Android肖像锁定相机预览

Question

I have implemented the Camera Preview just as it is in the ApiDemos application of Android. The thing is that I want my activity, where the Preview is shown to be locked to portrait. So I set screenOrientation to portrait in the manifest.

The 'getOptimalPreviewSize' method returns opposite values for the preview, meaning, when it's needed to return 480x720, the method returns 720x480, and I have small preview centered in my FrameLayout of the activity (which is not what I want, I want it to match the parent (yes, the layout is defined with "match_parent").

I tried:

• setDisplayOrientation(90);
• parameters.set("orientation", "portrait");
• parameters.set("rotation", "90");

Nothing seems to help.

Why can't I show Preview of the Camera in portrait mode? Locked.

Thanks

Answer 1

Here is a working example of a portrait preview of camera on SurfaceView :

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.main);

    SurfaceView surfaceView = (SurfaceView) findViewById(R.id.surface);
    surfaceView.getHolder().addCallback(new SurfaceHolder.Callback() {

        private Camera camera;

        @Override
        public void surfaceCreated(SurfaceHolder holder) {
            try {
                camera = Camera.open();
                camera.setPreviewDisplay(holder);
                camera.setDisplayOrientation(90);
                camera.startPreview();
            } catch (IOException e) {
                Log.e(TAG, "Error", e);
            }
        }

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

        @Override
        public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
        }
    });
}

With the following layout file:

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

    <SurfaceView
        android:id="@+id/surface"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</FrameLayout>

Answer 2

Try setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_SENSOR_PORTRAIT);

That will lock the activity to that orientation.

The following code from the Google Docs:

public static void setCameraDisplayOrientation(Activity activity,
     int cameraId, android.hardware.Camera camera) {
 android.hardware.Camera.CameraInfo info =
         new android.hardware.Camera.CameraInfo();
 android.hardware.Camera.getCameraInfo(cameraId, info);
 int rotation = activity.getWindowManager().getDefaultDisplay()
         .getRotation();
 int degrees = 0;
 switch (rotation) {
     case Surface.ROTATION_0: degrees = 0; break;
     case Surface.ROTATION_90: degrees = 90; break;
     case Surface.ROTATION_180: degrees = 180; break;
     case Surface.ROTATION_270: degrees = 270; break;
 }

 int result;
 if (info.facing == Camera.CameraInfo.CAMERA_FACING_FRONT) {
     result = (info.orientation + degrees) % 360;
     result = (360 - result) % 360;  // compensate the mirror
 } else {  // back-facing
     result = (info.orientation - degrees + 360) % 360;
 }
 camera.setDisplayOrientation(result);
}

Which will set the orientation of the camera and preview correctly.