在UITextField中检测退格事件
我正在寻找有关如何捕获退格事件的解决方案,大多数堆栈溢出答案都在Objective-C中,但是我需要使用Swift语言。
首先,我为UITextField设置了委托,并将其设置为self
self.textField.delegate = self;
然后,我知道使用shouldChangeCharactersInRange
委托方法来检测是否按下了退格键,因为所有代码都在Objective-
C中。我需要在Swift中使用以下方法。
-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string { const char * _char = [string cStringUsingEncoding:NSUTF8StringEncoding];
int isBackSpace = strcmp(_char, "\b");
if (isBackSpace == -8) {
// NSLog(@"Backspace was pressed");
}
return YES;
}
回答:
斯威夫特4.2
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool { if let char = string.cString(using: String.Encoding.utf8) {
let isBackSpace = strcmp(char, "\\b")
if (isBackSpace == -92) {
print("Backspace was pressed")
}
}
return true
}
较早的Swift版本
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool { let char = string.cStringUsingEncoding(NSUTF8StringEncoding)!
let isBackSpace = strcmp(char, "\\b")
if (isBackSpace == -92) {
println("Backspace was pressed")
}
return true
}
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