如何使用自动版式到水平线位置UIButtons(包装,左对齐)? [英] How to use AutoLayout to position UIButtons in horizontal lines (wrapping, left aligned)?
问题描述
我需要编程在我的应用(iOS 6.0及以上),以创建一对夫妻带着各种宽度UIButtons的。
I need to create a couple of UIButtons with various widths programmatically in my app (iOS 6.0 and above).
我想在一个环绕式显示按钮:从左侧边缘开始,每个按钮应该被彼此相邻水平设置(在一个定义的顺序),如果一个按钮不适合当前线,它应该在previous线下方的左边缘开始新行。
I want to display the buttons in a "wrap around" style: Starting from the left edge, each button should be positioned next to each other horizontally (in a defined order), and if a button does not fit in the current "line", it should start a new line on the left edge below the previous line.
请注意:我不想表/格,因为按钮具有不同的宽度,我想有一个紧挨着对方。
Note: I don't want a table/grid, since the buttons have different widths, and I want to have one right next to each other.
我可以手动计算我的code每个按钮的框架,但我应该使用自动版式(以编程方式创建NSLayoutConstraints)呢?我究竟如何,需要设置?
I could manually calculate the frame of each button in my code, but should I use AutoLayout (with programmatically created NSLayoutConstraints) instead? How exactly would I need to set it up?
编辑:通过阅读章iOS 6中通过教程<4中间自动布局后/一>我不知道是否使用纯自动版式可以实现这种环绕功能,我需要。
After reading through Chapter 4 "Intermediate Auto Layout" of "iOS 6 by Tutorials" I am not sure whether using pure AutoLayout could implement this "wrap around" functionality I require.
推荐答案
我目前的解决办法是这样的:没有自动版式,但手动设置正确的约束每个案件(第一个按钮,在一个新行最左边的按钮,其他任何按钮)。
My current solution looks like this: No AutoLayout, but manually setting the correct constraints for each case (first button, leftmost button in a new line, any other button).
(我的猜测是,设置框架为每个按钮,直接会导致更可读code比使用NSLayoutConstraints,反正)
(My guess is that setting the frame for each button directly would result in more readable code than using NSLayoutConstraints, anyway)
NSArray *texts = @[ @"A", @"Short", @"Button", @"Longer Button", @"Very Long Button", @"Short", @"More Button", @"Any Key"];
int indexOfLeftmostButtonOnCurrentLine = 0;
NSMutableArray *buttons = [[NSMutableArray alloc] init];
float runningWidth = 0.0f;
float maxWidth = 300.0f;
float horizontalSpaceBetweenButtons = 10.0f;
float verticalSpaceBetweenButtons = 10.0f;
for (int i=0; i<texts.count; i++) {
UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[button setTitle:[texts objectAtIndex:i] forState:UIControlStateNormal];
[button sizeToFit];
button.translatesAutoresizingMaskIntoConstraints = NO;
[self.view addSubview:button];
// check if first button or button would exceed maxWidth
if ((i == 0) || (runningWidth + button.frame.size.width > maxWidth)) {
// wrap around into next line
runningWidth = button.frame.size.width;
if (i== 0) {
// first button (top left)
// horizontal position: same as previous leftmost button (on line above)
NSLayoutConstraint *horizontalConstraint = [NSLayoutConstraint constraintWithItem:button attribute:NSLayoutAttributeLeft relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeLeft multiplier:1.0f constant:horizontalSpaceBetweenButtons];
[self.view addConstraint:horizontalConstraint];
// vertical position:
NSLayoutConstraint *verticalConstraint = [NSLayoutConstraint constraintWithItem:button attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeTop multiplier:1.0f constant:verticalSpaceBetweenButtons];
[self.view addConstraint:verticalConstraint];
} else {
// put it in new line
UIButton *previousLeftmostButton = [buttons objectAtIndex:indexOfLeftmostButtonOnCurrentLine];
// horizontal position: same as previous leftmost button (on line above)
NSLayoutConstraint *horizontalConstraint = [NSLayoutConstraint constraintWithItem:button attribute:NSLayoutAttributeLeft relatedBy:NSLayoutRelationEqual toItem:previousLeftmostButton attribute:NSLayoutAttributeLeft multiplier:1.0f constant:0.0f];
[self.view addConstraint:horizontalConstraint];
// vertical position:
NSLayoutConstraint *verticalConstraint = [NSLayoutConstraint constraintWithItem:button attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:previousLeftmostButton attribute:NSLayoutAttributeBottom multiplier:1.0f constant:verticalSpaceBetweenButtons];
[self.view addConstraint:verticalConstraint];
indexOfLeftmostButtonOnCurrentLine = i;
}
} else {
// put it right from previous buttom
runningWidth += button.frame.size.width + horizontalSpaceBetweenButtons;
UIButton *previousButton = [buttons objectAtIndex:(i-1)];
// horizontal position: right from previous button
NSLayoutConstraint *horizontalConstraint = [NSLayoutConstraint constraintWithItem:button attribute:NSLayoutAttributeLeft relatedBy:NSLayoutRelationEqual toItem:previousButton attribute:NSLayoutAttributeRight multiplier:1.0f constant:horizontalSpaceBetweenButtons];
[self.view addConstraint:horizontalConstraint];
// vertical position same as previous button
NSLayoutConstraint *verticalConstraint = [NSLayoutConstraint constraintWithItem:button attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:previousButton attribute:NSLayoutAttributeTop multiplier:1.0f constant:0.0f];
[self.view addConstraint:verticalConstraint];
}
[buttons addObject:button];
}
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