我看到在AOSP中有很多代码运行类似于:
v.post(new Runnable() {
@Override
public void run() {
// Here comes code
x += y;
}
});
与仅执行简单的 x += y;
相比,这样做有什么优势?
当视图附加到主用户界面线程时,此运行将获得调用。请查看View类中的post方法。
/**
* <p>Causes the Runnable to be added to the message queue.
* The runnable will be run on the user interface thread.</p>
*
* @param action The Runnable that will be executed.
*
* @return Returns true if the Runnable was successfully placed in to the
* message queue. Returns false on failure, usually because the
* looper processing the message queue is exiting.
*
* @see #postDelayed
* @see #removeCallbacks
*/
public boolean post(Runnable action) {
final AttachInfo attachInfo = mAttachInfo;
if (attachInfo != null) {
return attachInfo.mHandler.post(action);
}
// Postpone the runnable until we know on which thread it needs to run.
// Assume that the runnable will be successfully placed after attach.
getRunQueue().post(action);
return true;
}