Android开发之自带下载器DownloadManager的使用示例代码

public class DownloadUtils {  //下载器  private DownloadManager downloadManager;  //上下文  private Context mContext;  //下载的ID  private long downloadId;  public DownloadUtils(Context context){    this.mContext = context;  }  //下载apk  public void downloadAPK(String url, String name) {    //创建下载任务    Request request = new Request(Uri.parse(url));    //移动网络情况下是否允许漫游    request.setAllowedOverRoaming(false);    //在通知栏中显示，默认就是显示的    request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE);    request.setTitle("新版本Apk");    request.setDescription("Apk Downloading");    request.setVisibleInDownloadsUi(true);    //设置下载的路径    request.setDestinationInExternalPublicDir(Environment.getExternalStorageDirectory().getAbsolutePath() , name);    //获取DownloadManager    downloadManager = (DownloadManager) mContext.getSystemService(Context.DOWNLOAD_SERVICE);    //将下载请求加入下载队列，加入下载队列后会给该任务返回一个long型的id，通过该id可以取消任务，重启任务、获取下载的文件等等    downloadId = downloadManager.enqueue(request);    //注册广播接收者，监听下载状态    mContext.registerReceiver(receiver,        new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE));  }  //广播监听下载的各个状态  private BroadcastReceiver receiver = new BroadcastReceiver() {    @Override    public void onReceive(Context context, Intent intent) {      checkStatus();    }  };  //检查下载状态  private void checkStatus() {    Query query = new Query();    //通过下载的id查找    query.setFilterById(downloadId);    Cursor c = downloadManager.query(query);    if (c.moveToFirst()) {      int status = c.getInt(c.getColumnIndex(DownloadManager.COLUMN_STATUS));      switch (status) {         //下载暂停        case DownloadManager.STATUS_PAUSED:          break;        //下载延迟        case DownloadManager.STATUS_PENDING:          break;        //正在下载        case DownloadManager.STATUS_RUNNING:          break;        //下载完成        case DownloadManager.STATUS_SUCCESSFUL:          //下载完成安装APK          installAPK();          break;        //下载失败        case DownloadManager.STATUS_FAILED:          Toast.makeText(mContext, "下载失败", Toast.LENGTH_SHORT).show();          break;      }    }  }  //下载到本地后执行安装  private void installAPK() {    //获取下载文件的Uri    Uri downloadFileUri = downloadManager.getUriForDownloadedFile(downloadId);    if (downloadFileUri != null) {      Intent intent= new Intent(Intent.ACTION_VIEW);      intent.setDataAndType(downloadFileUri, "application/vnd.android.package-archive");      intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);      mContext.startActivity(intent);    }  }}

public class MainActivity extends AppCompatActivity {  private DownloadUtils downloadUtils;  @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    downloadUtils =  new DownloadUtils(MainActivity.this);     downloadUtils.downloadAPK("http://192.168.1.104:8080/XXX.apk", "XXX.apk");  }}

<!--在SDCard中创建与删除文件权限 --><uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/><!-- 往SDCard写入数据权限 --><uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/><!-- 从SDCard读取数据权限 --><uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/><!-- 访问网络权限 --><uses-permission android:name="android.permission.INTERNET"/>