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open
void 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();