實現這個功能也是被逼無奈，項目需要縮放移動有很多小頁簽的WKWebView，嘗試了UIScrollView，但是很不理想，因為webview需要側滑和上下滑動，所以縮放拖動絕大部分都無法觸發，只得采用手勢實現。在網上查閱了大量資料，終于實現了該功能，廢話不多說，上代碼：
1、定義縮放倍數和偏移量
// 縮放倍數#define minScale 1#define maxScale 2// 偏移量#define Offset 02、定義需要用到的屬性
@PRoperty (nonatomic,strong) UIImageView *imgView;// 要縮放的視圖// 縮放@property (nonatomic, assign) CGFloat lastScale;// 上一次縮放的比例@property (nonatomic, strong) UipinchGestureRecognizer *pinch;// 捏合手勢@property (nonatomic, strong) UIPanGestureRecognizer *pan;// 平移手勢3、初始化視圖、手勢，并設置手勢
_imgView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"2.jpg"]]; _imgView.frame = self.view.frame; _imgView.userInteractionEnabled = YES; [self.view addSubview:_imgView]; _pinch = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(pinchAction:)]; _pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(panAction:)]; [_imgView addGestureRecognizer:_pinch]; [_imgView addGestureRecognizer:_pan];4、 設置錨點
- (void)adjustAnchorPointForGestureRecognizer:(UIGestureRecognizer *)gestureRecognizer{ //UIGestureRecognizerStateBegan意味著手勢已經被識別 if (gestureRecognizer.state ==UIGestureRecognizerStateBegan) { //手勢發生在哪個view上 UIView *piece = gestureRecognizer.view; //獲得當前手勢在view上的位置。 CGPoint locationInView = [gestureRecognizer locationInView:piece]; piece.layer.anchorPoint =CGPointMake(locationInView.x / piece.bounds.size.width, locationInView.y / piece.bounds.size.height); //根據在view上的位置設置錨點。 //防止設置完錨點過后，view的位置發生變化，相當于把view的位置重新定位到原來的位置上。 CGPoint locationInSuperview = [gestureRecognizer locationInView:piece.superview]; piece.center = locationInSuperview; }}5、 縮放方法
- (void)pinchAction:(UIPinchGestureRecognizer *)gestureRecognizer{ UIGestureRecognizerState state = [gestureRecognizer state]; if(state == UIGestureRecognizerStateBegan) { _lastScale = [gestureRecognizer scale]; } if (gestureRecognizer.scale > 1) { [self adjustAnchorPointForGestureRecognizer:gestureRecognizer]; }else{ _imgView.layer.anchorPoint =CGPointMake(0.5, 0.5); _imgView.center = self.view.center; } CGFloat currentScale = [[[gestureRecognizer view].layer valueForKeyPath:@"transform.scale"] floatValue]; if (state == UIGestureRecognizerStateBegan || state == UIGestureRecognizerStateChanged) { CGFloat newScale = 1 - (_lastScale - [gestureRecognizer scale]); newScale = MIN(newScale, maxScale / currentScale); newScale = MAX(newScale, minScale / currentScale); CGAffineTransform transform = CGAffineTransformScale([[gestureRecognizer view] transform], newScale, newScale); NSLog(@"newScale = %f,currentScale = %f",newScale,currentScale); [gestureRecognizer view].transform = transform; _lastScale = [gestureRecognizer scale]; } if (state == UIGestureRecognizerStateEnded) { if (currentScale >= minScale && currentScale <= minScale + 0.1) { [_imgView removeGestureRecognizer:_pan]; }else if(currentScale > minScale + 0.1 && currentScale <= maxScale){ [_imgView addGestureRecognizer:_pan]; } }}6、 拖動方法
- (void)panAction:(UIPanGestureRecognizer *)gestureRecognizer{ if (gestureRecognizer.state == UIGestureRecognizerStateBegan || gestureRecognizer.state == UIGestureRecognizerStateChanged) { if (!(_imgView.frame.origin.x == 0 && _imgView.frame.origin.y == 0 && _imgView.frame.size.width == self.view.frame.size.width && _imgView.frame.size.height == self.view.frame.size.height)) { CGPoint translation = [gestureRecognizer translationInView:self.view]; gestureRecognizer.view.center = CGPointMake(gestureRecognizer.view.center.x + translation.x, gestureRecognizer.view.center.y + translation.y); [gestureRecognizer setTranslation:CGPointZero inView:self.view]; } } CGRect rect = _imgView.frame; if (_imgView.frame.origin.x > 0 + Offset) {//左邊進入屏幕 NSLog(@"左邊進入屏幕"); [UIView animateWithDuration:0.25 animations:^{ CGPoint point = CGPointMake(gestureRecognizer.view.center.x - gestureRecognizer.view.frame.origin.x, gestureRecognizer.view.center.y); gestureRecognizer.view.center = point; }]; }else if (CGRectGetMaxX(rect) < self.view.frame.size.width + Offset){ NSLog(@"右邊進入屏幕"); [UIView animateWithDuration:0.25 animations:^{ CGRect newRect = CGRectOffset(_imgView.frame, self.view.frame.size.width - CGRectGetMaxX(_imgView.frame), 0); _imgView.frame = newRect; }]; } if (_imgView.frame.origin.y > 0 + Offset) {//上邊進入屏幕 NSLog(@"上邊進入屏幕"); [UIView animateWithDuration:0.25 animations:^{ CGPoint point = CGPointMake(gestureRecognizer.view.center.x, gestureRecognizer.view.center.y - gestureRecognizer.view.frame.origin.y); gestureRecognizer.view.center = point; }]; }else if(CGRectGetMaxY(rect) < self.view.frame.size.height + Offset){ NSLog(@"下邊進入屏幕"); [UIView animateWithDuration:0.25 animations:^{ CGRect newRect = CGRectOffset(_imgView.frame, 0, self.view.frame.size.height - CGRectGetMaxY(_imgView.frame)); _imgView.frame = newRect; }]; }}手勢實現也是萬不得已才用的，如果有哪位大神解決了UIScrollView縮放有多個側滑頁簽，并且可以上下滑動的WKWebView，請給我留言，相互交流，萬分感謝。
轉載請注明出處，萬分感謝！
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