import net.majorkernelpanic.streaming.exceptions.CameraInUseException; //导入依赖的package包/类
public synchronized void startPreview() 
		throws CameraInUseException, 
		InvalidSurfaceException, 
		ConfNotSupportedException, 
		RuntimeException {
	
	mCameraOpenedManually = true;
	if (!mPreviewStarted) {
		createCamera();
		updateCamera();
		try {
			mCamera.startPreview();
			mPreviewStarted = true;
		} catch (RuntimeException e) {
			destroyCamera();
			throw e;
		}
	}
}
 

import net.majorkernelpanic.streaming.exceptions.CameraInUseException; //导入依赖的package包/类
/**
 * Opens the camera in a new Looper thread so that the preview callback is not called from the main thread
 * If an exception is thrown in this Looper thread, we bring it back into the main thread.
 * @throws RuntimeException Might happen if another app is already using the camera.
 */
private void openCamera() throws RuntimeException {
	final Semaphore lock = new Semaphore(0);
	final RuntimeException[] exception = new RuntimeException[1];
	mCameraThread = new Thread(new Runnable() {
		@Override
		public void run() {
			Looper.prepare();
			mCameraLooper = Looper.myLooper();
			try {
				mCamera = Camera.open(mCameraId);
			} catch (RuntimeException e) {
				exception[0] = e;
			} finally {
				lock.release();
				Looper.loop();
			}
		}
	});
	mCameraThread.start();
	lock.acquireUninterruptibly();
	if (exception[0] != null) throw new CameraInUseException(exception[0].getMessage());
}
 

import net.majorkernelpanic.streaming.exceptions.CameraInUseException; //导入依赖的package包/类
/**
 * Opens the camera in a new Looper thread so that the preview callback is not called from the main thread
 * If an exception is thrown in this Looper thread, we bring it back into the main thread.
 * @throws RuntimeException Might happen if another app is already using the camera.
 */
private void openCamera() throws RuntimeException {
	Log.e(TAG, "openCamera");

	final Semaphore lock = new Semaphore(0);
	final RuntimeException[] exception = new RuntimeException[1];
	mCameraThread = new Thread(new Runnable() {
		@Override
		public void run() {
			Looper.prepare();
			mCameraLooper = Looper.myLooper();
			try {
				mCamera = Camera.open(mCameraId);
			} catch (RuntimeException e) {
				exception[0] = e;
			} finally {
				lock.release();
				Looper.loop();
			}
		}
	});
	mCameraThread.start();
	lock.acquireUninterruptibly();
	if (exception[0] != null) throw new CameraInUseException(exception[0].getMessage());
}
 

import net.majorkernelpanic.streaming.exceptions.CameraInUseException; //导入依赖的package包/类
public synchronized void startPreview() 
		throws CameraInUseException, 
		InvalidSurfaceException, 
		RuntimeException {
	
	mCameraOpenedManually = true;
	if (!mPreviewStarted) {
		createCamera();
		updateCamera();
	}
}