Android线程

android中的线程可以分为两种:MainThread(主线程也叫UI线程)与UI相关的线程都是运行在主线程中与WorkerThread()，原则上是不可以操作UI的

在一个应用程序当中，主线程通常用于接收用户的输入，以及将运算的结果反馈给用户
所以必须将一些可能产生阻塞的操作，必须放在worker Thread中

MainActivity.java

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ProgressBar;
import android.widget.TextView;

public class MainActivity extends Activity {
    private TextView textview;
    private Button button;
    private ProgressBar progressbar;
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        textview = (TextView) findViewById(R.id.textview);
        progressbar = (ProgressBar) findViewById(R.id.progressbar);
        button = (Button) findViewById(R.id.button);
        button.setOnClickListener(new ButtonListener());
    }
    
    class ButtonListener implements OnClickListener{
        public void onClick(View v) {
            Thread thread = new MyThread();
            thread.start();
        }
        
    } 
    //worker Thread
    class MyThread extends Thread{
        public void run(){
            for (int i = 0; i <= 100; i++) {
                try {
                    Thread.sleep(1*100);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                progressbar.setProgress(progressbar.getProgress()+1);//在workerThread中是不可以修改UI的 progressbar列外
            }
            
            /*
            try {
                Thread.sleep(1*1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            //worker Thread是不允许操作IU的，程序运行会出错，（但是ProgressBar比较列外）
            //textview.setText("来自于线程的修改");//workerThreal线程修改了TestView，会出错
            */
        }
    }

}

 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"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <TextView
        android:id="@+id/textview"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" 
        />"
    
    <ProgressBar 
        android:id="@+id/progressbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        style="?android:attr/progressBarStyleHorizontal"
        android:layout_below="@id/textview"
        />"
    
    <Button 
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/progressbar"
        android:text="启动线程"
        />

</RelativeLayout>