java.lang.NullPointerException; android.view.View.dispatchTouchEvent(View.java:7713)

Question

I am making an application, it seems to work run very well, but the application has some kind of a bug. Every time i am touching the view and moving my finger outside the view and releasing, it crashes.

Here is an explanation of my problem:![enter image description here][1]

Here is some of my code that might be the problem:

public class Game extends View implements OnTurnBasedMatchUpdateReceivedListener  {

public Game(GameActivity activity){
    super(activity);
    this.mGameActivity = activity;
    this.mGameBoard    = new GameBoard(activity);
    this.setFocusable(true);
    this.setFocusableInTouchMode(true);
    this.setClickable(true);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
    // TODO Auto-generated method stub
    // TODO Subtract movementpoints
    int eventCode = event.getAction();
    switch(eventCode){
    case MotionEvent.ACTION_DOWN:
        return true;
    case MotionEvent.ACTION_MOVE:
        return true;
    case MotionEvent.ACTION_UP:
        return true;
    default:
        return true;            
    }
}

Here is the error log:

04-08 23:00:47.585: E/InputEventReceiver(18313): Exception dispatching input event.
04-08 23:00:47.585: E/MessageQueue-JNI(18313): Exception in MessageQueue callback: handleReceiveCallback
04-08 23:00:47.620: E/MessageQueue-JNI(18313): java.lang.NullPointerException
04-08 23:00:47.620: E/MessageQueue-JNI(18313):  at com.boentertainment.quizgame.Game.onTouchEvent(Game.java:199)
04-08 23:00:47.620: E/MessageQueue-JNI(18313):  at android.view.View.dispatchTouchEvent(View.java:7713)
04-08 23:00:47.620: E/MessageQueue-JNI(18313):  at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2216)
04-08 23:00:47.620: E/MessageQueue-JNI(18313):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1959)
04-08 23:00:47.620: E/MessageQueue-JNI(18313):  at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2216)
04-08 23:00:47.620: E/MessageQueue-JNI(18313):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1959)
04-08 23:00:47.620: E/MessageQueue-JNI(18313):  at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2216)
04-08 23:00:47.620: E/MessageQueue-JNI(18313):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1959)
04-08 23:00:47.620: E/MessageQueue-JNI(18313):  at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2216)
04-08 23:00:47.620: E/MessageQueue-JNI(18313):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1959)
04-08 23:00:47.620: E/MessageQueue-JNI(18313):  at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2216)
04-08 23:00:47.620: E/MessageQueue-JNI(18313):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1959)

what is line 199 of Game.java

panini
– panini

2014-04-08 21:47:26 +00:00
Commented Apr 8, 2014 at 21:47 — panini
– panini, Commented Apr 8, 2014 at 21:47
199? I cant see line 199!

user3399300
– user3399300

2014-04-09 08:27:00 +00:00
Commented Apr 9, 2014 at 8:27 — user3399300
– user3399300, Commented Apr 9, 2014 at 8:27

Community · Accepted Answer · 2017-05-23 12:21:23Z

0

You'll need to learn to debug your application. Then you can do the things that cause the bug, and see the values of your variables at that time. Another usefull thing is the logging system. You can find more information here if you're using Eclipse: How to Debug Android application line by line using Eclipse?

Your switch definitely needs break-statements if you are going to implement code for each case in the future:

switch(eventCode){
case MotionEvent.ACTION_DOWN:
    return true;
    break;
case MotionEvent.ACTION_MOVE:
    return true;
    break;
case MotionEvent.ACTION_UP:
    return true;
    break;
default:
    return true;            
}

edited May 23, 2017 at 12:21

CommunityBot

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answered Apr 8, 2014 at 21:56

blubbiedevis

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3 Comments

cheng yang Over a year ago

break is not needed after return

user3399300 Over a year ago

Thank you for the reply. I'll will debug and see what happens.

user3399300 Over a year ago

I did a debug of my code and found the problem. The problem was a null pointer exception caused by a logic error. Thanks for the help

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