Zoom In & Out Custom Camera - Null Pointer Exception

I am trying to Implement Zoom In & Out functionality in my Custom Camera. ``` NullPointerException: zoomControls.setVisibility(View.GONE); ``` I am using this : Zoom Control in Camera is not working in Android PreviewSurface.java:- ``` public class PreviewSurface extends SurfaceView implements SurfaceHolder.Callback { public static final String LOG_TAG = "CameraPreview"; private SurfaceHolder mSurfaceHolder; SurfaceView mSurfaceView; private Camera mCamera; Camera.Parameters params ; int currentZoomLevel = 0, maxZoomLevel = 0; // Constructor that obtains context and camera @SuppressWarnings("deprecation") public PreviewSurface(Context context, Camera camera) { super(context); this.mCamera = camera; mSurfaceView = (SurfaceView) findViewById(R.id.surfaceView); this.mSurfaceHolder = this.getHolder(); this.mSurfaceHolder.addCallback(this); this.mSurfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS); this.mSurfaceHolder.setFixedSize(100, 100); } @Override public void surfaceCreated(SurfaceHolder surfaceHolder) { try { mCamera.setPreviewDisplay(surfaceHolder); mCamera.startPreview(); } catch (IOException e) { // left blank for now } } @Override public void surfaceDestroyed(SurfaceHolder surfaceHolder) { mCamera.stopPreview(); mCamera.release(); } @Override public void surfaceChanged(SurfaceHolder surfaceHolder, int format, int width, int height) { ZoomControls zoomControls = (ZoomControls) findViewById(R.id.CAMERA_ZOOM_CONTROLS); params = mCamera.getParameters(); if (params.isZoomSupported() && params.isSmoothZoomSupported()) { //most phones maxZoomLevel = params.getMaxZoom(); zoomControls.setIsZoomInEnabled(true); zoomControls.setIsZoomOutEnabled(true); zoomControls.setOnZoomInClickListener(new OnClickListener() { public void onClick(View v) { if (currentZoomLevel < maxZoomLevel) { currentZoomLevel++; mCamera.startSmoothZoom(currentZoomLevel); } } }); zoomControls.setOnZoomOutClickListener(new OnClickListener() { public void onClick(View v) { if (currentZoomLevel > 0) { currentZoomLevel--; mCamera.startSmoothZoom(currentZoomLevel); } } }); } else if (params.isZoomSupported() && !params.isSmoothZoomSupported()){ //stupid HTC phones maxZoomLevel = params.getMaxZoom(); zoomControls.setIsZoomInEnabled(true); zoomControls.setIsZoomOutEnabled(true); zoomControls.setOnZoomInClickListener(new OnClickListener() { public void onClick(View v) { if (currentZoomLevel < maxZoomLevel) { currentZoomLevel++; params.setZoom(currentZoomLevel); mCamera.setParameters(params); } } }); zoomControls.setOnZoomOutClickListener(new OnClickListener() { public void onClick(View v) { if (currentZoomLevel > 0) { currentZoomLevel--; params.setZoom(currentZoomLevel); mCamera.setParameters(params); } } }); }else{ //no zoom on phone zoomControls.setVisibility(View.GONE); } // start preview with new settings try { mCamera.setDisplayOrientation(90); mCamera.setPreviewDisplay(surfaceHolder); mCamera.startPreview(); } catch (Exception e) { // intentionally left blank for a test } } } ``` activity_camera.xml:- ``` <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="horizontal" > <FrameLayout android:id="@+id/camera_preview" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_alignParentLeft="true" android:layout_alignParentTop="true" android:layout_toLeftOf="@+id/btnView" /> <SurfaceView android:id="@+id/surfaceView" android:layout_width="wrap_content" android:layout_height="wrap_content" /> <ZoomControls android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignBottom="@+id/camera_preview" android:layout_centerInParent="true" android:id="@+id/CAMERA_ZOOM_CONTROLS" /> <TextView android:id="@+id/title" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentTop="true" android:layout_marginTop="18dp" android:layout_toRightOf="@+id/camera_preview" android:maxLines="1" android:visibility="gone" android:textAppearance="?android:attr/textAppearanceSmall" /> <Button android:id="@+id/btnSettings" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignLeft="@+id/btnView" android:layout_alignParentBottom="true" android:layout_marginBottom="50dp" android:background="@drawable/settings" /> <Button android:id="@+id/btnView" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentRight="true" android:layout_alignParentTop="true" android:layout_marginTop="50dp" android:background="@drawable/gallery" /> <Button android:id="@+id/btnCapture" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerVertical="true" android:layout_toRightOf="@+id/camera_preview" android:background="@drawable/capture" /> </RelativeLayout> ``` CameraLauncherActivity.java:- ``` public class CameraLauncherActivity extends Activity { private Camera mCamera; private PreviewSurface mCameraPreview; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_camera); mCamera = getCameraInstance(); mCameraPreview = new PreviewSurface(this, mCamera); FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview); preview.addView(mCameraPreview); } private Camera getCameraInstance() { Camera camera = null; Log.d(CameraLauncherActivity.LOG_TAG, "getCameraInstance()Camera:: " + camera); try { camera = Camera.open(0); Log.d(CameraLauncherActivity.LOG_TAG, "getCameraInstance()open:: " + camera); } catch (Exception e) { // cannot get camera or does not exist } return camera; } PictureCallback mPicture = new PictureCallback() { @Override public void onPictureTaken(byte[] data, Camera camera) { File pictureFile = getOutputMediaFile(); camera.startPreview(); if (pictureFile == null) { return; } try { FileOutputStream fos = new FileOutputStream(pictureFile); fos.write(data); fos.close(); } catch (FileNotFoundException e) { } catch (IOException e) { } } }; static File getOutputMediaFile() { // folder name mediaStorageDir = new File(Environment .getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES), "/MyImages/"); if (!mediaStorageDir.exists()) { if (!mediaStorageDir.mkdirs()) { Log.d("App", "failed to create directory"); } } /* yyyy-MM-dd'T'HH:mm:ss.SSSZ */ String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date()); File mediaFile; // file name mediaFile = new File(mediaStorageDir.getPath() + File.separator + "IMG_" + timeStamp + ".jpg"); return mediaFile; } ``` Logcat:- ``` 11-28 01:52:43.179: E/AndroidRuntime(2135): FATAL EXCEPTION: main 11-28 01:52:43.179: E/AndroidRuntime(2135): java.lang.NullPointerException 11-28 01:52:43.179: E/AndroidRuntime(2135): at app.pd.PreviewSurface.surfaceChanged(PreviewSurface.java:113) 11-28 01:52:43.179: E/AndroidRuntime(2135): at android.view.SurfaceView.updateWindow(SurfaceView.java:582) 11-28 01:52:43.179: E/AndroidRuntime(2135): at android.view.SurfaceView.access$000(SurfaceView.java:86) 11-28 01:52:43.179: E/AndroidRuntime(2135): at android.view.SurfaceView$3.onPreDraw(SurfaceView.java:175) 11-28 01:52:43.179: E/AndroidRuntime(2135): at android.view.ViewTreeObserver.dispatchOnPreDraw(ViewTreeObserver.java:833) 11-28 01:52:43.179: E/AndroidRuntime(2135): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1860) 11-28 01:52:43.179: E/AndroidRuntime(2135): at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1004) 11-28 01:52:43.179: E/AndroidRuntime(2135): at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5481) 11-28 01:52:43.179: E/AndroidRuntime(2135): at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749) 11-28 01:52:43.179: E/AndroidRuntime(2135): at android.view.Choreographer.doCallbacks(Choreographer.java:562) 11-28 01:52:43.179: E/AndroidRuntime(2135): at android.view.Choreographer.doFrame(Choreographer.java:532) 11-28 01:52:43.179: E/AndroidRuntime(2135): at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735) 11-28 01:52:43.179: E/AndroidRuntime(2135): at android.os.Handler.handleCallback(Handler.java:730) 11-28 01:52:43.179: E/AndroidRuntime(2135): at android.os.Handler.dispatchMessage(Handler.java:92) 11-28 01:52:43.179: E/AndroidRuntime(2135): at android.os.Looper.loop(Looper.java:137) 11-28 01:52:43.179: E/AndroidRuntime(2135): at android.app.ActivityThread.main(ActivityThread.java:5103) 11-28 01:52:43.179: E/AndroidRuntime(2135): at java.lang.reflect.Method.invokeNative(Native Method) 11-28 01:52:43.179: E/AndroidRuntime(2135): at java.lang.reflect.Method.invoke(Method.java:525) 11-28 01:52:43.179: E/AndroidRuntime(2135): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737) 11-28 01:52:43.179: E/AndroidRuntime(2135): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 11-28 01:52:43.179: E/AndroidRuntime(2135): at dalvik.system.NativeStart.main(Native Method) ```