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"/>
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