在适配iOS13的过程中,UITextField
输入中文的时候三指撤销产生了 crash。
Bugly报错
NSInternalInconsistencyException
setGroupIdentifier:: _NSUndoStack 0x1206532f0 is in invalid state, calling setGroupIdentifier with no begin group mark
堆栈信息
0 CoreFoundation ___exceptionPreprocess + 220
1 libobjc.A.dylib objc_exception_throw + 56
2 Foundation -[_NSUndoStack groupIdentifier]
3 Foundation -[NSUndoManager undoNestedGroup] + 240
4 UIKitCore -[UIUndoGestureInteraction undo:] + 72
5 UIKitCore -[UIKBUndoInteractionHUD performDelegateUndoAndUpdateHUDIfNeeded] + 96
6 UIKitCore -[UIKBUndoInteractionHUD controlActionUpInside:] + 152
7 UIKitCore -[UIApplication sendAction:to:from:forEvent:] + 96
8 xxxxx -[UIApplication(MemoryLeak) swizzled_sendAction:to:from:forEvent:] + 288
9 UIKitCore -[UIControl sendAction:to:forEvent:] + 240
10 UIKitCore -[UIControl _sendActionsForEvents:withEvent:] + 408
11 UIKitCore -[UIControl touchesEnded:withEvent:] + 520
12 UIKitCore -[UIWindow _sendTouchesForEvent:] + 2324
13 UIKitCore -[UIWindow sendEvent:] + 3352
14 UIKitCore -[UIApplication sendEvent:] + 336
15 UIKitCore ___dispatchPreprocessedEventFromEventQueue + 5880
16 UIKitCore ___handleEventQueueInternal + 4924
17 UIKitCore ___handleHIDEventFetcherDrain + 108
18 CoreFoundation ___CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 24
19 CoreFoundation ___CFRunLoopDoSource0 + 80
20 CoreFoundation ___CFRunLoopDoSources0 + 180
21 CoreFoundation ___CFRunLoopRun + 1080
22 CoreFoundation CFRunLoopRunSpecific + 464
23 GraphicsServices GSEventRunModal + 104
24 UIKitCore UIApplicationMain + 1936
25 xxxxx main + 148
26 libdyld.dylib _start + 4
问题定位
没有太多思路的时候,通过注释代码,最终定位到了问题所在。
[self addTarget:observer
action:@selector(textChange:)
forControlEvents:UIControlEventEditingChanged];
- (void)textChange:(UITextField *)textField {
... ...
UITextRange *selectedRange = [textField markedTextRange];
if (!selectedRange || !selectedRange.start) {
if (destText.length > maxLength) {
textField.text = [destText substringToIndex:maxLength];
}
}
}
这段代码在输入的时候会限制文案的长度。三指撤销会触发UIControlEventEditingChanged
事件,执行textChange
,此时获取到的markedTextRange
是nil
,即便是存在markedText
。这就导致UITextField
的text
有可能会被修改。修改文案后再继续执行撤销操作,必定会产生 crash。
解决方案
将文案判长和截取异步添加到主队列,在下一个runloop
执行。
- (void)textChange:(UITextField *)textField {
dispatch_async(dispatch_get_main_queue(), ^{
... ...
});
}
数字截断后 crash
数字输入限制长度后,超过长度后继续输入,这个时候撤销也会产生crash,而且上面的方法不可行。目前想到的方案是在UITextField
的回调方法进行输入的拦截。
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
/// 输入数字后截取字符串仍旧可以触发撤销操作导致crash, 在这里拦截一下
if (textField.keyboardType == UIKeyboardTypeNumberPad
&& range.location >= textField.tt_maxLength) {
return NO;
}
return YES;
}