Android SD卡写入，权限被拒绝

发布于 2024-10-08 17:57:32 字数 1184 浏览 7 评论 0原文

我正在尝试使用以下代码将文件写入SDCard（权限android.permission.WRITE_EXTERNAL_STORAGE已在manifest.xml中设置）。执行 nmea_file.createNewFile(); 时，它会抛出 Permission Denied 异常。

任何猜测为什么会发生这种情况？

if(!Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) 
  {
     Log.d(TAG, "Sdcard was not mounted !!" ); 
  }
else
  {
    File nmea_file; 
    File root = Environment.getExternalStorageDirectory();
    FileWriter nmea_writer = null;
    try {
        nmea_file = new File(root,"NMEA.txt");
        if(!nmea_file.exists()) {
                Log.w(TAG, "File Doesn't Exists!");
                nmea_file.createNewFile();
            }
        nmea_writer = new FileWriter(nmea_file);
        nmea_writer.append(nmea);
        nmea_writer.flush();
    }
    catch (IOException e) 
    {
        Log.w(TAG, "Unable to write", e);
    } 
    finally 
    {
        if (nmea_writer != null) 
        {
            try 
            {
                nmea_writer.close();
            } 
            catch (IOException e) 
            {
                Log.w(TAG, "Exception closing file", e);
            }
        }
    }
  }

原文

I am trying to write a file to SDCard with below Code (permission android.permission.WRITE_EXTERNAL_STORAGE already set in manifest.xml).
Upon execution of nmea_file.createNewFile(); it throws exception with Permission Denied.

Any guesses why would this be happening?

if(!Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) 
  {
     Log.d(TAG, "Sdcard was not mounted !!" ); 
  }
else
  {
    File nmea_file; 
    File root = Environment.getExternalStorageDirectory();
    FileWriter nmea_writer = null;
    try {
        nmea_file = new File(root,"NMEA.txt");
        if(!nmea_file.exists()) {
                Log.w(TAG, "File Doesn't Exists!");
                nmea_file.createNewFile();
            }
        nmea_writer = new FileWriter(nmea_file);
        nmea_writer.append(nmea);
        nmea_writer.flush();
    }
    catch (IOException e) 
    {
        Log.w(TAG, "Unable to write", e);
    } 
    finally 
    {
        if (nmea_writer != null) 
        {
            try 
            {
                nmea_writer.close();
            } 
            catch (IOException e) 
            {
                Log.w(TAG, "Exception closing file", e);
            }
        }
    }
  }

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莫多说 2024-10-15 17:57:32

添加到manifest.xml

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

Add to manifest.xml

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

回复收藏 0 原文

睫毛上残留的泪 2024-10-15 17:57:32

如果 SD 卡被阻止执行某些操作，则可能会发生这种情况，例如：

准备从插槽中卸下 SD 卡
作为外部 USB 驱动器连接到 PC 的设备

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残龙傲雪 2024-10-15 17:57:32

您可能需要检查您是否有权访问 SDCARD。以下是在代码中执行此操作的方法：

if(!Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState())){
    Toast.makeText(this, "External SD card not mounted", Toast.LENGTH_LONG).show();
}

You might want to check that you have access to SDCARD. Here is how you can do it in code:

if(!Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState())){
    Toast.makeText(this, "External SD card not mounted", Toast.LENGTH_LONG).show();
}

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怪我太投入 2024-10-15 17:57:32

请注意，uses-sdk 语句会影响您写入 SD 卡的能力（！）。

我的 AndroidManifest.xml 具有以下内容：

<uses-sdk minSdkVersion="8"/>

即使我没有声明 android.permission.WRITE_EXTERNAL_STORAGE，我也可以毫无问题地写入 SD 卡。

当我将 use-sdk 语句更改为：

<uses-sdk android:targetSdkVersion="9" minSdkVersion="8" />

我的所有 SD 卡写入均因权限被拒绝而失败！诚然应该声明 android.permission.WRITE_EXTERNAL_STORAGE ，但为什么一个 use-sdk 语句可以工作，而另一个却不能呢？

Be aware that your uses-sdk statement can effect you ability to write to the SD card(!).

My AndroidManifest.xml had the following:

<uses-sdk minSdkVersion="8"/>

And I could write to the SD card without any problems even though I had not declared android.permission.WRITE_EXTERNAL_STORAGE.

When I changed my uses-sdk statement to:

<uses-sdk android:targetSdkVersion="9" minSdkVersion="8" />

All my SD card writes failed with a permission denied! Granted that android.permission.WRITE_EXTERNAL_STORAGE should have been declared, but why with one uses-sdk statement it worked and the other it did not?

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