iOS问题-控件

2018-06-05 阅读量

一、UIButton
1.实现按钮倒计时文本闪烁

一般和NSTimer结合使用容易出现;

解决方法：
UIButtonTypeSystem --> UIButtonTypeCustom

2.图文排序
UIEdgeInsets insets = {top, left, bottom, right};
正数就是距相应的边的距离增加，负数就是距相应的距离减少;

蓝色标识为可变区域， 绿色标识为不变区域。
UIEdgeInsets结构体的属性top与bottom为一对，用来指定纵向可变区域（黑色虚线矩形），left与right为一对，用来指定横向可变区域(白色虚线矩形)。
当UIButton/UIImageView的size大于UIImage的size时，会调整图片中可变区域大小以铺满整个控件,具体调整规则如下：
    (1)控件宽度大于图片宽度，拉伸白色虚线矩形
    (2)控件高度大于图片高度，拉伸黑色虚线矩形
    (3)控制宽度小于图片宽度时，横向整体缩小(可变区与不变区比例不变)
    (4)控制高度小于图片高度时，纵向整体缩小(可变区与不变区比例不变)

eg:
UIEdgeInsets insets = {top, left, bottom, right}
正数就是距相应的边的距离增加，负数就是距相应的距离减少
button1

1.图左文右 - 默认状态:
    UIButton *button1 = [buttonArray objectAtIndex:0];
    [button1 setImageEdgeInsets:UIEdgeInsetsMake(0,0,0,0)];
    [button1 setTitleEdgeInsets:UIEdgeInsetsMake(0,0,0,0)];
2.图片文字同时居中：
    图 右移Label Width
    文 左移ImageView Height
    UIButton *button2 = [buttonArray objectAtIndex:1];
    [button2 setImageEdgeInsets:UIEdgeInsetsMake(0,0,0,-button2.titleLabel.intrinsicContentSize.width)];
    [button2 setTitleEdgeInsets:UIEdgeInsetsMake(0,-button2.currentImage.size.width,0,0)];
3.图右 文左
    图 右移Label Width + 右移Label Width  
    文 左移ImageView Height + 左移ImageView Height
    UIButton *button3 = [buttonArray objectAtIndex:2];
    [button3 setImageEdgeInsets:UIEdgeInsetsMake(0,0,0,-button3.titleLabel.intrinsicContentSize.width * 2)];
    [button3 setTitleEdgeInsets:UIEdgeInsetsMake(0,-button3.currentImage.size.width * 2,0,0)];

4.图上 文下    
    图 右移Label Width，上移Label Height
    文 左移ImageView Width，下移ImageView Height
    UIButton *button4 = [buttonArray objectAtIndex:3];
    [button4 setImageEdgeInsets:UIEdgeInsetsMake(-button4.titleLabel.intrinsicContentSize.height,0,0,-button4.titleLabel.intrinsicContentSize.width)];
    [button4 setTitleEdgeInsets:UIEdgeInsetsMake(0,-button4.currentImage.size.width,-button4.currentImage.size.height,0)];
5.图文显示其一:
    图 或 文 居中显示    
    UIButton *button5 = [buttonArray objectAtIndex:4];
6.图下 文上
    图 右移Label Width，下移Label Height
    文 左移ImageView Width，上移ImageView Height
    UIButton *button6 = [buttonArray objectAtIndex:5];
[button6 setImageEdgeInsets:UIEdgeInsetsMake(0,0,-button6.titleLabel.intrinsicContentSize.height,-button6.titleLabel.intrinsicContentSize.width)];
[button6 setTitleEdgeInsets:UIEdgeInsetsMake(-button6.currentImage.size.height,-button6.currentImage.size.width,0,0)];

二、UITableView
1.最后一个Cell不显示分割线

解决方法：

//Objective-C
- (void)layoutSubviews {
    [super layoutSubviews];
    for (UIView *subview in self.contentView.superview.subviews) {
        if ([NSStringFromClass(subview.class) hasSuffix:@"SeparatorView"]) {
            subview.hidden = NO;
            CGRect frame = subview.frame;
            frame.origin.x += self.separatorInset.left;
            frame.size.width -= self.separatorInset.right;
            subview.frame =frame;
        }
    }
}
//Swift
override func layoutSubviews() {

    super.layoutSubviews()
    for item in self.contentView.superview!.subviews {
        var subview = item as! UIView
        if NSStringFromClass(subview.classForCoder).hasSuffix("SeparatorView") {
            subview.hidden = false
            var frame = subview.frame
            frame.origin.x += self.separatorInset.left
            frame.size.width -= self.separatorInset.right
            subview.frame  = frame
        }
    }
}

2.delegate执行的先后顺序：

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView;
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section;
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath;
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath;
- (CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section;
- (CGFloat)tableView:(UITableView *)tableView heightForFooterInSection:(NSInteger)section;
- (UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section;
- (UIView *)tableView:(UITableView *)tableView viewForFooterInSection:(NSInteger)section

三、UINavigationBar
1.导航栏渐变

方法一:
思路: 
    向下、上滑动时分别对navigationBar的alpha进行更新;
tips:
    如果你不希望自己 navigationBar 上的按钮也被改变透明度，可以通过自定义 UINavigationController 实现。
    用系统的 navigationBar 时，navigationBar上的按钮的透明度也会被更改;
eg:
    #pragma mark - UIScrollViewDelegate
    - (void)scrollViewDidScroll:(UIScrollView *)scrollView {

        self.currentPostion = scrollView.contentOffset.y;

        if (self.currentPostion > 0) {
            if (self.currentPostion - self.lastPosition >= 0) {
                if (self.topBool) {
                    self.topBool = NO;
                    self.bottomBool = YES;
                    self.stopPosition = self.currentPostion + 64;
                }
                self.lastPosition = self.currentPostion;
                self.navigationController.navigationBar.alpha = 1 - self.currentPostion / 500;
            } else {
                if (self.bottomBool) {
                    self.bottomBool = NO;
                    self.topBool = YES;
                    self.stopPosition = self.currentPostion + 64;
                }
                self.lastPosition = self.currentPostion;
                self.navigationController.navigationBar.alpha = (self.stopPosition - self.currentPostion) / 200;
            }
        }
    }
方法二:
思路:
    在 navigationBar 上加一个 view，然后设置 view 的 alpha;
eg:
    #pragma mark - UIScrollViewDelegate
    - (void)scrollViewDidScroll:(UIScrollView *)scrollView {

        self.currentPostion = scrollView.contentOffset.y;

        if (self.currentPostion > 0) {
            if (self.currentPostion - self.lastPosition >= 0) {
                if (self.topBool) {
                    self.topBool = NO;
                    self.bottomBool = YES;
                    self.stopPosition = self.currentPostion + 64;
                }
                self.lastPosition = self.currentPostion;
                self.customView.alpha = 1 - self.currentPostion / 500;
            } else {
                if (self.bottomBool) {
                    self.bottomBool = NO;
                    self.topBool = YES;
                    self.stopPosition = self.currentPostion + 64;
                }
                self.lastPosition = self.currentPostion;
                self.customView.alpha = (self.stopPosition - self.currentPostion) / 200;
            }
        }
    }

方法三：
思路：
    自定义导航控制器实现

四、UIImageView
1.动画实现

UIImageView *imageView = [UIImageView alloc] init];
//设置动画帧
imageView.animationImages=[NSArray arrayWithObjects:
     [UIImage imageNamed:@"gc_service_0"],
     [UIImage imageNamed:@"gc_service_1"],
     [UIImage imageNamed:@"gc_service_2"],
     [UIImage imageNamed:@"gc_service_3"],
     [UIImage imageNamed:@"gc_service_4"],
     [UIImage imageNamed:@"gc_service_5"],nil ];
imageView.animationDuration = 1.0//设置动画总时间
imageView.animationRepeatCount = 0;//设置重复次数,0表示不重复
[imageView startAnimating];   //开始动画

五、指定位置圆角
以UIButton为例:

UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];

按钮 底部 - 左边 - 圆角
UIRectCorner corners =  UIRectCornerBottomLeft;
按钮 底部 - 左边+右边 - 圆角
UIRectCorner corners =  UIRectCornerBottomLeft | UIRectCornerBottomRight;
按钮  底部(左) + 顶(右) - 圆角
UIRectCorner corners =  UIRectCornerBottomLeft | UIRectCornerTopRight;
...    

UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:button.bounds byRoundingCorners:corners cornerRadii:CGSizeMake(10, 10)];

CAShapeLayer *maskLayer = [[CAShapeLayer alloc] init];
maskLayer.frame = button.bounds;
maskLayer.path = maskPath.CGPath;
button.layer.mask = maskLayer;

枚举：
typedef NS_OPTIONS(NSUInteger, UIRectCorner) {
    UIRectCornerTopLeft     = 1 << 0,
    UIRectCornerTopRight    = 1 << 1,
    UIRectCornerBottomLeft  = 1 << 2,
    UIRectCornerBottomRight = 1 << 3,
    UIRectCornerAllCorners  = ~0UL
};

参考资料:
1.有footerView时最后一个cell不显示分割线
2.导航栏渐变
3.UIButton的图文排序
4.UIEdgeInsetsMake-重要