surfaceView.getHolder not returning SurfaceHolder
<p>I'm trying to code an app that uses the camera. I'm getting a NullPointerException when trying to get the surfaceHolder that i eventually pass to the surfaceCreated() that starts up the camera. is there any situation when the getHolder() returns NULL?</p>

<p>thanks.</p>

<pre><code>package com.tecmark;

import java.io.IOException;

import android.app.Activity;

import android.graphics.PixelFormat;
import android.hardware.Camera;
import android.os.Bundle;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.Window;
import android.view.WindowManager;

public class cameraView extends Activity implements SurfaceHolder.Callback{

    SurfaceView mSurfaceView;
    SurfaceHolder mSurfaceHolder;
    Camera mCamera;
    boolean mPreviewRunning;

 /** Called when the activity is first created. */
    @Override 
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);


        getWindow().setFormat(PixelFormat.TRANSLUCENT);

        requestWindowFeature(Window.FEATURE_NO_TITLE);

        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,

        WindowManager.LayoutParams.FLAG_FULLSCREEN);

        //setContentView(R.layout.camera_surface);   

        mSurfaceView = (SurfaceView) findViewById(R.id.surface_camera);
        Log.i("surfaceholder = ", "about to get surface holder");
        try{
        mSurfaceHolder = mSurfaceView.getHolder();
        }catch(Exception e){
         e.printStackTrace();
        }

        Log.i("surfaceholder = ", ""+mSurfaceHolder.toString());

        mSurfaceHolder.addCallback(this);

        mSurfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);

        setContentView(R.layout.camera_surface);

        surfaceCreated(mSurfaceHolder);







    }

 @Override
 public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {

  if (mPreviewRunning) {

   mCamera.stopPreview();

   }

   Camera.Parameters p = mCamera.getParameters();

   p.setPreviewSize(w, h);

   mCamera.setParameters(p);

   try {

   mCamera.setPreviewDisplay(holder);

   } catch (Exception e) {

   e.printStackTrace();

   }

   mCamera.startPreview();

   mPreviewRunning = true;

   }






 @Override
 public void surfaceCreated(SurfaceHolder holder) {




  try{
   Log.i("camera ", "about to open camera");
         mCamera = Camera.open();
         Log.i("camera ", " camera opened");
         mCamera.getParameters();
         mCamera.setPreviewDisplay(holder);
         mCamera.startPreview();
   } catch (IOException e) {

    e.printStackTrace();
   }
  Log.i("camera ", "ok");
 }

 @Override
 public void surfaceDestroyed(SurfaceHolder holder) {
  mCamera.stopPreview();

  mPreviewRunning = false;

  mCamera.release();

 }




}//end of activity



01-31 15:29:17.773: WARN/System.err(9144): java.lang.NullPointerException
01-31 15:29:17.778: WARN/System.err(9144):     at com.tecmark.cameraView.onCreate(cameraView.java:42)
01-31 15:29:17.778: WARN/System.err(9144):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
01-31 15:29:17.778: WARN/System.err(9144):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2459)
01-31 15:29:17.783: WARN/System.err(9144):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2512)
01-31 15:29:17.783: WARN/System.err(9144):     at android.app.ActivityThread.access$2200(ActivityThread.java:119)
01-31 15:29:17.783: WARN/System.err(9144):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1863)
01-31 15:29:17.783: WARN/System.err(9144):     at android.os.Handler.dispatchMessage(Handler.java:99)
01-31 15:29:17.783: WARN/System.err(9144):     at android.os.Looper.loop(Looper.java:123)
01-31 15:29:17.783: WARN/System.err(9144):     at android.app.ActivityThread.main(ActivityThread.java:4363)
01-31 15:29:17.783: WARN/System.err(9144):     at java.lang.reflect.Method.invokeNative(Native Method)
01-31 15:29:17.788: WARN/System.err(9144):     at java.lang.reflect.Method.invoke(Method.java:521)
01-31 15:29:17.788: WARN/System.err(9144):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
01-31 15:29:17.788: WARN/System.err(9144):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
01-31 15:29:17.788: WARN/System.err(9144):     at dalvik.system.NativeStart.main(Native Method)
01-31 15:29:17.793: DEBUG/AndroidRuntime(9144): Shutting down VM
01-31 15:29:17.793: WARN/dalvikvm(9144): threadid=3: thread exiting with uncaught exception (group=0x4001b180)
01-31 15:29:17.793: ERROR/AndroidRuntime(9144): Uncaught handler: thread main exiting due to uncaught exception
01-31 15:29:17.803: ERROR/AndroidRuntime(9144): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.tecmark/com.tecmark.cameraView}: java.lang.NullPointerException
01-31 15:29:17.803: ERROR/AndroidRuntime(9144):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2496)
01-31 15:29:17.803: ERROR/AndroidRuntime(9144):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2512)
01-31 15:29:17.803: ERROR/AndroidRuntime(9144):     at android.app.ActivityThread.access$2200(ActivityThread.java:119)
01-31 15:29:17.803: ERROR/AndroidRuntime(9144):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1863)
01-31 15:29:17.803: ERROR/AndroidRuntime(9144):     at android.os.Handler.dispatchMessage(Handler.java:99)
01-31 15:29:17.803: ERROR/AndroidRuntime(9144):     at android.os.Looper.loop(Looper.java:123)
01-31 15:29:17.803: ERROR/AndroidRuntime(9144):     at android.app.ActivityThread.main(ActivityThread.java:4363)
01-31 15:29:17.803: ERROR/AndroidRuntime(9144):     at java.lang.reflect.Method.invokeNative(Native Method)
01-31 15:29:17.803: ERROR/AndroidRuntime(9144):     at java.lang.reflect.Method.invoke(Method.java:521)
01-31 15:29:17.803: ERROR/AndroidRuntime(9144):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
01-31 15:29:17.803: ERROR/AndroidRuntime(9144):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
01-31 15:29:17.803: ERROR/AndroidRuntime(9144):     at dalvik.system.NativeStart.main(Native Method)
01-31 15:29:17.803: ERROR/AndroidRuntime(9144): Caused by: java.lang.NullPointerException
01-31 15:29:17.803: ERROR/AndroidRuntime(9144):     at com.tecmark.cameraView.onCreate(cameraView.java:47)
01-31 15:29:17.803: ERROR/AndroidRuntime(9144):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
01-31 15:29:17.803: ERROR/AndroidRuntime(9144):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2459)
01-31 15:29:17.803: ERROR/AndroidRuntime(9144):     ... 11 more
</code></pre>
