ios_弹框提示

• 应公司要求需要写个类似安卓提示框的东西.其实不想写…没办法人家要求的.
• 就用了两个知识点
  
  • 延迟执行某个方法(GCD实现)
  • 单例
• demo地址(git克隆) : https://code.csdn.net/alex_birdlion/label_alertview.git
• 或者直接下载: https://code.csdn.net/alex_birdlion/label_alertview/tree/master

---

• 思路: 将label加在keyWindow上,创建单例利用单例属性isShowing来防止多个label叠加在keyWindow上.用GCD延迟执行使label消失的方法,再将isShowing状态改为NO->即消失状态,下次调用可以弹出.

#import "HBToast.h"#define kScreenB [UIScreen mainScreen].bounds#define kScreenH [UIScreen mainScreen].bounds.size.height#define kScreenW [UIScreen mainScreen].bounds.size.width@implementation HBToast//创建单例是为了判断当前是否在显示lbl提示框.isShowing+(instancetype)sharedTost{    static HBToast * instance = nil;    static dispatch_once_t onceToken;    dispatch_once(&onceToken, ^{        instance = [self new];    });    return instance;}+(void)bb_showStatus:(NSString *)status withTime:(CGFloat)time{    HBToast * toast = [HBToast sharedTost];    if (!toast.isShowing) {        toast.isShowing = YES;        UIWindow * keyWindow = [UIApplication sharedApplication].keyWindow;        UILabel * lbl = [UILabel new];        lbl.text = status;        lbl.backgroundColor = [UIColor blackColor];        lbl.alpha = 0.7;        lbl.layer.cornerRadius = 3.0;        lbl.layer.masksToBounds = YES;        lbl.textColor = [UIColor whiteColor];        lbl.font = [UIFont systemFontOfSize:16];        lbl.textAlignment = NSTextAlignmentCenter;        CGFloat lblH = 27;        CGFloat lblW = 150;        CGFloat lblY = kScreenH - lblH - 60;        CGFloat lblX = (kScreenW - lblW) * 0.5;        lbl.frame = CGRectMake(lblX, lblY, lblW, lblH);        [keyWindow addSubview:lbl];        NSLog(@"显示");        //通过GCD方式延迟执行 移除lbl        dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(time * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{            NSLog(@"隐藏");            toast.isShowing = NO;            [lbl removeFromSuperview];        });    }}+(void)bb_showStatus:(NSString *)status{    HBToast * toast = [HBToast sharedTost];    if (!toast.isShowing) {    toast.isShowing = YES;    UIWindow * keyWindow = [UIApplication sharedApplication].keyWindow;    UILabel * lbl = [UILabel new];    lbl.text = status;    lbl.backgroundColor = [UIColor blackColor];    lbl.alpha = 0.7;    lbl.layer.cornerRadius = 3.0;    lbl.layer.masksToBounds = YES;    lbl.textColor = [UIColor whiteColor];    lbl.font = [UIFont systemFontOfSize:16];    lbl.textAlignment = NSTextAlignmentCenter;    CGFloat lblH = 27;    CGFloat lblW = 150;    CGFloat lblY = kScreenH - lblH - 60;    CGFloat lblX = (kScreenW - lblW) * 0.5;    lbl.frame = CGRectMake(lblX, lblY, lblW, lblH);    [keyWindow addSubview:lbl];    NSLog(@"显示");        //通过GCD方式延迟执行 移除lbl    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2.0 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{        NSLog(@"隐藏");        toast.isShowing = NO;        [lbl removeFromSuperview];    });    }}@end