Android中子线程和UI线程通信详解

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:tools="http://schemas.android.com/tools"
  android:id="@+id/container"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:orientation="vertical" >

  <Button
    android:id="@+id/btn"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="自定义Thread继承Thread" />


  <Button
    android:id="@+id/btn2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="自定义Runnable实现Runnable" />


  <Button
    android:id="@+id/btn3"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="定时更新UI界面，Handler分发Runnable对象" />


  <Button
    android:id="@+id/btn4"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="定时更新UI界面，Handler分发Message对象" />

  <TextView
    android:id="@+id/tv"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="0" />

</LinearLayout>

package com.chengdong.su.threaddemo;

import com.chengdong.su.threaddemo.util.MyRunnable;
import com.chengdong.su.threaddemo.util.MyThread;

import android.R.integer;
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
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 {
  /** TAG */
  private final String TAG = getClass().getSimpleName();
  /** the object of the button */
  private Button mButton;
  /** the object of the button */
  private Button mButton2;
  /** the object of the button */
  private Button mButton3;
  /** the object of the button */
  private Button mButton4;
  /** the object of the TextView */
  private TextView mTextView;
  /** 计数 */
  private int mCount = 0;
  /** 标志 */
  private int MESSAGE_FLAG = 1;

  /**
   * Handler分发Runnable对象的方式
   */
  private Handler mHandler = new Handler();

  Runnable runnable = new Runnable() {

    @Override
    public void run() {
      mCount++;
      mHandler.postDelayed(runnable, 1000);
      mTextView.setText(mCount + "");

    }
  };
  /***
   * Handler分发Message对象的方式
   */

  Handler mHandler2 = new Handler() {
    public void handleMessage(android.os.Message msg) {
      if (msg.what == 1) {

        mTextView.setText("Handler分发Message对象的方式");
      }
    }
  };

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    initView();

  }

  /**
   * 初始化组件对象
   */
  private void initView() {
    mButton = (Button) findViewById(R.id.btn);
    mButton2 = (Button) findViewById(R.id.btn2);
    mButton3 = (Button) findViewById(R.id.btn3);
    mButton4 = (Button) findViewById(R.id.btn4);

    mButton.setOnClickListener(this);
    mButton2.setOnClickListener(this);
    mButton3.setOnClickListener(this);
    mButton4.setOnClickListener(this);

    mTextView = (TextView) findViewById(R.id.tv);

  }

  @Override
  public void onClick(View v) {
    switch (v.getId()) {
    case R.id.btn: {
      // 方法一：继承的方式：自定义Thread继承Thread,开启一个新的线程
      new MyThread().start();
      break;
    }
    case R.id.btn2: {
      // 方法二：实现的方式：implement Runnable
      new Thread(new MyRunnable()).start();
      break;
    }
    // 方法三：handler分发Runnable对象：定时更新UI界面 提交计划任务马上执行
    case R.id.btn3: {

      // Handler分发Runnable对象
      mHandler.post(runnable);
      break;
    }
    // 方法四：Handler分发Message对象 ，定时更新UI界面 提交计划任务马上执行
    case R.id.btn4: {

      // 不推荐这种方式
      // Message msg = new Message();
      // 推荐使用这种获取对象的方式：从消息池中获得可用的Message对象
      Message msg = Message.obtain();
      msg.what = MESSAGE_FLAG;
      mHandler2.sendMessage(msg);
      break;
    }

    default:
      break;
    }

  }
}

package com.chengdong.su.threaddemo.util;

import android.util.Log;

/***
 * 自定义一个MyRunnable线程
 * 
 * @author scd
 * 
 */
public class MyRunnable implements Runnable {

  public MyRunnable() {
    super();
  }

  /** TAG */
  private final String TAG = getClass().getSimpleName();

  @Override
  public void run() {
    for (int i = 0; i < 20; i++) {
      Log.e(TAG, Thread.currentThread().getName() + ",实现的方法" + i);

    }

  }

}

package com.chengdong.su.threaddemo.util;

import android.util.Log;

/***
 * 自定义一个线程
 * 
 * @author scd
 * 
 */
public class MyThread extends Thread {

  public MyThread() {
    super();
  }

  /** TAG */
  private final String TAG = getClass().getSimpleName();

  @Override
  public void run() {
    super.run();
    for (int i = 0; i < 10; i++) {
      Log.e(TAG, Thread.currentThread().getName() + ",继承Thread类：" + i);

    }
  }

}