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：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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="com.hanqi.testapp2.PractiseActivity4"
    android:orientation="vertical">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/tvw1"/>
    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/tvw2"/>

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/btt1"
        android:text="随机选择"
        android:onClick="btn_onClick"/>
</LinearLayout>

java类：

package com.hanqi.testapp2;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

public class PractiseActivity4 extends AppCompatActivity {

    TextView tvw1;
    Button btt1;
    TextView tvw2;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_practise4);
        tvw1 = (TextView)findViewById(R.id.tvw1);
        btt1 = (Button)findViewById(R.id.btt1);
        tvw2 = (TextView)findViewById(R.id.tvw2);
    }
    String c1 = "北京";
    String c2 = "上海";
    public void btn_onClick(View v)
    {
        //创建子线程1
       new Thread(){
           @Override
           public void run() {
               for (int i=0;i<20;i++)
               {
                   if(i%2==0)
                   {
                     c1="";
                   }
                   else
                   {
                     c1="北京";
                   }
                   runOnUiThread(new Runnable() {
                       @Override
                       public void run() {
                           tvw1.setText(c1);
                       }
                   });
                   //暂停
                   try {
                       Thread.sleep((int) (Math.random()*1000));
                   }
                  catch (Exception e)
                  {

                  }
               }
               runOnUiThread(new Runnable() {
                   @Override
                   public void run() {
                       Toast.makeText(PractiseActivity4.this, c1 + "循环完成", Toast.LENGTH_SHORT).show();
                   }
               });
           }
       }.start();
        //创建子线程2
        new Thread(){
            @Override
            public void run() {
                for (int i=0;i<20;i++)
                {
                    if(i%2==0)
                    {
                        c2="";
                    }
                    else
                    {
                        c2="上海";
                    }
                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            tvw2.setText(c2);
                        }
                    });
                    //暂停
                    try {
                        Thread.sleep((int) (Math.random()*1000));
                    }
                    catch (Exception e)
                    {

                    }
                }
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        Toast.makeText(PractiseActivity4.this, c2 + "循环完成", Toast.LENGTH_SHORT).show();
                    }
                });
            }
        }.start();
    }

}

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。