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roller alloc] init];
readerVc.title = @"订阅";
[self addChildViewController:readerVc];
ScienceViewController *scienceVc = [[ScienceViewController alloc] init];
scienceVc.title = @"科技";
[self addChildViewController:scienceVc];
}
// 设置标题
- (void)setUpTitle
{
NSUInteger count = self.childViewControllers.count;
CGFloat btnX = 0;
CGFloat btnY = 0;
CGFloat btnW = 100;
CGFloat btnH = 44;
for (NSUInteger i = 0; i < count; i++) {
btnX = i * btnW;
UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom];
btn.tag = i;
[btn setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
UIViewController *vc = self.childViewControllers[i];
[btn setTitle:vc.title forState:UIControlStateNormal];
[btn setTitleColor:[UIColor redColor] forState:UIControlStateSelected];
btn.frame = CGRectMake(btnX, btnY, btnW, btnH);
[btn addTarget:self action:@selector(titleClick:) forControlEvents:UIControlEventTouchUpInside];
[self.titileScrollView addSubview:btn];
[self.titleBtns addObject:btn];
// 默认选中第一个
if (i == 0) {
[self titleClick:btn];
}
}
self.titileScrollView.contentSize = CGSizeMake(btnW * count, 0);
}
// 点击标题按钮
- (void)titleClick:(UIButton *)btn
{
// 0.设置标题按钮居中
[self setUpTitleBtnMiddle:btn];
// 1.滚动到对应的界面
CGFloat offsetX = btn.tag * ScreenW;
self.contentView.contentOffset = CGPointMake(offsetX, 0);
// 2.添加对应子控制器view到对应的位置
UIViewController *vc = self.childViewControllers[btn.tag];
vc.view.frame = CGRectMake(offsetX, 0, ScreenW, self.contentView.bounds.size.height);
// NSLog(@"%@",NSStringFromCGRect(self.contentView.bounds));
[self.contentView addSubview:vc.view];
// 还原之前标题的形变
[self setSelectBtn:btn];
}
- (void)setSelectBtn:(UIButton *)btn
{
_selButton.transform = CGAffineTransformIdentity;
[_selButton setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
_selButton.selected = NO;
btn.transform = CGAffineTransformMakeScale(1.3, 1.3);
btn.selected = YES;
_selButton = btn;
}
#pragma mark - UIScrollViewDelegate
// 减速完成的时候
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
// 获取当前的偏移量
CGFloat offsetX = scrollView.contentOffset.x;
// 获取页码
int page = offsetX / scrollView.bounds.size.width;
UIButton *btn = self.titileScrollView.subviews[page];
// 选中按钮
[self setSelectBtn:btn];
// 设置按钮居中
[self setUpTitleBtnMiddle:btn];
// 添加对应子控制器到界面上
UIViewController *vc = self.childViewControllers[page];
// 已经加载的view就不需要添加了
if (vc.isViewLoaded) return;
vc.view.frame = CGRectMake(offsetX , 0, self.contentView.bounds.size.width, self.contentView.bounds.size.height);
[self.contentView addSubview:vc.view];
}
// 设置标题按钮居中
- (void)setUpTitleBtnMiddle:(UIButton *)btn
{
// 计算偏移量
CGFloat offsetX = btn.center.x - ScreenW * 0.5;
// 左边偏移多了，表示需要往左边看，可视范围往左边，偏移量就减少，最少应该是0
if (offsetX < 0) offsetX = 0;
CGFloat maxOffsetX = self.titileScrollView.contentSize.width - ScreenW;
// 右边偏移多了，表示需要往右边看，可视范围往又边，偏移量就增加，最大不超过内容范围 - 屏幕宽度
if (offsetX > maxOffsetX) offsetX = maxOffsetX;
[self.titileScrollView setContentOffset:CGPointMake(offsetX, 0) animated:YES];
}
// 监听内容v |