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 Android教程網 >> Android技術 >> 關於Android編程 >> Android編程開發實現帶進度條和百分比的多線程下載

Android編程開發實現帶進度條和百分比的多線程下載

編輯:關於Android編程

本文實例講述了Android編程開發實現帶進度條和百分比的多線程下載。分享給大家供大家參考,具體如下:

繼上一篇《java多線程下載實例詳解》之後,可以將它移植到我們的安卓中來,下面是具體實現源碼:

DownActivity.java:

package com.example.downloads;
import java.io.File;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import com.example.downloads.utils.DownLoadThread;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.os.Message;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.text.TextUtils;
import android.view.Menu;
import android.view.View;
import android.widget.EditText;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;
public class DownActivity extends Activity {
  // 聲明控件
  // 路徑與線程數量
  public EditText et_url, et_num;
  // 進度條
  public static ProgressBar pb_thread;
  // 顯示進度的操作
  public TextView tv_pb;
  // 線程的數量
  public static int threadNum = 3;
  // 每個線程負責下載的大小
  public int blockSize;
  public static int threadCount;// 數量
  // 訪問的path
  public String path;
  public static boolean flag = true;
  // 記錄進度條的值
  public static int pb_count = 0;
  public static Handler handler;
  public static final int TEXTVALUE = 1;
  public static int pb_num = 0;
  public static int size = 0;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_down);
    et_url = (EditText) findViewById(R.id.et_path);
    et_num = (EditText) findViewById(R.id.et_threadNum);
    pb_thread = (ProgressBar) findViewById(R.id.pb_down);
    tv_pb = (TextView) findViewById(R.id.tv_pb);
    handler = new Handler() {
      @SuppressLint("HandlerLeak")
      @Override
      public void handleMessage(Message msg) {
        super.handleMessage(msg);
        switch (msg.what) {
        case TEXTVALUE:
          System.out.println("-------" + DownActivity.pb_count
              + "//////" + DownActivity.size);
          // 改變TEXTView
          pb_num = (DownActivity.pb_count * 100) / DownActivity.size;
          tv_pb.setText("當前進度是+" + pb_num + "%");
          break;
        default:
          break;
        }
      }
    };
  }
  @Override
  public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
  }
  public void downLoad(View v) {
    DownActivity.flag = true;
    DownActivity.pb_count = 0;
    path = et_url.getText().toString();
    String threadNum_et = et_num.getText().toString();
    if (TextUtils.isEmpty(path) || TextUtils.isEmpty(threadNum_et)) {
      Toast.makeText(this, "不能為空", Toast.LENGTH_LONG).show();
      return;
    }
    Toast.makeText(this, "url:" + path + "--" + threadNum_et,
        Toast.LENGTH_LONG).show();
    // 轉換成數字
    threadNum = Integer.valueOf(threadNum_et);
    new Thread(new Runnable() {
      @Override
      public void run() {
        try {
          // 創建出URL對象
          URL url = new URL(path);
          // 創建出 HttpURLConnection對象
          HttpURLConnection httpURLConnection = (HttpURLConnection) url
              .openConnection();
          // 設置 發請求發送的方式
          httpURLConnection.setRequestMethod("GET");
          // 設置請求是否超時時間
          httpURLConnection.setConnectTimeout(5000);
          // 設置
          httpURLConnection
              .setRequestProperty("User-Agent",
                  " Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.2; Trident/6.0)");
          // 是否響應成功
          if (httpURLConnection.getResponseCode() == 200) {
            // 獲取文件的大小
            size = httpURLConnection.getContentLength();
            System.out.println("文件的大小" + size);
            // 設置進度條的最大值
            pb_thread.setMax(size);
            // 創建文件 //保存到SD卡上
            // 首先判斷是否擁有sdcard
            if (Environment.getExternalStorageState().equals(
                Environment.MEDIA_MOUNTED)) {
              // 獲取sdCard文件目錄對象
              File sdFile = Environment
                  .getExternalStorageDirectory();
              // 創建文件對象
              File file = new File(sdFile, "youdao.exe");
              RandomAccessFile accessFile = new RandomAccessFile(
                  file, "rwd");
              // 設置文件的大小
              accessFile.setLength(size);
              // 每個線程下載的大小
              blockSize = size / threadNum;
              // 開三個線程 操作此文件
              for (int i = 1; i <= threadNum; i++) {
                // 1 2 3
                // 計算出每個線程開始的位置
                int startSize = (i - 1) * blockSize;
                // 結束位置
                int endSize = (i) * blockSize;
                // 當線程是最後一個線程的時候
                if (i == threadNum) {
                  // 判斷文件的大小是否大於計算出來的結束位置
                  if (size > endSize) {
                    // 結束位置 等於 文件的大小
                    endSize = size;
                  }
                }
                // 為每個線程創建一個隨機的讀取
                RandomAccessFile threadAccessFile = new RandomAccessFile(
                    file, "rwd");
                new Thread(new DownLoadThread(i,
                    threadAccessFile, startSize, endSize,
                    path)).start();
              }
            }
          }
        } catch (MalformedURLException e) {
          e.printStackTrace();
        } catch (IOException e) {
          e.printStackTrace();
        }
      }
    }).start();
  }
  /**
   * 暫停操作
   *
   * @param v
   */
  public void downPause(View v) {
    Toast.makeText(this, "暫停", Toast.LENGTH_LONG).show();
    this.flag = false;
  }
}

DownLoadThread.java:

package com.example.downloads.utils;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.RandomAccessFile;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import com.example.downloads.DownActivity;
import android.os.Environment;
public class DownLoadThread implements Runnable {
  public RandomAccessFile accessFile; // 每個線程 都擁有一個accessFile的文件對象 線程1 線程2 線程3
  // 線程下載文件的起始位置
  public int startSize;
  public int endSize;
  // 文件下載的path路徑
  public String path;
  public int threadId; // 線程的標識
  public DownLoadThread(int threadId, RandomAccessFile accessFile,
      int startSize, int endSize, String path) {
    this.threadId = threadId;
    this.accessFile = accessFile;
    this.startSize = startSize;
    this.endSize = endSize;
    this.path = path;
  }
  @Override
  public void run() {
    // 執行run方法
    try {
      // 創建文件到SD卡上去
      // 首先判斷是否擁有sdcard
      if (Environment.getExternalStorageState().equals(
          Environment.MEDIA_MOUNTED)) {
        // 獲取sdCard文件目錄對象
        File sdFile = Environment.getExternalStorageDirectory();
        File threadFile = new File(sdFile, threadId + ".txt");
        if (threadFile.exists()) {
          // 讀取該文件的內容
          // 創建文件的輸入流對象
          FileInputStream fis = new FileInputStream(threadFile);
          // 采用工具類讀取
          byte data[] = StreamTools.isToData(fis);
          // 轉化成字符串
          String threadLen = new String(data);
          if ((threadLen != null) && (!"".equals(threadLen))) {
            startSize = Integer.valueOf(threadLen);
            // 解決 416bug的錯誤
            if (startSize > endSize) {
              startSize = endSize - 1;
            }
          }
        }
        // 創建文件
        // 創建URL對象
        URL url = new URL(path);
        // 創建HttpURLConnection對象
        HttpURLConnection httpURLConnection = (HttpURLConnection) url
            .openConnection();
        // 設置請求的頭
        httpURLConnection.setRequestMethod("GET");
        // 設置請求是否超時時間
        httpURLConnection.setConnectTimeout(5000);
        // 設置
        httpURLConnection
            .setRequestProperty("User-Agent",
                " Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.2; Trident/6.0)");
        // 關鍵的設置
        httpURLConnection.setRequestProperty("Range", "bytes="
            + startSize + "-" + endSize);
        // 輸出當前線程
        System.out.println("當前線程" + threadId + " 下載開始位置:" + startSize
            + " 下載結束位置:" + endSize);
        // 響應成功
        // 設置隨機讀取文件的 開始位置
        accessFile.seek(startSize);
        // 獲取相應流對象
        InputStream is = httpURLConnection.getInputStream();
        // 創建輸出流對象
        byte buffer[] = new byte[1024];
        int len = 0;
        int threadTotal = 0;// 每個線程下載後保存記錄 /
        while ((len = is.read(buffer)) != -1) {
          accessFile.write(buffer, 0, len);
          threadTotal += len;// 記錄你寫入的長度 //xml文件
          //改變進度條:
          setProgressBar(len);
          // 通過文件記錄文件下載的長度
          FileOutputStream fos = new FileOutputStream(threadFile);
          fos.write((threadTotal + "").getBytes());
          fos.flush();
          fos.close();
          //發送handler消息
          DownActivity.handler.sendEmptyMessage(DownActivity.TEXTVALUE);
          if(!DownActivity.flag){
            return;
          }
        }
        accessFile.close();
        is.close();
        System.out.println(threadId + "線程執行完畢");
        // 線程操作
        synchronized (DownActivity.class) {
          DownActivity.threadCount++;
          if (DownActivity.threadCount >= DownActivity.threadNum) {
            for (int i = 1; i <= DownActivity.threadNum; i++) {
              // 獲取sdCard上的文件
              File deleteFile = new File(sdFile, i + ".txt");
              if (deleteFile.exists()) {
                // 文件刪除
                deleteFile.delete();
              }
            }
          }
        }
      }
    } catch (MalformedURLException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    } catch (IOException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
  }
  public synchronized void setProgressBar(int len){
    DownActivity.pb_count+=len;
    DownActivity.pb_thread.setProgress(DownActivity.pb_count);
  }
}

StreamTools.java:

package com.example.downloads.utils;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
public class StreamTools {
  public static byte[] isToData(InputStream is) throws IOException{
    // 字節輸出流
    ByteArrayOutputStream bops = new ByteArrayOutputStream();
    // 讀取數據的緩存區
    byte buffer[] = new byte[1024];
    // 讀取長度的記錄
    int len = 0;
    // 循環讀取
    while ((len = is.read(buffer)) != -1) {
      bops.write(buffer, 0, len);
    }
    // 把讀取的內容轉換成byte數組
    byte data[] = bops.toByteArray();
    bops.flush();
    bops.close();
    is.close();
    return data;
  }
}

strings.xml:

<?xml version="1.0" encoding="utf-8"?>
<resources>
  <string name="app_name">downloads</string>
  <string name="action_settings">Settings</string>
  <string name="tv_down">文件下載的地址</string>
  <string name="tv_threadNum">線程數量</string>
  <string name="tv_num">0%</string>
  <string name="btn_text">下載</string>
  <string name="btn_pause">暫停</string>
  <string name="et_path">http://172.22.64.8:8080/doudou/youdao.exe</string>
  <string name="et_threadNum">3</string>
</resources>

布局文件:

<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=".DownActivity" >
  <TextView
    android:id="@+id/textView1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_alignParentTop="true"
    android:text="@string/tv_down" />
  <EditText
    android:id="@+id/et_path"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_alignParentRight="true"
    android:layout_below="@+id/textView1"
    android:ems="10"
    android:inputType="none"
    android:text="@string/et_path" >
    <requestFocus />
  </EditText>
  <TextView
    android:id="@+id/textView2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_below="@+id/et_path"
    android:text="@string/tv_threadNum" />
  <EditText
    android:id="@+id/et_threadNum"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignLeft="@+id/textView2"
    android:layout_alignRight="@+id/et_path"
    android:layout_below="@+id/textView2"
    android:ems="10"
    android:inputType="number"
    android:text="@string/et_threadNum" />
  <ProgressBar
    android:id="@+id/pb_down"
    
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignLeft="@+id/et_threadNum"
    android:layout_alignRight="@+id/et_threadNum"
    android:layout_below="@+id/et_threadNum"
    android:layout_marginTop="14dp" />
  <TextView
    android:id="@+id/tv_pb"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignRight="@+id/textView1"
    android:layout_below="@+id/pb_down"
    android:layout_marginTop="24dp"
    android:text="@string/tv_num" />
  <Button
    android:id="@+id/btn_down"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignLeft="@+id/pb_down"
    android:layout_below="@+id/tv_pb"
    android:layout_marginTop="32dp"
    android:onClick="downLoad"
    android:text="@string/btn_text" />
  <Button
    android:id="@+id/button1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignLeft="@+id/btn_down"
    android:layout_below="@+id/btn_down"
    android:layout_marginTop="16dp"
    android:onClick="downPause"
    android:text="@string/btn_pause" />
</RelativeLayout>

效果如下:

最後要注意的是別忘了在項目清單文件中加入權限:

<!-- SDCard權限 -->
<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<!-- 訪問網絡的權限 -->
<uses-permission android:name="android.permission.INTERNET" />

希望本文所述對大家Android程序設計有所幫助。

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