package com.hebaijun.downloadtest;

import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;

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.content.SharedPreferences;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.util.Log;
import android.webkit.MimeTypeMap;

public class DownloadTestActivity extends Activity {
	private DownloadManager downloadManager;
	private SharedPreferences prefs;
	private static final String DL_ID = "downloadId";
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        downloadManager = (DownloadManager)getSystemService(DOWNLOAD_SERVICE);
        prefs = PreferenceManager.getDefaultSharedPreferences(this); 
    }
	@Override
	protected void onPause() {
		// TODO Auto-generated method stub
		super.onPause();
		unregisterReceiver(receiver);
	}
	@Override
	protected void onResume() {
		// TODO Auto-generated method stub
		super.onResume();
		if(!prefs.contains(DL_ID)) { 
			String url = "http://10.0.2.2/android/film/G3.mp4";
	        //開始下載 
	        Uri resource = Uri.parse(encodeGB(url)); 
	        DownloadManager.Request request = new DownloadManager.Request(resource); 
	        request.setAllowedNetworkTypes(Request.NETWORK_MOBILE | Request.NETWORK_WIFI); 
	        request.setAllowedOverRoaming(false); 
	        //設定檔案型別
	        MimeTypeMap mimeTypeMap = MimeTypeMap.getSingleton();
	        String mimeString = mimeTypeMap.getMimeTypeFromExtension(MimeTypeMap.getFileExtensionFromUrl(url));
	        request.setMimeType(mimeString);
	        //在通知欄中顯示 
	        request.setShowRunningNotification(true);
	        request.setVisibleInDownloadsUi(true);
	        //sdcard的目錄下的download資料夾
	        request.setDestinationInExternalPublicDir("/download/", "G3.mp4");
	        request.setTitle("移動G3廣告"); 
	        long id = downloadManager.enqueue(request); 
	        //儲存id 
	        prefs.edit().putLong(DL_ID, id).commit(); 
	    } else { 
	        //下載已經開始，檢查狀態
	        queryDownloadStatus(); 
	    } 

	    registerReceiver(receiver, new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE));
	}
	
	/**
	 * 如果伺服器不支援中文路徑的情況下需要轉換url的編碼。
	 * @param string
	 * @return
	 */
	public String encodeGB(String string)
	{
		//轉換中文編碼
		String split[] = string.split("/");
		for (int i = 1; i < split.length; i++) {
			try {
				split[i] = URLEncoder.encode(split[i], "GB2312");
			} catch (UnsupportedEncodingException e) {
				e.printStackTrace();
			}
			split[0] = split[0]+"/"+split[i];
		}
		split[0] = split[0].replaceAll("\\+", "%20");//處理空格
		return split[0];
	}
	
	private BroadcastReceiver receiver = new BroadcastReceiver() { 
	    @Override 
	    public void onReceive(Context context, Intent intent) { 
	    	//這裡可以取得下載的id，這樣就可以知道哪個檔案下載完成了。適用與多個下載任務的監聽
	    	Log.v("intent", ""+intent.getLongExtra(DownloadManager.EXTRA_DOWNLOAD_ID, 0));
	        queryDownloadStatus(); 
	    } 
	}; 
	
	private void queryDownloadStatus() { 
	    DownloadManager.Query query = new DownloadManager.Query(); 
	    query.setFilterById(prefs.getLong(DL_ID, 0)); 
	    Cursor c = downloadManager.query(query); 
	    if(c.moveToFirst()) { 
	        int status = c.getInt(c.getColumnIndex(DownloadManager.COLUMN_STATUS)); 
	        switch(status) { 
	        case DownloadManager.STATUS_PAUSED: 
	        	Log.v("down", "STATUS_PAUSED");
	        case DownloadManager.STATUS_PENDING: 
	        	Log.v("down", "STATUS_PENDING");
	        case DownloadManager.STATUS_RUNNING: 
	            //正在下載，不做任何事情
	        	Log.v("down", "STATUS_RUNNING");
	            break; 
	        case DownloadManager.STATUS_SUCCESSFUL: 
	            //完成
	            Log.v("down", "下載完成");
	            break; 
	        case DownloadManager.STATUS_FAILED: 
	            //清除已下載的內容，重新下載
	        	Log.v("down", "STATUS_FAILED");
	        	downloadManager.remove(prefs.getLong(DL_ID, 0)); 
	            prefs.edit().clear().commit(); 
	            break; 
	        } 
	    }
	}
}
 

最後需要的許可權是： <uses-permission android:name="android.permission.INTERNET"/> <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/> 如果需要隱藏下載工具的提示和顯示，修改程式碼： request.setShowRunningNotification(false); request.setVisibleInDownloadsUi(false); 加入下面的許可權： <uses-permission android:name="android.permission.DOWNLOAD_WITHOUT_NOTIFICATION"/>