Question

我遇到了一个我担心有一个简单解决方案的问题。每次调用'createNewSetInDB：'方法时，都会创建一个新的UIButton *，为用户按下按钮时分配一个目标，并在用户长按按钮时为其分配UILongPressGesture *。

当用户点击其中一个按钮时，正确调用'openSet：'方法。 'showHandles：'长按方法仅用于创建的最后UIButton *。因此，如果'createNewSetInDB：'方法被调用4次并因此创建4个UIButton，则前三个不处理UILongPressGesture。第四届UIButton确实如此。

有什么想法吗？

UILongPressGestureRecognizer *showHandlesLongPress;

- (void)viewDidLoad

{
    showHandlesLongPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(showHandles:)];
    showHandlesLongPress.minimumPressDuration = .5;
}

- (void)createNewSetInDB:(BOOL)doWeAddItToTheDatabase
{
    UIButton *newSet = [[UIButton alloc]initWithFrame:
                                   CGRectMake((sliderMusic.frame.origin.x + imgWhiteLine.frame.size.width / 2) + (_musicPlayer.currentPlaybackTime * 10),
                                                                 6,
                                                                 35,
                                                                 25)];

    [newSet addTarget:self action:@selector(openSet:) forControlEvents:UIControlEventTouchUpInside];
    [newSet setTitleColor:[MobileMarcherVariables sharedVariableInstance].systemColor forState:UIControlStateNormal];
    [newSet.layer setBorderColor:[[MobileMarcherVariables sharedVariableInstance].systemColor CGColor]];
    [newSet.layer setBorderWidth:1];
    [newSet.titleLabel setFont:[UIFont systemFontOfSize:15]];
    [newSet setTitle:[NSString stringWithFormat:@"%i",totalNumberOfSets] forState:UIControlStateNormal];
    [scrollviewMusic addSubview:newSet];
    [arrayofSetButtons addObject:newSet];
    [newSet addGestureRecognizer:showHandlesLongPress];

    if (doWeAddItToTheDatabase) [[NSNotificationCenter defaultCenter] postNotification:newSetNotification];

}


- (void)showHandles:(UILongPressGestureRecognizer*)gesture
{
    if (gesture.state == UIGestureRecognizerStateBegan)
    {
        NSLog(@"long press");
        for (UIButton *but in arrayofSetButtons)
        {
            if (but.tag != gesture.view.tag)
            {
                but.alpha = .5;
            }
        }

        [scrollviewMusic bringSubviewToFront:lefthandle];
        [scrollviewMusic bringSubviewToFront:righthandle];
        lefthandle.hidden = NO;
        righthandle.hidden = NO;

        lefthandle.frame = CGRectMake(gesture.view.frame.origin.x - 1,
                                      gesture.view.frame.origin.y - gesture.view.frame.size.height,
                                      2, 50);
        righthandle.frame = CGRectMake((gesture.view.frame.origin.x - 1) + gesture.view.frame.size.width,
                                       gesture.view.frame.origin.y - gesture.view.frame.size.height,
                                       2, 50);
    }
}

Answer 1

手势识别器一次只能附加到一个视图。您只创建一个手势识别器。每次创建按钮时，都会将现有的手势识别器附加到新按钮，从而将其从前一个按钮中删除。

为每个新按钮创建一个新的手势识别器。

- (void)createNewSetInDB:(BOOL)doWeAddItToTheDatabase
{
    UIButton *newSet = [[UIButton alloc]initWithFrame:
                                   CGRectMake((sliderMusic.frame.origin.x + imgWhiteLine.frame.size.width / 2) + (_musicPlayer.currentPlaybackTime * 10),
                                                                 6,
                                                                 35,
                                                                 25)];

    [newSet addTarget:self action:@selector(openSet:) forControlEvents:UIControlEventTouchUpInside];
    [newSet setTitleColor:[MobileMarcherVariables sharedVariableInstance].systemColor forState:UIControlStateNormal];
    [newSet.layer setBorderColor:[[MobileMarcherVariables sharedVariableInstance].systemColor CGColor]];
    [newSet.layer setBorderWidth:1];
    [newSet.titleLabel setFont:[UIFont systemFontOfSize:15]];
    [newSet setTitle:[NSString stringWithFormat:@"%i",totalNumberOfSets] forState:UIControlStateNormal];
    [scrollviewMusic addSubview:newSet];
    [arrayofSetButtons addObject:newSet];

    UILongPressGestureRecognizer *showHandlesLongPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(showHandles:)];
    showHandlesLongPress.minimumPressDuration = .5;
    [newSet addGestureRecognizer:showHandlesLongPress];

    if (doWeAddItToTheDatabase) [[NSNotificationCenter defaultCenter] postNotification:newSetNotification];

}

Answer 2

您必须为UILongPressGestureRecognizer分配一个UIButton。他们都可以指出相同的方法。

- (void)createNewSetInDB:(BOOL)doWeAddItToTheDatabase
{
    UIButton *newSet = [[UIButton alloc]initWithFrame:
                        CGRectMake((sliderMusic.frame.origin.x + imgWhiteLine.frame.size.width / 2) + (_musicPlayer.currentPlaybackTime * 10),
                                   6,
                                   35,
                                   25)];

    [newSet addTarget:self action:@selector(openSet:) forControlEvents:UIControlEventTouchUpInside];
    [newSet setTitleColor:[MobileMarcherVariables sharedVariableInstance].systemColor forState:UIControlStateNormal];
    [newSet.layer setBorderColor:[[MobileMarcherVariables sharedVariableInstance].systemColor CGColor]];
    [newSet.layer setBorderWidth:1];
    [newSet.titleLabel setFont:[UIFont systemFontOfSize:15]];
    [newSet setTitle:[NSString stringWithFormat:@"%i",totalNumberOfSets] forState:UIControlStateNormal];
    [scrollviewMusic addSubview:newSet];
    [arrayofSetButtons addObject:newSet];

    // Add gesture recognizer
    //
    UILongPressGestureRecognizer *showHandlesLongPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(showHandles:)];
    showHandlesLongPress.minimumPressDuration = .5;
    [newSet addGestureRecognizer:showHandlesLongPress];

    if (doWeAddItToTheDatabase) [[NSNotificationCenter defaultCenter] postNotification:newSetNotification];

}

UILongPressGestureRecognizer不适用于所有UIButton

2 个答案: