Android消息机制

HandlerThread

- mLooper:Looper

+ run()+ getLooper():Looper

Handler

- mLooper:Looper- mQueue:MessageQueue- mCallback:Callback

+ obtainMessage():Message+ sendMessage()+ post()+ handleMessage()+ distpatchMessage()

+ obtainMessage():Message+ sendMessage()+ post()+ handleMessage()+ distpatchMessage()

Handler::dispatchMessage(msg) {    if (msg.callback != null) {        handleCallback(msg);    } else {        if (mCallback != null) {            if (mCallback.handleMessage(msg)) {                return;            }        }        handleMessage(msg);    }}

MessageQueue

~ mMessages:Message

+ enqueueMessage()+ next():Message

Message

~ target:Handler~ next:Message

+ obtain():Message

HandlerThread::run() {    Looper::loop() {        for (;;) {            MessageQueue::next()；            Message.target::distpatchMessage() {                Handler::handleMessage()            }        }    }}

Looper

+ mThread:Tread+ mQueue:MessageQueue

+ loop()+ getThread():Thread+ getQueue():MessageQueue