qq侧边栏滑动效果

• 首先，效果图

qq侧边栏滑动.gif

实现思路：

• 基本布局： 左边自定义一个View，右边的主视图是TabBarVc，然后这两个添加在根视图上，并且设置TabBarVC成为根视图控制器的子视图（方便TabBarVC接受事件，并处理事件）
• 具体操作： 给根视图控制器添加一个拖拽手势，通过判断手势是否结束和拖拽的偏移量是否大于屏幕宽的一半（这个自己定义界限）来决定怎么改变左右view的形变属性

思路图.png

• 具体代码

//
//  RootViewController.m
//  QQ侧边栏效果
//
//  Created by liyang on 16/8/8.
//  Copyright © 2016年 liyang. All rights reserved.
//

#import "RootViewController.h"
#import "MainViewController.h"
#import "LeftView.h"

#define kAnimateDuration 0.5
#define kOffset_x self.view.frame.size.width * 3 / 4 // 偏移量

@interface RootViewController ()
@property (nonatomic, strong) LeftView *leftView;
@property (nonatomic, strong) UIButton *coverView;
@end

@implementation RootViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    self.view.backgroundColor = [UIColor whiteColor];
    
    [self setupUI];
}

- (void)setupUI
{
    LeftView *leftView = [LeftView leftView];
    leftView.frame = CGRectMake(-kOffset_x, 0, kOffset_x, self.view.frame.size.height);
    [self.view addSubview:leftView];
    self.leftView = leftView;
    
    MainViewController *mainVc = [[MainViewController alloc] init];
    UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:mainVc];
    mainVc.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"左侧按钮" style:UIBarButtonItemStylePlain target:self action:@selector(leftBarBtn:)];
    UITabBarController *barVc = [[UITabBarController alloc] init];
    [barVc addChildViewController:nav];
    [self addChildViewController:barVc];
    [self.view addSubview:barVc.view];
    nav.tabBarItem.title = @"首页";
    
    UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(panTheView:)];
    [self.view addGestureRecognizer:pan];
}
/**
 *  给主视图添加一个按钮挡板
 *
 *  @param view 视图
 */
- (void)addCoverToView:(UIView *)view
{
    UIButton *cover = [[UIButton alloc] initWithFrame:view.bounds];
    [cover addTarget:self action:@selector(coverPressed:) forControlEvents:UIControlEventTouchUpInside];
    [view addSubview:cover];
    self.coverView = cover;
}
// 点击了coverView
- (void)coverPressed:(UIButton *)sender
{
    [sender removeFromSuperview];
    UINavigationController *nav = [self.childViewControllers firstObject];
    [UIView animateWithDuration:kAnimateDuration animations:^{
        // clear transform
        nav.view.transform = CGAffineTransformIdentity;
        self.leftView.transform = CGAffineTransformIdentity;
    }];
}

// navBar上的左侧按钮
- (void)leftBarBtn:(UIBarButtonItem *)sender
{
    UINavigationController *nav = [self.childViewControllers firstObject];
    [UIView animateWithDuration:kAnimateDuration animations:^{
        // animation of View controller
        UIView *view = nav.view;
        // add cover
        [self addCoverToView:view];
        view.transform = CGAffineTransformMakeTranslation(kOffset_x, 0);
        // animation of left menu
        self.leftView.transform = CGAffineTransformMakeTranslation(kOffset_x, 0);
    }];
}

// 主视图上的拖拽手势
- (void)panTheView:(UIPanGestureRecognizer *)sender
{
    UINavigationController *nav = [self.childViewControllers firstObject];
    UIView *view = nav.view;
    CGPoint translation = [sender translationInView:self.view];
    CGFloat width = self.view.frame.size.width;

    // 判断此时手势是否结束了
    if (sender.state == UIGestureRecognizerStateEnded) {
        // 结束
        // 判断偏移量是否大于屏幕宽度的一半
        if (translation.x > width/2) {
            // 大于的话，改变左右的偏移量到指定位置
            [UIView animateWithDuration:kAnimateDuration animations:^{
                NSLog(@"动画进行中");
                view.transform = CGAffineTransformMakeTranslation(kOffset_x, 0);
                // animation of left menu
                self.leftView.transform = CGAffineTransformMakeTranslation(kOffset_x, 0);
            } completion:^(BOOL finished) {
                NSLog(@"动画完成");
                [self addCoverToView:view];
            }];
        }else{
            // 没有大于，清除偏移量
            [UIView animateWithDuration:kAnimateDuration animations:^{
                // clear transform
                nav.view.transform = CGAffineTransformIdentity;
                self.leftView.transform = CGAffineTransformIdentity;
            } completion:^(BOOL finished) {
                // 移除coverView
                if (self.coverView) {
                   [self.coverView removeFromSuperview];
                }
            }];
        }
    }else{
        // 手势动作还没有结束
        // 判断 偏移量有没有大于kOffset_x
        if (translation.x <= kOffset_x && translation.x > 0){
            // 不大于kOffset_x,并且偏移量是正的，左右偏移量随着拖拽改变
            self.leftView.transform = CGAffineTransformMakeTranslation(translation.x, 0);
            view.transform = CGAffineTransformMakeTranslation(translation.x, 0);
        }else if (translation.x < 0){
            // 此时小于0,说明往左滑动，用户是要关闭leftView，我们清空形变
            [UIView animateWithDuration:kAnimateDuration animations:^{
                self.leftView.transform = CGAffineTransformIdentity;
                view.transform = CGAffineTransformIdentity;
            }];
        }
    }
}

@end

• demo地址