在android中读取文件 - 文件权限被拒绝

Question

我想从外部存储中读取文件。我将Eclipse DDMS中的文件上传到storage / sdcard（下图）。但每当我试图阅读时，我都会收到拒绝许可的错误。我的文件权限有问题吗？或者我需要在清单文件中添加任何内容（我现在不写任何内容）？

任何帮助将不胜感激。

代码：

public void extimport(View v){
   EditText xedittxt = (EditText) findViewById(R.id.frmexttxt);
   String xedit = xedittxt.getText().toString();
   xedit = xedit.trim();
   File file;
   file = new File(xedit);
   StringBuilder text = new StringBuilder();
   Log.d("fcheck",""+xedit);
   try {
      BufferedReader br = new BufferedReader(new FileReader(file)); //THIS LINE THROWS ERROR
      Log.d("fcheck","f3"); //This line never got printed
      String line;
      while ((line = br.readLine()) != null) {
         text.append(line);
         text.append('\n');
      }
      br.close();
      resultView = (TextView) findViewById(R.id.header);
      resultView.setText(text);
   }
   catch (IOException e) {
      Log.d("File open error",""+e);
      Toast.makeText(getApplicationContext(), "Error opening the file.", Toast.LENGTH_SHORT).show();
   }
}

logcat的：

11-19 00:21:54.252: D/fcheck(5885): /storage/sdcard/mylibman.csv
11-19 00:21:54.272: D/File open error(5885): java.io.FileNotFoundException: /storage/sdcard/mylibman.csv: open failed: EACCES (Permission denied)

Answer 1

确保您已在清单文件中添加了读取外部存储的权限。

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

Answer 2

我遇到了同样的问题，可以通过以下任一步骤轻松删除它： 1.如果在Android N和O版本上安装，请使用-g安装您的应用程序。 2.手动授予权限  设置 - ＆gt; apps-＆gt;“app_name” - ＆gt;权限 - ＆gt;启用开关

对于步骤1和步骤2，在AndroidManifest.xml中定义uses-permission android：name =“android.permission.WRITE_EXTERNAL_STORAGE”并使用权限android：name =“android.permission.READ_EXTERNAL_STORAGE”

Answer 3

在访问功能之前，需要由用户授予存储权限

添加依赖性：

dependencies:
  permission_handler: ^5.0.1

代码段：

      var status = await Permission.storage.status;
       if (status.isUndetermined) {
            // You can request multiple permissions at once.
            Map<Permission, PermissionStatus> statuses = await [
              Permission.storage,
            ].request();
            print(statuses[Permission.storage]); // it should print PermissionStatus.granted
          }