for connecting. Ayone have any thoughts on how to make these two apps talk ? Thanks in advance, Linley

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  • local file access with javascript

    - by Jared
    is there any local file manipulation that's been done with javascript? i'm looking for a solution that can be accomplished with no install footprint like requiring AIR. specifically, i'd like to read the contents from a file and write those contents to another file. at this point i'm not worried about gaining permissions, just assuming i already have full permissions to these files.

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  • Does html5 allow desktop execution?

    - by Shawn Mclean
    I want a functionality similiar to Adobe AIR or Silverlight Out of Browser but without the need for downloading plugins. I want the user to be on the site, then click install, javascript takes over and save itself to the local file system where it can then be clicked, then started up in the browser. Similiar to save-file. Html5 will handle the offline execution, etc.

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  • why is my intent not useful?

    - by user1634887
    This is my first to ask here. I write the code for a Broadcast A start another Broadcast B. But the Broadcast B didn't get the intent's value. Broadcast A:get the sms contain message and start B public void onReceive(Context context, Intent intent) { Object[] pdus=(Object[])intent.getExtras().get("pdus"); for(Object pdu:pdus) { byte[] date=(byte[])pdu; SmsMessage message=SmsMessage.createFromPdu(date); String sender=message.getOriginatingAddress(); String body=message.getMessageBody(); if(sender.equals(AppUtil.herPhone)&&body.regionMatches(0, AppUtil.herSmsText, 0, 18)) { Toast.makeText(context, body, Toast.LENGTH_LONG).show(); String [] bodyArray=body.split(" "); String longitude=bodyArray[1]; String latitude=bodyArray[2]; **Intent uiIntent=new Intent(); Bundle bundle=new Bundle(); bundle.putString("longitude", longitude); bundle.putString("latitude", latitude); uiIntent.putExtras(bundle); uiIntent.setAction("android.janmac.location"); context.sendBroadcast(uiIntent);** abortBroadcast(); } } } Boardcast B: it nest in an Activity. register: button.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { AppUtil.SendMessage(MainActivity.this); uiReceiver=new UIReceiver(); IntentFilter filter=new IntentFilter(); filter.addAction("android.janmac.location"); registerReceiver(uiReceiver, filter); } }); extend: private class UIReceiver extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) { Log.v("location","uireceiver????!"); **Bundle bundle=new Bundle(); bundle=intent.getExtras(); herLongitude=Double.valueOf(bundle.getString("longitude")); herLatitude=Double.valueOf(bundle.getString("latitude"));** } } but the bundle couldn't get any values. here is log: 08-30 11:17:40.494: D/AndroidRuntime(2359): Shutting down VM 08-30 11:17:40.514: W/dalvikvm(2359): threadid=1: thread exiting with uncaught exception (group=0x40018560) 08-30 11:17:40.544: E/AndroidRuntime(2359): FATAL EXCEPTION: main 08-30 11:17:40.544: E/AndroidRuntime(2359): java.lang.RuntimeException: Error receiving broadcast Intent { act=android.janmac.location (has extras) } in com.example.locationclient.MainActivity$UIReceiver@40513690 08-30 11:17:40.544: E/AndroidRuntime(2359): at android.app.LoadedApk$ReceiverDispatcher$Args.run(LoadedApk.java:722) 08-30 11:17:40.544: E/AndroidRuntime(2359): at android.os.Handler.handleCallback(Handler.java:587) 08-30 11:17:40.544: E/AndroidRuntime(2359): at android.os.Handler.dispatchMessage(Handler.java:92) 08-30 11:17:40.544: E/AndroidRuntime(2359): at android.os.Looper.loop(Looper.java:130) 08-30 11:17:40.544: E/AndroidRuntime(2359): at android.app.ActivityThread.main(ActivityThread.java:3835) 08-30 11:17:40.544: E/AndroidRuntime(2359): at java.lang.reflect.Method.invokeNative(Native Method) 08-30 11:17:40.544: E/AndroidRuntime(2359): at java.lang.reflect.Method.invoke(Method.java:507) 08-30 11:17:40.544: E/AndroidRuntime(2359): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:864) 08-30 11:17:40.544: E/AndroidRuntime(2359): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:622) 08-30 11:17:40.544: E/AndroidRuntime(2359): at dalvik.system.NativeStart.main(Native Method) 08-30 11:17:40.544: E/AndroidRuntime(2359): Caused by: java.lang.NumberFormatException 08-30 11:17:40.544: E/AndroidRuntime(2359): at org.apache.harmony.luni.util.FloatingPointParser.parseDblImpl(Native Method) 08-30 11:17:40.544: E/AndroidRuntime(2359): at org.apache.harmony.luni.util.FloatingPointParser.parseDouble(FloatingPointParser.java:283) 08-30 11:17:40.544: E/AndroidRuntime(2359): at java.lang.Double.parseDouble(Double.java:318) 08-30 11:17:40.544: E/AndroidRuntime(2359): at java.lang.Double.valueOf(Double.java:356) 08-30 11:17:40.544: E/AndroidRuntime(2359): at com.example.locationclient.MainActivity$UIReceiver.onReceive(MainActivity.java:231) 08-30 11:17:40.544: E/AndroidRuntime(2359): at android.app.LoadedApk$ReceiverDispatcher$Args.run(LoadedApk.java:709) 08-30 11:17:40.544: E/AndroidRuntime(2359): ... 9 more enter code here

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  • Where is Prolog used for traffic control systems?

    - by Masi
    The user Laurent had an interesting reply to the question [Why hasn’t logic programming caught on?]: If you look at the influence logic-programming has had in the field of -- air traffic control -- I don't think it can be said logic-programming has not caught on. A question arises: Where is prolog used for traffic control systems on the roads? Why is it used instead of languages, such as C or Python, in such environments?

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  • Objective-C vs JavaScript loop performance

    - by micadelli
    I have a PhoneGap mobile application that I need to generate an array of match combinations. In JavaScript side, the code hanged pretty soon when the array of which the combinations are generated from got a bit bigger. So, I thought I'll make a plugin to generate the combinations, passing the array of javascript objects to native side and loop it there. To my surprise the following codes executes in 150 ms (JavaScript) whereas in native side (Objective-C) it takes ~1000 ms. Does anyone know any tips for speeding up those executing times? When players exceeds 10, i.e. the length of the array of teams equals 252 it really gets slow. Those execution times mentioned above are for 10 players / 252 teams. Here's the JavaScript code: for (i = 0; i < GAME.teams.length; i += 1) { for (j = i + 1; j < GAME.teams.length; j += 1) { t1 = GAME.teams[i]; t2 = GAME.teams[j]; if ((t1.mask & t2.mask) === 0) { GAME.matches.push({ Team1: t1, Team2: t2 }); } } } ... and here's the native code: NSArray *teams = [[NSArray alloc] initWithArray: [options objectForKey:@"teams"]]; NSMutableArray *t = [[NSMutableArray alloc] init]; int mask_t1; int mask_t2; for (NSInteger i = 0; i < [teams count]; i++) { for (NSInteger j = i + 1; j < [teams count]; j++) { mask_t1 = [[[teams objectAtIndex:i] objectForKey:@"mask"] intValue]; mask_t2 = [[[teams objectAtIndex:j] objectForKey:@"mask"] intValue]; if ((mask_t1 & mask_t2) == 0) { [t insertObject:[teams objectAtIndex:i] atIndex:0]; [t insertObject:[teams objectAtIndex:j] atIndex:1]; /* NSArray *newCombination = [[NSArray alloc] initWithObjects: [teams objectAtIndex:i], [teams objectAtIndex:j], nil]; */ [combinations addObject:t]; } } } ... the array in question (GAME.teams) looks like this: { count = 2; full = 1; list = ( { index = 0; mask = 1; name = A; score = 0; }, { index = 1; mask = 2; name = B; score = 0; } ); mask = 3; name = A; }, { count = 2; full = 1; list = ( { index = 0; mask = 1; name = A; score = 0; }, { index = 2; mask = 4; name = C; score = 0; } ); mask = 5; name = A; },

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  • Is there a limit to the size of an application in the Android Marketplace?

    - by Trukdero
    I know from reading this: http://stackoverflow.com/questions/1230457/is-there-a-size-limit-for-ota-android-market-downloads/1232145#1232145 That there wasn't a limit to the size of an application that could be downloaded over the air (OTA) but I wonder if a limit, like that imposed by the Apple App Store (20MB) exists now that the Nexus one is running on AT&T's 3G network as of today. Thanks in advance for your help/ Truk

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  • Real Excel Templates I

    - by Tim Dexter
    As promised, I'm starting to document the new Excel templates that I teased you all with a few weeks back. Leslie is buried in 11g documentation and will not get to officially documenting the templates for a while. I'll do my best to be professional and not ramble on about this and that, although the weather here has finally turned and its 'scorchio' here in Colorado today. Maybe our stand of Aspen will finally come into leaf ... but I digress. Preamble These templates are not actually that new, I helped in a small way to develop them a few years back with Excel 'meistress' Shirley for a company that was trying to use the Report Manager(RR) Excel FSG outputs under EBS 12. The functionality they needed was just not there in the RR FSG templates, the templates are actually XSL that is created from the the RR Excel template builder and fed to BIP for processing. Think of Excel from our RTF templates and you'll be there ie not really Excel but HTML masquerading as Excel. Although still under controlled release in EBS they have now made their way to the standlone release and are willing to share their Excel goodness. You get everything you have with hte Excel Analyzer Excel templates plus so much more. Therein lies a question, what will happen to the Analyzer templates? My understanding is that both will come together into a single Excel template format some time in the post-11g release world. The new XLSX format for Exce 2007/10 is also in the mix too so watch this space. What more do these templates offer? Well, you can structure data in the Excel output. Similar to RTF templates you can create sheets of data that have master-detail n relationships. Although the analyzer templates can do this, you have to get into macros whereas BIP will do this all for you. You can also use native XSL functions in your data to manipulate it prior to rendering. BP functions are not currently supported. The most impressive, for me at least, is the sheet 'bursting'. You can split your hierarchical data across multiple sheets and dynamically name those sheets. Finally, you of course, still get all the native Excel functionality. Pre-reqs You must be on 10.1.3.4.1 plus the latest rollup patch, 9546699. You can patch upa BIP instance running with OBIEE, no problem You need Excel 2000 or above to build the templates Some patience - there is no Excel template builder for these new templates. So its all going to have to be done by hand. Its not that tough but can get a little 'fiddly'. You can not test the template from Excel , it has to be deployed and then run. Limitations The new templates are definitely superior to the Analyzer templates but there are a few limitations. Re-grouping is not supported. You can only follow a data hierarchy not bend it to your will unless you want to get into macros. No support for BIP functions. The templates support native XSL functions only. No template builder Getting Started The templates make the use of named cells and groups of cells to allow BIP to find the insertion point for data points. It also uses a hidden sheet to store calculation mappings from named cells to XML data elements. To start with, in the great BIP tradition, we need some sample XML data. Becasue I wanted to show the master-detail output we need some hierarchical data. If you have not yet gotten into the data templates, now is a good time, I wrote a post a while back starting from the simple to more complex. They generate ideal data sets for these templates. Im working with the following data set: <EMPLOYEES> <LIST_G_DEPT> <G_DEPT> <DEPARTMENT_ID>10</DEPARTMENT_ID> <DEPARTMENT_NAME>Administration</DEPARTMENT_NAME> <LIST_G_EMP> <G_EMP> <EMPLOYEE_ID>200</EMPLOYEE_ID> <EMP_NAME>Jennifer Whalen</EMP_NAME> <EMAIL>JWHALEN</EMAIL> <PHONE_NUMBER>515.123.4444</PHONE_NUMBER> <HIRE_DATE>1987-09-17T00:00:00.000-06:00</HIRE_DATE> <SALARY>4400</SALARY> </G_EMP> </LIST_G_EMP> <TOTAL_EMPS>1</TOTAL_EMPS> <TOTAL_SALARY>4400</TOTAL_SALARY> <AVG_SALARY>4400</AVG_SALARY> <MAX_SALARY>4400</MAX_SALARY> <MIN_SALARY>4400</MIN_SALARY> </G_DEPT> ... <LIST_G_DEPT> <EMPLOYEES> Simple enough to follow and bread and butter stuff for an RTF template. Building the Template For an Excel template we need to start by thinking about how we want to render the data. Come up with a sample output in Excel. Its all dummy data, nothing marked up yet with one row of data for each level. I have the department name and then a repeating row for the employees. You can apply Excel formatting to the layout. The total is going to be derived from a data element. We'll get to Excel functions later. Marking Up Cells Next we need to start marking up the cells with custom names to map them to data elements. The cell names need to follow a specific format: For data grouping, XDO_GROUP_?group_name? For data elements, XDO_?element_name? Notice the question mark delimter, the group_name and element_name are case sensitive. The next step is to find how to name cells; the easiest method is to highlight the cell and then type in the name. You can also find the Name Manager dialog. I use 2007 and its available on the ribbon under the Formulas section Go thorugh the process of naming all the cells for the element values you have. Using my data set from above.You should end up with something like this in your 'Name Manager' dialog. You can update any mistakes you might have made through this dialog. Creating Groups In the image above you can see there are a couple of named group cells. To create these its a simple case of highlighting the cells that make up the group and then naming them. For the EMP group, highlight the employee row and then type in the name, XDO_GROUP?G_EMP? Notice the 10,000 total is outside of the G_EMP group. Its actually named, XDO_?TOTAL_SALARY?, a query calculated value. For the department group, we need to include the department name cell and the sub EMP grouping and name it, XDO_GROUP?G_DEPT? Notice, the 10,000 total is included in the G_DEPT group. This will ensure it repeats at the department level. Lastly, we do need to include a special sheet in the workbook. We will not have anything meaningful in there for now, but it needs to be present. Create a new sheet and name it XDO_METADATA. The name is important as the BIP rendering engine will looking for it. For our current example we do not need anything other than the required stuff in our XDO_METADATA sheet but, it must be present. Easy enough to hide it. Here's what I have: The only cell that is important is the 'Data Constraints:' cell. The rest is optional. To save curious users getting distracted, hide the metadata sheet. Deploying & Running Templates We should now have a usable Excel template. Loading it into a report is easy enough using the browser UI, just like an RTF template. Set the template type to Excel. You will now be able to run the report and hopefully get something like this. You will not get the red highlighting, thats just some conditional formatting I added to the template using Excel functionality. Your dates are probably going to look raw too. I got around this for now using an Excel function on the cell: =--REPLACE(SUBSTITUTE(E8,"T"," "),LEN(E8)-6,6,"") Google to the rescue on that one. Try some other stuff out. To avoid constantly loading the template through the UI. If you have BIP running locally or you can access the reports repository, once you have loaded the template the first time. Just save the template directly into the report folder. I have put together a sample report using a sample data set, available here. Just drop the xml data file, EmpbyDeptExcelData.xml into 'demo files' folder and you should be good to go. Thats the basics, next we'll start using some XSL functions in the template and move onto the 'bursting' across sheets.

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  • Parallelism in .NET – Part 7, Some Differences between PLINQ and LINQ to Objects

    - by Reed
    In my previous post on Declarative Data Parallelism, I mentioned that PLINQ extends LINQ to Objects to support parallel operations.  Although nearly all of the same operations are supported, there are some differences between PLINQ and LINQ to Objects.  By introducing Parallelism to our declarative model, we add some extra complexity.  This, in turn, adds some extra requirements that must be addressed. In order to illustrate the main differences, and why they exist, let’s begin by discussing some differences in how the two technologies operate, and look at the underlying types involved in LINQ to Objects and PLINQ . LINQ to Objects is mainly built upon a single class: Enumerable.  The Enumerable class is a static class that defines a large set of extension methods, nearly all of which work upon an IEnumerable<T>.  Many of these methods return a new IEnumerable<T>, allowing the methods to be chained together into a fluent style interface.  This is what allows us to write statements that chain together, and lead to the nice declarative programming model of LINQ: double min = collection .Where(item => item.SomeProperty > 6 && item.SomeProperty < 24) .Min(item => item.PerformComputation()); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Other LINQ variants work in a similar fashion.  For example, most data-oriented LINQ providers are built upon an implementation of IQueryable<T>, which allows the database provider to turn a LINQ statement into an underlying SQL query, to be performed directly on the remote database. PLINQ is similar, but instead of being built upon the Enumerable class, most of PLINQ is built upon a new static class: ParallelEnumerable.  When using PLINQ, you typically begin with any collection which implements IEnumerable<T>, and convert it to a new type using an extension method defined on ParallelEnumerable: AsParallel().  This method takes any IEnumerable<T>, and converts it into a ParallelQuery<T>, the core class for PLINQ.  There is a similar ParallelQuery class for working with non-generic IEnumerable implementations. This brings us to our first subtle, but important difference between PLINQ and LINQ – PLINQ always works upon specific types, which must be explicitly created. Typically, the type you’ll use with PLINQ is ParallelQuery<T>, but it can sometimes be a ParallelQuery or an OrderedParallelQuery<T>.  Instead of dealing with an interface, implemented by an unknown class, we’re dealing with a specific class type.  This works seamlessly from a usage standpoint – ParallelQuery<T> implements IEnumerable<T>, so you can always “switch back” to an IEnumerable<T>.  The difference only arises at the beginning of our parallelization.  When we’re using LINQ, and we want to process a normal collection via PLINQ, we need to explicitly convert the collection into a ParallelQuery<T> by calling AsParallel().  There is an important consideration here – AsParallel() does not need to be called on your specific collection, but rather any IEnumerable<T>.  This allows you to place it anywhere in the chain of methods involved in a LINQ statement, not just at the beginning.  This can be useful if you have an operation which will not parallelize well or is not thread safe.  For example, the following is perfectly valid, and similar to our previous examples: double min = collection .AsParallel() .Select(item => item.SomeOperation()) .Where(item => item.SomeProperty > 6 && item.SomeProperty < 24) .Min(item => item.PerformComputation()); However, if SomeOperation() is not thread safe, we could just as easily do: double min = collection .Select(item => item.SomeOperation()) .AsParallel() .Where(item => item.SomeProperty > 6 && item.SomeProperty < 24) .Min(item => item.PerformComputation()); In this case, we’re using standard LINQ to Objects for the Select(…) method, then converting the results of that map routine to a ParallelQuery<T>, and processing our filter (the Where method) and our aggregation (the Min method) in parallel. PLINQ also provides us with a way to convert a ParallelQuery<T> back into a standard IEnumerable<T>, forcing sequential processing via standard LINQ to Objects.  If SomeOperation() was thread-safe, but PerformComputation() was not thread-safe, we would need to handle this by using the AsEnumerable() method: double min = collection .AsParallel() .Select(item => item.SomeOperation()) .Where(item => item.SomeProperty > 6 && item.SomeProperty < 24) .AsEnumerable() .Min(item => item.PerformComputation()); Here, we’re converting our collection into a ParallelQuery<T>, doing our map operation (the Select(…) method) and our filtering in parallel, then converting the collection back into a standard IEnumerable<T>, which causes our aggregation via Min() to be performed sequentially. This could also be written as two statements, as well, which would allow us to use the language integrated syntax for the first portion: var tempCollection = from item in collection.AsParallel() let e = item.SomeOperation() where (e.SomeProperty > 6 && e.SomeProperty < 24) select e; double min = tempCollection.AsEnumerable().Min(item => item.PerformComputation()); This allows us to use the standard LINQ style language integrated query syntax, but control whether it’s performed in parallel or serial by adding AsParallel() and AsEnumerable() appropriately. The second important difference between PLINQ and LINQ deals with order preservation.  PLINQ, by default, does not preserve the order of of source collection. This is by design.  In order to process a collection in parallel, the system needs to naturally deal with multiple elements at the same time.  Maintaining the original ordering of the sequence adds overhead, which is, in many cases, unnecessary.  Therefore, by default, the system is allowed to completely change the order of your sequence during processing.  If you are doing a standard query operation, this is usually not an issue.  However, there are times when keeping a specific ordering in place is important.  If this is required, you can explicitly request the ordering be preserved throughout all operations done on a ParallelQuery<T> by using the AsOrdered() extension method.  This will cause our sequence ordering to be preserved. For example, suppose we wanted to take a collection, perform an expensive operation which converts it to a new type, and display the first 100 elements.  In LINQ to Objects, our code might look something like: // Using IEnumerable<SourceClass> collection IEnumerable<ResultClass> results = collection .Select(e => e.CreateResult()) .Take(100); If we just converted this to a parallel query naively, like so: IEnumerable<ResultClass> results = collection .AsParallel() .Select(e => e.CreateResult()) .Take(100); We could very easily get a very different, and non-reproducable, set of results, since the ordering of elements in the input collection is not preserved.  To get the same results as our original query, we need to use: IEnumerable<ResultClass> results = collection .AsParallel() .AsOrdered() .Select(e => e.CreateResult()) .Take(100); This requests that PLINQ process our sequence in a way that verifies that our resulting collection is ordered as if it were processed serially.  This will cause our query to run slower, since there is overhead involved in maintaining the ordering.  However, in this case, it is required, since the ordering is required for correctness. PLINQ is incredibly useful.  It allows us to easily take nearly any LINQ to Objects query and run it in parallel, using the same methods and syntax we’ve used previously.  There are some important differences in operation that must be considered, however – it is not a free pass to parallelize everything.  When using PLINQ in order to parallelize your routines declaratively, the same guideline I mentioned before still applies: Parallelization is something that should be handled with care and forethought, added by design, and not just introduced casually.

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