如何以编程方式在UIScrollView中使用AutoLayout设置子视图? [英] How to set subviews with AutoLayout in UIScrollView programmatically?

问题描述

我正在使用自动布局通过UiScrollview和UIPagectontrol创建应用程序，

I am creating app with UiScrollview and UIPagectontrol using Autolayout Programmatically, for

我已经创建了 TKScroller 作为UIView的子类，我使用Some Mode和Array对其进行了初始化.

I have Created TKScroller as subclass of UIView, I am init it using Some Mode and Array.

TKScroller.m

TKScroller.m

-(void)setData{

[self layoutIfNeeded];
CGRect mainFrame=self.frame;


[self layoutIfNeeded];
CGRect mainFrame=self.frame;
UIView *lastview;
NSMutableArray* manualConstraints = [NSMutableArray array];

for (int i=0; i<arrayData.count ; i++)
{
    CGRect frame;
    frame.origin.x = scrollView.frame.size.width * i;
    frame.origin.y = 0;
    frame.size = scrollView.frame.size;

    UIView *subview = [UIView new];

    subview.backgroundColor = [self getRandomColor];
    [scrollView addSubview:subview];

    if (i==0)
    {

        NSLayoutConstraint* b1_top = [NSLayoutConstraint constraintWithItem:subview attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:scrollView attribute:NSLayoutAttributeTop multiplier:1 constant:5];
        [manualConstraints addObject:b1_top];

        NSLayoutConstraint* b1_left = [NSLayoutConstraint constraintWithItem:subview attribute:NSLayoutAttributeLeading relatedBy:NSLayoutRelationEqual toItem:scrollView attribute:NSLayoutAttributeLeading multiplier:1 constant:5];
        [manualConstraints addObject:b1_left];

        NSLayoutConstraint* b1_right = [NSLayoutConstraint constraintWithItem:subview attribute:NSLayoutAttributeTrailing relatedBy:NSLayoutRelationEqual toItem:scrollView attribute:NSLayoutAttributeTrailing multiplier:1 constant:-5];
        [manualConstraints addObject:b1_right];
        NSLayoutConstraint* b1_bottom = [NSLayoutConstraint constraintWithItem:subview attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:scrollView attribute:NSLayoutAttributeTop multiplier:1 constant:-10];
        [manualConstraints addObject:b1_bottom];

        [subview layoutIfNeeded];
        [scrollView addConstraints:manualConstraints];
        lastview=subview;
    }
    else{

        NSLayoutConstraint* b1_top = [NSLayoutConstraint constraintWithItem:subview attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:scrollView attribute:NSLayoutAttributeTop multiplier:1 constant:5];
        [manualConstraints addObject:b1_top];

        NSLayoutConstraint* b1_left = [NSLayoutConstraint constraintWithItem:subview attribute:NSLayoutAttributeLeading relatedBy:NSLayoutRelationEqual toItem:lastview attribute:NSLayoutAttributeLeading multiplier:1 constant:5];
        [manualConstraints addObject:b1_left];

        NSLayoutConstraint* b1_right = [NSLayoutConstraint constraintWithItem:subview attribute:NSLayoutAttributeTrailing relatedBy:NSLayoutRelationEqual toItem:scrollView attribute:NSLayoutAttributeTrailing multiplier:1 constant:-5];
        [manualConstraints addObject:b1_right];
        NSLayoutConstraint* b1_bottom = [NSLayoutConstraint constraintWithItem:subview attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:scrollView attribute:NSLayoutAttributeTop multiplier:1 constant:-10];
        [manualConstraints addObject:b1_bottom];

        [subview layoutIfNeeded];
        [scrollView addConstraints:manualConstraints];
        lastview=subview;

    }
}

scrollView.contentSize = CGSizeMake(scrollView.frame.size.width * arrayData.count, mainFrame.size.height/2);

self.pageControl.currentPage = 0;
self.pageControl.numberOfPages = arrayData.count;

 pageControlBeingUsed = NO;
}

-(UIColor *)getRandomColor{
    int r = arc4random() % 255;
    int g = arc4random() % 255;
    int b = arc4random() % 255;
    return [UIColor colorWithRed:(r/255.0) green:(g/255.0) blue:(b/255.0) alpha:1.0];
}

现在我正在获得任何子视图，

Right now i am getting any subviews,

但是如果我改变方向会给出不正确的结果，那么我怎么给NSLayoutConstraint作为scrollview的子视图呢?

but if i change orientation it will give incorrect result, So how can i give NSLayoutConstraint for subviews of scrollview ?

编辑

添加NSLayoutConstraint后，不会显示子视图.我只是缺少一些约束，请在动态设置约束时纠正我.

After adding NSLayoutConstraint subviews are not shown. I am just missing some constraint , please correct me in setting constraints dynamically.

我的 源代码在此处 ，请帮助我. 谢谢你.对不起，语法不好.

My Source Code is here , Please Help Me. Thank you. And Sorry for bad grammar.

推荐答案

这是一个SO答案已说明了如何用自动布局可以做到这一点，他已经很好地解释了，这里有垂直文本字段，但是在您的情况下，您必须设置水平视图"约束.

Here is a SO answer has explained how to do this with auto layout, he has explain perfectly , In here there is vertically textfields are there But in your case it is you have to set Horizontal views constraints.

替代

通过设置约束，您可以仅设置子视图的框架并在Scrollview中进行设置，并且可以基于方向更改scrolview的子视图的框架.

Rather that setting constraints you can set just frame of the subview and set it in Scrollview, And based on orientation you can change frames of the scrolview's subviews.

您的setData方法，如

Your setData Method like,

-(void)setData{

    [self layoutIfNeeded];
    CGRect mainFrame=scrollView.frame;
    CGRect frame;
    for (int i=0; i<arrayData.count ; i++)
    {
        CGRect frame;
        frame.origin.x = scrollView.frame.size.width * i;
        frame.origin.y = 0;
        frame.size = scrollView.frame.size;

        frame.origin=CGPointMake(0, 0);
        UIView *subview = [[UIView alloc]initWithFrame:frame];
        subview.backgroundColor = [self getRandomColor];
        [scrollView addSubview:subview];
    }
    scrollView.contentSize = CGSizeMake(scrollView.frame.size.width * arrayData.count, mainFrame.size.height/2);
}

现在，您使用NSNotificationCenter可以在设备方向改变时得到通知，因此在此选择器方法中，它调用您的setData方法，

Now you using NSNotificationCenter you can get notify when device orientation chaged, so in this selector method of it call your setData method,

[[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(setData)
                                                 name:UIDeviceOrientationDidChangeNotification
                                               object:nil];

现在，在setData方法中，您需要删除所有子视图，因为当设备更改方向时，它将向滚动视图中添加新视图，因此在设置其框架之前，请从Scrollview中删除所有子视图，

Now in you setData method you need remove all subviews because when device changes Orientation it will add new views to your scrollview, so remove all subview from Scrollview before setting its frame,

        [scrollView.subviews makeObjectsPerformSelector:@selector(removeFromSuperview)];

确保像这样从类中删除观察者，

Make sure you are removing observer from your class like,

- (void)dealloc
{
    [[NSNotificationCenter defaultCenter] removeObserver:self];
}

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