UITabBar selectionIndicatorImage填充

Question

我設置自定義指標圖像我UITabBar這樣

UIImage *tabBarSelectedImage = [[UIImage imageNamed:@"tabBar_selected"] resizableImageWithCapInsets:UIEdgeInsetsMake(0, 0, 0, 0)]; 
[[UITabBar appearance] setSelectionIndicatorImage:tabBarSelectedImage]; 

，並讓我tabBarSelectedImage圍繞4PX填充。是否有可能將該填充設置爲0px？這樣我的tabBarSelectedImage就可以填滿整個空間了，沒有邊框可見了嗎？

Answer 1

這是您的問題的解決方案...我並沒有真的這樣做......我正在做其他事情，但下面的代碼將幫助你很多....首先，我告訴你我做了什麼.. 。

1. 我做了一個UITabbar和產品類別實現在

   - (void)recolorItemsWithColor:(UIColor *)color shadowColor:(UIColor *)shadowColor 
   shadowOffset:(CGSize)shadowOffset shadowBlur:(CGFloat)shadowBlur 
   { 
   CGColorRef cgColor = [color CGColor]; 
   CGColorRef cgShadowColor = [shadowColor CGColor]; 
   for (UITabBarItem *item in [self items]) { 
   
   if ([item respondsToSelector:@selector(selectedImage)] && 
       [item respondsToSelector:@selector(setSelectedImage:)] && 
       [item respondsToSelector:@selector(_updateView)]) 
   { 
       CGRect contextRect; 
       contextRect.origin.x = 0.0f; 
       contextRect.origin.y = 0.0f; 
   
       //instead of following line you can give our own desired size of contextRect. 
       //just change the method parameters and include a parameter of desired size in it. 
       // and this desired size would be the tabbarbutton size...so you will pass the size of 
       // you tabbarbutton here...because on the back of image there is a tabbarbutton and if 
       // set the image of button size it will occupy whole the are of button. 
   
       contextRect.size = desired size //[[item selectedImage] size]; 
       // Retrieve source image and begin image context 
       UIImage *itemImage = [item image]; 
       CGSize itemImageSize = [itemImage size]; 
   
       CGPoint itemImagePosition; 
       itemImagePosition.x = ceilf((contextRect.size.width - itemImageSize.width)/2); 
       itemImagePosition.y = ceilf((contextRect.size.height - itemImageSize.height)/2); 
       UIGraphicsBeginImageContext(contextRect.size); 
       CGContextRef c = UIGraphicsGetCurrentContext(); 
   
       // Setup shadow 
       CGContextSetShadowWithColor(c, shadowOffset, shadowBlur, cgShadowColor); 
   
       // Setup transparency layer and clip to mask 
       CGContextBeginTransparencyLayer(c, NULL); 
       CGContextScaleCTM(c, 1.0, -1.0); 
       CGContextClipToMask(c, CGRectMake(itemImagePosition.x, -itemImagePosition.y, 
       itemImageSize.width, -itemImageSize.height), [itemImage CGImage]); 
   
       // Fill and end the transparency layer 
       CGContextSetFillColorWithColor(c, cgColor); 
       contextRect.size.height = -contextRect.size.height; 
       CGContextFillRect(c, contextRect); 
       CGContextEndTransparencyLayer(c); 
   
   
       // Set selected image and end context 
       [item setSelectedImage:UIGraphicsGetImageFromCurrentImageContext()]; 
       UIGraphicsEndImageContext(); 
       // Update the view 
       [item _updateView]; 
       } 
       } 
   
       } 
   

   下面的方法現在，我叫我的自定義類的UITabBarController上面的方法......我覆蓋的方法
   -(void)setSelectedIndex:(NSUInteger)selectedIndex並在該方法中執行了以下操作。

   -(void)setSelectedIndex:(NSUInteger)selectedIndex { 
        self.selectedViewController = [self.viewControllers objectAtIndex:selectedIndex]; 
        NSLog(@"selectedIndex:%d, totalCount:%d",selectedIndex,[self.tabBar.subviews count]); 
       for (uint i=1; i < [self.tabBar.subviews count]; i++) 
       { 
        UIView *view = [self.tabBar.subviews objectAtIndex:i]; 
        NSLog(@"class:%@",NSStringFromClass([view class])); 
       if ([NSStringFromClass([view class]) isEqualToString:@"UITabBarButton"]) 
       { 
       //view.frame = CGRectMake(view.frame.origin.x, view.frame.origin.y, 
       view.frame.size.width, self.tabBar.frame.size.height); 
        NSLog(@"selectedIndex:%d,i:%d",self.selectedIndex,i); 
       if (self.selectedIndex+1==i) { 
        [self.tabBar recolorItemsWithColor:[UIColor whiteColor] shadowColor:[UIColor 
             blackColor] shadowOffset:view.frame.size shadowBlur:0.5]; 
   
       } 
       } 
       } 
   
       } 
   

您可以優化代碼，以避免產品類別或子類......但你必須有對目標C.握在任何問題，你能告訴我的情況下。 乾杯

Answer 2

1. 首先，setSelectionIndicatorImage到[UIColor clearColor]
2. 其次，在您添加任何viewcontrollers到tabbarcontroller，添加圖像作爲一個子視圖的TabBar。然後它將出現在tabbaritems下作爲指示圖像
3. 實施tabbarcontroller delegate方法來更改圖像的位置。

我已經實現了這種方式，它的工作原理非常完美。如果你想調整tabbar不同的方向，你應該調整一下。您可以繼承UITabbarController並實施layoutSubview方法。

Answer 3

我找到了一種簡單的解決方案：

self.tabBar.frame = CGRectInset(self.tabBar.frame,0,-6); 

Answer 4

好，這裏是我發現的是填充使用可調整大小的圖像時纔會出現。當使用不可調整大小的圖像時，填充不在那裏。

因此，一個可能的解決方案是子類UITabBar並配置項目大小更改時selectionIndicatorImage。

@interface TKTabBar 

@end 

@implementation TKTabBar 
{ 
    CGSize _selectionIndicatorImageSize; 
} 

- (void)tk_refreshSelectionIndicatorImageForItemSize:(CGSize)itemSize 
{ 
    // Recompute the selection indicator image only if the size of the item has changed. 
    if (!CGSizeEqualToSize(itemSize, _selectionIndicatorImageSize)) 
    { 
     _selectionIndicatorImageSize = itemSize; 

     // Compute here the new image from the item size. 
     // In this example I'm using a Cocoa Pod called UIImage+Additions to generate images dynamically. 

     UIImage *redImage = [UIImage add_imageWithColor:[UIColor add_colorWithRed255:208 green255:75 blue255:43] size:CGSizeMake(itemSize.width, 2)]; 
     UIImage *clearImage = [UIImage add_imageWithColor:[UIColor clearColor] size:CGSizeMake(itemSize.width, itemSize.height)]; 
     UIImage *mixImage = [clearImage add_imageAddingImage:redImage offset:CGPointMake(0, itemSize.height-2)]; 

     // Finally, I'm setting the image as the selection indicator image. 
     [self setSelectionIndicatorImage:mixImage]; 
    } 
} 

// Using the layout subviews method to detect changes on the tab size 
- (void)layoutSubviews 
{ 
    [super layoutSubviews]; 

    // Only needed if at least one item 
    if (self.items.count > 0) 
    { 
     CGSize itemSize = CGSizeZero; 

     // Iterating over all subviews 
     for (UIView *view1 in self.subviews) 
     { 
      // Searching for "UITabBarButtons" 
      if ([view1 isKindOfClass:NSClassFromString(@"UITabBarButton")]) 
      { 
       itemSize = view1.bounds.size; 
       break; 
      } 
     } 

     // Applying the new item size 
     [self tk_refreshSelectionIndicatorImageForItemSize:itemSize]; 
    } 
} 

@end