iOS如何判断灭屏,以及灭屏方式

- (void)applicationDidEnterBackground:(UIApplication *)application
{
  
    if ([self didUserPressLockButton]) {
        //User pressed lock button
        NSLog(@"锁屏 Lock screen.");
    } else {
        NSLog(@"自动熄屏幕.");
        //user pressed home button
    }
}

-(BOOL)didUserPressLockButton{
    //获取屏幕亮度
    CGFloat oldBrightness = [UIScreen mainScreen].brightness;
    //以较小的数量改变屏幕亮度
    [UIScreen mainScreen].brightness = oldBrightness + (oldBrightness <= 0.01 ? (0.01) : (-0.01));
    CGFloat newBrightness  = [UIScreen mainScreen].brightness;
    //恢复屏幕亮度
    [UIScreen mainScreen].brightness = oldBrightness;
    //判断屏幕亮度是否能够被改变
    return oldBrightness != newBrightness;
}