我正在玩关于使用录像机的谷歌教程，但无论如何我无法让它工作。我首先继续得到发布错误后调用的方法，对于我追踪的相机预览，意识到mCamera.stoppreview（）在再次调用onSurfaceChanged（）之前不起作用。另外，当调用MediaRecorder.start（）时，mediaserver死了，相机服务器死了，icamera死了，我得到了Camera 100错误。我似乎无法弄明白为什么。
这是我的CameraActivity代码
public class MainActivity extends Activity {
private Camera mCamera;
private MediaRecorder mMediaRecorder;
private CameraPreview mPreview;
private static final String TAG = "Message";
public static final int MEDIA_TYPE_IMAGE = 1;
public static final int MEDIA_TYPE_VIDEO = 2;
private boolean isRecording = false;
Button captureButton;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.preview);
System.out.println("Going to get the camera");
mCamera = getCameraInstance();
//mMediaRecorder = new MediaRecorder();
mPreview = new CameraPreview(this, mCamera);
FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview);
preview.addView(mPreview);
// setPreviewCallback(null);
captureButton = (Button) findViewById(R.id.button_capture);
captureButton.setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View v) {
if (isRecording) {
// stop recording and release camera
mMediaRecorder.stop(); // stop the recording
releaseMediaRecorder(); // release the MediaRecorder object
mCamera.lock(); // take camera access back from MediaRecorder
// inform the user that recording has stopped
captureButton.setText("Capture");
isRecording = false;
} else {
// initialize video camera
releaseCamera();
if (prepareVideoRecorder()) {
System.out.println("Starting to record");
// Camera is available and unlocked, MediaRecorder is prepared,
// now you can start recording
mMediaRecorder.start();
// inform the user that recording has started
captureButton.setText("Stop");
isRecording = true;
} else {
// prepare didn't work, release the camera
System.out.println("Recording failed");
releaseMediaRecorder();
// inform user
}
}
}
}
);
}
public static Camera getCameraInstance(){
Camera c = null;
try {
c = Camera.open();
System.out.println("This is the camera "+c);// attempt to get a Camera instance
}
catch (Exception e){
// Camera is not available (in use or does not exist)
System.out.println("Didn't get the camera ");
}
return c; // returns null if camera is unavailable
}
private boolean prepareVideoRecorder(){
mCamera = getCameraInstance();
mMediaRecorder = new MediaRecorder();
/*CameraPreview preview;
preview=new CameraPreview(this, mCamera);*/
// Step 1: Unlock and set camera to MediaRecorder
mCamera.unlock();
mMediaRecorder.setCamera(mCamera);
// Step 2: Set sources
mMediaRecorder.setAudioSource(MediaRecorder.AudioSource.CAMCORDER);
mMediaRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);
// Step 3: Set a CamcorderProfile (requires API Level 8 or higher)
mMediaRecorder.setProfile(CamcorderProfile.get(CamcorderProfile.QUALITY_HIGH));
// Step 4: Set output file
mMediaRecorder.setOutputFile(getOutputMediaFile(MEDIA_TYPE_VIDEO).toString());
// Step 5: Set the preview output
System.out.println("About to preview");
mMediaRecorder.setPreviewDisplay(mPreview.getHolder().getSurface());
System.out.println("Preview worked");
// Step 6: Prepare configured MediaRecorder
try {
mMediaRecorder.prepare();
} catch (IllegalStateException e) {
Log.d(TAG, "IllegalStateException preparing MediaRecorder: " + e.getMessage());
releaseMediaRecorder();
return false;
} catch (IOException e) {
Log.d(TAG, "IOException preparing MediaRecorder: " + e.getMessage());
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 (mMediaRecorder != null) {
mMediaRecorder.reset(); // clear recorder configuration
mMediaRecorder.release(); // release the recorder object
mMediaRecorder = null;
mCamera.lock(); // lock camera for later use
}
}
private void releaseCamera(){
if (mCamera != null){
mCamera.stopPreview();
mCamera.setPreviewCallback(null);
mCamera.release(); // release the camera for other applications
mCamera = null;
}
}
private PictureCallback mPicture = new PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera camera) {
System.out.println("Picture received");
File pictureFile = getOutputMediaFile(MEDIA_TYPE_IMAGE);
if (pictureFile == null){
Log.d(TAG, "Error creating media file, check storage permissions: ");
return;
}
try {
System.out.println("Saving");
FileOutputStream fos = new FileOutputStream(pictureFile);
fos.write(data);
fos.close();
} catch (FileNotFoundException e) {
Log.d(TAG, "File not found: " + e.getMessage());
} catch (IOException e) {
Log.d(TAG, "Error accessing file: " + e.getMessage());
}
}
};
/** Create a File for saving an image or video */
/** Create a File for saving an image or video */
private static File getOutputMediaFile(int type){
// To be safe, you should check that the SDCard is mounted
// using Environment.getExternalStorageState() before doing this.
System.out.println("Trying to save picture");
File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_PICTURES), "MyCameraApp");
// This location works best if you want the created images to be shared
// between applications and persist after your app has been uninstalled.
// Create the storage directory if it does not exist
if (! mediaStorageDir.exists()){
if (! mediaStorageDir.mkdirs()){
Log.d("MyCameraApp", "failed to create directory");
return null;
}
}
// Create a media file name
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
File mediaFile;
if (type == MEDIA_TYPE_IMAGE){
mediaFile = new File(mediaStorageDir.getPath() + File.separator +
"IMG_"+ timeStamp + ".jpg");
} else if(type == MEDIA_TYPE_VIDEO) {
mediaFile = new File(mediaStorageDir.getPath() + File.separator +
"VID_"+ timeStamp + ".mp4");
} else {
return null;
}
return mediaFile;
}
}
这是我的CameraPreview类
public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {
private static final String TAG = "Message";
private SurfaceHolder mHolder;
private Camera mCamera;
public CameraPreview(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);
}
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) {
Log.d(TAG, "Error setting camera preview: " + e.getMessage());
}
}
public void surfaceDestroyed(SurfaceHolder holder) {
// empty. Take care of releasing the Camera preview in your activity.
/*mCamera.setPreviewCallback(null);
mCamera.stopPreview();
mCamera.release();*/
}
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
// 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
System.out.println("Stop preview didn't work ");
}
// set preview size and make any resize, rotate or
// reformatting changes here
// start preview with new settings
try {
mCamera.setPreviewDisplay(mHolder);
mCamera.startPreview();
} catch (Exception e){
Log.d(TAG, "Error starting camera preview: " + e.getMessage());
}
}
}
编辑： XML布局
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<FrameLayout
android:id="@+id/camera_preview"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_weight="1"
/>
<Button
android:id="@+id/button_capture"
android:text="Capture"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
/>
</LinearLayout>
答案 0 :(得分：0)
我还可以通过在onPause（）中删除对Camera.release（）的调用来解决这个问题。这是一些代码：
//kv Only call release here if we're running an OS later than Gingerbread, otherwise, camera will freeze
if (android.os.Build.VERSION.SDK_INT > Build.VERSION_CODES.GINGERBREAD_MR1)
{
mCamera.release();
}