ios---顶部提示框

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: