ios/web/public/web_state/crw_web_view_scroll_view_proxy.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef IOS_WEB_PUBLIC_WEB_STATE_CRW_WEB_VIEW_SCROLL_VIEW_PROXY_H_
   6 #define IOS_WEB_PUBLIC_WEB_STATE_CRW_WEB_VIEW_SCROLL_VIEW_PROXY_H_
   7
   8 #import <UIKit/UIKit.h>
   9
  10 @protocol CRWWebViewScrollViewProxyObserver;
  11
  12 // Provides an interface for web state observers to access the WebState's
  13 // UIScrollView in a limited and controlled manner.
  14 // This class is designed to limit lifetime of the UIScrollView such that it is
  15 // not retained beyond WebState. It is also a way to tunnel UIScrollViewDelegate
  16 // callbacks.
  17 // NOTE: The API exposed by the proxy class isn't intended to be restrictive.
  18 // The features needing to access other UIScrollView properties and methods
  19 // needed to drive the UIScrollView are free to extend the proxy class as
  20 // needed.
  21 // The class forwards some of the methods onto the UIScrollView. For more
  22 // information look at the UIScrollView documentation.
  23 @interface CRWWebViewScrollViewProxy : NSObject<UIScrollViewDelegate>
  24 @property(nonatomic, assign) CGPoint contentOffset;
  25 @property(nonatomic, assign) UIEdgeInsets contentInset;
  26 @property(nonatomic, readonly) BOOL isZooming;
  27 @property(nonatomic, assign) UIEdgeInsets scrollIndicatorInsets;
  28 @property(nonatomic, assign) CGSize contentSize;
  29 @property(nonatomic, readonly) CGRect frame;
  30 @property(nonatomic, getter=isScrollEnabled) BOOL scrollEnabled;
  31 @property(nonatomic, assign) BOOL bounces;
  32 @property(nonatomic, readonly) UIPanGestureRecognizer* panGestureRecognizer;
  33 // Returns the scrollview's gesture recognizers.
  34 @property(nonatomic, readonly) NSArray* gestureRecognizers;
  35
  36 // Calls UIScrollView's implementation of setContentInset: directly. This
  37 // bypasses a very slow update path in UIWebView.
  38 - (void)setContentInsetFast:(UIEdgeInsets)contentInset;
  39
  40 - (void)addGestureRecognizer:(UIGestureRecognizer*)gestureRecognizer;
  41 - (void)removeGestureRecognizer:(UIGestureRecognizer*)gestureRecognizer;
  42 - (void)setContentOffset:(CGPoint)contentOffset animated:(BOOL)animated;
  43
  44 // Used by the CRWWebViewProxy to set the UIScrollView to be managed.
  45 - (void)setScrollView:(UIScrollView*)scrollView;
  46
  47 // Adds |observer| to subscribe to change notifications.
  48 - (void)addObserver:(id<CRWWebViewScrollViewProxyObserver>)observer;
  49
  50 // Removes |observer| as a subscriber for change notifications.
  51 - (void)removeObserver:(id<CRWWebViewScrollViewProxyObserver>)observer;
  52
  53 @end
  54
  55 // A protocol to be implemented by objects to listen for changes to the
  56 // UIScrollView.
  57 // This is an exact mirror of the UIScrollViewDelegate callbacks. For more
  58 // information look at the UIScrollViewDelegate documentation.
  59 @protocol CRWWebViewScrollViewObserver<NSObject>
  60 @optional
  61 - (void)webViewScrollViewDidScroll:
  62         (CRWWebViewScrollViewProxy*)webViewScrollViewProxy;
  63 - (void)webViewScrollViewWillBeginDragging:
  64         (CRWWebViewScrollViewProxy*)webViewScrollViewProxy;
  65 - (void)webViewScrollViewWillEndDragging:
  66             (CRWWebViewScrollViewProxy*)webViewScrollViewProxy
  67                             withVelocity:(CGPoint)velocity
  68                      targetContentOffset:(inout CGPoint*)targetContentOffset;
  69 - (void)webViewScrollViewDidEndDragging:
  70             (CRWWebViewScrollViewProxy*)webViewScrollViewProxy
  71                          willDecelerate:(BOOL)decelerate;
  72 - (void)webViewScrollViewDidEndScrollingAnimation:
  73         (CRWWebViewScrollViewProxy*)webViewScrollViewProxy;
  74 - (void)webViewScrollViewDidEndDecelerating:
  75         (CRWWebViewScrollViewProxy*)webViewScrollViewProxy;
  76 - (BOOL)webViewScrollViewShouldScrollToTop:
  77         (CRWWebViewScrollViewProxy*)webViewScrollViewProxy;
  78 @end
  79
  80 // A protocol to be implemented by objects to listen for changes to the
  81 // CRWWebViewScrollViewProxyObserver.
  82 // It inherit from CRWWebViewScrollViewScrollViewObserver which only implements
  83 // methods for listening to scrollview changes.
  84 @protocol CRWWebViewScrollViewProxyObserver<CRWWebViewScrollViewObserver>
  85 @optional
  86 // Called when the underlying scrollview of the proxy is set.
  87 - (void)webViewScrollViewProxyDidSetScrollView:
  88         (CRWWebViewScrollViewProxy*)webViewScrollViewProxy;
  89 @end
  90
  91 #endif  // IOS_WEB_PUBLIC_WEB_STATE_CRW_WEB_VIEW_SCROLL_VIEW_PROXY_H_