LooperActivity.java
package com.jing.example.nknu_.looperactivity;
import android.annotation.SuppressLint;
import android.os.Bundle;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.TextView;
public class LooperActivity extends AppCompatActivity {
LooperThread mLooperThread;
TextView txv;
int i = 3;
private class LooperThread extends Thread{
public Handler mHandler;
private TextView txv;
public void run(){
Looper.prepare();
mHandler = new Handler(){
public void handleMessage(Message msg){
System.out.println("已進入handler and msg.what = " + String.valueOf(msg.what));
if(msg.what==0){
doLongRunningOperation(msg);
}
}
};
Looper.loop();
}
private void doLongRunningOperation(Message msg){
System.out.println(msg.arg1);
final int i = msg.arg1;
runOnUiThread(new Runnable() {
public void run() {
txv = (TextView) findViewById(R.id.textView);
txv.setText(String.valueOf(i));
}
});
}
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_looper);
txv=(TextView)findViewById(R.id.textView);
mLooperThread = new LooperThread();
mLooperThread.start();
}
public void start(View v){
if(mLooperThread.mHandler !=null){
Message msg = mLooperThread.mHandler.obtainMessage(0);
msg.arg1 = i;
mLooperThread.mHandler.sendMessage(msg);
System.out.println("已進入start");
}
}
@SuppressLint("MissingSuperCall")
protected void onDestroy(){
mLooperThread.mHandler.getLooper().quit();
}
}
content_looper.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:context="com.jing.example.nknu_.looperactivity.LooperActivity"
tools:showIn="@layout/activity_looper">
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="New Button"
android:id="@+id/button"
android:layout_centerVertical="true"
android:layout_alignParentStart="true"
android:onClick="start" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="New Text"
android:id="@+id/textView"
android:layout_alignParentTop="true"
android:layout_alignParentStart="true" />
</RelativeLayout>