如何在 android 工作室中将文件创建到新文件夹中

Question

I still dont see any folder or file created. what is wrong.

            try {
                String rootPath = Environment.getExternalStorageDirectory()
                        .getAbsolutePath() + "/MyFolder/";
                File root = new File(rootPath);
                if (!root.exists()) {
                    root.mkdirs();
                }
                File f = new File(rootPath + "mttext.txt");
                if (f.exists()) {
                    f.delete();
                }
                f.createNewFile();

                FileOutputStream out = new FileOutputStream(f);

                out.flush();
                out.close();
            } catch (Exception e) {
                e.printStackTrace();
            }
    

Please what is wrong please.

Answer 1

try this and check!

try {
        String path = Environment.getExternalStorageDirectory().getAbsolutePath() + "/newfoldername/";    // it will return root directory of internal storage
        File root = new File(path);
        if (!root.exists()) {
            root.mkdirs();       // create folder if not exist 
        }
        File file = new File(rootPath + "log.txt");
        if (!file.exists()) {
            file.createNewFile();   // create file if not exist 
        }
        BufferedWriter buf = new BufferedWriter(new FileWriter(file, true));
        buf.append("hi this will write in to file");
        buf.newLine();  // pointer will be nextline
        buf.close();

    } 
 catch (Exception e) {
        e.printStackTrace();
    }

Add your AndroidManifest.xml

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