broadcast receiver won't receive camera event

问题:

I'm trying to make an app that detects when a user takes a photo. I set up a broadcast receiver class and registered it in the manifest file by:

<receiver android:name="photoReceiver" >
  <intent-filter>
    <action android:name="com.android.camera.NEW_PICTURE"/>
      <data android:mimeType="image/*"/>
 </intent-filter>
</receiver>

No matter what I try to do the program won't receive the broadcast. Here is my receiver class:

public class photoReceiver extends BroadcastReceiver {
  private static final String TAG = "photoReceiver";

@Override
public void onReceive(Context context, Intent intent) {
    CharSequence text = "caught it";
    int duration = Toast.LENGTH_LONG;
    Log.d(TAG, "Received new photo");

    Toast toast = Toast.makeText(context, text, duration);
    toast.show();
 }
}

If I remove the mimeType line in the manifest and in my activity I send my own broadcast using

Intent intent = new Intent("com.android.camera.NEW_PICTURE");
sendBroadcast(intent);

then I successfully receive the broadcast and can see the log and toast window. Am I approaching this the right way? Is there any thing that I need to add?

回答1:

I solved this but by using a different method. Instead of using a broadcast receiver I set up a fileobserver on separate folders that the camera saved to. It's not as practical as the other way, but it still works fine. Here's how I set it up:

FileObserver observer = new FileObserver(android.os.Environment.getExternalStorageDirectory().toString() + "/DCIM/100MEDIA") { // set up a file observer to watch this directory on sd card
            @Override
        public void onEvent(int event, String file) {
            if(event == FileObserver.CREATE && !file.equals(".probe")){ // check if its a "create" and not equal to .probe because thats created every time camera is launched
                Log.d(TAG, "File created [" + android.os.Environment.getExternalStorageDirectory().toString() + "/DCIM/100MEDIA/" + file + "]");
                fileSaved = "New photo Saved: " + file;
            }
        }
    };
    observer.startWatching(); // start the observer

回答2:

I sure this way works 100% . I tested carefully.

Register your broadcast receiver in AndroidManifest. Most of answers above miss "category android:name="android.intent.category.DEFAULT" . BroadcastReceiver can't start without this

  <receiver
    android:name=".CameraReciver"
    android:enabled="true" >
        <intent-filter>
            <action android:name="com.android.camera.NEW_PICTURE" />
            <action android:name="android.hardware.action.NEW_PICTURE" />
            <category android:name="android.intent.category.DEFAULT" />
            <data android:mimeType="image/*" />

        </intent-filter>
    </receiver>

And finally, you create a class named "CameraReciver.java" extend from BroadcastReceiver and this my code :

public class CameraReciver extends BroadcastReceiver {

@Override
public void onReceive(Context context, Intent intent) {
    // TODO Auto-generated method stub
    Log.i("INFO", "Enter BroadcastReceiver");



Cursor cursor = context.getContentResolver().query(intent.getData(),
                null, null, null, null);
        cursor.moveToFirst();
        String image_path = cursor.getString(cursor.getColumnIndex("_data"));
        Toast.makeText(context, "New Photo is Saved as : " + image_path, 1000)
                .show();



}

After that, deploy your project to Emulator ( I use genymotion),of course nothing happened because your BroadCastReceiver works without GUI. Let you open camera app, and click capture button. If everything OK, you'll get a toast with content like "New Photo is Saved as : storage/emulated/0/DCIM/Camera/IMG_20140308.jpg". Let enjoy ^_^

Thanks "tanay khandelwal" (answered above) for how to get the path of new Photo captured by camera ^_^

My English grammar not very good, maybe wrong somewhere, but i think you can understand what I mean (^_^) . Hope to help everyone

回答3:

you should check out here: ImageTableObserver and here PicasaPhotoUploader how they do it.

Basically, they have an observer for Media.EXTERNAL_CONTENT_URI that will notify of whatever happens on the SD card, then in the Observer, they check if the data returned is a photo.

camera = new ImageTableObserver(new Handler(), this, queue);
getContentResolver().registerContentObserver(Media.EXTERNAL_CONTENT_URI, true, camera);

At least this way you don't have to hardcode the directory.

回答4:

Hello friends I was also trying to implement some task on capture event and after studying and working on it I prepared this code which is working fine so it may help you

first create a receiver for your event say CameraEventReciver and in that you can implement your code I m also giving you the path of the new image so it will be more useful to you for your code

    public class CameraEventReciver extends BroadcastReceiver {

@Override
public void onReceive(Context context, Intent intent) {

    Cursor cursor = context.getContentResolver().query(intent.getData(),      null,null, null, null);
    cursor.moveToFirst();
    String image_path = cursor.getString(cursor.getColumnIndex("_data"));
    Toast.makeText(context, "New Photo is Saved as : -" + image_path, 1000).show();
      }
    }

And in Android Manifest you just have to take some permissions and register your reciever with intent filter and appropriate action for image capture also make your receiver android enabled

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

   <receiver
        android:name="com.android.application.CameraEventReciver"
        android:enabled="true" >
        <intent-filter>
            <action android:name="com.android.camera.NEW_PICTURE" />
            <data android:mimeType="image/*" />
        </intent-filter>
    </receiver>

回答5:

The issue is that, you've put the constant name with package into apostrophes (as string). The actual string constant has different value.