如何在scrollview中从uibutton触发的事件中滚动uiscrollview
结构 UIViewController - UIScrollview - UIButton
我要让scrollview可以接收按钮事件。 所以每当用户在按钮上滚动（拖动），滚动视图就会自动滚动。
我按下了按钮，并像下面一样移动事件转发处理程序
- (IBAction)buttonTouchedMove:(id)sender withEvent:(UIEvent *)event {
[[sender nextResponder] touchesMoved:[event allTouches] withEvent:event];
}
- (IBAction)buttonTouchedDown:(id)sender withEvent:(UIEvent *)event {
[[sender nextResponder] touchesBegan:[event allTouches] withEvent:event];
}
并将scrollview作为触摸变化来移动，我在代码中做了下面的代码
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *touch = [touches anyObject];
self.oldPoint = [touch locationInView:self.view];
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
CGPoint offset = self.scrollView1.contentOffset;
UITouch *touch = [touches anyObject];
self.newPoint = [touch locationInView:self.view];
int diffX = newPoint.x - oldPoint.x;
offset.x = offset.x - diffX;
[scrollView1 setContentOffset:offset animated:YES];
self.oldPoint = self.newPoint;
}
但是，scrollview反应奇怪..移动不够我触摸移动。
// get the button width
CGFloat buttonWidth = self.theButton.frame.size.width;
// replace your button name here
// now get the view width
CGFloat viewWidth = self.view.frame.size.width;
// replace your view name here
// now get the multiplier which i said u as 10
CGFloat mult = viewWidth / buttonWidth;
// and now use it in your code
.
.
.
diffX = mult*(newPoint.x - oldPoint.x);
.
.
.
最终答案，使用UIView动画，我得到了我想要的。
- (IBAction)buttonTouchedDown:(id)sender withEvent:(UIEvent *)event {
UITouch *touch = [[event allTouches] anyObject];
self.oldPoint = [touch locationInView:self.view];
self.velocity = 0;
isButtonTouchedDown = YES;
}
- (IBAction)buttonTouchedMove:(id)sender withEvent:(UIEvent *)event {
CGPoint offset = self.scrollView1.contentOffset;
UITouch *touch = [[event allTouches] anyObject];
self.newPoint = [touch locationInView:self.view];
int diffX = self.newPoint.x - self.oldPoint.x;
velocity = diffX;
offset.x = offset.x - diffX;
[self.scrollView1 setContentOffset:offset animated:NO];
self.oldPoint = self.newPoint;
}
有一个技巧..我通过区分TouchedMove功能中的移动距离来计算速度。 在Button TouchUp事件处理程序中，我使用速度值和CurveEaseout动画控制滚动查看滚动更多。 通过提供非常短的动画持续时间，并在没有事件（按下按钮）时重复播放。 它与scrollview的动画非常相似。
- (IBAction)buttonTouchedUp:(id)sender withEvent:(UIEvent *)event {
CGPoint offset = self.scrollView1.contentOffset;
amountX = (self.velocity)*(abs(self.velocity));
dX = amountX;
isButtonTouchedDown = NO;
if (offset.x - amountX < 0) {
offset.x = 0;
[scrollView1 setContentOffset:offset animated:YES];
}
else if (abs(dX) < 70) { // 70: content item size
offset.x = roundf(offset.x/70)*70;
[scrollView1 setContentOffset:offset animated:YES];
}
else {
[self endScrollAnimation];
}
- (void)startAnimation:(float)x moveAmount:(float)moveAmount
{
CGPoint offset = self.scrollView1.contentOffset;
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:duration];
offset.x = x < 0 ? offset.x + moveAmount : offset.x -moveAmount;
[UIView setAnimationCurve:UIViewAnimationCurveLinear];
[UIView setAnimationDelegate:self];
[UIView setAnimationDidStopSelector:@selector(endScrollAnimation)];
[scrollView1 setContentOffset:offset animated:NO];
[UIView commitAnimations];
}
- (void)endScrollAnimation
{
CGPoint offset = self.scrollView1.contentOffset;
float slowMoveAmount = abs(amountX) * 0.05;
float fastMoveAmount = abs(amountX) * 0.1;
if (isButtonTouchedDown) {
return;
}
else if (abs(dX) > abs(amountX)*0.35 && offset.x > 0) {
[self startAnimation:dX moveAmount:fastMoveAmount];
dX = dX < 0 ? dX + fastMoveAmount : dX -fastMoveAmount;
}
else if (abs(dX) > slowMoveAmount && offset.x > 0) {
[self startAnimation:dX moveAmount:slowMoveAmount];
dX = dX < 0 ? dX + slowMoveAmount : dX - slowMoveAmount;
}
else {
offset.x = roundf(offset.x/70)*70;
[scrollView1 setContentOffset:offset animated:YES];
}
}
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