Android在子线程中更新UI的方法汇总(共七种)
1、常规写法:new Handler()的handleMessage()和handler.sendMessage(msg)
Handler handler = new Handler() {
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
}
};
new Thread(new Runnable() {
@Override
public void run() {
Message msg = Message.obtain();
msg.what = 1000;
msg.arg1 = 10;
handler.sendMessage(msg);
}
}).start();
2、handler的另一种用法:
private Handler.Callback callback = new Handler.Callback() {
@Override
public boolean handleMessage(Message msg) {
return true;
}
};
Handler handler1 = new Handler(callback);
new Thread(new Runnable() {
@Override
public void run() {
Message msg = Message.obtain();
msg.what = 1001;
msg.arg1 = 11;
handler1.sendMessage(msg);
}
}).start();
3、handler.post(runnable)
Handler handler = new Handler() {
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
}
};
new Thread(new Runnable() {
@Override
public void run() {
handler.post(new Runnable() {
@Override
public void run() {
}
});
}
}).start();
4、handler.postDelayed(runnable, milliseconds)
Handler handler = new Handler() {
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
}
};
new Thread(new Runnable() {
@Override
public void run() {
handler.postDelayed(new Runnable() {
@Override
public void run() {
}
}, 3000);
}
}).start();
5、activity.runOnUiThread(runnable)
new Thread(new Runnable() {
@Override
public void run() {
runOnUiThread(new Runnable() {
@Override
public void run() {
}
});
}
}).start();
6、view.post(runnable)
new Thread(new Runnable() {
@Override
public void run() {
button.post(new Runnable() {
@Override
public void run() {
}
});
}
}).start();
7、view.postDelayed(runnable, milliseconds)
new Thread(new Runnable() {
@Override
public void run() {
button.postDelayed(new Runnable() {
@Override
public void run() {
}
}, 3000);
}
}).start();
1、Handler机制
在子线程中通过下图两种方式将UI更新交给Handle来做。在我看来两种用法其实是一致的,没有什么区别,看个人喜好
a. b.
2、Handler.Post
handler.post(new Runnable(){
public void run(){
......更新.....
}
});
3、Looper
通过Looper可将UI更新的代码写在线程中
4、runUiThread
runUiThread(new Runnable()......)
下图为我在fragment中的调用,这里要注意一点就是在fragment中要先判断getActivity()是否为空,因为很有可能存在activity还未获取到就运行UI更新的情况,其实跟调用handler.xxx同理,保证调用对象activity / handler的存在。
但是吧,getActivity()获取不一定会非常的迅速,不要问我为什么会知道这个。。。。
最近用了一下okhttp,原本以为异步callback里面的onResponse是运行在主线程的,后面发现在onResponse里面放了Toast,半天没有反映,一度以为Toast写错了,把Toast放外面发现可以正常弹出提示的,后来查了下资料,原来okhttp的callback,onResponse其实还是运行在子线程的,那么如果在子线程更新主线程呢。这里提供几种方法。
//定义handler
static final int SUCCESS=1;
static final int FAIL=0;
Handler handler=new Handler(){
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
switch (msg.what) {
case SUCCESS:
Toast.makeText(LoginActivity.this, msg.getData().get("msg").toString(), Toast.LENGTH_SHORT).show();
break;
case FAIL:
Toast.makeText(LoginActivity.this, msg.getData().get("msg").toString(), Toast.LENGTH_SHORT).show();
break;
default:
super.handleMessage(msg);
}
}
};
//方法一:通过handler.sendMessage,更新UI主线程
private void makeToastByHandlerSendMessage(String msgStr)
{
Message msg=new Message();
msg.what=0;
Bundle bundle=new Bundle();
bundle.putString("msg",msgStr);
msg.setData(bundle);
handler.sendMessage(msg);
}
//方法二:通过handler.post,更新UI主线程
private void makeToastByHandlerPost(final String msg)
{
handler.post(new Runnable() {
@Override
public void run() {
Toast.makeText(LoginActivity.this, msg, Toast.LENGTH_SHORT).show();
}
});
}
//方法三:通过handler.post,延迟seconds秒后更新UI主线程
private void makeToastByHandlerPostDelay(final String msg,int seconds)
{
handler.postDelayed(new Runnable() {
@Override
public void run() {
Toast.makeText(LoginActivity.this, msg, Toast.LENGTH_SHORT).show();
}
},seconds*1000);
}
//方法四:使用runOnUiThread,更新UI主线程
private void makeToastByRunOnUiThread(final String msg)
{
LoginActivity.this.runOnUiThread(new Runnable() {
@Override
public void run() {
Toast.makeText(LoginActivity.this, msg, Toast.LENGTH_SHORT).show();
}
});
}
//方法五:通过view.post,更新UI主线程
private void makeToatByViewPost(View view,final String msg)
{
view.post(new Runnable() {
@Override
public void run() {
Toast.makeText(LoginActivity.this, msg, Toast.LENGTH_SHORT).show();
}
});
}
//方法六:通过AsyncTask,更新UI主线程
private void makeToastByAysncTask(final String msg)
{
AsyncTask asyncTask=new AsyncTask() {
@Override
protected Object doInBackground(Object[] params) {
return null;
}
@Override
protected void onPostExecute(Object o) {
super.onPostExecute(o);
Toast.makeText(LoginActivity.this, msg, Toast.LENGTH_SHORT).show();
}
@Override
protected void onProgressUpdate(Object[] values) {
super.onProgressUpdate(values);
}
};
asyncTask.execute();
}
调用:
//1、Handler.SendMessage
makeToastByHandlerSendMessage(msg);
//2、Handler.Post
makeToastByHandlerPost(msg);
//3、Handler.PostDelay
makeToastByHandlerPostDelay(msg,1);
//4、context.RunOnUiThread
makeToastByRunOnUiThread(msg);
//5、View.Post
makeToatByViewPost(btnLogin,msg);
//6、AysncTask
makeToastByAysncTask(msg);
其实通过查看源代码,发现非handler的实现方法最终还是通过handler来实现的。
LoginActivity.this.runOnUiThread(new Runnable() {});
view.post(new Runnable() );
//以上两个方法最终都调用handler的sendMessageDelayed方法
public final boolean sendMessageDelayed(Message msg, long delayMillis)