用户行为
- 用户使用手机拍摄照片
- 用户下载网页上的照片，网盘的照片，微博的照片到手机
- 用户导入照片到SD卡
需求
- 当用户发生上述行为的时候，将增加的照片导入到程序并上传
实现思路
监听相机应用
如果用户拍摄了照片，可能会触发一个Intent，发送广播通知给其他程序
public static final String ACTION_NEW_PICTURE
Added in API level 14
Broadcast Action: A new picture is taken by the camera, and the entry of the picture has been added to the media store. getData() is URI of the picture.
Constant Value: "android.hardware.action.NEW_PICTURE"
public static final String ACTION_NEW_VIDEO
Added in API level 14
Broadcast Action: A new video is recorded by the camera, and the entry of the
video has been added to the media store. getData() is URI of the video.
Constant Value: "android.hardware.action.NEW_VIDEO"
代码
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();
}
}
<receiver
android:name="sample.grass.category.mediastore.CameraEventReciver"
android:enabled="true"
android:exported="true" >
<intent-filter>
<action android:name="android.hardware.action.NEW_PICTURE" />
<category android:name="android.intent.category.DEFAULT" />
<data android:mimeType="image/*" />
</intent-filter>
</receiver>
测试结果：
能够监听到用户拍摄了照片，但是仅限于系统相机，使用其他的相机apk可能收到广播，也有可能收不到
优点
- 即使应用程序没有启动，也能接收到通知，从而被唤醒
缺点
- 有的相机应用并没有实现发送广播，不是完全可以被依赖
- 无法监测用户下载图片或者导入照片
监听Meida数据库
无论是用户使用哪个相机拍摄照片，还是用户导入图片到sd卡，还是用户下载照片到手机，都会引起Media 数据库的变化，监听这个变化，导入照片到Trunx
代码
class UriObserver extends ContentObserver {
public UriObserver(Handler handler) {
super(handler);
// TODO Auto-generated constructor stub
}
@Override
public void onChange(boolean selfChange) {
// TODO Auto-generated method stub
super.onChange(selfChange);
Log.d("INSTANT", "GETTING CHANGES");
}
}
UriObserver observer = new UriObserver(new Handler());
this.getApplicationContext()
.getContentResolver()
.registerContentObserver(
MediaStore.Images.Media.EXTERNAL_CONTENT_URI, false,
observer);
优点
- 可以监听用户导入图片，用户下载图片，用户使用各种第三方相机拍摄图片
缺点
- 依赖于程序被启动，如果程序被杀掉了,就无法监听了
监听文件目录
代码
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
优点
- 能够监听到上述的所有的用户行为
缺点
- 需要硬编码，并且监听的目录太多，事倍功半