在将 iPhone 应用程序移植到 android 的过程中,我正在寻找在应用程序内进行通信的最佳方式。 Intent 似乎是要走的路,这是最好的(唯一)选择吗? NSUserDefaults 在性能和编码方面似乎都比 Intent 轻得多。
我还应该添加我有一个状态的应用程序子类,但我需要让另一个 Activity 知道一个事件。
最佳答案
我找到的最佳等价物是 LocalBroadcastManager这是 Android Support Package 的一部分.
来自 LocalBroadcastManager 文档:
Helper to register for and send broadcasts of Intents to local objects within your process. This is has a number of advantages over sending global broadcasts with sendBroadcast(Intent):
- You know that the data you are broadcasting won't leave your app, so don't need to worry about leaking private data.
- It is not possible for other applications to send these broadcasts to your app, so you don't need to worry about having security holes they can exploit.
- It is more efficient than sending a global broadcast through the system.
使用它时,您可以说 Intent
相当于 NSNotification
.这是一个例子:
ReceiverActivity.java
监视名为 "custom-event-name"
的事件通知的 Activity .
@Override
public void onCreate(Bundle savedInstanceState) {
...
// Register to receive messages.
// This is just like [[NSNotificationCenter defaultCenter] addObserver:...]
// We are registering an observer (mMessageReceiver) to receive Intents
// with actions named "custom-event-name".
LocalBroadcastManager.getInstance(this).registerReceiver(mMessageReceiver,
new IntentFilter("custom-event-name"));
}
// Our handler for received Intents. This will be called whenever an Intent
// with an action named "custom-event-name" is broadcasted.
private BroadcastReceiver mMessageReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
// Get extra data included in the Intent
String message = intent.getStringExtra("message");
Log.d("receiver", "Got message: " + message);
}
};
@Override
protected void onDestroy() {
// Unregister since the activity is about to be closed.
// This is somewhat like [[NSNotificationCenter defaultCenter] removeObserver:name:object:]
LocalBroadcastManager.getInstance(this).unregisterReceiver(mMessageReceiver);
super.onDestroy();
}
SenderActivity.java
发送/广播通知的第二个 Activity 。
@Override
public void onCreate(Bundle savedInstanceState) {
...
// Every time a button is clicked, we want to broadcast a notification.
findViewById(R.id.button_send).setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
sendMessage();
}
});
}
// Send an Intent with an action named "custom-event-name". The Intent sent should
// be received by the ReceiverActivity.
private void sendMessage() {
Log.d("sender", "Broadcasting message");
Intent intent = new Intent("custom-event-name");
// You can also include some extra data.
intent.putExtra("message", "This is my message!");
LocalBroadcastManager.getInstance(this).sendBroadcast(intent);
}
使用上面的代码,每次按钮 R.id.button_send
被点击,一个 Intent 被广播并被 mMessageReceiver
接收在 ReceiverActivity
.
调试输出应如下所示:
01-16 10:35:42.413: D/sender(356): Broadcasting message
01-16 10:35:42.421: D/receiver(356): Got message: This is my message!
关于Android 相当于 NSNotificationCenter,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/3947641/