UITextView委托从来没有调用过 [英] UITextView delegate never called

问题描述

我有一个UITextview委托 - （BOOL）textView：（UITextView *）textView ，从来没有得到调用，我一直在努力这个几天徒劳无功。这是我有的

I have a UITextview delegate - (BOOL)textView:(UITextView *)textView that is never getting called and I have been struggling with this for a couple of days to no avail. Here is what I have

我在我的头文件和ViewDidLoad中声明了< UITextViewDelegate> 设置委托，我尝试过 self.myTextView.delegate = self;
和 myTextView.delegate = self;

I have declared the <UITextViewDelegate> in my header file and in ViewDidLoad I am setting the delegate, I have tried self.myTextView.delegate = self; and myTextView.delegate = self; along with wiring up the delegate in the NIB file instead of declaring it programmatically.

我有几个自定义按钮，通过2种不同的方法将文本插入到我的UITextView中取决于按钮，这里的第一个方法是...

I have a few custom buttons that insert the text into my UITextView by 2 different methods depending on the button, the first method here is...

-(IBAction)string1:(id)sender {

NSRange range = myTextView.selectedRange;  
NSString * firstHalfString = [myTextView.text substringToIndex:range.location];  
NSString * secondHalfString = [myTextView.text substringFromIndex: range.location];  
myTextView.scrollEnabled = NO;  

NSString * insertingString = [NSString stringWithFormat:@"insert my text string"];

myTextView.text = [NSString stringWithFormat: @"%@%@%@",  
                 firstHalfString,  
                 insertingString,  
                 secondHalfString];  
range.location += [insertingString length];  
myTextView.selectedRange = range;  
myTextView.scrollEnabled = YES;}

，第二个方法是...

and the second method is ...

-(IBAction)string2:(id)sender {

myTextView.text = [myTextView.text stringByAppendingString:@"my other string value"];}

在NSLog打开的情况下， / p>

With NSLog turned on, I can see that

- (void)textViewDidChange:(UITextView *)textView{
 NSLog(@"something changed");}

确实被调用，但是这个代理从不被调用

does get called but this delegate never gets called

- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text {
NSUInteger newLength = (textView.text.length - range.length) + text.length;
if(newLength <= MAX_LENGTH)
{
    return YES;
} else {
    NSUInteger emptySpace = MAX_LENGTH - (textView.text.length - range.length);
    textView.text = [[[textView.text substringToIndex:range.location] 
                      stringByAppendingString:[text substringToIndex:emptySpace]]
                     stringByAppendingString:[textView.text substringFromIndex:(range.location + range.length)]];
    return NO;
}
NSLog(@"something else changed");}

我的.M文件的顶部我已经定义 #define MAX_LENGTH 100

At the top of my .M file I have defined #define MAX_LENGTH 100

任何帮助将非常感谢，我的总体目标是限制UITextView中的章程数。

Any help would be very much appreciated, my overall goal is to limit the number of charters in the UITextView.

推荐答案

UITextView 只传送 textView：shouldChangeTextInRange ：replacementText：到其代理以响应用户事件。当您的程序设置 myTextView.text 属性时，它不会发送该消息。

UITextView only sends textView:shouldChangeTextInRange:replacementText: to its delegate in response to user events. It does not send that message when your program sets the myTextView.text property.

UITextView 正在向代理发送 textViewDidChange：，因为文档说此方法是

I'm surprised that the UITextView is sending textViewDidChange: to the delegate, since the documentation says "This method is not called in response to programmatically initiated changes."

因此，您可以在 textViewDidChange：中剪辑文本并且依赖于它的行为与文档不同），或者修改 string1：和 string2： 。

So, you could clip the text in textViewDidChange: instead (and rely on its behavior being different from the documentation), or modify and string1: and string2: to clip the text.

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