Android 7.1 写入文本文件

来自果冻豆的牛轧糖新手尝试将文本文件写入 SD 卡我知道我现在必须请求权限，但找不到任何有效的代码

尝试了以下方法

        StringBuilder bodyStr=new StringBuilder();
                 bodyStr.append(data1Str.toString()).append(",").append(data2Str.toString()).append(",").append(data3Str.toString()).append(",").append(data4Str.toString()).append(",").append(data5Str.toString()).append(",").append(data22Str.toString()).append(",").append(data23Str.toString()).append(lineSep);; 
             String bodytextStr=bodyStr.toString();

                boolean hasPermission = (ContextCompat.checkSelfPermission(data_entry.this,
                        Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED);
                if (!hasPermission) {
                    ActivityCompat.requestPermissions(data_entry.this,
                            new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},
                            REQUEST_WRITE_STORAGE);
                }


                try {

                    File myFile = new File(fileName);
                    myFile.createNewFile();
                    FileOutputStream fOut = new FileOutputStream(myFile);
                    OutputStreamWriter myOutWriter =
                            new OutputStreamWriter(fOut);
                    myOutWriter.append(bodytextStr);
                    myOutWriter.close();
                    fOut.close();
                    Toast.makeText(getBaseContext(),
                            "Done writing SD 'mysdfile.txt'",
                            Toast.LENGTH_SHORT).show();
                } catch (Exception e) {
                    Toast.makeText(getBaseContext(), e.getMessage(),
                            Toast.LENGTH_SHORT).show();
                }

回来了[权限被拒绝]

已在清单中设置常用权限

任何我出错的地方的想法

任何帮助表示赞赏

Mark

您要么拥有权限并且可以在写入文件的地方执行 try catch 块，要么必须在 onRequestPermissionsResult 中执行此操作。

就像是 ：

public void yourMethod(){
    boolean hasPermission = (ContextCompat.checkSelfPermission(data_entry.this,
                    Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED);
    if(hasPermission){
      // write
    }else{
      // ask the permission
      ActivityCompat.requestPermissions(data_entry.this,
                        new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},
                        REQUEST_WRITE_STORAGE);
      // You have to put nothing here (you can't write here since you don't
      // have the permission yet and requestPermissions is called asynchronously)
   }
}

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions,
                                       @NonNull int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    // The result of the popup opened with the requestPermissions() method
    // is in that method, you need to check that your application comes here
    if (requestCode == REQUEST_WRITE_STORAGE) {
        if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
            // write
        }
    }
}

我建议您检查此链接：https://developer.android.com/training/permissions/requesting.html https://developer.android.com/training/permissions/requesting.html