点击空白区域回收键盘

• 回收键盘的关键语句是

[self.view endEditing:YES];

• 点击空白处调用的函数是控制器的touch begin

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{

}

• 点击空白区域回收键盘，两个方法组合

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
    [self.view endEditing:YES];
}