Null reading in stream images? Unable to start activity ComponentInfo

Posted by lasmith on Stack Overflow See other posts from Stack Overflow or by lasmith
Published on 2012-10-15T20:48:30Z Indexed on 2012/10/15 21:37 UTC
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I have reviewed a lot of similar questions regarding not being able to launch an activity but they don't seem to quite match my problem. I am working on a simple black jack game but its force quitting. I suspect there is a problem with loading up the card png images I have. Stepping through the debugger it crashes right while in the resetGame() function. I'm sure I am doing something dumb.

My Logcat:

10-15 20:21:43.309: E/AndroidRuntime(2863): FATAL EXCEPTION: main
10-15 20:21:43.309: E/AndroidRuntime(2863): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.smith.blackjack/com.smith.blackjack.Main}: java.lang.NullPointerException
10-15 20:21:43.309: E/AndroidRuntime(2863):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059)
10-15 20:21:43.309: E/AndroidRuntime(2863):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
10-15 20:21:43.309: E/AndroidRuntime(2863):     at android.app.ActivityThread.access$600(ActivityThread.java:130)
10-15 20:21:43.309: E/AndroidRuntime(2863):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
10-15 20:21:43.309: E/AndroidRuntime(2863):     at android.os.Handler.dispatchMessage(Handler.java:99)
10-15 20:21:43.309: E/AndroidRuntime(2863):     at android.os.Looper.loop(Looper.java:137)
10-15 20:21:43.309: E/AndroidRuntime(2863):     at android.app.ActivityThread.main(ActivityThread.java:4745)
10-15 20:21:43.309: E/AndroidRuntime(2863):     at java.lang.reflect.Method.invokeNative(Native Method)
10-15 20:21:43.309: E/AndroidRuntime(2863):     at java.lang.reflect.Method.invoke(Method.java:511)
10-15 20:21:43.309: E/AndroidRuntime(2863):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
10-15 20:21:43.309: E/AndroidRuntime(2863):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
10-15 20:21:43.309: E/AndroidRuntime(2863):     at dalvik.system.NativeStart.main(Native Method)
10-15 20:21:43.309: E/AndroidRuntime(2863): Caused by: java.lang.NullPointerException
10-15 20:21:43.309: E/AndroidRuntime(2863):     at com.smith.blackjack.DeckOfCards.<init>(DeckOfCards.java:17)
10-15 20:21:43.309: E/AndroidRuntime(2863):     at com.smith.blackjack.Main.resetGame(Main.java:98)
10-15 20:21:43.309: E/AndroidRuntime(2863):     at com.smith.blackjack.Main.onCreate(Main.java:67)
10-15 20:21:43.309: E/AndroidRuntime(2863):     at android.app.Activity.performCreate(Activity.java:5008)
10-15 20:21:43.309: E/AndroidRuntime(2863):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
10-15 20:21:43.309: E/AndroidRuntime(2863):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023)
10-15 20:21:43.309: E/AndroidRuntime(2863):     ... 11 more

My androidmanifest:

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.smith.blackjack"
android:versionCode="1"
android:versionName="1.0" >

<uses-sdk
    android:minSdkVersion="11"
    android:targetSdkVersion="15" />

<application
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >
    <activity
        android:name=".Main"
        android:label="@string/title_activity_main" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
</application>

Here is my Main.java

package com.smith.blackjack;

import android.os.Bundle;
import android.app.Activity;
import android.content.res.AssetManager;
import android.graphics.drawable.Drawable;

import java.io.IOException;
import java.io.InputStream;

import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;

public class Main extends Activity {

private ImageView dealerCard0;
private ImageView dealerCard1;
private ImageView dealerCard2;
private ImageView dealerCard3;
private ImageView playerCard0;
private ImageView playerCard1;
private ImageView playerCard2;
private ImageView playerCard3;
private ImageView imgResult;
private Button btnDeal;
private Button btnDraw;
private Button btnHold;
private DeckOfCards deckOfCards;
private int[] dealerValues;
private int dealerSum;
private int dealerCardNumber;
private int[] playerValues;
private int playerSum;
private int playerCardNumber;
private InputStream dealerHiddenCard;
private Card dealerCard;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    dealerCard0 = (ImageView) findViewById(R.id.dealerCard0);
    dealerCard1 = (ImageView) findViewById(R.id.dealerCard1);
    dealerCard2 = (ImageView) findViewById(R.id.dealerCard2);
    dealerCard3 = (ImageView) findViewById(R.id.dealerCard3);

    playerCard0 = (ImageView) findViewById(R.id.playerCard0);
    playerCard1 = (ImageView) findViewById(R.id.playerCard1);
    playerCard2 = (ImageView) findViewById(R.id.playerCard2);
    playerCard3 = (ImageView) findViewById(R.id.playerCard3);

    imgResult = (ImageView) findViewById(R.id.imgResult);

    btnDeal = (Button) findViewById(R.id.deal);
    btnDraw = (Button) findViewById(R.id.draw);
    btnHold = (Button) findViewById(R.id.hold);

    btnDeal.setOnClickListener(btnDealListener);
    btnDraw.setOnClickListener(btnDrawListener);
    btnHold.setOnClickListener(btnHoldListener); 


    resetGame();

}

private void resetGame(){

    AssetManager assets = getAssets();
    dealerValues = new int[4];
    playerValues = new int[4];
    dealerSum = 0;
    playerSum = 0;
    dealerCardNumber = 0;
    playerCardNumber = 0;
    for (int i = 0; i < 4; i++) {
        dealerValues[i] = 0;
        playerValues[i] = 0;
    }

    try {
        InputStream stream = assets.open("cardback.png");
        // stream = assets.open("cardback.png");
        Drawable cardImage = Drawable.createFromStream(stream,  null);
        dealerCard0.setImageDrawable(cardImage);
        dealerCard1.setImageDrawable(cardImage);
        dealerCard2.setImageDrawable(cardImage);
        dealerCard3.setImageDrawable(cardImage);
        playerCard0.setImageDrawable(cardImage);
        playerCard1.setImageDrawable(cardImage);
        playerCard2.setImageDrawable(cardImage);
        playerCard3.setImageDrawable(cardImage);
        imgResult.setImageDrawable(cardImage);
        deckOfCards = new DeckOfCards();
        deckOfCards.shuffle();
        assets.close();
    }
    catch (IOException e){
        Log.e("Reset Game", "Error Loading", e);
    }
}

public OnClickListener btnDealListener = new OnClickListener()
{
//      @Override 
    public void onClick(View v) {


        try {
            AssetManager assets = getAssets();
            InputStream stream;

            // first player card
            Card newCard;
            newCard = deckOfCards.dealCard();
            playerValues[playerCardNumber] = newCard.faceValue;
            playerCardNumber++;             
            stream = assets.open(newCard.File);
            Drawable cardImage = Drawable.createFromStream(stream, newCard.File);
            playerCard0.setImageDrawable(cardImage);
            assets.close();

            // second player card
            newCard = deckOfCards.dealCard();
            playerValues[playerCardNumber] = newCard.faceValue;
            playerCardNumber++; 
            stream = assets.open(newCard.File);
            cardImage = Drawable.createFromStream(stream, newCard.File);
            playerCard1.setImageDrawable(cardImage);
            assets.close();

            // first dealer card hidden
            newCard = deckOfCards.dealCard();
            dealerCard = newCard;
            dealerValues[dealerCardNumber] = newCard.faceValue;
            dealerCardNumber++;
            dealerHiddenCard = assets.open(newCard.File);
            stream = assets.open("cardback.png");
            cardImage = Drawable.createFromStream(stream,  "cardback");
            dealerCard0.setImageDrawable(cardImage);
            assets.close();

            // second dealer card open
            newCard = deckOfCards.dealCard();
            dealerValues[dealerCardNumber] = newCard.faceValue;
            dealerCardNumber++;
            stream = assets.open(newCard.File);
            cardImage = Drawable.createFromStream(stream,  newCard.File);
            dealerCard1.setImageDrawable(cardImage);
            assets.close();
        }
        catch (IOException e){
            Log.e("Deal", "Error Loading", e);
        }

    };
};

public OnClickListener btnDrawListener = new OnClickListener()
{
//      @Override 
    public void onClick(View v) {
        try {
            AssetManager assets = getAssets();
            InputStream stream;

            // get next player card
            Card newCard;
            newCard = deckOfCards.dealCard();
            playerValues[playerCardNumber] = newCard.faceValue;
            playerCardNumber++;             
            stream = assets.open(newCard.File);
            Drawable cardImage = Drawable.createFromStream(stream, newCard.File);
            switch (playerCardNumber){
            case 3:
                playerCard2.setImageDrawable(cardImage);
            case 4:
                playerCard3.setImageDrawable(cardImage);
            }
            assets.close();
        }
        catch (IOException e){
            Log.e("Draw", "Error Loading", e);
        }
    };
};


public OnClickListener btnHoldListener = new OnClickListener()
{
//      @Override 
    public void onClick(View v) {
        Drawable cardImage;
        // evaluate player hand
        playerSum = evaluate(playerValues);
        if (playerSum > 21){
            // player losses
        }
        // flip over the dealer hidden card
        cardImage = Drawable.createFromStream(dealerHiddenCard, dealerCard.File);
        Card newCard;
        InputStream stream;
        AssetManager assets = getAssets();
        for (int i=2; i<4; i++){
            dealerSum = evaluate(dealerValues);
            if (dealerSum < 16 ) {
                newCard = deckOfCards.dealCard();
                dealerValues[dealerCardNumber] = newCard.faceValue;
                dealerCardNumber++;
                try {
                    stream = assets.open(newCard.File);
                    cardImage = Drawable.createFromStream(stream,  newCard.File);
                    switch (dealerCardNumber){
                    case 3:
                        dealerCard2.setImageDrawable(cardImage);
                    case 4:
                        dealerCard3.setImageDrawable(cardImage);
                    }
                    assets.close();
                }
                catch (IOException e){
                    Log.e("Draw", "Error Loading", e);
                } 
                if (dealerSum < playerSum) {
                    // player wins
                }
                if (dealerSum > playerSum){
                    // dealer wins
                }
                if (dealerSum == playerSum){
                    // it is a draw
                }
            }

        }


    };
};

public int evaluate (int[]values)   {
    int sumCards = 0;
    for (int i = 0; i < 4; i++){
        sumCards += values[i];
    }
    if (sumCards > 21) {
        for (int i = 0; i < 4; i++){
            if (values[i] == 11) {
                values[i] = 1;
                sumCards -= 10;
                continue;
            }
        }
    }
    return sumCards;
}

}

My DeckOfCards class:

package com.smith.blackjack;

import java.util.Random;

public class DeckOfCards {

private Card [] deck;
private int currentCard;
private static final int NUMBER_OF_CARDS = 52;
private static final Random randomNumbers = new Random();

public DeckOfCards () {
    deck = new Card[NUMBER_OF_CARDS];
    currentCard = 0 ;
    for(int count = 0; count < deck.length; count++)
    {
        deck[count].faceValue = count + 1;
    }
}

public void shuffle () {
    currentCard = 0;
    for (int first = 0; first < deck.length; first ++){
        int second = randomNumbers.nextInt(NUMBER_OF_CARDS);
        int temp = deck[first].faceValue;
        deck[first].faceValue=deck[second].faceValue;
        deck[second].faceValue = temp;
    }
}

public Card dealCard(){
    Card temp = new Card();
    temp.faceValue = 0;
    temp.File = "";
    if(currentCard < deck.length)
    {
        temp.faceValue = deck[currentCard].faceValue / 4;

        int suit = deck[currentCard].faceValue % 4;
        String suitString = "";
        switch (suit){
        case 0:
            suitString = "c";
        case 1:
            suitString = "d";
        case 2:
            suitString = "h";
        case 3:
            suitString = "s";   
        }

        Integer face = temp.faceValue / 4 ;
        String faceString = face.toString();
        temp.File = faceString + suitString + ".png";

        switch (temp.faceValue){
        case 11:
            temp.faceValue = 10;
        case 12:
            temp.faceValue = 10;
        case 13:
            temp.faceValue = 10;
        }

        return temp;
    }

    else
        return temp;
}
}

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