【发布时间】：2014-02-20 00:50:49
【问题描述】：
我正在构建一个自定义录像机，并注意到如果手机在相机活动运行时进入睡眠或锁定模式.. 唤醒时相机预览卡在静态静止图像上。如果我在活动之间来回走动，相机在返回时就可以了。这个错误显然只在手机进入睡眠状态并醒来时才会出现。
我的录像机活动
public class DRPVideoCaptureActivity extends Activity {
private Camera myCamera;
private DRPCameraSurfaceView myCameraSurfaceView;
private MediaRecorder mediaRecorder;
SurfaceHolder surfaceHolder;
boolean recording = false;
Globals g = new Globals();
ImageButton btn_record;
FrameLayout _videoView;
ImageView btn_flashToggle;
ImageView btn_cameraToggle;
ImageView btn_close;
public enum FlashState {
off, on, auto
}
FlashState _flashState = FlashState.off;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.video_camera);
_videoView = (FrameLayout) findViewById(R.id.video_frame);
btn_record = (ImageButton) findViewById(R.id.btn_record);
btn_flashToggle = (ImageView) findViewById(R.id.btn_flash_toggle);
btn_cameraToggle = (ImageView) findViewById(R.id.btn_camera_toggle);
btn_close = (ImageView) findViewById(R.id.btn_close);
recording = false;
// myButton = (Button)findViewById(R.id.mybutton);
}
@Override
public void onResume() {
super.onResume();
// Get Camera for preview
_videoView.setVisibility(View.INVISIBLE);
myCamera = getCameraInstance();
if (myCamera == null) {
Toast.makeText(DRPVideoCaptureActivity.this, "Fail to get Camera",
Toast.LENGTH_LONG).show();
}else{
myCameraSurfaceView = new DRPCameraSurfaceView(this, myCamera);
_videoView.addView(myCameraSurfaceView);
}
_videoView.setVisibility(View.VISIBLE);
}
Button.OnClickListener recordListener = new Button.OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
if (recording) {
// stop recording and release camera
mediaRecorder.stop(); // stop the recording
releaseMediaRecorder(); // release the MediaRecorder object
// Exit after saved
finish();
} else {
// Release Camera before MediaRecorder start
releaseCamera();
if (!prepareMediaRecorder()) {
Toast.makeText(DRPVideoCaptureActivity.this,
"Fail in prepareMediaRecorder()!\n - Ended -",
Toast.LENGTH_LONG).show();
finish();
}
mediaRecorder.start();
recording = true;
// myButton.setText("STOP");
}
}
};
private Camera getCameraInstance() {
// TODO Auto-generated method stub
Camera c = null;
try {
c = Camera.open(); // attempt to get a Camera instance
c.setDisplayOrientation(90);
} catch (Exception e) {
Log.v("cam","EXCEPTION: "+e);// Camera is not available (in use or does not exist)
}
return c; // returns null if camera is unavailable
}
private boolean prepareMediaRecorder() {
myCamera = getCameraInstance();
mediaRecorder = new MediaRecorder();
myCamera.unlock();
mediaRecorder.setCamera(myCamera);
mediaRecorder.setAudioSource(MediaRecorder.AudioSource.CAMCORDER);
mediaRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);
mediaRecorder.setProfile(CamcorderProfile
.get(CamcorderProfile.QUALITY_HIGH));
mediaRecorder.setOutputFile(g.kExtStorageDirectory + g.kVideoDirectory
+ "myvideo.mp4");
mediaRecorder.setMaxDuration(60000); // Set max duration 60 sec.
mediaRecorder.setMaxFileSize(5000000); // Set max file size 5M
mediaRecorder.setPreviewDisplay(myCameraSurfaceView.getHolder()
.getSurface());
try {
mediaRecorder.prepare();
} catch (IllegalStateException e) {
releaseMediaRecorder();
return false;
} catch (IOException e) {
releaseMediaRecorder();
return false;
}
return true;
}
@Override
protected void onPause() {
super.onPause();
releaseMediaRecorder(); // if you are using MediaRecorder, release it
// first
releaseCamera(); // release the camera immediately on pause event
}
private void releaseMediaRecorder() {
if (mediaRecorder != null) {
mediaRecorder.reset(); // clear recorder configuration
mediaRecorder.release(); // release the recorder object
mediaRecorder = null;
myCamera.lock(); // lock camera for later use
}
}
private void releaseCamera() {
if (myCamera != null) {
myCamera.stopPreview();
myCamera.release(); // release the camera for other applications
myCamera = null;
}
}
}
我的相机表面视图
public class DRPCameraSurfaceView extends SurfaceView implements SurfaceHolder.Callback{
private SurfaceHolder mHolder;
private Camera mCamera;
public DRPCameraSurfaceView(Context context, Camera camera) {
super(context);
mCamera = camera;
// Install a SurfaceHolder.Callback so we get notified when the
// underlying surface is created and destroyed.
mHolder = getHolder();
mHolder.addCallback(this);
// deprecated setting, but required on Android versions prior to 3.0
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int weight,
int height) {
// If your preview can change or rotate, take care of those events here.
// Make sure to stop the preview before resizing or reformatting it.
if (mHolder.getSurface() == null){
// preview surface does not exist
return;
}
// stop preview before making changes
try {
mCamera.stopPreview();
} catch (Exception e){
// ignore: tried to stop a non-existent preview
}
// make any resize, rotate or reformatting changes here
// start preview with new settings
try {
mCamera.setPreviewDisplay(mHolder);
mCamera.startPreview();
} catch (Exception e){
}
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
// The Surface has been created, now tell the camera where to draw the preview.
try {
mCamera.setPreviewDisplay(holder);
mCamera.startPreview();
} catch (IOException e) {
}
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
this.getHolder().removeCallback(this);
//mCamera.stopPreview();
// mCamera.release();
// mCamera = null;
Log.v("surfaceDestroyed", "surfaceDestroyed");
}
}
【问题讨论】：