android 打开文件

private void openFile(File f) 
    {
      Intent intent = new Intent();
      intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
      intent.setAction(android.content.Intent.ACTION_VIEW);
      
      /* 调用getMIMEType()来取得MimeType */
      String type = getMIMEType(f);
      /* 设置intent的file与MimeType */
      intent.setDataAndType(Uri.fromFile(f),type);
      startActivity(intent); 
    }

    /* 判断文件MimeType的method */
    private String getMIMEType(File f) 
    { 
      String type="";
      String fName=f.getName();
      /* 取得扩展名 */
      String end=fName.substring(fName.lastIndexOf(".")
      +1,fName.length()).toLowerCase(); 
      
      /* 依扩展名的类型决定MimeType */
      if(end.equals("m4a")||end.equals("mp3")||end.equals("mid")||
      end.equals("xmf")||end.equals("ogg")||end.equals("wav"))
      {
        type = "audio"; 
      }
      else if(end.equals("3gp")||end.equals("mp4"))
      {
        type = "video";
      }
      else if(end.equals("jpg")||end.equals("gif")||end.equals("png")||
      end.equals("jpeg")||end.equals("bmp"))
      {
        type = "image";
      }
      else if(end.equals("apk")) 
      { 
        /* android.permission.INSTALL_PACKAGES */ 
        type = "application/vnd.android.package-archive"; 
      } 
      else
      {
        type="*";
      }
      /*如果无法直接打开，就跳出软件列表给用户选择 */
      if(end.equals("apk")) 
      { 
      } 
      else 
      { 
        type += "/*";  
      } 
      return type;  
    }