如何判断sdcard是否安装在Android中？

我正在研究一个需要查看用户存储的图像的Android应用程序。问题是，如果用户通过USB电缆安装了SD卡，我无法读取磁盘上的图像列表。如何判断sdcard是否安装在Android中？

有谁知道一种方法来告诉如果安装了USB，以便我可以弹出一条消息，通知用户它将无法工作？

2009-05-23 KFB

只是为了记录在案，将USB电缆是不要让SD卡容量卸载的唯一途径 - 在存储设置中卸载卡或物理移除卡也会执行此操作。而且，由t-mobile uk提供的8GB SD卡没有正确预格式化，因为它们只是在没有正确格式化的情况下才会一直未安装。我只是说，因为有时只是告诉用户拔掉电缆是不够的。 – 2009-05-23 18:16:08

如果你想访问设备上的图像，最好的方法是使用MediaStore content provider。访问它作为content provider将允许您查询存在的图像，并在适当的情况下将content:// URL映射到设备上的文件路径。

如果您仍需要访问SD卡，相机应用程序包括ImageUtils类，如果SD卡安装进行如下的检查：

static public boolean hasStorage(boolean requireWriteAccess) { 
    //TODO: After fix the bug, add "if (VERBOSE)" before logging errors. 
    String state = Environment.getExternalStorageState(); 
    Log.v(TAG, "storage state is " + state); 

    if (Environment.MEDIA_MOUNTED.equals(state)) { 
     if (requireWriteAccess) { 
      boolean writable = checkFsWritable(); 
      Log.v(TAG, "storage writable is " + writable); 
      return writable; 
     } else { 
      return true; 
     } 
    } else if (!requireWriteAccess && Environment.MEDIA_MOUNTED_READ_ONLY.equals(state)) { 
     return true; 
    } 
    return false; 
}

来源

2009-05-23 22:50:47 jargonjustin

An lo，有人提供了android api的做事方式。投票！ – 2009-05-23 22:52:48

方法`checkFsWritable（）;`？ – GrIsHu 2015-06-29 10:22:10

我很抱歉发布非Android方法来做到这一点，希望有人可以使用Android API提供答案。

您可以列出sdcard根目录下的文件。如果没有，则SD卡要么完全空白（不寻常，但可能）或未安装。如果你尝试在SD卡上创建一个空文件并且失败，这意味着你试图在SD卡的挂载点上创建一个文件，由于权限问题而被拒绝，所以你会知道sdcard不是安装。

是的，我知道这是丑陋....

来源

2009-05-23 20:38:43

public static boolean isSdPresent() { 

return android.os.Environment.getExternalStorageState().equals(android.os.Environment.MEDIA_MOUNTED); 

}

来源

2011-09-27 07:03:35 Harinder

这里是jargonjustin的checkFsWritable缺少的功能后

private static boolean checkFsWritable() { 
     // Create a temporary file to see whether a volume is really writeable. 
     // It's important not to put it in the root directory which may have a 
     // limit on the number of files. 
     String directoryName = Environment.getExternalStorageDirectory().toString() + "/DCIM"; 
     File directory = new File(directoryName); 
     if (!directory.isDirectory()) { 
      if (!directory.mkdirs()) { 
       return false; 
      } 
     } 
     return directory.canWrite(); 
    }

来源

2012-06-20 03:33:05 kakopappa

我用光标从SD卡上检索图像，当没有SD卡插入设备游标为空。事实上，当通过从设备上物理移除卡来卸载SD卡时，就是这种情况。这是我所使用的代码：

Cursor mCursor = this.getContentResolver().query(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, null, null, null, null); 
    if (mCursor == null || !mCursor .moveToFirst()) { 
       /** 
       *mCursor == null: 
       * - query failed; the app don't have access to sdCard; example: no sdCard 
       * 
       *!mCursor.moveToFirst(): 
       *  - there is no media on the device 
       */ 
      } else { 
       // process the images... 
       mCursor.close(); 
    }

来源

2012-07-17 14:40:53 Paul

在jargonjustin的帖子：

文件ImageManager.java

方法hasStorage - >

public static boolean hasStorage(boolean requireWriteAccess) { 
     String state = Environment.getExternalStorageState(); 

     if (Environment.MEDIA_MOUNTED.equals(state)) { 
      if (requireWriteAccess) { 
       boolean writable = checkFsWritable(); 
       return writable; 
      } else { 
       return true; 
      } 
     } else if (!requireWriteAccess 
       && Environment.MEDIA_MOUNTED_READ_ONLY.equals(state)) { 
      return true; 
     } 
     return false; 
    }

方法checkFsWritable - >

private static boolean checkFsWritable() { 
     // Create a temporary file to see whether a volume is really writeable. 
     // It's important not to put it in the root directory which may have a 
     // limit on the number of files. 
     String directoryName = 
       Environment.getExternalStorageDirectory().toString() + "/DCIM"; 
     File directory = new File(directoryName); 
     if (!directory.isDirectory()) { 
      if (!directory.mkdirs()) { 
       return false; 
      } 
     } 
     File f = new File(directoryName, ".probe"); 
     try { 
      // Remove stale file if any 
      if (f.exists()) { 
       f.delete(); 
      } 
      if (!f.createNewFile()) { 
       return false; 
      } 
      f.delete(); 
      return true; 
     } catch (IOException ex) { 
      return false; 
     } 
    }

来源

2013-08-11 15:29:15 KitKat

Cool....Check it out... 
try { 
      File mountFile = new File("/proc/mounts"); 
      usbFoundCount=0; 
      sdcardFoundCount=0; 
      if(mountFile.exists()) 
      { 
       Scanner usbscanner = new Scanner(mountFile); 
       while (usbscanner.hasNext()) { 
        String line = usbscanner.nextLine(); 
        if (line.startsWith("/dev/fuse /storage/usbcard1")) { 
         usbFoundCount=1; 
         Log.i("-----USB--------","USB Connected and properly mounted---/dev/fuse /storage/usbcard1"); 
        } 
      } 
     } 
      if(mountFile.exists()){ 
       Scanner sdcardscanner = new Scanner(mountFile); 
       while (sdcardscanner.hasNext()) { 
        String line = sdcardscanner.nextLine(); 
        if (line.startsWith("/dev/fuse /storage/sdcard1")) { 
         sdcardFoundCount=1; 
         Log.i("-----USB--------","USB Connected and properly mounted---/dev/fuse /storage/sdcard1"); 
        } 
      } 
     } 
      if(usbFoundCount==1) 
      { 
       Toast.makeText(context,"USB Connected and properly mounted", 7000).show(); 
       Log.i("-----USB--------","USB Connected and properly mounted"); 
      } 
      else 
      { 
       Toast.makeText(context,"USB not found!!!!", 7000).show(); 
       Log.i("-----USB--------","USB not found!!!!"); 

      } 
      if(sdcardFoundCount==1) 
      { 
       Toast.makeText(context,"SDCard Connected and properly mounted", 7000).show(); 
       Log.i("-----SDCard--------","SDCard Connected and properly mounted"); 
      } 
      else 
      { 
       Toast.makeText(context,"SDCard not found!!!!", 7000).show(); 
       Log.i("-----SDCard--------","SDCard not found!!!!"); 

      } 
     }catch (Exception e) { 
      e.printStackTrace(); 
     }

来源

2014-06-09 07:15:26 Sam

在你做与外部存储的任何工作，你应该总是调用getExternalStorageState（）检查介质是否可用。媒体可能被挂载到计算机，缺失，只读或其他状态。例如，这里是你可以用它来检查可用性一对夫妇的方法：

/* Checks if external storage is available for read and write */ 
public boolean isExternalStorageWritable() { 
    String state = Environment.getExternalStorageState(); 
    if (Environment.MEDIA_MOUNTED.equals(state)) { 
     return true; 
    } 
    return false; 
} 

/* Checks if external storage is available to at least read */ 
public boolean isExternalStorageReadable() { 
    String state = Environment.getExternalStorageState(); 
    if (Environment.MEDIA_MOUNTED.equals(state) || 
     Environment.MEDIA_MOUNTED_READ_ONLY.equals(state)) { 
     return true; 
    } 
    return false; 
}

来源： http://developer.android.com/guide/topics/data/data-storage.html

来源

2015-01-04 06:39:18

如何判断sdcard是否安装在Android中？

回答

相关问题