surfaceCreated is not called

I'm trying to put a camera preview (SurfaceView) together with a button on the display, but all I get is a blank screen only showing the button. If I'm setting the SurfaceView as the only content (with setContentView(surfaceView) then the preview is displaying fine on the screen. What am I doing wrong?

Thanks in advance

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent" 
    and开发者_如何学运维roid:layout_height="fill_parent"
    android:orientation="vertical">
    <FrameLayout
        android:layout_width="fill_parent"
        android:layout_height="0px"
        android:layout_weight="1">
        <SurfaceView
            android:id="@+id/camera_surface"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent" />
        <Button 
            android:layout_width="wrap_content" 
            android:layout_height="wrap_content"
            android:text="@string/trigger"
            android:id="@+id/trigger_picture_button" 
            android:layout_gravity="bottom" />
    </FrameLayout>
</LinearLayout>

My Activity:

public class CameraActivity extends Activity {

    private SurfaceView cameraPreview;
    private Button triggerPicture;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.camera);

        cameraPreview = (SurfaceView) findViewById(R.id.camera_surface);
        triggerPicture = (Button) findViewById(R.id.trigger_picture_button);

        setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
        cameraPreview = new CameraPreview(this);
//      setContentView(cameraPreview);
    }

My CameraPreview:

public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {

private SurfaceHolder holder;
private Camera camera;

public CameraPreview(Context context) {
    super(context);
    holder = getHolder();
    holder.addCallback(this);
    holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}

public void surfaceCreated(SurfaceHolder holder) {
    camera = openFrontFacingCamera();
    try {
        camera.setPreviewDisplay(holder);
    } catch (IOException e) {
        camera.release();
        camera = null;
    }
}

public void surfaceDestroyed(SurfaceHolder holder) {
    camera.stopPreview();
    camera.release();
    camera = null;
}

public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
    Camera.Parameters parameters = camera.getParameters();
    parameters.setPreviewSize(width, height);
    parameters.set("orientation", "portrait");
    camera.setParameters(parameters);
    camera.startPreview();
}

private Camera openFrontFacingCamera() {
    // returns Camera.open(
}

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When you declare SurfaceView in the layout you tell Android to use built-in class. What you need to do is make it use your class by replacing SurfaceView in XML with your.package.name.CameraPreview.

One other thing: you should add a constructor to the CameraPreview taking parameters Context and AttributeSet, otherwise layout inflater won't be able to inflate your class. Also you don't need the line cameraPreview = new CameraPreview(this);.

---

When your onCreate() is the right one, than you overriding the cameraPreview from the xml with a new created one which you never add to any layout (last line). That means its never inflated so there is never a surface created.

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Maybe it's a bit late answer ,but it really works for me.

1、set the layout as below:

<FrameLayout
        android:id="@+id/camera_preview"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:layout_weight="1"
        />

<Button
        android:id="@+id/button_capture"
        android:text="Capture"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        />

2、In onCreate:

// Create our Preview view and set it as the content of our activity.
    mPreview = new CameraPreview(this, mCamera);
    FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview);
    preview.addView(mPreview);

3、And in Manifest.xml:

android:screenOrientation="landscape"

, of course , don't forget permissions and features. Hope it helps.