Handler的用法大汇总

************************************mHandler.postDelayed (图片轮询)和 mHandler.post（跟新UI）************************************

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    tools:context="com.example.handlerdemo.MainActivity" >    <TextView        android:id="@+id/tv"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="@string/hello_world" />    <ImageView        android:id="@+id/imageView"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignParentRight="true"        android:layout_below="@+id/tv"        android:layout_marginRight="52dp"        android:layout_marginTop="84dp"        android:src="@drawable/ic_launcher" /></RelativeLayout>

MainActivity

package com.example.handlerdemo;import android.R.mipmap;import android.app.Activity;import android.os.Bundle;import android.os.Handler;import android.view.Menu;import android.view.MenuItem;import android.widget.ImageView;import android.widget.TextView;public class MainActivity extends Activity {private TextView tv;private Handler mHandler = new Handler();private ImageView mImageView;private int images[] = {R.drawable.ic_launcher,R.drawable.ic_launcher1,R.drawable.ic_launcher2};//图片位置private int index;private MyRun myRun = new MyRun();class MyRun implements Runnable{@Overridepublic void run() {index ++;index = index%3;mImageView.setImageResource(images[index]);/**在分线程中mHandler.post更新UI界面，1秒后handler再次循环发送Runnable对象*/mHandler.postDelayed(myRun, 1000);}}@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);/** * Handler被绑定到主线程中，在分线程中mHandler.post更新UI界面， * handler可以分发Message对象和Runnable对象到主线程中 */tv = (TextView) findViewById(R.id.tv);new Thread() {public void run() {mHandler.post(new Runnable() {@Overridepublic void run() {tv.setText("xxx");}});};}.start();/** * 定时器作用，Handler被绑定到主线程中，在主线程中，1秒后handler直接发送Runnable对象 */mImageView = (ImageView) findViewById(R.id.imageView);mHandler.postDelayed(myRun, 1000);}}

</pre><pre name="code" class="java">***************************************更新uI的5种方式********************************

布局文件只有一个textview

<pre name="code" class="java">package com.example.handlerdemo;import android.app.Activity;import android.os.Bundle;import android.os.Handler;import android.os.HandlerThread;import android.os.Looper;import android.os.Message;import android.util.Log;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.TextView;import android.widget.Toast;public class MainActivity extends Activity {private TextView textView;private Handler handler = new Handler() {public void handleMessage(Message msg) {textView.setText("ok2");Log.e("TAG", ""+msg.what);//1};};/*** * 方法一 */private void handler1() {handler.post(new Runnable() {@Overridepublic void run() {textView.setText("ok1");}});}/** * 方法二 */private void handler2() {handler.sendEmptyMessage(1);}/** * 方法三 */private void updateUI(){runOnUiThread(new Runnable() {@Overridepublic void run() {textView.setText("ok3");}});}/** * 方法四 */private void viewUpdateUi(){textView.post(new Runnable() {@Overridepublic void run() {textView.setText("ok4");}});}@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);textView = (TextView) findViewById(R.id.textView);/** * 方法五 */handler.post(new Runnable() {@Overridepublic void run() {// TODO Auto-generated method stubtextView.setText("ok5");}});new Thread() {public void run() {try {Thread.sleep(1000);//handler1();//handler2();//updateUI();//viewUpdateUi();} catch (InterruptedException e) {e.printStackTrace();}};}.start();}}

***********************************创建消息，发送消息各2种方式***************************************

Ui界面不变，复用上例的xml布局

MainActivity

package com.example.handlerdemo;import android.R.mipmap;import android.app.Activity;import android.os.Bundle;import android.os.Handler;import android.os.Message;import android.view.Menu;import android.view.MenuItem;import android.widget.ImageView;import android.widget.TextView;public class MainActivity extends Activity {private TextView tv;private Handler mHandler = new Handler() {public void handleMessage(android.os.Message msg) {tv.setText(""+msg.arg1+">>>"+msg.arg2+""+msg.obj);};};private ImageView mImageView;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);tv = (TextView) findViewById(R.id.tv);mImageView = (ImageView) findViewById(R.id.imageView);new Thread() {public void run() {try {Thread.sleep(2000);Message message = mHandler.obtainMessage();//Message message = new Message();  或者可以用这个创建msgmessage.arg1 =88;message.arg2 =100;Person person = new Person();person.age =10;person.name = "wyf";message.obj = person;message.sendToTarget();//mHandler.sendMessage(message); 或者可以用这个发送消息} catch (InterruptedException e) {e.printStackTrace();}};}.start();}class Person{public int age;public String name;@Overridepublic String toString() {return "Person [age=" + age + ", name=" + name + "]";}}}

**********************************移除消息以及handleMessage返回值意义*******************************************************

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    tools:context="com.example.handlerdemo.MainActivity" >    <TextView        android:id="@+id/tv"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="@string/hello_world" />    <ImageView        android:id="@+id/imageView"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignParentRight="true"        android:layout_below="@+id/tv"        android:layout_marginRight="52dp"        android:layout_marginTop="84dp"        android:src="@drawable/ic_launcher" />    <Button        android:id="@+id/button"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_below="@+id/imageView"        android:layout_marginTop="32dp"        android:layout_toLeftOf="@+id/imageView"        android:text="Button" /></RelativeLayout>

MainActivity

package com.example.handlerdemo;import android.app.Activity;import android.os.Bundle;import android.os.Handler;import android.os.Message;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.ImageView;import android.widget.TextView;import android.widget.Toast;public class MainActivity extends Activity implements OnClickListener {private TextView tv;private ImageView mImageView;private Button button;private Handler mHandler = new Handler(new Handler.Callback() {@Overridepublic boolean handleMessage(Message msg) {Toast.makeText(MainActivity.this, "1", 0).show();//这里为false,弹出1 2 如果为true,就只弹出1return false;}}){@Overridepublic void handleMessage(Message msg) {// TODO Auto-generated method stubToast.makeText(MainActivity.this, "2", 0).show();}};private int images[] = {R.drawable.ic_launcher,R.drawable.ic_launcher1,R.drawable.ic_launcher2};//图片位置private int index;private MyRun myRun = new MyRun();class MyRun implements Runnable{@Overridepublic void run() {index ++;index = index%3;mImageView.setImageResource(images[index]);/**在分线程中mHandler.post更新UI界面，1秒后handler再次循环发送Runnable对象*/mHandler.postDelayed(myRun, 1000);}}@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);tv = (TextView) findViewById(R.id.tv);mImageView = (ImageView) findViewById(R.id.imageView);mHandler.postDelayed(myRun, 1000);button = (Button) findViewById(R.id.button);button.setOnClickListener(this);}@Overridepublic void onClick(View v) {//清空消息mHandler.removeCallbacks(myRun);mHandler.sendEmptyMessage(1);}}

*************************************Handler进阶--Handler既可在主线程执行，也可以在分线程执行--与线程相关的handler***************************************

Looper内部包含一个MessageQueue
Looper.Looper死循环，不断的从MessageQueue取消息
并处理消息
Handler内部可以找到Looper,进而找到MessageQueue
进而在向MessageQueue队列发送消息

总结：
handler负责发送消息，Looper负责接收handler发送的消息
并直接把消息回传给handler自己

//ActivityThread负责创建所有的Activity
//创建Main线程
//ThreadLocal在线程中，set、get变量信息，比如Looper
//线程中有Looper
//创建一个MessageQuene

package com.example.handlerdemo;import android.app.Activity;import android.os.Bundle;import android.os.Handler;import android.os.Looper;import android.os.Message;import android.util.Log;import android.widget.TextView;public class MainActivity extends Activity {private Handler UIHandler = new Handler() {public void handleMessage(Message msg) {Log.e("UI", "" + Thread.currentThread());};};private MyThread myThread;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);TextView textView = new TextView(this);textView.setText("hello");setContentView(textView);myThread = new MyThread();myThread.start();try {Thread.sleep(1000);} catch (InterruptedException e) {e.printStackTrace();}// 分线程handler发消息，在分线程执行myThread.mHandler.sendEmptyMessage(1);// 主线程handler发消息，在主线程执行UIHandler.sendEmptyMessage(1);}/** * 创建一个子线程，里面有个属性mHandler *  */class MyThread extends Thread {public Handler mHandler;@Overridepublic void run() {super.run();Looper.prepare();mHandler = new Handler() {@Overridepublic void handleMessage(Message msg) {// TODO Auto-generated method stubsuper.handleMessage(msg);Log.e("Thread", "" + Thread.currentThread());}};Looper.loop();}}}

*************************************HandlerThread*************************************

package com.example.handlerdemo;import android.app.Activity;import android.os.Bundle;import android.os.Handler;import android.os.HandlerThread;import android.os.Looper;import android.os.Message;import android.util.Log;import android.widget.TextView;public class MainActivity extends Activity {private TextView textView;private HandlerThread thread;private Handler handler;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);textView = new TextView(this);textView.setText("hello");setContentView(textView);thread = new HandlerThread("handler thread");thread.start();handler = new Handler(thread.getLooper()){@Overridepublic void handleMessage(Message msg) {super.handleMessage(msg);Log.e("TAG", ""+Thread.currentThread());}};handler.sendEmptyMessage(1);}}

**************************************主线程子线程消息交互*****************************************

布局文件只有一个Button用来发送消息

package com.example.handlerdemo;import android.app.Activity;import android.os.Bundle;import android.os.Handler;import android.os.HandlerThread;import android.os.Looper;import android.os.Message;import android.util.Log;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.TextView;public class MainActivity extends Activity implements OnClickListener {private Button sendButton;/** * 主线程的handler */private Handler handler = new Handler() {public void handleMessage(Message msg) {Message message = new Message();Log.e("TAG", "主线程");//主线程收到消息后，向子线程发送消息threadHandler.sendMessageDelayed(message, 1000);};};private Handler threadHandler;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);sendButton = (Button) findViewById(R.id.send);sendButton.setOnClickListener(this);//HandlerThread是线程，这里是子线程的handlerHandlerThread thread = new HandlerThread("handler stread");thread.start();threadHandler = new Handler(thread.getLooper()) {@Overridepublic void handleMessage(Message msg) {super.handleMessage(msg);Message message = new Message();// 子线程接受消息后，向主线程发送消息handler.sendMessageDelayed(message, 1000);Log.e("TAG", "子线程");}};}@Overridepublic void onClick(View v) {// TODO Auto-generated method stubswitch (v.getId()) {case R.id.send:handler.sendEmptyMessage(1);break;default:break;}}}

Log日记 主线程 子线程 主线程 子线程。。。。。

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