重写UIPageControl实现自定义按钮

新建类继承UIPageControl :

MyPageControl.h文件：

@interface MyPageControl : UIPageControl
{
    UIImage *imagePageStateNormal;
    UIImage *imagePageStateHighlighted;
}
- (id)initWithFrame:(CGRect)frame;
@property (nonatomic, retain) UIImage *imagePageStateNormal;
@property (nonatomic, retain) UIImage *imagePageStateHighlighted;
@end

MyPageControl.m文件:

@interface MyPageControl(private)  // 声明一个私有方法, 该方法不允许对象直接使用
- (void)updateDots;
@end

@implementation MyPageControl  // 实现部分

@synthesize imagePageStateNormal;
@synthesize imagePageStateHighlighted;

- (id)initWithFrame:(CGRect)frame { // 初始化
    self = [super initWithFrame:frame];
    return self;
}

- (void)setImagePageStateNormal:(UIImage *)image {  // 设置正常状态点按钮的图片
    [imagePageStateNormal release];
    imagePageStateNormal = [image retain];
    [self updateDots];
}

- (void)setImagePageStateHighlighted:(UIImage *)image { // 设置高亮状态点按钮图片
    [imagePageStateHighlighted release];
    imagePageStateHighlighted = [image retain];
    [self updateDots];
}

//重写 setCurrentPage方法
- (void)setCurrentPage:(NSInteger)currentPage
{
    [super setCurrentPage:currentPage];
    [self updateDots];
}

- (void)updateDots { // 更新显示所有的点按钮
    if (imagePageStateNormal || imagePageStateHighlighted)
    {
        NSArray *subview = self.subviews;  // 获取所有子视图
        for (NSInteger i = 0; i < [subview count]; i++)
        {
            UIImageView *dot = [subview objectAtIndex:i];  // 以下不解释, 看了基本明白
            dot.image = self.currentPage == i ? imagePageStateNormal : imagePageStateHighlighted;
        }
    }
}

- (void)dealloc { // 释放内存
    [imagePageStateNormal release], imagePageStateNormal = nil;
    [imagePageStateHighlighted release], imagePageStateHighlighted = nil;
    [super dealloc];
}

@end

调用:

MyPageControl *pageControl = [[MyPageControl alloc] initWithFrame:CGRectMake(0,0, 200, 30)];
pageControl.backgroundColor = [UIColor clearColor];
pageControl.numberOfPages = 5;
pageControl.currentPage = 0;
[pageControl setImagePageStateNormal:[UIImage imageNamed:@"pageControlStateNormal.png"]];
[pageControl setImagePageStateHighlighted:[UIImage imageNamed:@"pageControlStateHighlighted.png"]];
[self.view addSubview:pageControl];
[pageControl release];