添加设置读写权限：

判断是否屏幕旋转被关闭，如果关闭则打开：

// check whether the screen rotation works    int flag = Settings.System.getInt(getContentResolver(),        Settings.System.ACCELEROMETER_ROTATION, 0);    if (0 == flag) {      // open screen rotation and give user infomation alert      Toast.makeText(getApplicationContext(), "open screen rotation",          Toast.LENGTH_LONG).show();      Settings.System.putInt(getContentResolver(),          Settings.System.ACCELEROMETER_ROTATION, 1);