在实际开发中，想要实现类似于Android系统自带的Toast弹出信息提示窗，那么该如何实现呢？相信大家对于windows窗口并不陌生，此处的实现思路是利用UIApplication中windows窗口添加视图，设置定时消失实现类似于Android系统自带Toast弹出信息提示窗。

ToastUtil.h

#import <UIKit/UIKit.h>typedef NS_ENUM(NSInteger, Gravity) {TOP,CENTRE,BOTTOM
};@interface ToastUtil : NSObject+(instancetype)toast;// 显示Toast（默认时长2.5秒，默认底部显示）
-(void)showToast:(NSString *)msg;// 显示Toast：设置时长（默认底部显示）
-(void)showToast:(NSString *)msg duration:(NSTimeInterval)duration;// 显示Toast：设置时长，设置显示位置（TOP，CENTRE，BOTTOM）
-(void)showToast:(NSString *)msg duration:(NSTimeInterval)duration gravity:(Gravity)gravity;// 显示Toast：设置时长，设置显示位置（TOP，CENTRE，BOTTOM），设置消失回调监听
-(void)showToast:(NSString *)msg duration:(NSTimeInterval)duration gravity:(Gravity)gravity finishHandler:(dispatch_block_t)finishHandler;@end

ToastUtil.m

#import <Foundation/Foundation.h>
#import "ToastUtil.h"#if __IPHONE_OS_VERSION_MIN_REQUIRED >= __IPHONE_7_0
#define MultilineTextSize(text, font, maxSize) [text length] > 0 ? [text \
boundingRectWithSize:maxSize options:(NSStringDrawingUsesLineFragmentOrigin) \
attributes:@{NSFontAttributeName:font} context:nil].size : CGSizeZero;
#else
#define MultilineTextSize(text, font, maxSize) [text length] > 0 ? [text \
sizeWithFont:font constrainedToSize:maxSize] : CGSizeZero;
#endif// 获取屏幕的宽度和高度
#define SCREEN_WIDTH ([UIScreen mainScreen].bounds.size.width)
#define SCREEN_HEIGHT ([UIScreen mainScreen].bounds.size.height)// 文字视图间距
const CGFloat toast_padding = 12;
// 视图圆角半径
const CGFloat toast_cornerRadius = 4;
// 字体大小
const CGFloat toast_fontSize = 12;// Toast显示透明度动画时间
const NSTimeInterval ANIM_DURATION = 0.2;
// 默认Toast显示时间
const NSTimeInterval Toast_DEFAULT_DURATION = 2.5;@interface ToastUtil()@property (strong, nonatomic) UIView *toastView;
@property (nonatomic, strong) NSTimer *toastTimer;
@property (nonatomic, strong) NSTimer *dismissTimer;
@property (nonatomic, copy) dispatch_block_t finishHandler;@end@implementation ToastUtil@synthesize toastView;
@synthesize toastTimer;
@synthesize dismissTimer;
@synthesize finishHandler;+ (instancetype)toast{static ToastUtil *instance;static dispatch_once_t onceToken;dispatch_once(&onceToken, ^{instance = [[ToastUtil alloc] init];});return instance;
}- (void)showToast:(NSString *)msg{[self toastShow:msg duration:Toast_DEFAULT_DURATION gravity:BOTTOM finishHandler:^{NSLog(@"Toast消失：msg：%@",msg);}];
}- (void)showToast:(NSString *)msg duration:(NSTimeInterval)duration{[self toastShow:msg duration:duration gravity:BOTTOM finishHandler:^{NSLog(@"Toast消失：msg：%@",msg);}];
}- (void)showToast:(NSString *)msg duration:(NSTimeInterval)duration gravity:(Gravity)gravity{[self toastShow:msg duration:duration gravity:gravity finishHandler:^{NSLog(@"Toast消失：msg：%@",msg);}];
}- (void)showToast:(NSString *)msg duration:(NSTimeInterval)duration gravity:(Gravity)gravity finishHandler:(dispatch_block_t)finishHandler{[self toastShow:msg duration:duration gravity:gravity finishHandler:finishHandler];
}-(void)toastShow:(NSString *)msg duration:(NSTimeInterval)duration gravity:(Gravity)gravity finishHandler:(dispatch_block_t)finishHandler{self.finishHandler = finishHandler;if (toastView || toastView.superview) {[self removeToast];}[self initToastView:msg gravity:gravity];if (toastView) {toastView.alpha = 0;[[[UIApplication sharedApplication].windows firstObject] addSubview:toastView];[[[UIApplication sharedApplication].windows firstObject] bringSubviewToFront:toastView];}[UIView animateWithDuration:ANIM_DURATION animations:^{if (self->toastView) {self->toastView.alpha = 1;}}];toastTimer = [NSTimer scheduledTimerWithTimeInterval:duration target:self selector:@selector(finishDismiss) userInfo:nil repeats:NO];
}- (void)initToastView:(NSString *)msg gravity:(Gravity)gravity{CGSize toastSize = [self getToastSizeWithMessage:msg];CGFloat toastWidth = toastSize.width;CGFloat toastHeight = toastSize.height;CGFloat x = (SCREEN_WIDTH - toastWidth) / 2;CGFloat y = (SCREEN_HEIGHT - toastHeight) * 5 / 6;switch (gravity) {case TOP:y = (SCREEN_HEIGHT - toastHeight) * 1 / 6;break;case CENTRE:y = (SCREEN_HEIGHT - toastHeight) / 2;break;case BOTTOM:y = (SCREEN_HEIGHT - toastHeight) * 5 / 6;break;}toastView = [[UIView alloc] init];toastView.backgroundColor = [UIColor colorWithWhite:0 alpha:0.6];toastView.layer.cornerRadius = toast_cornerRadius;toastView.frame = CGRectMake(x, y, toastWidth, toastHeight);UILabel *messageLabel = [[UILabel alloc] initWithFrame:toastView.bounds];messageLabel.text = msg;messageLabel.textColor = [UIColor whiteColor];messageLabel.font = [UIFont systemFontOfSize:toast_fontSize];messageLabel.numberOfLines = 0;messageLabel.textAlignment = NSTextAlignmentCenter;// 文字自适应宽高CGSize expectSize = [messageLabel sizeThatFits:CGSizeMake(toastWidth, SCREEN_HEIGHT)];messageLabel.frame = CGRectMake((toastWidth - expectSize.width) / 2, (toastHeight - expectSize.height) / 2, expectSize.width, expectSize.height);[toastView addSubview:messageLabel];[toastView addSubview:messageLabel];
}- (void)finishDismiss {[UIView animateWithDuration:ANIM_DURATION animations:^{if (self->toastView) {self->toastView.alpha = 0;}}];dismissTimer = [NSTimer scheduledTimerWithTimeInterval:ANIM_DURATION target:self selector:@selector(dismiss) userInfo:nil repeats:NO];
}- (void) dismiss{[self removeToast];if (self->finishHandler) { self->finishHandler(); }
}- (void)removeToast {if (toastView) {[toastView removeFromSuperview];toastView = nil;}
}- (void)dealloc {if (toastTimer) {[toastTimer invalidate];toastTimer = nil;}if (dismissTimer) {[dismissTimer invalidate];dismissTimer = nil;}
}- (CGSize)getToastSizeWithMessage:(NSString *)msg{UIFont *font = [UIFont systemFontOfSize:toast_fontSize];CGSize textSize = MultilineTextSize(msg, font, CGSizeMake(SCREEN_WIDTH - 60, SCREEN_HEIGHT ));CGFloat labelWidth = textSize.width + 1;CGFloat labelHeight = textSize.height + 1;CGFloat heightPadding = 2 * toast_padding;CGFloat toastHeight = labelHeight + heightPadding;CGFloat toastWidth = labelWidth + heightPadding;return CGSizeMake(toastWidth, toastHeight);
}@end