如何限制UITextView iOS中的字符
我有一个UITextView,我想限制用户可以输入的字符数。我还试图显示一个警告,如果文本字段是空的,但没有运气如何限制UITextView iOS中的字符,ios,objective-c,nsstring,uitextview,nsinteger,Ios,Objective C,Nsstring,Uitextview,Nsinteger,我有一个UITextView,我想限制用户可以输入的字符数。我还试图显示一个警告,如果文本字段是空的,但没有运气 textview.h @property (nonatomic,strong) IBOutlet UITextView *textField; @property (nonatomic, retain) NSString *userText; textview.m - (IBAction)next:(id)sender { self.userText = self.t
textview.h
@property (nonatomic,strong) IBOutlet UITextView *textField;
@property (nonatomic, retain) NSString *userText;
textview.m
- (IBAction)next:(id)sender {
self.userText = self.textField.text;
if ([self.textField.text length] == 0) {
UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"Error!"
message:@"Enter some text"
delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
[alertView show];
}
}
这里是文本限制方法,它似乎不起作用
- (BOOL)textView:(UITextView *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{
if(range.length + range.location > textField.text.length)
{
return NO;
} else {
NSUInteger newLength = [textField.text length] + [string length] - range.length;
return newLength <= 70;
return (textField.text.length <= 70);
}
}
-(BOOL)textView:(UITextView*)textField应更改字符范围:(NSRange)范围替换字符串:(NSString*)字符串{
if(range.length+range.location>textField.text.length)
{
返回否;
}否则{
NSUInteger newLength=[textField.text length]+[string length]-range.length;
return newLength试试这个
- (BOOL)isAcceptableTextLength:(NSUInteger)length {
return length <= 70;
}
- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)string {
return [self isAcceptableTextLength:textField.text.length + string.length - range.length];
}
-(IBAction)checkIfCorrectLength:(id)sender{
if (![self isAcceptableTextLength:self.textField.text.length]) {
// do something to make text shorter
}
}
-(BOOL)isAcceptableTextLength:(nsInteger)长度{
返回长度1)像这样在viewcontroller中添加UITextViewDelegate
@interface ViewController : UIViewController <UITextViewDelegate>
@界面ViewController:UIViewController
每次用户在键盘上键入字符时,就在字符显示之前,将调用以下方法。这是一个方便的位置,用于测试用户正在键入的字符,并禁止您要限制的特定字符
textView:ShouldChangeCharactersRange:replacementString
2) 然后编写以下代码。
你可以用你想要的数字代替140
- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text
{
return textView.text.length + (text.length - range.length) <= 140;
}
-(BOOL)textView:(UITextView*)textView应更改textinrange:(nsrrange)范围替换text:(NSString*)文本
{
返回textView.text.length+(text.length-range.length)Bool{
返回textView.text.characters.count+(text.characters.count-range.length)您可以使用下面的代码限制textView字符。在第一种方法中,您可以为textfield设置限制长度,或者如果您过去的文本超过了限制文本,它将创建该字符串的子字符串以固定textView的长度
#pragma mark - Textview Delegate
-(void)textViewDidChange:(UITextView *)textView
{
NSString *temp = textView.text;
titleLength = textView.text.length;
if (titleLength > RESTRICTED_LENGHT )
{
textView.text = [temp substringToIndex:RESTRICTED_LENGHT];
}
}
或者,如果文本视图文本长度大于限制长度,则可以使用此委托方法并返回No
- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text
{
if([text length] == 0)
{
if([textView.text length] != 0)
{
return YES;
}
}
else if([[textView text] length] > 139)
{
return NO;
}
return YES;
}
您好,谢谢您的回答,我对ios开发非常陌生,如有任何进一步的帮助,将不胜感激
- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text
{
if([text length] == 0)
{
if([textView.text length] != 0)
{
return YES;
}
}
else if([[textView text] length] > 139)
{
return NO;
}
return YES;
}