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{

		@Override
		public 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);
		}
		
	}
	@Override
	protected 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() {
					
					@Override
					public 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() {

			@Override
			public void run() {
				textView.setText("ok1");
			}
		});
	}
	/**
	 * 方法二
	 */
	private void handler2() {
		handler.sendEmptyMessage(1);
	}
/**
 * 方法三
 */
	private void updateUI(){
		runOnUiThread(new Runnable() {
			
			@Override
			public void run() {
				textView.setText("ok3");
			}
		});
	}
	/**
	 * 方法四
	 */
	private void viewUpdateUi(){
		textView.post(new Runnable() {
			
			@Override
			public void run() {
				textView.setText("ok4");
			}
		});
	}
	@Override
	protected 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() {
			
			@Override
			public void run() {
				// TODO Auto-generated method stub
				textView.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;

	@Override
	protected 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msg
					message.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;
		@Override
		public 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() {
		
		@Override
		public 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1
			return false;
		}
	}){
		@Override
		public void handleMessage(Message msg) {
			// TODO Auto-generated method stub
			Toast.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{

		@Override
		public 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);
		}
		
	}
	@Override
	protected 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);
	}


	@Override
	public 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;

	@Override
	protected 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;

		@Override
		public void run() {
			super.run();
			Looper.prepare();
			mHandler = new Handler() {
				@Override
				public void handleMessage(Message msg) {
					// TODO Auto-generated method stub
					super.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;

	@Override
	protected 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()){
			@Override
			public 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;

	@Override
	protected 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handler
		HandlerThread thread = new HandlerThread("handler stread");
		thread.start();
		threadHandler = new Handler(thread.getLooper()) {
			@Override
			public 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");
			}
		};

	}

	@Override
	public void onClick(View v) {
		// TODO Auto-generated method stub
		switch (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。。。。。

******************************************************