7.0以上建文件夹失败

[x443137254]

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            if (checkSelfPermission(Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
                requestPermissions(new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 100);
            }else mkdirrrr();
        }else mkdirrrr();
    }

    private void mkdirrrr() {
        File file = new File(Environment.getExternalStorageDirectory().getPath() + "/aaaa", "abc.txt");
        if (file.getParentFile().mkdirs()) {
            Log.d("abc", "success");
        } else {
            Log.d("abc", "failed");
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        if (grantResults[0] == PackageManager.PERMISSION_GRANTED) mkdirrrr();
    }
}

权限加了就不贴了。7.0以后对文件操作就是一脸懵逼了，怎么搞都不行，求大神指教

[x443137254]

忘记说是什么问题了...其实有时间跑一下也就知道了，文件夹建不了，我是用8.0模拟器运行的，但应该是卡在7.0系统，手机6.0没有问题