ios - 动态UIButton定位？

Question

我有用户可以在我的游戏中获得的奖励。现在只有解锁后才会显示。他们可以获得 4 种不同的奖励。现在他们可能解锁了 1 个奖励，或者 2 个、3 个或 4 个奖励。但是我希望图像能够动态定位，如下图所示。在下图中，每行看起来都应与解锁奖励的数量相同。

现在，我将如何继续这样做？ (注意:图像在 Y 轴上不会发生变化，它们只是在 X 轴上动态定位，所以不要被图像愚弄了)

谢谢!

Answer 1

我将创建一个自定义 UIView 子类来执行此操作，以便您可以在可以使用 View 的任何地方使用它。

用法:

MyFlexibleSpacedButtons *myButtons = [[MyFlexibleSpacedButtons alloc] initWithFrame:CGRectMake(50, 50, 250, 60)];
[myButtons setButtonAtIndex:2 hidden:NO];
[myButtons setButtonAtIndex:0 hidden:NO];
[self.view addSubview:myButtons];

这是示例类:

MyFlexibleSpacedButtons.h:

#import <UIKit/UIKit.h>

@interface MyFlexibleSpacedButtons : UIView

@property (nonatomic, readonly) NSArray *allButtons;

- (void)setButtonAtIndex:(NSUInteger)index hidden:(BOOL)hidden;

@end

MyFlexibleSpacedButtons.m:

#import "MyFlexibleSpacedButtons.h"

const NSUInteger    maxButtons          = 9;
const NSUInteger    buttonsPerRow       = 3; // This can not be 0.
const CGFloat       buttonHeight        = 50;
const CGFloat       buttonWidth         = 50;
const CGFloat       spaceBetweenButtons = 10.0;

@interface MyFlexibleSpacedButtons ()
@property (nonatomic, readwrite) NSArray        *allButtons;
@end

@implementation MyFlexibleSpacedButtons

@synthesize allButtons;

- (id)initWithFrame:(CGRect)frame
{
    NSUInteger numberOfRows = ceil((double)maxButtons / (double)buttonsPerRow);
    CGFloat    minHeight    = buttonHeight * numberOfRows + spaceBetweenButtons * (numberOfRows - 1);
    if (frame.size.height < minHeight)
    {
        frame.size.height = minHeight;
    }

    CGFloat minWidth = buttonWidth * maxButtons + spaceBetweenButtons * (maxButtons-1);
    if (frame.size.width < minWidth)
    {
        frame.size.width = minWidth;
    }

    self = [super initWithFrame:frame];
    if (self) {
        // Defaults
        // Uncomment the following line if needed for debugging:
        // self.backgroundColor = [UIColor grayColor];

        // Create the buttons and add them to the array.  Default to hidden buttons
        self.allButtons = [NSArray new];
        for (int i = 0; i < maxButtons; i++)
        {
            UIButton *button   = [UIButton buttonWithType:UIButtonTypeRoundedRect];
            button.hidden      = YES;
            [button setTitle:[NSString stringWithFormat:@"%d", i] forState:UIControlStateNormal];
            [self addSubview:button];
            self.allButtons = [self.allButtons arrayByAddingObject:button];
        }

        [self setButtonFrames];
    }
    return self;
}

- (void)dealloc
{
    allButtons = nil;
}

- (void)setButtonFrames
{
    CGFloat viewHeight                  = self.bounds.size.height;
    CGFloat viewWidth                   = self.bounds.size.width;

    NSUInteger  buttonCount             = [self visibleButtonsCount];
    NSUInteger  numberOfRows            = ceil((double)maxButtons / (double)buttonsPerRow);
    CGFloat     buttonY                 = (viewHeight - buttonHeight * numberOfRows - spaceBetweenButtons * (numberOfRows - 1)) / 2;
    CGFloat     buttonGroupTotalWidth   = buttonCount * buttonWidth + (buttonCount - 1) * spaceBetweenButtons;
    CGFloat     buttonGroupStartingX    = (viewWidth - buttonGroupTotalWidth) / 2;

    // Set frames of buttons
    NSUInteger  visibleButtonIndex      = 0;
    for (int i = 0; i < maxButtons; i++)
    {
        UIButton *button    = [self.allButtons objectAtIndex:i];

        if (!button.hidden)
        {
            CGFloat buttonX     = buttonGroupStartingX + visibleButtonIndex % buttonsPerRow * (buttonWidth + spaceBetweenButtons);
            button.frame        = CGRectMake(buttonX, buttonY, buttonWidth, buttonHeight);
            visibleButtonIndex++;

            if (visibleButtonIndex % buttonsPerRow == 0)
            {
                buttonY = buttonY + buttonHeight + spaceBetweenButtons;
            }
        }
    }
}

- (void)setButtonAtIndex:(NSUInteger)index hidden:(BOOL)hidden
{
    if (index > maxButtons - 1)
    {
        return;
    }

    UIButton *button    = [self.allButtons objectAtIndex:index];
    button.hidden       = hidden;

    [self setButtonFrames];
}

- (NSUInteger)visibleButtonsCount
{
    NSUInteger buttonCount = 0;

    for (UIButton *button in self.allButtons)
    {
        if (!button.hidden)
        {
            buttonCount++;
        }
    }
    return buttonCount;
}

@end