We know main(UI) Thread is having implicit Looper attach with it so that its having MessageQueue.
And we also know that we can attach MessageQueue to worker thread with the help of Looper.prepare()
My question is that is it both Queue are same?
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same? what do you mean? did you compare their references?pskink– pskink2014-12-30 12:16:02 +00:00Commented Dec 30, 2014 at 12:16
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@pskink i am not worry about hasCode()...we know why we have MessageQueue...to render UI in pipeline Thread...a single thread (UI Thread) is responsible to do this job...if we have more than one Thread having MessageQueue then what about the pipeline concept for rendering...in my concern both should be same.Amit Yadav– Amit Yadav2014-12-30 12:16:51 +00:00Commented Dec 30, 2014 at 12:16
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sorry i dont understand you at all, what you wanna do?pskink– pskink2014-12-30 12:18:08 +00:00Commented Dec 30, 2014 at 12:18
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1 Answer
It's not the same MessageQueue, when you call Looper.loop() in a new thread, a new MessageQueue will attache to the new created thread. Then we usually use Handler to communicate with the thread. The main UI thread's MessageQueue is created by system when you app start. You can compare the message queues by their reference.
private static final String TAG = MainActivity.class.getSimpleName();
private Handler mHandler;
private MessageQueue messageQueue;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
messageQueue = Looper.myQueue();
new Thread() {
@Override
public void run() {
super.run();
Looper.prepare();
mHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
if (Looper.myQueue().equals(messageQueue)) {
Log.d(TAG, "same message queue");
} else {
Log.d(TAG, "not the same queue");
}
}
};
mHandler.sendEmptyMessage(0);
Looper.loop();
}
}.start();
}
Here is a related discussion.
