TableView下拉之视图放大及图片展示

下面是动画效果

动画.gif

话不多说，直接上代码

---

视图的创建

    //UITableView顶部的ImageView
    self.imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, V_Width, V_height/3)];
    self.imageView.image = [UIImage imageNamed:@"3"];
    //设置imageView的填充模式
    self.imageView.contentMode = UIViewContentModeScaleAspectFill;
    self.imageView.userInteractionEnabled = YES;
    UITapGestureRecognizer * tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(createAllImageView)];
    [self.imageView addGestureRecognizer:tap];
    
    //UITableView
    self.tableView = [[UITableView alloc] initWithFrame:CGRectMake(0, 0, V_Width, V_height) style:UITableViewStylePlain];
    //设置tableView的内边距
    self.tableView.contentInset = UIEdgeInsetsMake(V_height/3, 0, 0, 0);
    self.tableView.delegate = self;
    self.tableView.dataSource = self;
    
    [self.view addSubview:self.tableView];

    [self.view addSubview:self.imageView];

---

拖动TableView时的事件

- (void)scrollViewDidScroll:(UIScrollView *)scrollView{
    
    CGPoint point = scrollView.contentOffset;
    //下拉图片放大
    if (point.y < -V_height/3 && point.y >= -V_height/3-60) {
        CGRect rect = self.imageView.frame;
        rect.origin.y = 0;
        rect.size.height = -point.y;
        self.imageView.frame = rect;
    }
    //上拉图片跟随移动
    if (point.y > -V_height/3) {
        CGRect rect = self.imageView.frame;
        rect.origin.y = -point.y - V_height/3;
        self.imageView.frame = rect;
    }
    //下拉到一定程度，创建新的View
    if (point.y <= -V_height/3-60) {
        [self createAllImageView];
    }
}

---

创建新的视图

/**
 *  在Window上创建新的View
 */
- (void)createAllImageView{
    //V_Width 屏幕宽的宏定义
    //V_height 屏幕高的宏定义
    
    //判断如果已经创建_allView,则不在创建
    if (_allView) {
        return;
    }
    
    //Window上的View
    _allView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, V_Width, V_height/3)];
    _allView.backgroundColor = [UIColor blackColor];
    
    UITapGestureRecognizer * tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(removeAllImageView:)];
    [_allView addGestureRecognizer:tap];
    
    //新视图上的ImageView
    _likeImageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, V_Width, V_height/3)];
    _likeImageView.image = [UIImage imageNamed:@"3"];
    [_allView addSubview:_likeImageView];
    
    //在Window上添加视图
    [[UIApplication sharedApplication].keyWindow addSubview:_allView];
    
    CGRect rect1 = _allView.frame;
    rect1.size.height = V_height;
    
    CGRect rect2 = _likeImageView.frame;
    rect2.origin.y = (V_height - V_height/3)/2;
    
    //动画显示
    [UIView animateWithDuration:0.8 animations:^{
        _allView.frame = rect1;
        _likeImageView.frame = rect2;
    }];
}

---

Window上视图销毁

/**
 *  移除Window上的View
 *
*/
- (void)removeAllImageView:(UITapGestureRecognizer *)tap{
    
    CGRect rect1 = _allView.frame;
    rect1.size.height = V_height/3;
    
    CGRect rect2 = _likeImageView.frame;
    rect2.origin.y = 0;
    
    //动画显示
    [UIView animateWithDuration:0.5 animations:^{
        _allView.frame = rect1;
        _likeImageView.frame = rect2;
        _allView.alpha = 0;
    } completion:^(BOOL finished) {
        [_likeImageView removeFromSuperview];
        [_allView removeFromSuperview];
        _allView = nil;
    }];
}

tableView的一些代理事件这里就不在详细的写了，欢迎大家指正