ios - 在ViewDidLoad 里添加UIButton的点击事件，不能触发。

Question

UIButton *btn2 = [[UIButton alloc] initWithFrame:CGRectMake(0, 38, 100, 38)];
[btn2 setTitle:@"添加好友" forState:UIControlStateNormal]; btn2.titleLabel.font = [UIFont systemFontOfSize:16];
[btn2 addTarget:self action:@selector(btn2Click:) forControlEvents:UIControlEventTouchDown];

之前可以触发， 现在不知是何原因不能触发了？

Answer 1

Change first

[btn2 addTarget:self action:@selector(btn2Click:) forControlEvents:UIControlEventTouchUpInside];

If this still doesn’t work, check the properties of the parent view User Interaction Enabled, or check the btn2Click: method

Answer 2

Change to the following code and try again

UIButton *btn2 = [[UIButton alloc] initWithFrame:CGRectMake(0, 38, 100, 38)];
[btn2 setTitle:@"添加好友" forState:UIControlStateNormal]; btn2.titleLabel.font = [UIFont systemFontOfSize:16];
[btn2 addTarget:self action:@selector(btn2Click:) forControlEvents:UIControlEventTouchUpInside];

Answer 3

Isn’t this the right way to write it? Why is it good and bad?

Answer 4

Trouble changing the enumeration of forControlEvents to:
UIControlEventTouchUpInside
In addition, button has intrinsicSize. Are you clicking within this range