Android——多线程编程练习题

随便选择两个城市作为预选旅游目标。实现两个独立的线程分别显示10次城市名，每次显示后休眠一段随机时间(1000ms以内)，哪个先显示完毕，就决定去哪个城市。分别用Runnable接口和Thread类实现。

layout文件：

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 3     xmlns:tools="http://schemas.android.com/tools"
 4     android:layout_width="match_parent"
 5     android:layout_height="match_parent"
 6     android:paddingBottom="@dimen/activity_vertical_margin"
 7     android:paddingLeft="@dimen/activity_horizontal_margin"
 8     android:paddingRight="@dimen/activity_horizontal_margin"
 9     android:paddingTop="@dimen/activity_vertical_margin"
10     tools:context="com.hanqi.testapp2.PractiseActivity4"
11     android:orientation="vertical">
12 
13     <TextView
14         android:layout_width="match_parent"
15         android:layout_height="wrap_content"
16         android:id="@+id/tvw1"/>
17     <TextView
18         android:layout_width="match_parent"
19         android:layout_height="wrap_content"
20         android:id="@+id/tvw2"/>
21 
22     <Button
23         android:layout_width="wrap_content"
24         android:layout_height="wrap_content"
25         android:id="@+id/btt1"
26         android:text="随机选择"
27         android:onClick="btn_onClick"/>
28 </LinearLayout>

java类：

  1 package com.hanqi.testapp2;
  2 
  3 import android.os.Bundle;
  4 import android.support.v7.app.AppCompatActivity;
  5 import android.view.View;
  6 import android.widget.Button;
  7 import android.widget.TextView;
  8 import android.widget.Toast;
  9 
 10 public class PractiseActivity4 extends AppCompatActivity {
 11 
 12     TextView tvw1;
 13     Button btt1;
 14     TextView tvw2;
 15     @Override
 16     protected void onCreate(Bundle savedInstanceState) {
 17         super.onCreate(savedInstanceState);
 18         setContentView(R.layout.activity_practise4);
 19         tvw1 = (TextView)findViewById(R.id.tvw1);
 20         btt1 = (Button)findViewById(R.id.btt1);
 21         tvw2 = (TextView)findViewById(R.id.tvw2);
 22     }
 23     String c1 = "北京";
 24     String c2 = "上海";
 25     public void btn_onClick(View v)
 26     {
 27         //创建子线程1
 28        new Thread(){
 29            @Override
 30            public void run() {
 31                for (int i=0;i<20;i++)
 32                {
 33                    if(i%2==0)
 34                    {
 35                      c1="";
 36                    }
 37                    else
 38                    {
 39                      c1="北京";
 40                    }
 41                    runOnUiThread(new Runnable() {
 42                        @Override
 43                        public void run() {
 44                            tvw1.setText(c1);
 45                        }
 46                    });
 47                    //暂停
 48                    try {
 49                        Thread.sleep((int) (Math.random()*1000));
 50                    }
 51                   catch (Exception e)
 52                   {
 53 
 54                   }
 55                }
 56                runOnUiThread(new Runnable() {
 57                    @Override
 58                    public void run() {
 59                        Toast.makeText(PractiseActivity4.this, c1 + "循环完成", Toast.LENGTH_SHORT).show();
 60                    }
 61                });
 62            }
 63        }.start();
 64         //创建子线程2
 65         new Thread(){
 66             @Override
 67             public void run() {
 68                 for (int i=0;i<20;i++)
 69                 {
 70                     if(i%2==0)
 71                     {
 72                         c2="";
 73                     }
 74                     else
 75                     {
 76                         c2="上海";
 77                     }
 78                     runOnUiThread(new Runnable() {
 79                         @Override
 80                         public void run() {
 81                             tvw2.setText(c2);
 82                         }
 83                     });
 84                     //暂停
 85                     try {
 86                         Thread.sleep((int) (Math.random()*1000));
 87                     }
 88                     catch (Exception e)
 89                     {
 90 
 91                     }
 92                 }
 93                 runOnUiThread(new Runnable() {
 94                     @Override
 95                     public void run() {
 96                         Toast.makeText(PractiseActivity4.this, c2 + "循环完成", Toast.LENGTH_SHORT).show();
 97                     }
 98                 });
 99             }
100         }.start();
101     }
102 
103 }