Android线程相关编程

原文：https://blog.csdn.net/uyy203/article/details/51938462

定时每秒递增，向handler发送消息以刷新UI

注意：Handler所需导入的相关包为android.os.Handler;

public class MainActivity extends AppCompatActivity {

    private Button button1, button2, button3;
    private TextView Tx1;
    private TextView Tx2;

    public Timer mTimer1;
    public TimerTask mTimerTask1;

    public Timer mTimer2;
    public TimerTask mTimerTask2;

    public int i=0;
    public int j=0;
    public boolean isTimer1Running=false;
    public boolean isTimer2Running=false;

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


        button1 = (Button) findViewById(R.id.button1);
        button2 = (Button) findViewById(R.id.button2);
        button3 = (Button) findViewById(R.id.button3);



        button1.setOnClickListener(new View.OnClickListener() {//启动或终止每秒+1的线程  
            @Override
            public void onClick(View view) {
//                Toast.makeText(getBaseContext(),"Button1",Toast.LENGTH_SHORT).show();  
                manager1();//处理函数1  
            }
        });

        button2.setOnClickListener(new View.OnClickListener() {//启动或终止每秒+5的线程  
            @Override
            public void onClick(View view) {
//                Toast.makeText(getBaseContext(),"button2",Toast.LENGTH_SHORT).show();  
                manager2();//处理函数2  
            }
        });

        button3.setOnClickListener(new View.OnClickListener() {//清零所有数值  
            @Override
            public void onClick(View view) {
                i=0;
                j=0;
                Toast.makeText(getBaseContext(),"清零",Toast.LENGTH_SHORT).show();
            }
        });

    }
    

    public void manager1(){//向handle1发送刷新UI的消息  
        isTimer1Running=!isTimer1Running;

        if(isTimer1Running) {
            mTimer1=new Timer();
            mTimerTask1 = new TimerTask() {
                @Override
                public void run() {
                    i++;

                    Bundle b1 = new Bundle();

                    b1.putString("mes", Integer.toString(i));


                    Message msg = new Message();

                    msg.setData(b1);

                    MainActivity.this.myHandler.sendMessage(msg);
                    
                }
            };

            mTimer1.schedule(mTimerTask1, 1000, 1000);

            Toast.makeText(getBaseContext(),"每秒+1线程启动",Toast.LENGTH_SHORT).show();
        }
        else {
            mTimer1.cancel();
            mTimerTask1.cancel();
            Toast.makeText(getBaseContext(),"每秒+1线程终止",Toast.LENGTH_SHORT).show();
        }
        
    }



    void manager2(){//向handle1发送刷新UI的消息  

        isTimer2Running=!isTimer2Running;

        if(isTimer2Running) {
            mTimer2 = new Timer();
            mTimerTask2 = new TimerTask() {
                @Override
                public void run() {
                    j += 50;

                    Bundle b2 = new Bundle();
                    b2.putString("mes2", Integer.toString(j));

                    Message msg = new Message();
                    msg.setData(b2);

                    MainActivity.this.myHandler.sendMessage(msg);

                }
            };

            mTimer2.schedule(mTimerTask2, 1000, 1000);

            Toast.makeText(getBaseContext(),"每秒+50线程启动",Toast.LENGTH_SHORT).show();
        }
        else{
            mTimer2.cancel();
            mTimerTask2.cancel();

            Toast.makeText(getBaseContext(),"每秒+50线程终止",Toast.LENGTH_SHORT).show();

        }

    }

    

    private final Handler myHandler=new Handler(){
        @Override
        public void handleMessage(Message msg) {//收到消息后刷新UI界面  
            super.handleMessage(msg);

            Tx1=(TextView)findViewById(R.id.TX1);
            Tx2=(TextView) findViewById(R.id.TX2);
            Bundle b=msg.getData();


            String mess=b.getString("mes");
            if(mess!=null&&mess!="")
                Tx1.setText(mess);


            String mess2=b.getString("mes2");
            if(mess2!=null&&mess2!="")
                Tx2.setText(mess2);

        }

    };
    
}  

New Thread

public void onClick(View view) {

    new Thread(new Runnable(){
        @Override
        public void run() {
            i++;
            Bundle b=new Bundle();
            b.putString("mes1",Integer.toString(i));

            Message m=new Message();
            m.setData(b);

            MainActivity.this.myHandler.sendMessage(m);//向myHandler发送消息，以刷新UI
        }
    }).start();

AsyncTask

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<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="com.example.xyz.test.MainActivity">


    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="下载"
        android:id="@+id/download"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true" />
    <android.support.v4.widget.ContentLoadingProgressBar
        android:id="@+id/pb"
        android:layout_below="@id/download"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        style="?android:progressBarStyleHorizontal"
        />

    <ImageView
        android:id="@+id/image"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/pb"
        />

</RelativeLayout>

MainActivity.java

package com.example.xyz.test;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.ProgressBar;
import android.widget.Toast;

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;

import java.io.ByteArrayOutputStream;
import java.io.InputStream;


public class MainActivity extends AppCompatActivity {
    private Button download;
    public ImageView image;
    public ProgressBar pb;


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

        download=(Button)findViewById(R.id.download);
        pb=(ProgressBar) findViewById(R.id.pb);
        image=(ImageView) findViewById(R.id.image);


        download.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                pb.setProgress(0);//进度条清零
                DownLoad dt=new DownLoad();//每次调用都需要NEW一次
                dt.execute("http://avatar.csdn.net/7/0/6/1_uyy203.jpg");//执行异步任务
            }
        });


    }

    class DownLoad extends AsyncTask<String,Integer,Bitmap> {
        Bitmap bm=null;
        byte[] data=new byte[1024];

        @Override
        protected void onPreExecute() {//执行处理前执行的函数
            super.onPreExecute();
            image.setImageBitmap(null);
            pb.setProgress(0);//设置进度为0
        }

        @Override
        protected Bitmap doInBackground(String... params) {//后台处理，主要完成耗时操作
            publishProgress(0);//将会调用onProgressUpdate(Integer... progress)方法，并向其以整型的形式传递处理进度信息

            ByteArrayOutputStream outputStream = new ByteArrayOutputStream();//字节输出流
            InputStream inputStream=null;//字节输入流

            try{
                HttpClient httpClient=new DefaultHttpClient();
                HttpGet httpGet=new HttpGet(params[0]);//获取图片
                HttpResponse httpResponse=httpClient.execute(httpGet);

                if(httpResponse.getStatusLine().getStatusCode()==200){//判断响应是否有效
                    inputStream=httpResponse.getEntity().getContent();

                    long file_length=httpResponse.getEntity().getContentLength();//获取文件总长度
                    int len=0;
                    int total_length=0;//已下载文件的长度
                    int value=0;//进度值

                    while ((len=inputStream.read(data))!=-1){//当输入流有数据即循环获取数据
                        total_length+=len;
                        value=(int)((total_length/(float)file_length)*100);//计算下载进度

                        publishProgress(value);//传递进度值，并刷新UI
                        outputStream.write(data,0,len);//将下载的数据放进输出流中

                        bm=BitmapFactory.decodeByteArray(outputStream.toByteArray(),0,outputStream.toByteArray().length);//将输出流字节转为Bitmap
                    }

                }
            }catch (Exception e){
                e.printStackTrace();
                return null;//返回空值
            }
            finally {
                if(inputStream!=null)
                    try{
                        inputStream.close();//输入流关闭
                    }catch (Exception e){
                        e.printStackTrace();
                    }

            }

            return bm;//图片数据以Bitmap形式返回，以参数形式传入onPostExecute中，作后续处理
        }

        @Override
        protected void onProgressUpdate(Integer... values) {//在调用publishProgress之后被调用，在ui线程执行
            super.onProgressUpdate(values);
            pb.setProgress(values[0]);//更新UI进度条
        }

        @Override
        protected void onPostExecute(Bitmap bitmap) {//在doInBackground执行后自动执行的处理函数，以参数的形式传入doInBackground的返回值
            super.onPostExecute(bitmap);
            if(bitmap!=null){
                Toast.makeText(MainActivity.this,"successed!",Toast.LENGTH_SHORT).show();
                image.setImageBitmap(bitmap);//显示图片
            }
            else {
                Toast.makeText(MainActivity.this,"failed!",Toast.LENGTH_SHORT).show();
            }

        }

        protected void onCancelled () {//在ui线程执行
            pb.setProgress(0);//进度条复位
        }

    }



}

AndroidManifest.xml

在<application></application>外 加入访问互联网权限

<uses-permission  android:name="android.permission.INTERNET"/>