内存内部android中的Writer文件TXT

Question

我需要在智能手机的内存中写入文本文件，然后需要通过USB线将此.txt文件复制到您的计算机并访问他的内存(此复制过程将进行手动操作，需要找到此文件并了解将记录哪个内存位置)。

我正在使用下面的代码，它在我运行时没有显示任何错误，但我不知道此录制是否正确，我也不知道它在您的智能手机上应该是什么目录。

此函数是调用函数salvarInternalStorage的按钮

    findViewById(R.id.distance_demo_button).setOnClickListener(new View.OnClickListener() {
   @Override public void onClick(View v) {
     Trilateration tri = new Trilateration(v.getContext());
     try {
       tri.salvarInternalStorage("Trying to Save This text Example");
     } catch (IOException e) {
       e.printStackTrace();
     }
     startListBeaconsActivity(DistanceBeaconActivity.class.getName());
   }
});

此函数用于将参数传递的文本写入"File.txt“。

public void salvarInternalStorage(String texto) throws IOException{
            // Use Activity method to create a file in the writeable directory
            FileOutputStream fos = context.openFileOutput("FileTeste.txt", context.MODE_PRIVATE);
            // Create buffered writer
            BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(fos));
            writer.write(String.valueOf(texto.getBytes()));
            writer.close();
}

Answer 1

使用SAF：

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);


    createFile("text/plain","Arquivo.txt");
}

private static final int WRITE_REQUEST_CODE = 43;

private void createFile(String mimeType, String fileName) {
    Intent intent = new Intent(Intent.ACTION_CREATE_DOCUMENT);

    // Filter to only show results that can be "opened", such as
    // a file (as opposed to a list of contacts or timezones).
    intent.addCategory(Intent.CATEGORY_OPENABLE);

    // Create a file with the requested MIME type.
    intent.setType(mimeType);
    intent.putExtra(Intent.EXTRA_TITLE, fileName);
    startActivityForResult(intent, WRITE_REQUEST_CODE);
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (requestCode==WRITE_REQUEST_CODE&&resultCode==RESULT_OK)
        alterDocument(data.getData());
}

private void alterDocument(Uri uri) {
    try {
        ParcelFileDescriptor txt = getContentResolver().
                openFileDescriptor(uri, "w");
        FileOutputStream fileOutputStream =
                new FileOutputStream(txt.getFileDescriptor());
        fileOutputStream.write(("Tentando Gravar Esse Texto Exemplo").getBytes());
        fileOutputStream.close();
        txt.close();
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

或者，您可以使用OPEN_DOCUMENT_TREE一次来选择一个目录，然后您就拥有了在该目录下保存任何文件的所有权限，而无需询问用户。如下所示：

Uri sdCardUri;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

        Intent intent = new Intent(Intent.ACTION_OPEN_DOCUMENT_TREE);
        startActivityForResult(intent, 1);
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    switch (requestCode)
    {
        case 1:

            if (resultCode == Activity.RESULT_OK) {
                sdCardUri = data.getData();

                getContentResolver().takePersistableUriPermission(sdCardUri, Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
            }
            createFile();

            break;
    }
}

private void createFile() {
    DocumentFile sdCard=DocumentFile.fromTreeUri(this,sdCardUri);
    DocumentFile createFile=sdCard.findFile("teste.txt");
    if (createFile==null)
        createFile=sdCard.createFile("text","teste.txt");
    OutputStream outStream = null;
    try {
        outStream = getContentResolver().openOutputStream(createFile.getUri());
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    }
    try {
        String teste="Isto é um teste";
        outStream.write(teste.getBytes());
        outStream.flush();
        outStream.close();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

}