重写UIPageControl实现自定义按钮

有时候UIPageControl需要用到白色的背景, 那么会导致上面的点 按钮看不见或不清楚,

我们可以通过继承该类重写函数来更换点按钮的 图片现实.

实现思路如下.

新建类继承UIPageControl :

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

声明了初始化该类的函数

用了两个UIImage保存两张图片, 大家知道的, UIPageCotrol的按钮分为两态, 一个是正常, 一个是高亮

接下来实现该类以及重写父类方法:

复制代码 @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     [imagePageStateHighlighted release];     imagePageStateHighlighted = [image retain];     [self updateDots]; } - (void)setImagePageStateHighlighted:(UIImage *)image { // 设置高亮状态点按钮图片     [imagePageStateNormal release];     imagePageStateNormal = [image retain];     [self updateDots]; } - (void)endTrackingWithTouch:(UITouch *)touch withEvent:(UIEvent *)event { // 点击事件     [super endTrackingWithTouch:touch withEvent:event];     [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

OK, 在添加处加入以下来实例化该对象 代码:

复制代码

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