如何检测NSTextAttachment上的触摸
当iOS上的用户点击NSTextAttachment
时,什么是最佳方式?如何检测NSTextAttachment上的触摸
我认为其中一种方法是检查carret的位置上的字符是否是NSAttachmentCharacter
,但它看起来不正确。
我也试过UITextViewDelegate
方法:-(BOOL)textView:(UITextView *)textView shouldInteractWithTextAttachment:(NSTextAttachment *)textAttachment inRange:(NSRange)characterRange
但当textView.editable=YES
委托方法做工作,它不被调用,但只有当附着在图像属性,如果编辑图像= NO!所以如果你从别的地方将图像粘贴到了attributesString中,那么数据似乎最终被存储在fileWrapper中,并且下一次将attributesString放回到textView中时,image属性为零,而布局管理器或任何获取图像来自fileWrapper。
在文档中的某处它确实提到NSTextAttachment中没有用于持久化图像属性的方法。
为了测试这个尝试从照片应用程序复制照片并将其粘贴到您的textView,现在如果你按住你的手指,你应该看到默认菜单弹出。现在,如果你保存这个丰富的文本,说一个核心数据实体,然后检索它的图像属性将为零,但图像数据将在attachment.fileWrapper.regularFileContents
它的痛苦,我很想知道工程师的意图。所以你看起来有两个选择。
- 把你的字符串回的TextView你发现之前创建自己的自定义NSTextAttachment,包括用于归档图像和其他设置方法(请告诉我怎么过当你明白这出一个)
-
每次所有附件并重新创建图像属性,如下所示:
attachment.image = [UIImage imageWithData:attachment.fileWrapper.regularFileContents];
记住这样做的副作用是使fileWrapper无效。我想调整图像大小,但也要保留原始图像,以免丢失全部分辨率。我认为这样做的唯一方法可能是将NSTextAttachment转换为子类。
编辑:
我想出了如何创建自定义NSTextAttachments - 这里是一个链接为那些有兴趣http://ossh.com.au/design-and-technology/software-development/implementing-rich-text-with-images-on-os-x-and-ios/
编辑2:自定义菜单时,在编辑模式下看到下面的Apple文档中,问题是'touchEnded'似乎永远不会被调用,所以你可能不得不尝试使用touchesBegan。小心你不要干预默认的编辑行为。
注意,在下面的代码,你需要后// selection management
评论添加代码,以确定哪些字符被感动了,检查它是否是特殊文本附件的性格和 然后修改编辑菜单或采取一些其他行动。
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
UITouch *theTouch = [touches anyObject];
if ([theTouch tapCount] == 2 && [self becomeFirstResponder]) {
// selection management code goes here...
// bring up edit menu.
UIMenuController *theMenu = [UIMenuController sharedMenuController];
CGRect selectionRect = CGRectMake (currentSelection.x, currentSelection.y, SIDE, SIDE);
[theMenu setTargetRect:selectionRect inView:self];
[theMenu setMenuVisible:YES animated:YES];
}
}
或者,您可以通过添加菜单项然后修改canPerformAction方法来添加自定义菜单。
- (BOOL)canPerformAction:(SEL)action withSender:(id)sender {
LOG(@"canPerformAction: called");
if (action == @selector(viewImage)) {
// Check the selected character is the special text attachment character
return YES;
}
return NO;
}
这是一些附加代码,但它有点挑剔。第二种方法只是在检测到附件时禁用默认编辑菜单。
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
FLOG(@"touchesBegan:withEvent: called");
if (self.selectedRange.location != NSNotFound) {
FLOG(@" selected location is %d", self.selectedRange.location);
int ch;
if (self.selectedRange.location >= self.textStorage.length) {
// Get the character at the location
ch = [[[self textStorage] string] characterAtIndex:self.selectedRange.location-1];
} else {
// Get the character at the location
ch = [[[self textStorage] string] characterAtIndex:self.selectedRange.location];
}
if (ch == NSAttachmentCharacter) {
FLOG(@" selected character is %d, a TextAttachment", ch);
} else {
FLOG(@" selected character is %d", ch);
}
}
}
- (BOOL)canPerformAction:(SEL)action withSender:(id)sender {
FLOG(@"canPerformAction: called");
FLOG(@" selected location is %d", self.selectedRange.location);
FLOG(@" TextAttachment character is %d", NSAttachmentCharacter);
if (self.selectedRange.location != NSNotFound) {
int ch;
if (self.selectedRange.location >= self.textStorage.length) {
// Get the character at the location
ch = [[[self textStorage] string] characterAtIndex:self.selectedRange.location-1];
} else {
// Get the character at the location
ch = [[[self textStorage] string] characterAtIndex:self.selectedRange.location];
}
if (ch == NSAttachmentCharacter) {
FLOG(@" selected character is %d, a TextAttachment", ch);
return NO;
} else {
FLOG(@" selected character is %d", ch);
}
// Check for an attachment
NSTextAttachment *attachment = [[self textStorage] attribute:NSAttachmentAttributeName atIndex:self.selectedRange.location effectiveRange:NULL];
if (attachment) {
FLOG(@" attachment attribute retrieved at location %d", self.selectedRange.location);
return NO;
}
else
FLOG(@" no attachment at location %d", self.selectedRange.location);
}
return [super canPerformAction:action withSender:sender];
}
感谢您的回答,但我认为最初的问题是如何设置检测触摸,即使'textView.editable = YES'设置。 – Jon
使用与用于显示文本编辑弹出式菜单相同的方法即可。你必须检查选定的字符是否是特殊的文本附加字符 - 我会看看我能否找到一个例子。 –
@DuncanGroenewald - 这个答案的很大一部分似乎对这个问题完全没有影响。 – ArtOfWarfare
使用hitTest获取子类UITextView中的触摸。这样可以避免混淆标准编辑功能的问题。从该位置获取字符索引,然后检查附件的字符。
斯威夫特3回答:
func textView(_ textView: UITextView, shouldInteractWith textAttachment: NSTextAttachment, in characterRange: NSRange) -> Bool {
return true
}
确保TextView isEditable = false
,isSelectable = true
和isUserInteractionEnabled = true
。邓肯的回答没有提到isUserInteractionEnabled
,这必须是true
,否则它不会工作。
苹果使这个真的很难。正如其他人指出的,代表方法被调用,但只有当isEditable
是false
时,或者当用户点击并按住附件时。如果您想在编辑过程中了解简单的点按互动,请将其忽略。
我走下touchesBegan:
和hitTest:
路径,两者都有问题。触摸方法在之后被称为UITextView
已经处理了交互,并且hitTest:
太粗糙了,因为它与第一响应者状态等混乱。
我的解决方案最后是手势识别器。 Apple在内部使用这些内容,这就解释了为什么touchesBegan:
首先不是真正可行的:手势识别器已经处理了该事件。
我创建了一个新的手势识别器类,与UITextView
一起使用。它只是检查水龙头的位置,如果它是附件,它会处理它。我让所有其他的手势识别器都属于我的手势识别器,所以我们首先看看事件,其他手势识别器只在我们的失败时才起作用。
手势识别器类如下,以及将其添加到UITextView
的扩展名。我将它添加到awakeFromNib
的UITextView
子类中,就像这样。 (你不需要使用一个子类,如果你没有一个。)
override func awakeFromNib() {
super.awakeFromNib()
let recognizer = AttachmentTapGestureRecognizer(target: self, action: #selector(handleAttachmentTap(_:)))
add(recognizer)
,我通过调用现有UITextViewDelegate
方法textView(_:,shouldInteractWith:,in:,interaction:)
处理动作。您可以轻松地将处理代码直接放在操作中,而不是使用委托。
@IBAction func handleAttachmentTap(_ sender: AttachmentTapGestureRecognizer) {
let _ = delegate?.textView?(self, shouldInteractWith: sender.attachment!, in: NSRange(location: sender.attachmentCharacterIndex!, length: 1), interaction: .invokeDefaultAction)
}
这里是主类。
import UIKit
import UIKit.UIGestureRecognizerSubclass
/// Recognizes a tap on an attachment, on a UITextView.
/// The UITextView normally only informs its delegate of a tap on an attachment if the text view is not editable, or a long tap is used.
/// If you want an editable text view, where you can short cap an attachment, you have a problem.
/// This gesture recognizer can be added to the text view, and will add requirments in order to recognize before any built-in recognizers.
class AttachmentTapGestureRecognizer: UIGestureRecognizer {
/// Character index of the attachment just tapped
private(set) var attachmentCharacterIndex: Int?
/// The attachment just tapped
private(set) var attachment: NSTextAttachment?
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent) {
attachmentCharacterIndex = nil
attachment = nil
let textView = view as! UITextView
if touches.count == 1, let touch = touches.first, touch.tapCount == 1 {
let point = touch.location(in: textView)
let glyphIndex: Int? = textView.layoutManager.glyphIndex(for: point, in: textView.textContainer, fractionOfDistanceThroughGlyph: nil)
let index: Int? = textView.layoutManager.characterIndexForGlyph(at: glyphIndex ?? 0)
if let characterIndex = index, characterIndex < textView.textStorage.length {
if NSAttachmentCharacter == (textView.textStorage.string as NSString).character(at: characterIndex) {
attachmentCharacterIndex = characterIndex
attachment = textView.textStorage.attribute(.attachment, at: characterIndex, effectiveRange: nil) as? NSTextAttachment
state = .recognized
} else {
state = .failed
}
}
} else {
state = .failed
}
}
}
extension UITextView {
/// Add an attachment recognizer to a UITTextView
func add(_ attachmentRecognizer: AttachmentTapGestureRecognizer) {
for other in gestureRecognizers ?? [] {
other.require(toFail: attachmentRecognizer)
}
addGestureRecognizer(attachmentRecognizer)
}
}
这种方法大概可以用于链接上的点击。
嗨米歇尔,我现在有完全相同的问题,并希望能够检测到'NSTextAttachment'即使'textView.editable = YES'上的点击和触摸 - 您是否找到了解决方案? – Jon