Question

我正在尝试在我的应用中导出一些数据。即使我多次在清单和已删除的构建上设置了所需的权限，它也会产生相同的错误。我该如何解决？ FileNotFoundException：/storage/emulated/0/VocAppFile/output.txt（没有这样的文件或目录）事情是我的手机没有上面这样的文件夹。但/ storage / emulated / 0 /是默认目录。

我的代码是：

String state = Environment.getExternalStorageState();
    if(Environment.MEDIA_MOUNTED.equals(state)){
        File Root = Environment.getExternalStorageDirectory();
        Log.d("Export to", Root.getAbsolutePath());
        File Dir = new File(Root.getAbsolutePath()+"/AppFile");
        if(!Dir.exists()){
            Dir.mkdir();
        }
        File file = new File(Dir,"output.txt");
        try {
            FileOutputStream fos = new FileOutputStream(file);
            for(String[] d : data){
//data comes ready
                fos.write(d[0].getBytes());
                fos.write(d[1].getBytes());
            }
            fos.close();
            Toast.makeText(getApplicationContext(), "Data exported", 
Toast.LENGTH_SHORT).show();
        }catch (FileNotFoundException e){
            Log.wtf("My activity", "Error in exporting words");
            e.printStackTrace();
        }catch (IOException e){
            Log.wtf("My activity", "Error in exporting words");
            e.printStackTrace();
        }

Answer 1

在File Dir = ...

之后加上这一行

新行

file.createNewFile();

最终守则将是这样的

    String state = Environment.getExternalStorageState();
        if(Environment.MEDIA_MOUNTED.equals(state)){
            File Root = Environment.getExternalStorageDirectory();
            Log.d("Export to", Root.getAbsolutePath());
            File Dir = new File(Root.getAbsolutePath()+"/AppFile");
            if(!Dir.exists()){
                Dir.mkdir();
            }
            File file = new File(Dir,"output.txt");
            file.createNewFile();
            try {
                FileOutputStream fos = new FileOutputStream(file);
                for(String[] d : data){
    //data comes ready
                    fos.write(d[0].getBytes());
                    fos.write(d[1].getBytes());
                }
                fos.close();
                Toast.makeText(getApplicationContext(), "Data exported", 
    Toast.LENGTH_SHORT).show();
            }catch (FileNotFoundException e){
                Log.wtf("My activity", "Error in exporting words");
                e.printStackTrace();
            }catch (IOException e){
                Log.wtf("My activity", "Error in exporting words");
                e.printStackTrace();
            }

Answer 2

我按照stackoverflow.com/a/41221852/5488468

的步骤1-2-4解决了问题

Android Studio如何修复FileNotFoundException

2 个答案: