将广播消息从类发送到Android中的活动(Send Broadcast message from a class to an Activity in Android)

我正在编写一个应用程序，它需要监视正在创建的文件的文件夹，然后根据创建的文件的文件名执行操作。

我已经将广播接收器用于来自电池和USB连接的其他通知，因此能够从实现fileObserver的类发送广播会很好。

在Main活动中，我为fileObserver实现了一个子类，但我无法弄清楚如何在一个事件中我可以通知MAin Activity创建了一个文件。

这是子类

class FileListener extends FileObserver { private String mAbsolutePath; public FileListener(String path){ super(path); mAbsolutePath = path; Log.d("FileObserver",path); } @Override public void onEvent(int event, String path){ switch(event){ case FileObserver.CREATE: Intent i = new Intent("CREATED"); context.sendBroadcast(i); break; case FileObserver.DELETE: Log.d("FileObserver", "DELETE"); break; case FileObserver.DELETE_SELF: Log.d("FileObserver", "DELETE_SELF"); break; case FileObserver.MODIFY: Log.d("FileObserver", "MODIFY"); break; case FileObserver.MOVED_FROM: Log.d("FileObserver", "MOVED_FROM"); break; case FileObserver.MOVED_TO: Log.d("FileObserver", "MOVED_TO"); break; case FileObserver.MOVE_SELF: Log.d("FileObserver", "MOVE_SELF"); break; } }

}

我不能在类中使用context.sendBroadcast，因为它没有上下文。这一切都非常令人困惑。

谢谢

I am writing an application that will need to monitor a folder for files being created and then take actions based on the file name of the file that was created.

I am already using a Broadcast Receiver for other notifications coming from the battery and the usb connection so it would be nice to be able to send a broadcast from the class that is implementing a fileObserver.

In the Main activity I implemented a sub class for the fileObserver but I cannot figure out how, upon an event I can notify the MAin Activity that a file was created.

Here is the Sub Class

class FileListener extends FileObserver { private String mAbsolutePath; public FileListener(String path){ super(path); mAbsolutePath = path; Log.d("FileObserver",path); } @Override public void onEvent(int event, String path){ switch(event){ case FileObserver.CREATE: Intent i = new Intent("CREATED"); context.sendBroadcast(i); break; case FileObserver.DELETE: Log.d("FileObserver", "DELETE"); break; case FileObserver.DELETE_SELF: Log.d("FileObserver", "DELETE_SELF"); break; case FileObserver.MODIFY: Log.d("FileObserver", "MODIFY"); break; case FileObserver.MOVED_FROM: Log.d("FileObserver", "MOVED_FROM"); break; case FileObserver.MOVED_TO: Log.d("FileObserver", "MOVED_TO"); break; case FileObserver.MOVE_SELF: Log.d("FileObserver", "MOVE_SELF"); break; } }

}

I can't use context.sendBroadcast in the class because it has no context. This is all very confusing.

Thanks

最满意答案

您需要做的就是将构造函数传递给您的类，如下所示：

class FileListener extends FileObserver { private String mAbsolutePath; private Context mContext; public FileListener(String path, Context context){ super(path); mAbsolutePath = path; mContext = context; Log.d("FileObserver",path); } //use context in your file.

然后，您可以将类称为： new FileListener(path, getApplicationContext()来自您的活动或片段的new FileListener(path, getApplicationContext() 。

All you need to do is pass your constructor into you class like so:

class FileListener extends FileObserver { private String mAbsolutePath; private Context mContext; public FileListener(String path, Context context){ super(path); mAbsolutePath = path; mContext = context; Log.d("FileObserver",path); } //use context in your file.

You can then call you class like: new FileListener(path, getApplicationContext() from your activity or fragment.

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