How to Use iOS100 Line Code to Implement a Simple Drawer Effect

Introduction

A simple implementation of the drawer effect in iOS is widely used in many applications now, and there are also many examples online. This article mainly achieves it through some simple code, and those who need it can learn together.

Here is the effect diagram

The following is an example code

#import <UIKit/UIKit.h>
@interface MainViewController : UIViewController
+ (instancetype)mainViewControllerWithLeftViewController:(UIViewController *)leftViewController withMainPageViewController:(UIViewController *)mainPageViewController;
@end

#import "MainViewController.h"
#define KWidth self.view.frame.size.width
#define KHeight self.view.frame.size.height
@interface MainViewController ()
@property (nonatomic,strong)UIViewController *leftVC;
@property (nonatomic,strong)UIViewController *centerVC;
@property (nonatomic,assign)BOOL isSlider;
@property (nonatomic,strong)UIView *corverView;
@end
@implementation MainViewController
+ (instancetype)mainViewControllerWithLeftViewController:(UIViewController *)leftViewController withMainPageViewController:(UIViewController *)mainPageViewController{
  MainViewController *mainVC = [[MainViewController alloc] init];
  mainVC.leftVC = leftViewController;
  mainVC.centerVC = mainPageViewController;
  return mainVC;
}
- (void)viewDidLoad{
  [super viewDidLoad];
  self.isSlider = NO;
  self.view.backgroundColor = [UIColor whiteColor];
  [self addChildViewController:self.leftVC];
  [self.view addSubview:self.leftVC.view];
  [self addChildViewController:self.centerVC];
  [self.view addSubview:self.centerVC.view];
  // Add gestures to the left view and the main view
  [self addGestureForView];
}
// Add cover to the main view
- (void)addCorverView{
  if (self.corverView) {
    [self.corverView removeFromSuperview];
    self.corverView = nil;
  }
  self.corverView = [[UIView alloc] initWithFrame:self.centerVC.view.bounds];
  _corverView.backgroundColor = [[UIColor blackColor] colorWithAlphaComponent:0.0];
  [self.centerVC.view addSubview:self.corverView];
}
// Remove the main view cover
- (void)removeCoverView{
  if (self.corverView) {
    [self.corverView removeFromSuperview];
    self.corverView = nil;
  }
}
// Add gestures to the left view and the main view
- (void)addGestureForView{
  UISwipeGestureRecognizer *rightGesture = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swipeRightAction:)];
  rightGesture.direction = UISwipeGestureRecognizerDirectionRight;
  [self.centerVC.view addGestureRecognizer:rightGesture];
  UISwipeGestureRecognizer *leftGesture = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swipeLeftAction:)];
  leftGesture.direction = UISwipeGestureRecognizerDirectionLeft;
  [self.centerVC.view addGestureRecognizer:leftGesture];
  UISwipeGestureRecognizer *leftVCLeftSwipeGesture = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(leftVCLeftSwipeAction:)];
  leftVCLeftSwipeGesture.direction = UISwipeGestureRecognizerDirectionLeft;
  [self.leftVC.view addGestureRecognizer:leftVCLeftSwipeGesture];
}
- (void)swipeRightAction:(id)sender{
  [self moveView:self.centerVC.view scale:0.8 panValue:KWidth];
  self.isSlider = YES;
  [self addCorverView];
}
- (void)swipeLeftAction:(id)sender{}}
  [self moveView:self.centerVC.view scale:1 panValue:KWidth / 2];
  self.isSlider = NO;
  [self removeCoverView];
}
- (void)leftVCLeftSwipeAction:(id)sender{
  [self moveView:self.centerVC.view scale:1 panValue:KWidth / 2];
  self.isSlider = NO;
  [self removeCoverView];
}
// Translate and scale a view
- (void)moveView:(UIView *)view scale:(CGFloat)scale panValue:(CGFloat)value{
  [UIView beginAnimations:nil context:nil];
  view.transform = CGAffineTransformScale(CGAffineTransformIdentity, scale, scale);
  view.center = CGPointMake(value, view.center.y);
  [UIView commitAnimations];
}
@end

Summary

That's all for this article. I hope the content of this article will be helpful to everyone's learning or work. If you have any questions, you can leave messages for communication.

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