Android 使用 DowanloadManager 实现下载并获取下载进度

本文介绍 Android 使用 DowanloadManager 实现下载并获取下载进度的功能。

package com.koolsee.gallery;
import java.util.ArrayList;
import java.util.List;
import java.util.Timer;
import java.util.TimerTask;
import android.app.Activity;
import android.app.DownloadManager;
import android.app.DownloadManager.Request;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.database.ContentObserver;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.util.Log;
import android.view.KeyEvent;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnKeyListener;
import android.view.View.OnTouchListener;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;
import com.koolsee.gallery.adapter.RecommendAdapter;
import com.koolsee.gallery.model.Recommend;
import com.koolsee.gallery.widget.GalleryFlow;
/**
 * 首页
 *
 * @author zengxiaotao
 */
public class testActivity extends Activity {
  private DownloadManager dowanloadmanager = null;
  private DownloadChangeObserver downloadObserver;
  private long lastDownloadId = 0;
  public static final Uri CONTENT_URI = Uri.parse("content://downloads/my_downloads");
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.test);
    String serviceString = Context.DOWNLOAD_SERVICE;
    dowanloadmanager = (DownloadManager) getSystemService(DOWNLOAD_SERVICE);
    Uri uri = Uri.parse("http://commonsware.com/misc/test.mp4");
    Environment.getExternalStoragePublicDirectory(
    Environment.DIRECTORY_DOWNLOADS).mkdir();
    lastDownloadId = dowanloadmanager.enqueue(new DownloadManager.Request(uri)
                     .setAllowedNetworkTypes(DownloadManager.Request.NETWORK_MOBILE | DownloadManager.Request.NETWORK_WIFI)
                     .setAllowedOverRoaming(false)
                     .setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, "test.mp4"));
    registerReceiver(receiver, new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE));
    downloadObserver = new DownloadChangeObserver(null);
    getContentResolver().registerContentObserver(CONTENT_URI, true, downloadObserver);
  }
  class DownloadChangeObserver extends ContentObserver {
    public DownloadChangeObserver(Handler handler) {
      super(handler);
      // TODO Auto-generated constructor stub
    }
    @Override
    public void onChange(boolean selfChange) {
      queryDownloadStatus();
    }
  }
  private BroadcastReceiver receiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
      //这里可以取得下载的id，这样就可以知道哪个文件下载完成了。适用与多个下载任务的监听
      Log.v("tag", "" + intent.getLongExtra(DownloadManager.EXTRA_DOWNLOAD_ID, 0));
      queryDownloadStatus();
    }
  };
  private void queryDownloadStatus() {
    DownloadManager.Query query = new DownloadManager.Query();
    query.setFilterById(lastDownloadId);
    Cursor c = dowanloadmanager.query(query);
    if(c != null && c.moveToFirst()) {
      int status = c.getInt(c.getColumnIndex(DownloadManager.COLUMN_STATUS));
      int reasonIdx = c.getColumnIndex(DownloadManager.COLUMN_REASON);
      int titleIdx = c.getColumnIndex(DownloadManager.COLUMN_TITLE);
      int fileSizeIdx = c.getColumnIndex(DownloadManager.COLUMN_TOTAL_SIZE_BYTES);
      int bytesDLIdx = c.getColumnIndex(DownloadManager.COLUMN_BYTES_DOWNLOADED_SO_FAR);
      String title = c.getString(titleIdx);
      int fileSize = c.getInt(fileSizeIdx);
      int bytesDL = c.getInt(bytesDLIdx);
      // Translate the pause reason to friendly text.
      int reason = c.getInt(reasonIdx);
      StringBuilder sb = new StringBuilder();
      sb.append(title).append("\n");
      sb.append("Downloaded ").append(bytesDL).append(" / " ).append(fileSize);
      // Display the status
      Log.d("tag", sb.toString());
      switch(status) {
      case DownloadManager.STATUS_PAUSED:
        Log.v("tag", "STATUS_PAUSED");
      case DownloadManager.STATUS_PENDING:
        Log.v("tag", "STATUS_PENDING");
      case DownloadManager.STATUS_RUNNING:
        // 正在下载，不做任何事情
        Log.v("tag", "STATUS_RUNNING");
        break;
      case DownloadManager.STATUS_SUCCESSFUL:
        // 完成
        Log.v("tag", "下载完成");
        // dowanloadmanager.remove(lastDownloadId);
        break;
      case DownloadManager.STATUS_FAILED:
        // 清除已下载的内容，重新下载
        Log.v("tag", "STATUS_FAILED");
        dowanloadmanager.remove(lastDownloadId);
        break;
      }
    }
  }
  @Override
  protected void onDestroy() {
    // TODO Auto-generated method stub
    super.onDestroy();
    unregisterReceiver(receiver);
    getContentResolver().unregisterContentObserver(downloadObserver);
  }
}

（完）