ios---顶部提示框

来源：互联网发布：android 手机淘宝源码编辑：程序博客网时间：2024/06/11 22:37

一、简介

有时候我们在做程序的时候,项目要求我们给用户提示信息的时候,从顶部自动下拉下来,前些日子我接到过这样的需求,感觉用第三方的集成进来,如果以后修改样式的话或者其它的需求会很麻烦,所以我自己写了一个,代码有点简单,请大家指导一下,有什么意见或者有什么疑问可以直接评论询问我,很乐意和大家一起探讨学习.

二、代码

1.创建一个单例,我是继承NSOject的

+(instancetype)shareInstance
{
    static ShowChatStateView *stateView = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        stateView = [[ShowChatStateView alloc]init];
    });
    return stateView;
}

2.初始化UIWindow

-(instancetype)init
{
    self = [super init];
    id <UIApplicationDelegate> delegate = [[UIApplication sharedApplication] delegate];
    if ([delegate respondsToSelector:@selector(window)])
    {
        self.window = [delegate performSelector:@selector(window)];
    }
    else
    {
        self.window = [[UIApplication sharedApplication] keyWindow];
    }
    [self createUI];
    return self;

}

3.创建UILabel,使label唯一

-(void)createUI
{
    if (self.label == nil)
    {
        self.label = [[UILabel alloc]initWithFrame:CGRectMake(0, -64, SCREEN_WIDTH, 64)];
        self.label.textAlignment = NSTextAlignmentCenter;
        self.label.textColor = [UIColor whiteColor];
        self.label.backgroundColor = [MyTool colorWithString:@"50D2C2"];
        self.label.font = [UIFont systemFontOfSize:Font(14.0f)];
        self.label.alpha = 0.f;
    }
    if (self.label.superview == nil)
    {
        [self.window addSubview:self.label];
    }
}

4.将文字显示在Label上,并且从上面自动下拉,隔段时间(自己设定)在弹回去

-(void)show
{
    if (!self.label.alpha)
    {
        self.label.alpha = 1.f;
        CGRect rect = self.label.frame;
        rect.origin.y = 0;
        [UIView animateWithDuration:0.5 animations:^{
            self.label.frame = rect;
        } completion:^(BOOL finished) {
            CGRect rect = self.label.frame;
            rect.origin.y = -64;
            [UIView animateWithDuration:0.5 delay:1.0 options:UIViewAnimationOptionCurveEaseIn animations:^{
                self.label.frame = rect;
            } completion:^(BOOL finished) {
                self.label.alpha = 0.f;
            }];
        }];
    }
}
-(void)showLabelWithString:(NSString *)string
{
    self.label.text = string;
    [self show];
}

5.调用方法

[[ShowChatStateView shareInstance] showLabelWithString:@"您已签过到"];

三、总结

我是利用UIWindow来实现下拉,这样有导航栏也不影响view的向下弹出,如果你有更好的方法,欢迎讨论,下面是效果图:

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