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POSurfaceView goes black when comes to foreground, for Camera App
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  1. POSurfaceView goes black when comes to foreground, for Camera App
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    copied!<p>I am using Camera feature in my app. Everything works fine but when the device gets locked/sleep, upon returning to the app the camera portion(SurfaceView) is just black. Below is my code. Can someone please identify the problem?</p> <pre><code>public class Activity_Camera extends Activity implements SurfaceHolder.Callback, Camera.AutoFocusCallback, Observer { // Surface vars private SurfaceView preview; private SurfaceHolder previewHolder; // Camera vars private Camera mCamera; private boolean mPreviewRunning = false; private boolean mCaptureFrame = false; private int frame_number = 1; private byte[] frame = new byte[1]; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); preview = (SurfaceView) findViewById(R.id.preview); previewHolder = preview.getHolder(); previewHolder.addCallback(this); previewHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS); } @Override public void onPause() { super.onPause(); if (mPreviewRunning) { mCamera.stopPreview(); mPreviewRunning = false; } mCamera.setPreviewCallback(null); mCamera.release(); } // implements SurfaceHolder.Callback public void surfaceCreated(SurfaceHolder holder) { mCamera = Camera.open(); } // implements SurfaceHolder.Callback public void surfaceDestroyed(SurfaceHolder holder) { mPreviewRunning = false; } // implements Camera.AutoFocusCallback public void onAutoFocus(boolean success, Camera camera) { } PreviewCallback previewCallback = new PreviewCallback() { public void onPreviewFrame(byte[] data, Camera camera) { } }; // implements SurfaceHolder.Callback public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) { if (mPreviewRunning) { mCamera.stopPreview(); } Camera.Parameters p = mCamera.getParameters(); p.setPreviewSize(640, 480); mCamera.setParameters(p); try { mCamera.setPreviewDisplay(holder); } catch (IOException e) { e.printStackTrace(); } mCamera.setPreviewCallback(previewCallback); int rotation = getWindowManager().getDefaultDisplay().getRotation(); int degrees = 0; switch (rotation) { case Surface.ROTATION_0: degrees = 90; break; case Surface.ROTATION_90: degrees = 0; break; case Surface.ROTATION_180: degrees = 270; break; case Surface.ROTATION_270: degrees = 180; break; } Log.i("DEGREES ARE WHAT??", Integer.toString(degrees)); // mCamera.setDisplayOrientation(degrees); mCamera.setDisplayOrientation(90); mCamera.startPreview(); mPreviewRunning = true; } // implements Observer // captures a frame when the compass listener says it is appropriate public void update(Observable observable, Object data) { mCaptureFrame = true; } } </code></pre> <p>Please identify the issue, as I suspect something wrong with onPause(), it also gives me exception when I press back button after the black camera screen:</p> <pre><code>java.lang.RuntimeException: Method called after release() </code></pre> <p>on this line:</p> <pre><code> mCamera.setPreviewCallback(null); // (in onPause()) </code></pre> <p>Here is the XML:</p> <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt; &lt;LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical" android:background="#E6E5E6"&gt; &lt;LinearLayout android:layout_width="fill_parent" android:layout_height="wrap_content" android:orientation="vertical" android:gravity="center_horizontal"&gt; &lt;TextView android:id="@+id/tv_camera_url" android:layout_width="wrap_content" android:layout_height="wrap_content" android:maxLines="1" android:textColor="@android:color/black" android:text="URL goes here........" android:layout_marginTop="3dp" android:textStyle="bold"/&gt; &lt;TextView android:id="@+id/tv_speaknow" android:layout_width="wrap_content" android:layout_height="wrap_content" android:padding="3dp" android:background="#ffffff" android:layout_marginTop="3dp" android:text="Speak Now" android:textColor="#ff0000" android:textStyle="bold"/&gt; &lt;/LinearLayout&gt; &lt;RelativeLayout android:id="@+id/rl_main" android:layout_width="wrap_content" android:layout_height="wrap_content"&gt; &lt;SurfaceView android:id="@+id/preview" android:layout_width="480px" android:layout_height="640px" android:layout_alignParentBottom="true"/&gt; &lt;Button android:id="@+id/btn_take_picture" android:layout_width="wrap_content" android:layout_height="wrap_content" android:background="@drawable/camera" android:layout_alignBottom="@+id/preview" android:layout_centerHorizontal="true" android:layout_marginBottom="5dp"/&gt; &lt;/RelativeLayout&gt; &lt;/LinearLayout&gt; </code></pre>
 

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