为什么我点击UISwitch，它不起作用？

Question

- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];

    if (self) {
        self.sw = [[[UISwitch alloc] initWithFrame:CGRectMake(210, 8, 50, 30)] autorelease];
       [sw setOn:YES];
        [sw addTarget:self action:@selector(switchChanged) forControlEvents:UIControlEventTouchUpInside];

       [self addSubview:sw];
    }

    return self;
}

-(void)switchChanged
{
    //    [self setImage];
    [sw setOn:NO];
    if (_delegate && [_delegate respondsToSelector:@selector(selectedWith:)]){
        [_delegate selectedWith:self];
    }
}

当我点击开关，但是函数switchChanged没有被调用？

Answer 1

将forControlEvents更改为 UIControlEventValueChanged ，而不是UIControlEventTouchUpInside

试试这个，

 [sw addTarget:self action:@selector(switchChanged) forControlEvents:UIControlEventValueChanged];

Answer 2

因为当您需要更改UISwitch中的值时，您指定的事件应为 UIControlEventValueChanged

[sw addTarget:self action:@selector(switchChanged) forControlEvents: UIControlEventValueChanged];