模仿通知UIVIew与黑暗的背景

Question

我有兴趣创建一个弹出式通知视图，类似于下面看到的设计模式，其中弹出UIView，屏幕的其余部分变暗，并且不使用新的模态视图。由于这种设计模式如此常见，我想知道是否有“经过验证的”方法（或者有一个广泛使用的开源框架，如AFNetworking下载/上传文件和图像）？

感谢。

Answer 1

这是一个好的开始：

PopupView.h

#import <UIKit/UIKit.h>

@interface PopupView : NSObject

+ (void)addSubview:(UIView *)view;
+ (void)show;
+ (void)hide;

@end

PopupView.m：

#import "PopupView.h"

@implementation PopupView

+(UIView *)sharedView {
    static UIView *_view = nil;
    static dispatch_once_t onceToken = 0;
    dispatch_once(&onceToken, ^{
        _view = [[UIView alloc] initWithFrame:CGRectMake(0, 0, [[UIScreen mainScreen] bounds].size.width, [[UIScreen mainScreen] bounds].size.height)];
        _view.backgroundColor = [UIColor blackColor];
        _view.alpha = 0.6;

        UITapGestureRecognizer *singleFingerTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(hide)];
        [_view addGestureRecognizer:singleFingerTap];
    });
    return _view;
}

+ (void)addSubview:(UIView *)view {
    UIView *v = [PopupView sharedView];
    [v addSubview:view];
}

+ (void)show {
    UIView *v = [PopupView sharedView];

    v.frame = CGRectMake(0, 0, [[UIScreen mainScreen] bounds].size.width, [[UIScreen mainScreen] bounds].size.height);

    id<UIApplicationDelegate> appDelegate = [[UIApplication sharedApplication] delegate];

    [[appDelegate window] addSubview:v];
}

+ (void)hide {
    UIView *v = [PopupView sharedView];
    [v removeFromSuperview];
    [v.subviews makeObjectsPerformSelector: @selector(removeFromSuperview)];
}

用法：

UILabel *l = [[UILabel alloc] initWithFrame:CGRectMake(50, 50, 200, 21)];
l.text = @"Hello";
l.textColor = [UIColor whiteColor];
[PopupView addSubview:l];
[PopupView show];

或者当然不是标签，你可以放任何你想要的视图。