循环
public static class Looper {
final static ThreadLocal<Looper> threadLooper = new ThreadLocal<>();
public static void prepare() {
if (threadLooper.get() != null) {
throw new RuntimeException("此线程已经创建了Looper");
}
threadLooper.set(new Looper());
}
private Looper() {
}
static Looper mLooper() {
return threadLooper.get();
}
MessageQueue queue = new MessageQueue();
void loop() {
for (; ; ) {
System.out.println("loop loop");
Message next = queue.lastOrNull();
if (next == null) {
return;
}
System.out.println("deal message = " + next.code);
next.target.handleMessage(next);
queue.remove(next);
}
}
}
消息
static class Message {
int code = 0;
Handler target;
}
消息队列
简单用stack结构构建了下
static class MessageQueue extends Stack<Message> {
private final Object lock = new Object();
Message lastOrNull() {
for (; ; ) {
System.out.println("message queue");
try {
return lastElement();
} catch (Exception e) {
synchronized (lock) {
try {
lock.wait();
} catch (InterruptedException interruptedException) {
interruptedException.printStackTrace();
}
}
}
}
}
@Override
public Message push(Message item) {
Message push = super.push(item);
synchronized (lock) {
try {
lock.notify();
} catch (Exception e) {
e.printStackTrace();
}
}
return push;
}
}
处理消息
abstract static class Handler {
private final Looper mLooper;
public Handler() {
this(Looper.mLooper());
}
public Handler(Looper looper) {
mLooper = looper;
}
abstract void handleMessage(Message message);
void sendMessage(Message message) {
message.target = this;
mLooper.queue.push(message);
}
}
main方法
public static void main(String[] args) {
Looper.prepare();
Looper looper = Looper.mLooper();
Handler handler = new Handler(looper) {
@Override
void handleMessage(Message message) {
if (message.code > 0) {
message.code--;
sendMessage(message);
}
}
};
new Thread() {
@Override
public void run() {
for (int i = 0; i < 3; i++) {
Message m = new Message();
m.code = i * 10;
handler.sendMessage(m);
}
}
}.start();
looper.loop();
System.out.println("========end");
}
