1 http://m.blog.csdn.net/article/details?id=52927536
  2 
  3 
  4 package com.wuxianedu.httpdemo;
  5 
  6 import android.app.ProgressDialog;
  7 import android.content.Intent;
  8 import android.net.Uri;
  9 import android.os.AsyncTask;
 10 import android.support.v7.app.AppCompatActivity;
 11 import android.os.Bundle;
 12 import android.view.View;
 13 import android.widget.Button;
 14 import android.widget.Toast;
 15 
 16 import org.apache.http.HttpResponse;
 17 import org.apache.http.client.HttpClient;
 18 import org.apache.http.client.methods.HttpGet;
 19 import org.apache.http.impl.client.DefaultHttpClient;
 20 
 21 import java.io.FileOutputStream;
 22 import java.io.IOException;
 23 import java.io.InputStream;
 24 import java.io.OutputStream;
 25 
 26 public class Main2Activity extends AppCompatActivity implements View.OnClickListener{
 27 
 28     private Button button;
 29     private ProgressDialog dialog;
 30     private String path;
 31     private final int TA_C = 0;//成功
 32     private final int TA_S = -1;//失败
 33 
 34     @Override
 35     protected void onCreate(Bundle savedInstanceState) {
 36         super.onCreate(savedInstanceState);
 37         setContentView(R.layout.activity_main2);
 38         button = (Button) findViewById(R.id.but_id);
 39         button.setOnClickListener(this);
 40     }
 41 
 42     @Override
 43     public void onClick(View view) {
 44         switch (view.getId()){
 45             case R.id.but_id:
 46                 new Myhui().execute("http://g.pc6.com/0942666043/apk/4001_ZMJ2016_04_20161028_rnikgd.apk");
 47                 break;
 48         }
 49     }
 50 
 51     class Myhui extends AsyncTask<String,Integer,Integer>{
 52         //异步任务执行前的操作
 53         @Override
 54         protected void onPreExecute() {
 55             dialog = new ProgressDialog(Main2Activity.this);
 56             dialog.setTitle("正在下载");
 57             dialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
 58             dialog.show();
 59             super.onPreExecute();
 60         }
 61         //更新进度的方法 调用使用publishProgress
 62         @Override
 63         protected void onProgressUpdate(Integer... values) {
 64             dialog.setProgress(values[0]);
 65             super.onProgressUpdate(values);
 66         }
 67         //任务执行中方法
 68         @Override
 69         protected Integer doInBackground(String... strings) {
 70             //构建URL地址链接
 71             HttpGet httpGet = new HttpGet(strings[0]);
 72             //建立客户端链接
 73             HttpClient httpClient = new DefaultHttpClient();
 74             try {
 75                 //获取服务器响应的数据
 76                 HttpResponse response = httpClient.execute(httpGet);
 77                 //获取状态码
 78                 int code = response.getStatusLine().getStatusCode();
 79                 switch (code){
 80                     case 201:
 81                     case 200:
 82                         //获取文件最大值
 83                         int zuimax = (int) response.getEntity().getContentLength();
 84                         //给进度条赋最大值
 85                         dialog.setMax(zuimax);
 86                         //获取文件的输入流
 87                         InputStream is = response.getEntity().getContent();
 88                         //获取储存地址
 89                         path = getExternalCacheDir().getParent()+"/tanchishe.apk";
 90                         //获取文件的输出流,传入写入文件的地址
 91                         OutputStream os = new FileOutputStream(path);
 92                         int length;
 93                         //进度条进度
 94                         int jindu = 0;
 95                         byte[] bytes = new byte[1024];
 96                         while ((length = is.read(bytes))!= -1){
 97                             os.write(bytes,0,length);
 98                             jindu+=length;
 99                             //启动赋值方法
100                             publishProgress(jindu);
101                         }
102                         //关闭流
103                         is.close();
104                         os.flush();
105                         os.close();
106                         return TA_C;
107                     case 401:
108                         break;
109                 }
110             } catch (IOException e) {
111                 e.printStackTrace();
112             }
113             return TA_S;
114         }
115 
116         //任务结束方法
117         @Override
118         protected void onPostExecute(Integer integer) {
119             //关闭进度条
120             dialog.dismiss();
121             switch (integer){
122                 case TA_C:
123                     Toast.makeText(Main2Activity.this, "下载成功了", Toast.LENGTH_SHORT).show();
124                     setupApk();
125                     break;
126                 case TA_S:
127                     Toast.makeText(Main2Activity.this, "下载失败了", Toast.LENGTH_SHORT).show();
128                     break;
129             }
130             super.onPostExecute(integer);
131         }
132     }
133 
134     /**
135      * 启动应用安装。
136      */
137     private void setupApk() {
138         Intent intent = new Intent(Intent.ACTION_VIEW);
139         //"file：//"+文件路径。
140         Uri uri = Uri.parse("file://"+ path);
141         intent.setDataAndType(uri, "application/vnd.android.package-archive");
142         startActivity(intent);
143     }
144 }

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <RelativeLayout 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 
 7     tools:context="com.wuxianedu.httpdemo.Main2Activity">
 8 
 9     <Button android:id="@+id/but_id" android:text="下载APP"
10         android:layout_width="wrap_content"
11         android:layout_height="wrap_content" />
12 </RelativeLayout>