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java – Android Development: "thread exiting with uncaught exception"

Posted by: admin June 15, 2020 Leave a comment


I’m trying to create my first Android App (a game) but I’m having some difficulties getting started.

When I run my code I get this error log:

05-25 02:41:51.022: WARN/dalvikvm(634): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
05-25 02:41:51.040: ERROR/AndroidRuntime(634): FATAL EXCEPTION: main
05-25 02:41:51.040: ERROR/AndroidRuntime(634): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.stickfigs.nmg/com.stickfigs.nmg.NMG}: java.lang.NullPointerException
05-25 02:41:51.040: ERROR/AndroidRuntime(634):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
05-25 02:41:51.040: ERROR/AndroidRuntime(634):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
05-25 02:41:51.040: ERROR/AndroidRuntime(634):     at android.app.ActivityThread.access$2300(ActivityThread.java:125)
05-25 02:41:51.040: ERROR/AndroidRuntime(634):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
05-25 02:41:51.040: ERROR/AndroidRuntime(634):     at android.os.Handler.dispatchMessage(Handler.java:99)
05-25 02:41:51.040: ERROR/AndroidRuntime(634):     at android.os.Looper.loop(Looper.java:123)
05-25 02:41:51.040: ERROR/AndroidRuntime(634):     at android.app.ActivityThread.main(ActivityThread.java:4627)
05-25 02:41:51.040: ERROR/AndroidRuntime(634):     at java.lang.reflect.Method.invokeNative(Native Method)
05-25 02:41:51.040: ERROR/AndroidRuntime(634):     at java.lang.reflect.Method.invoke(Method.java:521)
05-25 02:41:51.040: ERROR/AndroidRuntime(634):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
05-25 02:41:51.040: ERROR/AndroidRuntime(634):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
05-25 02:41:51.040: ERROR/AndroidRuntime(634):     at dalvik.system.NativeStart.main(Native Method)
05-25 02:41:51.040: ERROR/AndroidRuntime(634): Caused by: java.lang.NullPointerException
05-25 02:41:51.040: ERROR/AndroidRuntime(634):     at com.stickfigs.nmg.NMG.onCreate(NMG.java:32)
05-25 02:41:51.040: ERROR/AndroidRuntime(634):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
05-25 02:41:51.040: ERROR/AndroidRuntime(634):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
05-25 02:41:51.040: ERROR/AndroidRuntime(634):     ... 11 more
05-25 02:41:51.062: WARN/ActivityManager(59):   Force finishing activity com.stickfigs.nmg/.NMG

I think the problem is this “thread exiting with uncaught exception” part, I have no idea what the exception could be or what’s causing it.

Here is my code:

package com.stickfigs.NMG;

import android.content.Context;
import android.os.Bundle;
import android.util.AttributeSet;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

class NMGView extends SurfaceView implements SurfaceHolder.Callback {

    class NMGThread extends Thread {
        //State-tracking constants
        public static final int STATE_LOSE = 1;
        public static final int STATE_PAUSE = 2;
        public static final int STATE_READY = 3;
        public static final int STATE_RUNNING = 4;
        public static final int STATE_WIN = 5;

        /** The state of the game. One of READY, RUNNING, PAUSE, LOSE, or WIN */
        private int mode;

        /** Handle to the surface manager object we interact with */
        private SurfaceHolder surfaceHolder;

        public NMGThread(SurfaceHolder surfaceHolderc, Context contextc) {
            // get handles to some important objects
            surfaceHolder = surfaceHolderc;
            context = contextc;


         * Restores game state from the indicated Bundle. Typically called when
         * the Activity is being restored after having been previously
         * destroyed.
         * @param savedState Bundle containing the game state
        public synchronized void restoreState(Bundle savedState) {
            synchronized (surfaceHolder) {

         * Sets the game mode. That is, whether we are running, paused, in the
         * failure state, in the victory state, etc.
         * @param mode one of the STATE_* constants
         * @param message string to add to screen or null
        public void setState(int modec) {
            synchronized (surfaceHolder) {
                mode = modec;

    public void surfaceChanged(SurfaceHolder holder, int format, int width,
            int height) {
        // TODO Auto-generated method stub


    public void surfaceCreated(SurfaceHolder holder) {
        // TODO Auto-generated method stub


    public void surfaceDestroyed(SurfaceHolder holder) {
        // TODO Auto-generated method stub


    /** Handle to the application context, used to e.g. fetch Drawables. */
    private Context context;

    /** The thread that actually draws the animation */
    private NMGThread thread;

    public NMGView(Context context, AttributeSet attrs) {
        super(context, attrs);

        // register our interest in hearing about changes to our surface
        SurfaceHolder holder = getHolder();

        // create thread only; it's started in surfaceCreated()
        thread = new NMGThread(holder, context);

        setFocusable(true); // make sure we get key events

     * Fetches the animation thread corresponding to this LunarView.
     * @return the animation thread
    public NMGThread getThread() {
        return thread;


package com.stickfigs.nmg;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.Window;

import com.stickfigs.nmg.NMGView.NMGThread;

public class NMG extends Activity {
    /** Called when the activity is first created. */

    /** A handle to the thread that's actually running the animation. */
    private NMGThread nMGThread;

    /** A handle to the View in which the game is running. */
    private NMGView nMGView;

    public void onCreate(Bundle savedInstanceState) {

        //Turn off the window's title bar
        // TODO Turn off the status bar

        // tell system to use the layout defined in our XML file

        // get handles to the LunarView from XML, and its LunarThread
        nMGView = (NMGView) findViewById(R.id.nmg);
        nMGThread = nMGView.getThread();

        if (savedInstanceState == null) {
            // we were just launched: set up a new game
            Log.w(this.getClass().getName(), "SIS is null");
        } else {
            // we are being restored: resume a previous game
            Log.w(this.getClass().getName(), "SIS is nonnull");

UPDATE: Here is my R.java and nmg_layout.xml:

package com.stickfigs.nmg;

public final class R {
    public static final class attr {
    public static final class drawable {
        public static final int icon=0x7f020000;
    public static final class id {
        public static final int nmg=0x7f050000;
    public static final class layout {
        public static final int nmg_layout=0x7f030000;
    public static final class string {
        public static final int app_name=0x7f040001;
        public static final int hello=0x7f040000;


<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"

How to&Answers:

If you look through the stack trace, you will see a “Caused by…” line (sometimes more than one). The last one of those is the important one. It says that there was a null pointer exception on line 32 of NMG.java. That line, and the line before it, are:

nMGView = (NMGView) findViewById(R.id.nmg);
nMGThread = nMGView.getThread();

Evidently, no view with id R.id.nmg is in layout R.layout.nmg_layout. That’s what’s causing your problem.


In your XML file, the R.id.nmg do exist.
So I think the problem is caused by inflating the NMGView object from the resource.
You should examine your NMGView source code, especially in its constructor.


If you are using “multiDexEnabled true” in your “build.gradle(Module:app)” , remove this line from “defaultConfig” and sync project.
It works in my case !!!


This problems happens because most of the time the SurfaceView onDraw() method is running when you destroy the surfaceView then you get a NULL POINTER ERROR because the canvas doesn´t exist by that moment. I have fixed this problem catching all the drawing stuff with the NullPointerException:

public void onDraw(Canvas canvas) {

    try {
         //Drawing Stuff

   }catch(NullPointerException e){

If you implement onPause(), onDestroy() methods in your Main activity you will get the following order: first: E/onPause﹕ ON PAUSE –> next E/surfaceDestroyed﹕ SURFACE DESTROYED –> E/NULL POINTER EXCEPTION﹕ Canvas NULL POINTER –> finally
E/onDestroy﹕ ON DESTROY

this is surfaceDestroyed method I am using:

public void surfaceDestroyed(SurfaceHolder arg0) {
    Log.e("surfaceDestroyed", "SURFACE DESTROYED ");

        try {
            } catch (InterruptedException e) {
           Log.e("Surface Thread Stopped","SURFACE THREAD STOPPED");