Android学习笔记--使用HttpURLConnection实现网络下载效果，附带进度条显示

下面我就直接上代码了，因为代码中我已经写了非常详细的注释

  1 package com.wuxianedu.httpdemo;
  2 
  3 import android.app.ProgressDialog;
  4 import android.content.Intent;
  5 import android.net.Uri;
  6 import android.os.AsyncTask;
  7 import android.os.Handler;
  8 import android.os.Message;
  9 import android.support.v7.app.AppCompatActivity;
 10 import android.os.Bundle;
 11 import android.view.View;
 12 import android.widget.Button;
 13 import android.widget.Toast;
 14 
 15 import org.apache.http.HttpResponse;
 16 import org.apache.http.client.HttpClient;
 17 import org.apache.http.client.methods.HttpGet;
 18 import org.apache.http.impl.client.DefaultHttpClient;
 19 
 20 import java.io.FileOutputStream;
 21 import java.io.IOException;
 22 import java.io.InputStream;
 23 import java.io.OutputStream;
 24 import java.net.HttpURLConnection;
 25 import java.net.MalformedURLException;
 26 import java.net.URL;
 27 
 28 public class Main2Activity extends AppCompatActivity implements View.OnClickListener{
 29 
 30     private Button button;
 31     private ProgressDialog dialog;
 32     private String path;
 33     private Handler handler = new Handler(){
 34         @Override
 35         public void handleMessage(Message msg) {
 36             dialog.setProgress(msg.what);
 37             super.handleMessage(msg);
 38         }
 39     };
 40 
 41     @Override
 42     protected void onCreate(Bundle savedInstanceState) {
 43         super.onCreate(savedInstanceState);
 44         setContentView(R.layout.activity_main2);
 45         button = (Button) findViewById(R.id.but_id);
 46         button.setOnClickListener(this);
 47         dialog = new ProgressDialog(this);
 48     }
 49 
 50     @Override
 51     public void onClick(View view) {
 52         switch (view.getId()){
 53             case R.id.but_id:
 54                 dialog.setTitle("下载呢");
 55                 dialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
 56                 dialog.show();
 57                 new Thread(new Runnable() {
 58                     @Override
 59                     public void run() {
 60                         getURL();
 61                     }
 62                 }).start();
 63                 break;
 64         }
 65     }
 66 
 67     /**
 68      * 启动应用安装。
 69      */
 70     private void setupApk() {
 71         Intent intent = new Intent(Intent.ACTION_VIEW);
 72         //"file：//"+文件路径。
 73         Uri uri = Uri.parse("file://"+ path);
 74         intent.setDataAndType(uri, "application/vnd.android.package-archive");
 75         startActivity(intent);
 76     }
 77 
 78     private void getURL(){
 79         try {
 80             //构建URL地址
 81             URL url = new URL("http://g.pc6.com/0942666043/apk/4001_ZMJ2016_04_20161028_rnikgd.apk");
 82             try {
 83                 //打开打开打开
 84                 HttpURLConnection hcont = (HttpURLConnection) url.openConnection();
 85                 //建立实际链接
 86                 hcont.connect();
 87                 //获取输入流内容
 88                 InputStream is = hcont.getInputStream();
 89                 //获取文件长度
 90                 int ddddd =hcont.getContentLength();
 91                 //为进度条赋值
 92                 dialog.setMax(ddddd);
 93                 //手机存储地址
 94                 path = getExternalCacheDir().getPath()+"/wuxl.apk";
 95                 //写入文件
 96                 OutputStream os = new FileOutputStream(path);
 97                 int length;
 98                 int lengtsh = 0;
 99                 byte [] bytes = new byte[1024];
100                 while ((length = is.read(bytes))!= -1){
101                     os.write(bytes,0,length);
102                     //获取当前进度值
103                     lengtsh+=length;
104                     //把值传给handler
105                     handler.sendEmptyMessage(lengtsh);
106                 }
107                 //关闭流
108                 is.close();
109                 os.close();
110                 os.flush();
111                 dialog.dismiss();
112                 runOnUiThread(new Runnable() {
113                     @Override
114                     public void run() {
115                         Toast.makeText(Main2Activity.this, "下载成功了", Toast.LENGTH_SHORT).show();
116                     }
117                 });
118             } catch (IOException e) {
119                 e.printStackTrace();
120             }
121 
122         } catch (MalformedURLException e) {
123             e.printStackTrace();
124         }
125     }
126 }

下面是布局文件

 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>

很简单，大家在使用的时候别忘记加网络权限哈