iOS悬浮提示窗

作用：

该悬浮窗显示后切换viewController也会显示，需要手动或设置定时器使之消失。

用法：

在需要用到该悬浮提示窗的时候，使用工厂方法，并传入参数2个参数：AlertWindowPositionOption和要显示的文字text。
其中AlertWindowPositionOption为自定义的位置选项，分别为：

AlertWindowPositionTopMiddle 靠窗口上部并纵向居中
AlertWindowPositionCenter 窗口中心位置
AlertWindowPositionBottomMiddle 靠窗口�下部并纵向居中

步骤：

step1：新建一个类CustomAlertWindow，基于UIWindow
step2：自定义该Window
分别在2个文件中写入如下代码：

//CustomAlertWindow.h

#import <UIKit/UIKit.h>
typedef NS_ENUM(NSInteger, AlertWindowPositionOption) {
    AlertWindowPositionTopMiddle = 0,
    AlertWindowPositionCenter,
    AlertWindowPositionBottomMiddle
};

@interface CustomAlertWindow : UIWindow
+ (instancetype)aletWindowWithPositionOption:(AlertWindowPositionOption)positionType andInfoText:(NSString *)text;
//显示
- (void)show;
// 消失
- (void)dismiss;
@end

//CustomAlertWindow.m

#import "CustomAlertWindow.h"

#define LABEL_MARGIN      10       //Label的外边距
#define CENTER_Y_TO_EDGE  80       //悬浮窗中心点距边缘的纵坐标值

@implementation CustomAlertWindow

+ (instancetype)aletWindowWithPositionOption:(AlertWindowPositionOption)positionType andInfoText:(NSString *)text {
    return [[CustomAlertWindow alloc] initWithPositionOption:positionType andInfoText:text];
}

- (instancetype)initWithPositionOption:(AlertWindowPositionOption)positionType andInfoText:(NSString *)text {
    self = [super init];
    if (self) {
        UILabel *infoLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 40, 15)];
        infoLabel.text = text;
        infoLabel.textAlignment = NSTextAlignmentCenter;
        infoLabel.font = [UIFont systemFontOfSize:13];
        infoLabel.textColor = [UIColor whiteColor];
        //label尺寸适应文字大小
        [infoLabel sizeToFit];
        
        //根据labelSize确定window的大小
        CGSize labelSize = infoLabel.frame.size;
        CGSize windowSize = CGSizeMake(labelSize.width + 2*LABEL_MARGIN, labelSize.height + 2*LABEL_MARGIN);
        //根据window的尺寸确定label的中心点位置
        infoLabel.center = CGPointMake(windowSize.width / 2, windowSize.height / 2);
        
        //得到屏幕的尺寸
        CGRect superRect = [[UIScreen mainScreen] bounds];
        CGSize superSize = superRect.size;
        //计算window的大小
        self.frame = CGRectMake((superSize.width - windowSize.width) / 2, 0, windowSize.width, windowSize.height);
        
        //根据指定的positionType设置window的center
        switch (positionType) {
            case AlertWindowPositionTopMiddle:
                self.center = CGPointMake(superSize.width / 2, CENTER_Y_TO_EDGE);
                break;
                
            case AlertWindowPositionCenter:
                self.center = CGPointMake(superSize.width / 2, superSize.height / 2);
                break;
                
            case AlertWindowPositionBottomMiddle:
                self.center = CGPointMake(superSize.width / 2, superSize.height - CENTER_Y_TO_EDGE);
                break;
                
            default:
                break;
        }
        
        self.windowLevel = UIWindowLevelAlert + 1;
        self.backgroundColor = [UIColor colorWithRed:64  / 255.0 green:64 / 255.0 blue:64 / 255.0 alpha:0.7];
        self.layer.cornerRadius = 5;
        
        [self addSubview:infoLabel];
    }
    
    return self;
}

//显示window
- (void)show {
    [self makeKeyAndVisible];
}

//window消失
- (void)dismiss {
    [self resignKeyWindow];
}

@end

step3：调用的时候可以这样处理：

#import "ViewController.h"
#import "CustomAlertWindow.h"

@interface ViewController ()
@property (nonatomic, strong) CustomAlertWindow *alertWindow;
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
}

- (IBAction)displayFloatingWindow:(id)sender {
    self.alertWindow = [CustomAlertWindow aletWindowWithPositionOption:AlertWindowPositionCenter andInfoText:@"网络不给力"];
    [self.alertWindow show];
    //设置定时器使之消失
    [NSTimer scheduledTimerWithTimeInterval:4.0 target:self selector:@selector(resignWindow) userInfo:nil repeats:NO];
}

- (void)resignWindow {
    [self.alertWindow dismiss];
    //需要消失的时候不要忘了赋值nil
    self.alertWindow = nil;
}
@end