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

 1 import android.app.Activity;

 2 import android.os.Bundle;

 3 import android.view.View;

 4 import android.view.View.OnClickListener;

 5 import android.widget.Button;

 6 import android.widget.ProgressBar;

 7 import android.widget.TextView;

 8 

 9 public class MainActivity extends Activity {

10     private TextView textview;

11     private Button button;

12     private ProgressBar progressbar;

13     protected void onCreate(Bundle savedInstanceState) {

14         super.onCreate(savedInstanceState);

15         setContentView(R.layout.activity_main);

16         textview = (TextView) findViewById(R.id.textview);

17         progressbar = (ProgressBar) findViewById(R.id.progressbar);

18         button = (Button) findViewById(R.id.button);

19         button.setOnClickListener(new ButtonListener());

20     }

21     

22     class ButtonListener implements OnClickListener{

23         public void onClick(View v) {

24             Thread thread = new MyThread();

25             thread.start();

26         }

27         

28     } 

29     //worker Thread

30     class MyThread extends Thread{

31         public void run(){

32             for (int i = 0; i <= 100; i++) {

33                 try {

34                     Thread.sleep(1*100);

35                 } catch (InterruptedException e) {

36                     e.printStackTrace();

37                 }

38                 progressbar.setProgress(progressbar.getProgress()+1);//在workerThread中是不可以修改UI的 progressbar列外

39             }

40             

41             /*

42             try {

43                 Thread.sleep(1*1000);

44             } catch (InterruptedException e) {

45                 e.printStackTrace();

46             }

47             //worker Thread是不允许操作IU的，程序运行会出错，（但是ProgressBar比较列外）

48             //textview.setText("来自于线程的修改");//workerThreal线程修改了TestView，会出错

49             */

50         }

51     }

52 

53 }

 activity_main.xml

 1 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

 2     xmlns:tools="http://schemas.android.com/tools"

 3     android:layout_width="match_parent"

 4     android:layout_height="match_parent"

 5     android:paddingBottom="@dimen/activity_vertical_margin"

 6     android:paddingLeft="@dimen/activity_horizontal_margin"

 7     android:paddingRight="@dimen/activity_horizontal_margin"

 8     android:paddingTop="@dimen/activity_vertical_margin"

 9     tools:context=".MainActivity" >

10 

11     <TextView

12         android:id="@+id/textview"

13         android:layout_width="wrap_content"

14         android:layout_height="wrap_content"

15         android:text="@string/hello_world" 

16         />"

17     

18     <ProgressBar 

19         android:id="@+id/progressbar"

20         android:layout_width="match_parent"

21         android:layout_height="wrap_content"

22         style="?android:attr/progressBarStyleHorizontal"

23         android:layout_below="@id/textview"

24         />"

25     

26     <Button 

27         android:id="@+id/button"

28         android:layout_width="wrap_content"

29         android:layout_height="wrap_content"

30         android:layout_below="@id/progressbar"

31         android:text="启动线程"

32         />

33 

34 </RelativeLayout>