#import "ViewController.h"#define maxY 60@interface ViewController ()@PRoperty (nonatomic, weak) UIView *mainView;@property (nonatomic, weak) UIView *leftView;@property (nonatomic, weak) UIView *rightView;@property (nonatomic, assign) BOOL isDraging;@end@implementation ViewController- (void)viewDidLoad { [super viewDidLoad]; // 添加所有子控件 [self addAllChildView]; // 監(jiān)聽主視圖的frame的變化 [self.mainView addObserver:self forKeyPath:@"frame" options:NSKeyValueObservingOptionNew context:nil];}// 屬性變化,會調(diào)用此方法- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary<NSString *,id> *)change context:(void *)context { if (self.mainView.frame.origin.x < 0) { self.rightView.hidden = NO; self.leftView.hidden = YES; }else if(self.mainView.frame.origin.x > 0){ self.rightView.hidden = YES; self.leftView.hidden = NO; }}- (void)addAllChildView { // leftView UIView *leftView = [[UIView alloc] initWithFrame:self.view.bounds]; leftView.backgroundColor = [UIColor greenColor]; leftView.alpha = 0.3; [self.view addSubview:leftView]; self.leftView = leftView; // rightView UIView *rightView = [[UIView alloc] initWithFrame:self.view.bounds]; rightView.backgroundColor = [UIColor redColor]; rightView.alpha = 0.3; [self.view addSubview:rightView]; // mainView UIView *mainView = [[UIView alloc] initWithFrame:self.view.bounds]; mainView.backgroundColor = [UIColor blueColor]; mainView.alpha = 0.3; [self.view addSubview:mainView]; self.mainView = mainView;}// 添加拖拽方法- (void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event { // 獲取手指 UITouch *touch = [touches anyObject]; CGPoint curP = [touch locationInView:self.view]; CGPoint preP = [touch previousLocationInView:self.view]; // 獲取手指每移動一下, X軸的偏移量 CGFloat offsetX = curP.x - preP.x; // 設(shè)置當(dāng)前視圖的frame self.mainView.frame = [self frameWithOffsetX:offsetX]; // 記錄下當(dāng)前正在拖拽 self.isDraging = YES;}// 根據(jù)X的偏移量計算出當(dāng)前視圖的frame- (CGRect)frameWithOffsetX:(CGFloat)offsetX { CGFloat screenW = [UIScreen mainScreen].bounds.size.width; CGFloat screenH = [UIScreen mainScreen].bounds.size.height; // 獲取手指每偏移一點, Y值需要偏移多少 CGFloat offsetY = offsetX * maxY / screenW; // 獲取縮放比例 CGFloat scale = (screenH - 2 * offsetY) / screenH; if (self.mainView.frame.origin.x < 0) { scale = (screenH + 2 * offsetY) / screenH; } // 計算當(dāng)前視圖的frame CGRect frame = self.mainView.frame; frame.origin.x += offsetX; frame.size.height = frame.size.height * scale; frame.size.width = frame.size.width * scale; frame.origin.y = (screenH - frame.size.height) * 0.5; return frame;}#define targetRX 300#define targetLX -250- (void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event { if (self.isDraging == NO && self.mainView.frame.origin.x != 0) { [UIView animateWithDuration:0.25 animations:^{ self.mainView.frame = self.view.bounds; }]; return; } // 定位功能 CGFloat screenW = [UIScreen mainScreen].bounds.size.width; // 獲取當(dāng)前主視圖的frame CGRect frame = self.mainView.frame; CGFloat target = 0; if (frame.origin.x > screenW * 0.5) { // target = targetRX; }else if(CGRectGetMaxX(self.mainView.frame) < screenW * 0.5){ // 定位到左邊 target = targetLX; } if(target == 0) { [UIView animateWithDuration:0.25 animations:^{ self.mainView.frame = self.view.bounds; }]; }else { [UIView animateWithDuration:0.25 animations:^{ // 獲取X軸的偏移量 CGFloat offsetX = target - frame.origin.x; self.mainView.frame = [self frameWithOffsetX:offsetX]; }]; } // 沒有拖拽 self.isDraging = NO;}新聞熱點
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