iOS收起键盘的三种方法

在UIViewController中收起键盘，除了调用相应控件的resignFirstResponder。例：

• 利用textField的代理方法

  - (BOOL)textFieldShouldReturn:(UITextField *)textField{

    if (![self.textField isExclusiveTouch]) {
        [self.textField resignFirstResponder];
    }
    return YES;
} 

还有另外的三种方法：

• 重载UIViewcontroller中的touchesBegin方法，然后在里面执行[self.view endEditing:YES]; ，这样单击UIViewController的任意地方就可以收起键盘。

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

    [self.view endEditing:YES];
}

• 直接执行[[UIApplication sharedApplication] sendAction: @selector(resignFirstResponder to:nil from:nil forEvent:nil];，用于在获得当前UIViewController比较困难的时候用。

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

     [[UIApplication sharedApplication]sendAction:@selector(resignFirstResponder) to:nil from:nil forEvent:nil];
}

• 直接执行 [[[UIApplication sharedApplication] keyWindow] endEditing:YES];

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

    [[[UIApplication sharedApplication] keyWindow] endEditing:YES];
}