新浪微博---首页技术点二.轮播图的实现

@interface NewfeatureViewController ()<UIScrollViewDelegate>

//声明一个UIScrollView的属性
@property(nonatomic,strong)UIScrollView *scrollView;
//声明一个可变数组
@property(nonatomic,strong)NSMutableArray *imageArray;
//声明一个UIPageControl 的属性
@property(nonatomic,strong)UIPageControl *pageControl;


@end

/*
 
 轮播图的实现
 
 
*/



@implementation NewfeatureViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    
    /**这里的执行顺序不能乱 */
   [self loadScrollView];
    [self loadImageView];
    [self loadPageControl];
  
    
}

-(void)loadScrollView
{
    //初始化一个UIScrollView
    self.scrollView = [[UIScrollView alloc] initWithFrame:self.view.frame];
    //是否整屏翻滚
    self.scrollView.pagingEnabled = YES;
    //设置边框是否回弹
    self.scrollView.bounces = NO;
    //设置背景色
   self.scrollView.backgroundColor = [UIColor orangeColor];
    //设置代理人
    self.scrollView.delegate = self;
    //添加在view上
    [self.view addSubview:self.scrollView];

}

-(void)loadImageView
{
    self.imageArray = [NSMutableArray array];
    for (int i = 0; i<4; i++) {
        //取出图片名字放假呢imageStr中
        NSString *imageStr =[NSString stringWithFormat:@"new_feature_%d",i+1];
        //根据imageStr , 初始化一个UIImage类型的对象
        UIImage *myImage = [UIImage imageNamed:imageStr];
        //定义UIImageView   通过循环变量控制图片位置
        UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(i*self.view.frame.size.width, 0, 
self.view.frame.size.width, self.view.frame.size.height)];
        imageView.image = myImage;
        //把imageview 添加进scrollview中进行显示  subView是一个数组存的是view所有的子视图
        [self.scrollView addSubview:imageView];
        //把图片添加进定义的可变数组中
        [self.imageArray addObject:imageView];
        
        //如果是最后一个imageView 就往里面添加其他内容
        if (self.imageArray.count == 4) {
            [self setupLastImageView:imageView];
        }
        
        
    }

    //要在确保有数据之后  在设置contentSize
    self.scrollView.contentSize = CGSizeMake(self.view.frame.size.width * self.imageArray.count, 
self.view.frame.size.height);


}

-(void)loadPageControl
{
    //UIPageControl 的初始化
    self.pageControl = [[UIPageControl alloc] initWithFrame:CGRectMake(0, self.view.frame.size.height - 40, 
self.view.frame.size.width, 40)];
    //指定页面的个数
    self.pageControl.numberOfPages = 4;
    //指定当前页
    self.pageControl.currentPage = 0;
    
    [self.view addSubview:self.pageControl];
    //设置背景色
    self.pageControl.backgroundColor =[[UIColor blackColor]colorWithAlphaComponent:0.3];
    //UIPageControl 的addTarget/action事件
    [self.pageControl addTarget:self action:@selector(pageAction)  forControlEvents:UIControlEventTouchUpInside];

}

-(void)pageAction
{
    //通过pageControl 当前页乘以宽度 计算出当前的偏移量,从而通过偏移量的变化是实现相片的变化
    [self.scrollView setContentOffset:CGPointMake(self.pageControl.currentPage * self.view.frame.size.width, 0)
 animated:YES];
    //打印偏移量的方法  (注意上面的动画效果对于偏移量造成一定的延迟,偏移量是在动画效果结束之后才最终确定下来,而打印事件是在setPoi
ntoffset(设置偏移量)时就打印的)
    NSLog(@"pagecontrol = %@",NSStringFromCGPoint(self.scrollView.contentOffset));

}

-(void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
   //利用偏移量计算当前是第几张图片
    NSInteger index = self.scrollView.contentOffset.x/self.view.frame.size.width;
    //然后将计算出的第几张图片的下标赋给cuuentPage,从而实现图片切换
    self.pageControl.currentPage = index;
    //打印偏移量的方法
    NSLog(@"%@",NSStringFromCGPoint(self.scrollView.contentOffset));

}

-(void)setupLastImageView:(UIImageView *)imageView
{
    //开启用户交互功能
    imageView.userInteractionEnabled = YES;
    //1.分享给大家
    UIButton *shareBtn = [[UIButton alloc]initWithFrame:CGRectMake(90, 400, 200, 40)];
    //设置图片
    [shareBtn setImage:[UIImage imageNamed:@"new_feature_share_false"] forState:UIControlStateNormal];
    [shareBtn setImage:[UIImage imageNamed:@"new_feature_share_true"]
        forState:UIControlStateSelected];
    //设置文字
    [shareBtn setTitle:@"分享给大家" forState:UIControlStateNormal];
    [shareBtn setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
    shareBtn.titleLabel.font = [UIFont systemFontOfSize:16];
    [shareBtn addTarget:self action:@selector(shareClick:) forControlEvents:UIControlEventTouchUpInside];
    //调整内边距
    shareBtn.titleEdgeInsets = UIEdgeInsetsMake(0, 10, 0, 0);
    [imageView addSubview:shareBtn];

    //2.开始微博
    UIButton *startBtn = [[UIButton alloc] initWithFrame:CGRectMake(115, 480, 150, 40)];
    [startBtn setBackgroundImage:[UIImage imageNamed:@"new_feature_finish_button"] forState:UIControlStateNormal];
    [startBtn setBackgroundImage:[UIImage imageNamed:@"new_feature_finish_button_highlighted"] 
forState:UIControlStateSelected];
    [startBtn setTitle:@"开始微博" forState:UIControlStateNormal];
    [startBtn addTarget:self action:@selector(startClick) forControlEvents:UIControlEventTouchUpInside];
    [imageView addSubview:startBtn];
    


}

-(void)shareClick:(UIButton *)shareBtn
{

  //状态取反
    shareBtn.selected = !shareBtn.isSelected;


}

//开始微博按钮的设置
-(void)startClick
{
    //切换到TabBarVieewController
    /*
     切换控制器的方法
     1.push 依赖于UInavigationController 控制器的切换是可逆的  
     2.modal 模态推出
     2.切换window的rootViewController
 
    */
    //这是模态推出视图的方法
//   TabBarViewController *main = [[TabBarViewController alloc] init];
//    [self presentViewController:main animated:YES completion:nil];
    
    UIWindow *window = [UIApplication sharedApplication].keyWindow;
    window.rootViewController = [[TabBarViewController alloc] init];



}