onPictureTaken从未调用

Question

该代码可以正常工作。 唯一的问题是onPictureTaken函数从未调用过。 我需要使用此功能将图像存储到SD卡。

主要活动

public class MainActivity extends Activity {

//private static Camera mCamera;
//private CameraPreview mPreview;
private static String TAG = "CamraOne";

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.camera_layout);
    Log.d(TAG, "setContentView end");
    Intent intent = new Intent(this, CameraServiceOne.class);
    Log.d(TAG,"start intent");
    startService(intent);
    Log.d(TAG,"run in bkgrd");

}

摄影服务

CameraService

public class CameraServiceOne extends Service{
private SurfaceHolder sHolder; 
//a variable to control the camera
private static Camera mCamera;
//the camera parameters
private Parameters parameters;
private static String TAG = "CameraOne";
/** Called when the activity is first created. */



@Override
public void onCreate()
{
    super.onCreate();

}
@Override
public void onStart(Intent intent, int startId) {
// TODO Auto-generated method stub
super.onStart(intent, startId);

mCamera = Camera.open();
SurfaceView sv = new SurfaceView(getApplicationContext());


try {
mCamera.setPreviewDisplay(sv.getHolder());
parameters = mCamera.getParameters();

//set camera parameters
mCamera.setParameters(parameters);
mCamera.startPreview();
Thread.sleep(1000);
Log.d(TAG,"take pic");
mCamera.takePicture(null, null, mCall);
Log.d(TAG,"pic end");
Thread.sleep(5000);
mCamera.stopPreview();
mCamera.release();


} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}


//Get a surface
sHolder = sv.getHolder();
//tells Android that this surface will have its data constantly replaced
sHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}



public static Camera.PictureCallback mCall = new Camera.PictureCallback()
{
public void onPictureTaken(byte[] data, Camera camera)
{   
mCamera = null;
Log.d(TAG,"in callback");
//decode the data obtained by the camera into a Bitmap
/*
FileOutputStream outStream = null;
try{
outStream = new FileOutputStream("/sdcard/Image.jpg");
Log.d(TAG,"write pic");
outStream.write(data);
Log.d(TAG,"write end");
outStream.close();
} catch (FileNotFoundException e){
Log.d("CAMERA", e.getMessage());
} catch (IOException e){
Log.d("CAMERA", e.getMessage());
}
*/

File pictureFile = getOutputMediaFile(MEDIA_TYPE_IMAGE);
if (pictureFile == null){
Log.d(TAG, "Error creating media file, check storage permissions: ");
return;
}

try {
FileOutputStream fos = new FileOutputStream(pictureFile);
fos.write(data);
fos.close();
/*
File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_PICTURES), "MyCameraApp");
sendBroadcast(new Intent(Intent.ACTION_MEDIA_MOUNTED, 
Uri.parse("file://"+ mediaStorageDir)));
*/
} catch (FileNotFoundException e) {
Log.d(TAG, "File not found: " + e.getMessage());
} catch (IOException e) {
Log.d(TAG, "Error accessing file: " + e.getMessage());
}
}
};


@Override
public IBinder onBind(Intent intent) {
// TODO Auto-generated method stub
return null;
}



public static final int MEDIA_TYPE_IMAGE = 1;
public static final int MEDIA_TYPE_VIDEO = 2;

/** Create a file Uri for saving an image or video */
private static Uri getOutputMediaFileUri(int type){

return Uri.fromFile(getOutputMediaFile(type));
}

/** 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.
if(Environment.getExternalStorageDirectory() == null){
Log.d("MyCameraApp","getExternalStorageDirectory null");
}
File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(
                Environment.DIRECTORY_PICTURES), "CameraServiceOne");
      // 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 path: " +    
mediaStorageDir.getPath());
              return null;
          }
      }

      // Create a media file name
      String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
      File mediaFile;
      Log.d(TAG,"write 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;
  }

Manifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.cameraone"
android:versionCode="1"
android:versionName="1.0" >

<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>


<uses-sdk
    android:minSdkVersion="19"
    android:targetSdkVersion="19" />

<application
    android:allowBackup="true"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >

    <service android:name=".CameraServiceOne"/>
    <activity
        android:name="com.example.cameraone.MainActivity"
        android:label="@string/app_name" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
</application>

</manifest>

更新了CameraService

public class CameraServiceOne extends Service implements SurfaceHolder.Callback{
  private SurfaceHolder sHolder; 
  //a variable to control the camera
  private static Camera mCamera;
  //the camera parameters
  private Parameters parameters;
  private static String TAG = "CameraOne";
  /** Called when the activity is first created. */
@Override
public void onCreate()
{
    super.onCreate();

}
@Override
public void onStart(Intent intent, int startId) {
  // TODO Auto-generated method stub
  super.onStart(intent, startId);
  Log.d(TAG,"on start");
   mCamera = Camera.open();
   //change sv to findViewByID
   //SurfaceView sv = new SurfaceView(getApplicationContext());

   LayoutInflater inflater = (LayoutInflater)
           getSystemService(LAYOUT_INFLATER_SERVICE);
         View layout = inflater.inflate(R.layout.camera_layout, null);
         SurfaceView sv = (SurfaceView) layout.findViewById(R.id.camera_surfaceview);
          parameters = mCamera.getParameters();
          mCamera.setParameters(parameters);

          mCamera.startPreview();
          Log.d(TAG,"startPreview");
         sv.post(new Runnable() { public void run() { mCamera.takePicture(null, null, mCall); } });
/*
   try {
              mCamera.setPreviewDisplay(sv.getHolder());
              parameters = mCamera.getParameters();

               //set camera parameters
             mCamera.setParameters(parameters);
             mCamera.startPreview();
             Thread.sleep(1000);
             Log.d(TAG,"take pic");
             mCamera.takePicture(null, null, mCall);
             Log.d(TAG,"pic end");
             Thread.sleep(5000);
             mCamera.stopPreview();
             mCamera.release();


        } catch (IOException e) {
              // TODO Auto-generated catch block
              e.printStackTrace();
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
*/       

   //Get a surface
     sHolder = sv.getHolder();
    //tells Android that this surface will have its data constantly replaced
     sHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}

public static Camera.PictureCallback mCall = new Camera.PictureCallback()
{
   public void onPictureTaken(byte[] data, Camera camera)
   {    
       mCamera = null;
       Log.d(TAG,"in callback");
         //decode the data obtained by the camera into a Bitmap
       /*
         FileOutputStream outStream = null;
              try{
                  outStream = new FileOutputStream("/sdcard/Image.jpg");
                  Log   .d(TAG,"write pic");
                  outStream.write(data);
                  Log.d(TAG,"write end");
                  outStream.close();
              } catch (FileNotFoundException e){
                  Log.d("CAMERA", e.getMessage());
              } catch (IOException e){
                  Log.d("CAMERA", e.getMessage());
              }
    */

        File pictureFile = getOutputMediaFile(MEDIA_TYPE_IMAGE);
        if (pictureFile == null){
            Log.d(TAG, "Error creating media file, check storage permissions: ");
            return;
        }

        try {
            FileOutputStream fos = new FileOutputStream(pictureFile);
            fos.write(data);
            fos.close();
            /*
            File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(
            Environment.DIRECTORY_PICTURES), "MyCameraApp");
            sendBroadcast(new Intent(Intent.ACTION_MEDIA_MOUNTED, 
            Uri.parse("file://"+ mediaStorageDir)));
            */
        } catch (FileNotFoundException e) {
            Log.d(TAG, "File not found: " + e.getMessage());
        } catch (IOException e) {
            Log.d(TAG, "Error accessing file: " + e.getMessage());
        }
   }
};


  @Override
  public IBinder onBind(Intent intent) {
        // TODO Auto-generated method stub
        return null;
  }



  public static final int MEDIA_TYPE_IMAGE = 1;
  public static final int MEDIA_TYPE_VIDEO = 2;

  /** Create a file Uri for saving an image or video */
  private static Uri getOutputMediaFileUri(int type){

        return Uri.fromFile(getOutputMediaFile(type));
  }

  /** 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.
    if(Environment.getExternalStorageDirectory() == null){
        Log.d("MyCameraApp","getExternalStorageDirectory null");
    }
      File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(
                Environment.DIRECTORY_PICTURES), "CameraServiceOne");
      // 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 path: " + mediaStorageDir.getPath());
              return null;
          }
      }

      // Create a media file name
      String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
      File mediaFile;
      Log.d(TAG,"write 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;
  }

 @Override
  public void surfaceCreated(SurfaceHolder holder) {
      // The Surface has been created, now tell the camera where to draw the preview.
  }       
@Override
public void surfaceChanged(SurfaceHolder arg0, int arg1, int arg2, int arg3) {
    // TODO Auto-generated method stub

}
@Override
public void surfaceDestroyed(SurfaceHolder arg0) {
    // TODO Auto-generated method stub
}

Answer 1

您正确地发现，不应在startPreview()之前或之后立即调用takePicture() 。 但是不幸的是，在它们之间添加额外的sleep()是不够的。

诀窍在于，在发出takePicture()之前，必须执行的回调很少：必须准备好SurfaceView，并且预览才能在此SurfaceView上播放。

因此，首先必须显示sv视图。 您可以简单地准备一个SurfaceView作为camera_layout.xml的一部分，而不是使用findViewById(R.id.camera_surface_view)来调用new SurfaceView(getApplicationContext()) findViewById(R.id.camera_surface_view) 。

其次，向您的CameraServiceOne类添加implements SurfaceHolder.Callback ，并实现回调（请参见例如Android教程）。

现在，您可以直接从SurfaceCreated() 发布 （另一个异步执行级别） takePicture() SurfaceCreated() ：

sv.post(new Runnable() { public void run() { mCamera.takePicture(null, null, mCall); } } });

最后，考虑为Camera.open（）和配置使用后台HandlerThread ：这些冗长的操作可能会使UI（主）线程冻结不可接受的长时间。

Answer 2

从未调用过onPictureTaken 。 我发现这是因为Camera.takePicture()方法已被多次调用，导致onPictureTaken不被调用。 如果ShutterCallback返回了代码，则也不会调用onPictureTaken 。