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59 lines
1.4 KiB
59 lines
1.4 KiB
5 years ago
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---
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怎么同步处理消息？
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---
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```c++
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status_t Client::createSurface(const String&& name, ...){
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sp<MessageBase> msg = new MessageCreateLayer(mFlinger.get(), name, this, w, h, format, flags, handle, gbp);
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mFlinger->postMessageSync(msg);
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return static_cast<MessageCreateLayer*>(msg.get())->getResult();
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}
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status_t postMessageSync(const sp<MessageBase>& msg, ...){
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mEventQueue.postMessage(msg, reltime);
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msg.wait();
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}
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class MessageCreateLayer:public MessageBase{
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status_t getResult() const{return result;}
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virtual bool handler(){
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result = flinger->createLayer(name, client,w, h, format, ...);
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return true;
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}
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}
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```
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```java
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public final boolean runWithScissors(final Runnable r, long timeout){
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if(Looper.myLooper()==mLooper){
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r.run();
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return true;
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}
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BlockingRunnable br = new BlockingRunnable(r);
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return br.postAndWait(this, timeout);
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}
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private static final class BlockingRunnable implements Runnable{
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public BlockingRunnable(Runnable task){
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mTask = task;
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}
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@Override
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public void run(){
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mTask.run();
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mDone = true;
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notifyAll();
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}
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}
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public boolean postAndWait(Handler handler, ...){
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if(!handler.post(this)){
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return false;
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}
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while(!mDone){
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wait();
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}
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return true;
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}
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```
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#### 总结
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1. 同步等待消息的处理
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2. Binder 调用统一切换工作线程
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