Android线程相关编程

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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"/>

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