iOS：类似于网易云音乐的刷新条目显示弹框

一、介绍

在app中使用刷新控件或者第三方刷新库是最常见的功能，在请求服务器时，获取数据的过程是处于不可见状态的，那么通过这个刷新状态可以给用户以直观的感受，这是增强用户体验的一个相当好的方法。我个人认为，有时这个方法仍有不足，就是当拉取到数据时，用户只是知道数据有了，并没有直接告知用户拉取了或者刷新了多少条数据。所以，这里我写了一个类似于网易云音乐的“朋友”模块中的一个刷新条目显示弹框。

二、思想

1、创建一个messageView，内部包含一个label，使用masonry约束，将其放到navigationBar后面，默认状态是透明的；

2、navigationBar可以是系统的，也可以是自定义的，根据需求去应用；

3、刷新结束时通过UIView的block动画改编透明度并显示，显示一定时间后自动显示隐藏；

4、创建的实例都放在基类中进行，暴露给子类去调用即可；

三、代码

ShowMessageView.h

//
//  ShowMessageView.h
//  ShowMessageTest
//
//  Created by 夏远全 on 2018/3/22.
//  Copyright © 2018年 夏远全. All rights reserved.
//

#import <UIKit/UIKit.h>

@interface ShowMessageView : UIView

//创建显示弹框（这个直接放在基类中创建，并将该实例对象暴露给子类使用，vc的系统导航栏没有隐藏掉）
+(instancetype)createShowMessageViewInViewController:(UIViewController *)vc;

//创建显示弹框（这个直接放在基类中创建，并将该实例对象暴露给子类使用，vc的系统导航栏被隐藏掉了，传入vc自定义的导航栏customNav）
+(instancetype)createShowMessageViewInViewController:(UIViewController *)vc customNav:(UIView *)customNav;

//显示消息 (刷新结束后调用)
-(void)showMessage:(NSString *)message;

//隐藏消息 (需要在基类的viewWillDisappear调用一次就行了)
-(void)hideMessage;

@end

ShowMessageView.m

//
//  ShowMessageView.m
//  ShowMessageTest
//
//  Created by 夏远全 on 2018/3/22.
//  Copyright © 2018年 夏远全. All rights reserved.
//

#import "ShowMessageView.h"
#import <Masonry.h>

#define isIphoneX_YML (kScreenWidth == 375.0 && kScreenHeight == 812.0) //没有横屏模式才能这么判断
#define kStatusBarHeight (isIphoneX_YML ? 44.0 : 20.0)
#define kNavigationHeight 44.0
#define kNavigationAndStatusBarHeight    (kStatusBarHeight + kNavigationHeight)

@interface ShowMessageView ()
@property (nonatomic, strong) UILabel *messageLabel;
@property (nonatomic, assign) CGFloat messsageWidth;
@end

@implementation ShowMessageView

#pragma mark - life cycle
+(instancetype)createShowMessageViewInViewController:(UIViewController *)vc
{
    ShowMessageView *messageView = [[self alloc] initWithFrame:CGRectMake(, kNavigationAndStatusBarHeight-, , )];

    messageView.backgroundColor = [UIColor clearColor];
    messageView.alpha = ;
    messageView.hidden = YES;

    messageView.centerX  = vc.navigationController.navigationBar.centerX;

    [messageView setShadowForView:messageView];

    [vc.navigationController.navigationBar addSubview:messageView];

    [vc.navigationController.navigationBar sendSubviewToBack:messageView];

    [messageView setup];

    return messageView;
}

+(instancetype)createShowMessageViewInViewController:(UIViewController *)vc customNav:(UIView *)customNav;{

    ShowMessageView *messageView = [[self alloc] initWithFrame:CGRectMake(, kNavigationAndStatusBarHeight-, , )];

    messageView.backgroundColor = [UIColor clearColor];
    messageView.alpha = ;
    messageView.hidden = YES;

    messageView.centerX  = customNav.centerX;

    [ShadowUtility setShadowForView:messageView];

    [customNav addSubview:messageView];

    [customNav sendSubviewToBack:messageView];

    [messageView setup];

    return messageView;
}

-(void)setup
{
    [self setDefalut];
    [self addSubViews];
    [self setupSubviewsConstraints];
}

-(void)setDefalut
{

}

#pragma mark - add subViews
-(void)addSubViews
{
    [self addSubview:self.messageLabel];
}

#pragma mark - layout subviews
-(void)setupSubviewsConstraints
{
    [self.messageLabel mas_remakeConstraints:^(MASConstraintMaker *make) {
        make.centerX.equalTo(self.mas_centerX);
        make.centerY.equalTo(self.mas_centerY);
        make.height.equalTo(self.mas_height);
        if (self.messsageWidth > ) {
            make.width.equalTo(@(MAX(, self.messsageWidth)+));
        }
    }];
}

#pragma mark - event response

#pragma mark - public methods
-(void)showMessage:(NSString *)message{

    self.messageLabel.text = message;

    if (message.length > ) {
        self.messsageWidth = [message boundingRectWithSize:CGSizeMake(MAXFLOAT, ) options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName:[UIFont systemFontOfSize:]} context:nil].size.width;
        [self setupSubviewsConstraints];
    }

    if (self.alpha == ) {

        self.hidden = NO;

        [UIView animateWithDuration:0.8 animations:^{

            self.alpha = 1.0;
            self.transform = CGAffineTransformMakeTranslation(,+);

        } completion:^(BOOL finished) {

            dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.5 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{

                [UIView animateWithDuration:0.3 animations:^{

                    self.alpha = ;

                } completion:^(BOOL finished) {

                    self.hidden = YES;
                    self.transform = CGAffineTransformIdentity;
                }];

            });

        }];
    }

}

-(void)hideMessage{
    self.alpha = ;
    self.transform = CGAffineTransformIdentity;
}

#pragma mark - private methods
- (void)setShadowForView:(UIView *)view
{
    view.layer.shadowColor = HEXCOLOR(0xaeaeae).CGColor;
    view.layer.shadowOffset = CGSizeMake(, );
    view.layer.shadowRadius = 4.0;
    view.layer.shadowOpacity = 0.2;
    view.layer.shouldRasterize = YES;
    view.layer.rasterizationScale = [UIScreen mainScreen].scale;
}

#pragma mark - getters and setters
-(UILabel *)messageLabel{
    if (!_messageLabel) {
        _messageLabel = [[UILabel alloc] init];
        _messageLabel.layer.cornerRadius = ;
        _messageLabel.layer.masksToBounds = YES;
        _messageLabel.font = [UIFont systemFontOfSize:];
        _messageLabel.textAlignment = NSTextAlignmentCenter;
        _messageLabel.textColor = [UIColor whiteColor];
        _messageLabel.backgroundColor = [[UIColor blackColor] colorWithAlphaComponent:0.7];
    }
    return _messageLabel;
}

@end

四、使用

1、在基类创建

@property (nonatomic, strong) ShowMessageView *showMessageView; //在基类中定义实例属性

self.showMessageView = [ShowMessageView createShowMessageViewInViewController:self]; //在基类中创建实例

2、在基类实现必要的方法

- (void)viewWillDisappear:(BOOL)animated   //在基类中调用必要的方法
{
    [super viewWillDisappear:animated];
    [self.showMessageView hideMessage];
}

3、子类调用

[weakSelf.tableView.mj_header endRefreshing];
[weakSelf.showMessageView showMessage:@"刷新了20条新数据"];  //结束刷新后显示条目弹框

五、效果