camera2_api_summary.java

// Activity or Fragment ::onResume
// 1. Wait for the surface ready.
mTextureView.setSurfaceTextureListener(new TextureView.SurfaceTextureListener() {
    @Override
    public void onSurfaceTextureAvailable(SurfaceTexture texture,
                                          int width, int height) {
        
        // 2. Open the camera.
        manager.openCamera(
            cameraId,
            new CameraDevice.StateCallback() {
                @Override
                public void onOpened(CameraDevice device) {
                    
                    // 3. Create a capture session.
                    device.createCaptureSession(
                        previewSurfaces,
                        new CameraCaptureSession.StateCallback() {
                            @Override
                            public void onConfigured(CameraCaptureSession session) {
                                
                                // 4. Create a capture request.
                                mPreviewSession.setRepeatingRequest(
                                    mPreviewBuilder.build(),
                                    null,
                                    mBackgroundHandler);
                            }
                        }, mBackgroundHandler);
                }
            },
            null);
    }
});

// Activity or Fragment ::onPause
if (captureSession != null) {
    captureSession.close();
    captureSession = null;
}
if (cameraDevice != null) {
    cameraDevice.close();
    cameraDevice = null;
}
if (previewReader != null) {
    previewReader.close();
    previewReader = null;
}