原文 https://www.zhangman523.cn/361.html
最近需要修改项目中的视频录制功能，原来没怎么理会，可以正常录制。
但是不录制直接返回Camera就会出现占用情况，而且连系统相机都无法正常使用了。
只能重新手机，调试起来也比较麻烦。
最好发现 由于不当的调用
camera.lock()和camera.unlock()导致的
看一看这两个方法的解释
/**
* Re-locks the camera to prevent other processes from accessing it.
* Camera objects are locked by default unless {@link #unlock()} is
* called. Normally {@link #reconnect()} is used instead.
*
* <p>Since API level 14, camera is automatically locked for applications in
* {@link android.media.MediaRecorder#start()}. Applications can use the
* camera (ex: zoom) after recording starts. There is no need to call this
* after recording starts or stops.
*
* <p>If you are not recording video, you probably do not need this method.
*
* @throws RuntimeException if the camera cannot be re-locked (for
* example, if the camera is still in use by another process).
*/
public native final void lock();
lock()方法是一个native方法
注释的大概意思是
调用这个方法重新锁定相机以防止其他进程访问它。系统默认的状态就是locked状态,可以调用unlock()或者reconnect()来使用
还有注释说API 14 之后当你调用了MediaRecorder.start()方法lock()会自动调用。这就解释了为什么正常录制视频不会占用相机
看看另外一个方法
/**
* Unlocks the camera to allow another process to access it.
* Normally, the camera is locked to the process with an active Camera
* object until {@link #release()} is called. To allow rapid handoff
* between processes, you can call this method to release the camera
* temporarily for another process to use; once the other process is done
* you can call {@link #reconnect()} to reclaim the camera.
*
* <p>This must be done before calling
* {@link android.media.MediaRecorder#setCamera(Camera)}. This cannot be
* called after recording starts.
*
* <p>If you are not recording video, you probably do not need this method.
*
* @throws RuntimeException if the camera cannot be unlocked.
*/
public native final void unlock();
这个注释写的很清楚了
调用unlock()方法允许其他进程使用,同时正在使用Camera是locked状态
还有调视频录制的时候必须先调unlock()然后在调MediaRecorder.setCamera(Camera)
总结
视频录制的步骤如下:
- 调用
unlock()方法 - 调用
MediaRecorder.setCamera(Camera)方法 - 开始录制
- 停止录制
- 释放
MediaRecorder - 调用
lock()方法 - 释放
Camera
这就是完整的步骤了。
这里有个Demo可以参考一下GITHUB
