在Android中保存文件-对于初学者（内部/外部存储）

每个许可都有其自己的权限，这意味着，例如，如果您仅希望读取文件而不是编写文件，则无需同时拥有这两个权限

验证存储是否可用 -这是在运行时完成的，并在文档中进行了详细说明。我们需要确保将存储器安装到设备中/以某种方式不会导致问题的方式导致读取/写入请求失败。

时间示例！

在给定的方法中，我们将文本文件保存在根目录中。

归功于本文

public void writeFileExternalStorage() {

    //Text of the Document
    String textToWrite = "bla bla bla";

    //Checking the availability state of the External Storage.
    String state = Environment.getExternalStorageState();
    if (!Environment.MEDIA_MOUNTED.equals(state)) {

        //If it isn't mounted - we can't write into it.
        return;
    }

    //Create a new file that points to the root directory, with the given name:
    File file = new File(getExternalFilesDir(null), filenameExternal);

    //This point and below is responsible for the write operation
    FileOutputStream outputStream = null;
    try {
        file.createNewFile();
        //second argument of FileOutputStream constructor indicates whether
        //to append or create new file if one exists
        outputStream = new FileOutputStream(file, true);

        outputStream.write(cashback.getBytes());
        outputStream.flush();
        outputStream.close();
    } catch (Exception e) {
        e.printStackTrace();
    }
}