UIScrollView与IOS中的向左和向右箭头

Question

我有一个UIScrollView，带有带有左右按钮的图像集。 我已经实现了使用此代码的向左移动图像左侧按钮的动作

 if ( scroll.contentOffset.x <= scroll.frame.size.width ) {
        CGRect frame;
        frame.origin.x = scroll.contentOffset.x + scroll.frame.size.width;
        frame.origin.y = 0;
        frame.size = scroll.frame.size;
         //NSLog(@"%f %f %f", frame.origin.y ,scroll.frame.size.width, frame.origin.x);
        [scroll scrollRectToVisible:frame animated:YES];
    }

它完美地工作

同样，我实现了右键操作的功能，无法正常工作，我做错了下面的代码

if (  scroll.frame.size.width <= scroll.contentOffset.x ) {
        CGRect frame;
        frame.origin.x = scroll.contentOffset.x - scroll.frame.size.width;
        frame.origin.y = 0;
        frame.size = scroll.frame.size;

        [scroll scrollRectToVisible:frame animated:YES];
    }

Answer 1

它应该与左侧相反，检查：如果大于，然后从当前x位置减去scrollview宽度

if ( scroll.contentOffset.x >= scroll.frame.size.width ) {
    CGRect frame;
    frame.origin.x = scroll.contentOffset.x - scroll.frame.size.width;
    frame.origin.y = 0;
    frame.size = scroll.frame.size;
     //NSLog(@"%f %f %f", frame.origin.y ,scroll.frame.size.width, frame.origin.x);
    [scroll scrollRectToVisible:frame animated:YES];
}

Answer 2

MMm ..我建议您以其他方式执行此操作。 创建两个按钮和单独的操作方法rightArrowNavigation，leftArrowNavigation。 在我的代码currentPage中在此处添加全局int值，并在viewDidLoad中分配0。请参见下文

- (IBAction)rightArrowNavigation:(id)sender {

    CGRect bounds = self.scrollView.bounds;
    bounds.origin.x = CGRectGetWidth(bounds) * (currentPage + 1);
    [self.scrollView scrollRectToVisible:bounds animated:YES];
}

- (IBAction)leftArrowNavigation:(id)sender {

    CGRect bounds = self.scrollView.bounds;
    bounds.origin.x = CGRectGetWidth(bounds) * (currentPage - 1);
    [self.scrollView scrollRectToVisible:bounds animated:YES];
}

Answer 3

对于右键，为什么要检查contentOffset.y？ 它应该是contentOffset.x，是否启用了分页？

使用这个，我认为它将解决

if ( _scroll.contentOffset.x >= _scroll.frame.size.width/2 ) {
        CGRect frame;
        frame.origin.x = _scroll.contentOffset.x - _scroll.frame.size.width;
        frame.origin.y = 0;
        frame.size = _scroll.frame.size;
        //NSLog(@"%f %f %f", frame.origin.y ,scroll.frame.size.width, frame.origin.x);
        [_scroll scrollRectToVisible:frame animated:YES];
    }

Answer 4

左侧功能正确，而对于要创建水平滚动条的右侧功能，则应使用x原点和宽度。 您的右侧条件和代码应基于x原点，宽度，基本上是所有那些负责水平滚动的参数

Answer 5

启用滚动视图分页。 如果您不希望启用分页，请尝试更多数学。

(IBAction)leftButtonClicked:(id)sender {

      if (self.iTemScrollView.contentOffset.x <
self.iTemScrollView.contentSize.width - self.iTemScrollView.frame.size.width){           
    [self.iTemScrollView setContentOffset:CGPointMake(self.iTemScrollView .contentOffset.x + self.iTemScrollView .frame.size.width, 0) animated:YES];
    }

}

(IBAction)rightButtonClicked:(id)sender {

    NSLog(@" rightbutton self.iTemScrollView.contentOffset.x %f",self.iTemScrollView.contentOffset.x);
    NSLog(@"rightbutton self.iTemScrollView.contentOffset.y %f",self.iTemScrollView.contentOffset.y);

    if (self.iTemScrollView.contentOffset.x>0){
    [self.iTemScrollView setContentOffset:CGPointMake(self.iTemScrollView .contentOffset.x - self.iTemScrollView .frame.size.width, 0) animated:YES];
    }

}

Answer 6

-(IBAction)leftScroll:(id)sender 
      {
  //page variable initialize to 0 in view did load method
      if(page!=0)
       {
         CGRect frame = scrollEvent.frame;
         frame.origin.x = frame.size.width * (--page);
         frame.origin.y = 0;
         [scrollEvent scrollRectToVisible:frame animated:YES];
       }
  }
- (IBAction)rightScroll:(id)sender 
     {

         if(arrData.count>page)
          {
           CGRect frame = scrollEvent.frame;
           frame.origin.x = frame.size.width * (++page);
           frame.origin.y = 0;
           [scrollEvent scrollRectToVisible:frame animated:YES];
          }
      }