1.方法 一

-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
    [myTextView resignFirstResponder];
}

2.方法二

第一响应存在于self.view

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