线程操作经常用到wait和notify，用起来稍显繁琐，而Android给我们封装好了一个ConditionVariable类，用于线程同步。提供了三个方法block()、open()、close()。
void block()//阻塞当前线程，直到条件为openvoid block(long timeout)//阻塞当前线程，直到条件为open或超时void open()//释放所有阻塞的线程void close()//将条件重置为close
ConditionVariable 在创建时还有一种构造方法是 public ConditionVariable (boolean state) ，如果为true，默认时为opened，如果为false则是closed. ，默认public ConditionVariable()为closed.
源码
其实很好理解
private volatile boolean mCondition;
成员内部变量。
//默认构造函数 public ConditionVariable(){ mCondition = false;} public ConditionVariable(boolean state){ mCondition = state;} open，释放阻塞，即notifyAll一下，此时成员变量变为true。
public void open(){ synchronized (this) { boolean old = mCondition; mCondition = true; if (!old) { this.notifyAll(); } }} close，重置成员变量为false
public void close(){ synchronized (this) { mCondition = false; }} block，只有在成员变量为false的时候进行wait等待
public void block(){ synchronized (this) { while (!mCondition) { try { this.wait(); } catch (InterruptedException e) { } } }} public boolean block(long timeout){ // Object.wait(0) means wait forever, to mimic this, we just // call the other block() method in that case. It simplifies // this code for the common case. if (timeout != 0) { synchronized (this) { long now = System.currentTimeMillis(); long end = now + timeout; while (!mCondition && now < end) { try { this.wait(end-now); } catch (InterruptedException e) { } now = System.currentTimeMillis(); } return mCondition; } } else { this.block(); return true; }} code
简单的延时：
new Thread(new Runnable() { @Override public void run() { // TODO Auto-generated method stub while(isStart) { //延时等待3秒 mConditionVariable.block(3000); //将条件重置，否则block会失效 mConditionVariable.close(); //线程唤醒后通知主线程 mHandler.sendEmptyMessage(REFRESHTEXT); } } }).start();