在UIButton中使用UIBarButtonItem图标
Zvi*_*Bar 33 cocoa-touch uibutton uibarbuttonitemstyle ios
UIBarButtonItem有多个图标可用.是否可以使用将其标识符设置为"垃圾"后出现的图标:
用UIButton？设置标识符或样式没有直接的方法.
yyc*_*ing 23
对于swift 4.2 (在主线程上调用它)
extension UIBarButtonItem.SystemItem {
func image() -> UIImage? {
let tempItem = UIBarButtonItem(barButtonSystemItem: self,
target: nil,
action: nil)
// add to toolbar and render it
let bar = UIToolbar()
bar.setItems([tempItem],
animated: false)
bar.snapshotView(afterScreenUpdates: true)
// got image from real uibutton
let itemView = tempItem.value(forKey: "view") as! UIView
for view in itemView.subviews {
if let button = view as? UIButton,
let image = button.imageView?.image {
return image.withRenderingMode(.alwaysTemplate)
}
}
return nil
}
}
UIBarButtonSystemItem.play.image()
对于Objective-C:
+ (UIImage *)imageFromSystemBarButton:(UIBarButtonSystemItem)systemItem {
UIBarButtonItem* tempItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:systemItem target:nil action:nil];
// Add to toolbar and render it
UIToolbar *bar = [[UIToolbar alloc] init];
[bar setItems:@[tempItem] animated:NO];
[bar snapshotViewAfterScreenUpdates:YES];
// Get image from real UIButton
UIView *itemView = [(id)tempItem view];
for (UIView* view in itemView.subviews) {
if ([view isKindOfClass:[UIButton class]]) {
return [(UIButton*)view imageForState:UIControlStateNormal];
}
}
return nil;
}
- 不再适用于Xcode 9.图像必须在提取之前进行渲染. (2认同)
Isl*_* Q. 15
这是一个适用于任何系统栏按钮项+ 的解决方案+它支持tintColor:
- (void)viewDidLoad {
[super viewDidLoad];
[self.button setImage:[self imageFromSystemBarButton:UIBarButtonSystemItemTrash]
forState:UIControlStateNormal];
self.button.tintColor = [UIColor redColor];
}
- (UIImage *)imageFromSystemBarButton:(UIBarButtonSystemItem)systemItem {
// Holding onto the oldItem (if any) to set it back later
// could use left or right, doesn't matter
UIBarButtonItem *oldItem = self.navigationItem.rightBarButtonItem;
UIBarButtonItem *tempItem = [[UIBarButtonItem alloc]
initWithBarButtonSystemItem:systemItem
target:nil
action:nil];
// Setting as our right bar button item so we can traverse its subviews
self.navigationItem.rightBarButtonItem = tempItem;
// Don't know whether this is considered as PRIVATE API or not
UIView *itemView = (UIView *)[self.navigationItem.rightBarButtonItem performSelector:@selector(view)];
UIImage *image = nil;
// Traversing the subviews to find the ImageView and getting its image
for (UIView *subView in itemView.subviews) {
if ([subView isKindOfClass:[UIImageView class]]) {
image = ((UIImageView *)subView).image;
break;
}
}
// Setting our oldItem back since we have the image now
self.navigationItem.rightBarButtonItem = oldItem;
return image;
}
PS如果您知道更好的方式,请随意改进,谢谢.
- 隐藏了一个陷阱;-)此代码仅在UINavigationItem当前在屏幕上呈现时才有效.例如,如果视图控制器当前未加载(例如,如果它是UITabBarController中未选择的视图控制器之一),则失败. (2认同)
根据@yycking的回答,我写了一个合适的Swift 4扩展:
// UIImage+FromSystemItem.swift
import UIKit
extension UIImage {
public convenience init?(systemItem sysItem: UIBarButtonItem.SystemItem, renderingMode:UIImage.RenderingMode = .automatic) {
guard let sysImage = UIImage.imageFromSystemItem(sysItem, renderingMode: renderingMode)?.cgImage else {
return nil
}
self.init(cgImage: sysImage)
}
private class func imageFromSystemItem(_ systemItem: UIBarButtonItem.SystemItem, renderingMode:UIImage.RenderingMode = .automatic) -> UIImage? {
let tempItem = UIBarButtonItem(barButtonSystemItem: systemItem, target: nil, action: nil)
// add to toolbar and render it
let bar = UIToolbar()
bar.setItems([tempItem], animated: false)
bar.snapshotView(afterScreenUpdates: true)
// got image from real uibutton
let itemView = tempItem.value(forKey: "view") as! UIView
for view in itemView.subviews {
if view is UIButton {
let button = view as! UIButton
let image = button.imageView!.image!
image.withRenderingMode(renderingMode)
return image
}
}
return nil
}
}
带操作按钮的示例(默认着色):
let actionImage = UIImage(systemItem: .action)
let myButton = UIButton(frame: CGRect(x: 0, y: 0, width: 30, height: 30))
myButton.setImage(actionImage, for: .normal)
view.addSubview(myButton)
如果您希望始终将图像视为模板而不考虑上下文,请将renderingMode设置为.alwaysTemplate
let actionImage = UIImage(systemItem: .action, renderingMode: .alwaysTemplate)
- 感谢Peter的回答,我只是想指出它不再适用于Swift 4,`tempItem.value(forKey:"view")`是nil并且强有力的展开会产生错误. (3认同)
- 我一直在线上获得零回报....让itemView = tempItem.value(forKey:"view")为!的UIView (2认同)
正如在对@Islam Q 的回答的评论中已经提到的那样，如果UINavigationItem当前未在屏幕上呈现，则所提出的解决方案可能会失败。例如，如果当前未加载视图控制器，则会失败。事实上，在这些情况下，问题似乎是UINavigationBar缺少布局。
更“防弹”的版本是使用专门创建的 UINavigationBar 对象来获取系统项目图像。这也将使保存和恢复任何现有 UIBarButtonItems 过时。
我已经把它打包成一个小的帮助类：
LEABarButtonSystemItemImage.h：
#import <UIKit/UIKit.h>
/**
LEABarButtonSystemItemImage interface
*/
@interface LEABarButtonSystemItemImage : NSObject
+ (UIImage *)imageFromBarButtonSystemItem:(UIBarButtonSystemItem)pBarButtonSystemItem;
+ (UIImage *)customImageForBarButtonSystemItem:(UIBarButtonSystemItem)pBarButtonSystemItem;
+ (NSDictionary<__kindof NSNumber*, __kindof UIImage*> *)barButtonItemImages;
@end
LEABarButtonSystemItemImage.m
#import "LEABarButtonSystemItemImage.h"
/**
LEABarButtonSystemItemImage implementation
*/
@implementation LEABarButtonSystemItemImage
/*
imageFromBarButtonSystemItem:
*/
+ (UIImage *)imageFromBarButtonSystemItem:(UIBarButtonSystemItem)pBarButtonSystemItem {
static const CGFloat defaultNBBtnHW = 44.0;
UINavigationBar * tempNavigationBar = [[UINavigationBar alloc] initWithFrame:CGRectMake(0, 0, defaultNBBtnHW, defaultNBBtnHW)];
UINavigationItem * tempNavigationItem = [[UINavigationItem alloc] init];
UIBarButtonItem * tempBarButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:pBarButtonSystemItem target:nil action:NULL];
tempNavigationBar.items = @[tempNavigationItem];
tempNavigationItem.rightBarButtonItems = @[tempBarButtonItem];
UIImage * barButtonSystemItemImage = nil;
@try {
UIView * barButtonItemView = [tempBarButtonItem valueForKey:@"view"];
for (UIView* subview in barButtonItemView.subviews) {
if ([subview isKindOfClass:UIImageView.class]) {
barButtonSystemItemImage = ((UIImageView *)subview).image;
break;
}
}
} @catch (...) { NSLog(@"%s: Exception while retrieving image from UIBarButtonItem!", __PRETTY_FUNCTION__); }
return (barButtonSystemItemImage ?: [LEABarButtonSystemItemImage customImageForBarButtonSystemItem:pBarButtonSystemItem]);
}
/*
customImageForBarButtonSystemItem:
*/
+ (UIImage *)customImageForBarButtonSystemItem:(UIBarButtonSystemItem)pBarButtonSystemItem {
NSString * customBarButtonSystemItemImageName = nil;
switch (pBarButtonSystemItem) {
case UIBarButtonSystemItemDone: customBarButtonSystemItemImageName = @"customBarButtonSystemItemDone"; break;
case UIBarButtonSystemItemCancel: customBarButtonSystemItemImageName = @"customBarButtonSystemItemCancel"; break;
case UIBarButtonSystemItemEdit: customBarButtonSystemItemImageName = @"customBarButtonSystemItemEdit"; break;
case UIBarButtonSystemItemSave: customBarButtonSystemItemImageName = @"customBarButtonSystemItemSave"; break;
case UIBarButtonSystemItemAdd: customBarButtonSystemItemImageName = @"customBarButtonSystemItemAdd"; break;
case UIBarButtonSystemItemCompose: customBarButtonSystemItemImageName = @"customBarButtonSystemItemCompose"; break;
case UIBarButtonSystemItemReply: customBarButtonSystemItemImageName = @"customBarButtonSystemItemReply"; break;
case UIBarButtonSystemItemAction: customBarButtonSystemItemImageName = @"customBarButtonSystemItemAction"; break;
case UIBarButtonSystemItemOrganize: customBarButtonSystemItemImageName = @"customBarButtonSystemItemOrganize"; break;
case UIBarButtonSystemItemBookmarks: customBarButtonSystemItemImageName = @"customBarButtonSystemItemBookmarks"; break;
case UIBarButtonSystemItemSearch: customBarButtonSystemItemImageName = @"customBarButtonSystemItemSearch"; break;
case UIBarButtonSystemItemRefresh: customBarButtonSystemItemImageName = @"customBarButtonSystemItemRefresh"; break;
case UIBarButtonSystemItemStop: customBarButtonSystemItemImageName = @"customBarButtonSystemItemStop"; break;
case UIBarButtonSystemItemCamera: customBarButtonSystemItemImageName = @"customBarButtonSystemItemCamera"; break;
case UIBarButtonSystemItemTrash: customBarButtonSystemItemImageName = @"customBarButtonSystemItemTrash"; break;
case UIBarButtonSystemItemPlay: customBarButtonSystemItemImageName = @"customBarButtonSystemItemPlay"; break;
case UIBarButtonSystemItemPause: customBarButtonSystemItemImageName = @"customBarButtonSystemItemPause"; break;
case UIBarButtonSystemItemRewind: customBarButtonSystemItemImageName = @"customBarButtonSystemItemRewind"; break;
case UIBarButtonSystemItemFastForward: customBarButtonSystemItemImageName = @"customBarButtonSystemItemFastForward"; break;
case UIBarButtonSystemItemUndo: customBarButtonSystemItemImageName = @"customBarButtonSystemItemUndo"; break;
case UIBarButtonSystemItemRedo: customBarButtonSystemItemImageName = @"customBarButtonSystemItemRedo"; break;
case UIBarButtonSystemItemPageCurl: customBarButtonSystemItemImageName = @"customBarButtonSystemItemPageCurl"; break;
default: break;
}
return (customBarButtonSystemItemImageName
? [UIImage imageNamed:customBarButtonSystemItemImageName]
: nil);
}
/*
barButtonItemImages
*/
+ (NSDictionary<__kindof NSNumber*, __kindof UIImage*> *)barButtonItemImages {
NSMutableDictionary<__kindof NSNumber*, __kindof UIImage*> * barButtonItemImages = [NSMutableDictionary dictionary];
// From: https://github.com/nst/iOS-Runtime-Headers/blob/master/Frameworks/UIKit.framework/UIBarButtonItem.h
// unsigned int systemItem : 7;
for (NSUInteger uIndex = 0; uIndex < (1<<7); ++uIndex) {
UIImage* systemImage = [LEABarButtonSystemItemImage imageFromBarButtonSystemItem:uIndex];
if (systemImage) {
[barButtonItemImages setObject:systemImage forKey:@(uIndex)];
}
}
NSLog(@"%s: %@", __PRETTY_FUNCTION__, barButtonItemImages);
return barButtonItemImages;
}
@end
作为附加/回退，如果无法检索到系统项目图像，该方法将返回自定义图像。当然，这些自定义图像必须存在于应用程序包中。
最后一个方法 'barButtonImages' 只是为了好奇而实现的......在 UIBarButtonItem 标头中，成员 systemItem 被声明为使用 7 位（0..127）。目前，从 UIBarButtonSystemItemDone 到 UIBarButtonItemSystemItemPageCurl 只记录了 22 个值……事实上；我发现了一些索引高于 100 的未记录图像（在 6S+ 模拟器中在 iOS 9.3 上测试）:-)
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