Objective-c中有三个UITextView时如何使用UITextView委托

Question

创建 UITextViews

//Text View 1  
textview1.layer.borderWidth = 1.0f;
textview1.layer.borderColor = [[UIColor blackColor] CGColor];
textview1.delegate = self;

UIToolbar* doneToolbar = [[UIToolbar alloc]initWithFrame:CGRectMake(0, 0, 320, 50)];
doneToolbar.barStyle = UIBarStyleBlackTranslucent;
doneToolbar.items = [NSArray arrayWithObjects:
    [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil],
    [[UIBarButtonItem alloc]initWithTitle:@"Done" style:UIBarButtonItemStyleDone target:self action:@selector(donedescButtonClickedDismissKeyboard)],
    nil];
[doneToolbar sizeToFit];
textview1.inputAccessoryView = doneToolbar;

//Text View 2
textview2.layer.borderWidth = 1.0f;
textview2.layer.borderColor = [[UIColor blackColor] CGColor];
textview2.delegate = self;

UIToolbar* doneToolbarmeasure = [[UIToolbar alloc]initWithFrame:CGRectMake(0, 0, 320, 50)];
doneToolbarmeasure.barStyle = UIBarStyleBlackTranslucent;
doneToolbarmeasure.items = [NSArray arrayWithObjects:
    [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil],
    [[UIBarButtonItem alloc]initWithTitle:@"Done" style:UIBarButtonItemStyleDone target:self action:@selector(donemeasureButtonClickedDismissKeyboard)],
    nil];
[doneToolbarmeasure sizeToFit];
textview2.inputAccessoryView = doneToolbarmeasure;

//Text View 3
textview3.layer.borderWidth = 1.0f;
textview3.layer.borderColor = [[UIColor blackColor] CGColor];
textview3.delegate = self;

UIToolbar* doneToolbarreportdesc = [[UIToolbar alloc]initWithFrame:CGRectMake(0, 0, 320, 50)];
doneToolbarreportdesc.barStyle = UIBarStyleBlackTranslucent;
doneToolbarreportdesc.items = [NSArray arrayWithObjects:
    [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil],
    [[UIBarButtonItem alloc]initWithTitle:@"Done" style:UIBarButtonItemStyleDone target:self action:@selector(donereportdescButtonClickedDismissKeyboard)],
    nil];
[doneToolbarreportdesc sizeToFit];
textview3.inputAccessoryView = doneToolbarreportdesc;

委托和方法

-(void)donedescButtonClickedDismissKeyboard
{
    [textview1 resignFirstResponder]; 
}

-(void)donemeasureButtonClickedDismissKeyboard
{
    [textview2 resignFirstResponder];
}

-(void)donereportdescdamageButtonClickedDismissKeyboard
{
    [textview3 resignFirstResponder];
}

- (void)textViewDidBeginEditing:(UITextView *)textView
{
     textviewlbl1.hidden = YES;
     textviewlbl2.hidden = YES;
     textviewlbl3.hidden = YES;
}

- (void)textViewDidEndEditing:(UITextView *)textView
{
    if(textview1.text.length == 0)
    {
        textviewlbl1.hidden = NO;
    }

    if(textview2.text.length == 0)
    {
        textviewlbl2.hidden = NO;
    }

    if(textview3.text.length == 0)
    {
        textviewlbl3.hidden = NO;
    }
}

问题

当我单击 UITextView 时，所有三个标签都被隐藏，第二次单击时，所有三个标签都未隐藏。 我需要将它们分别隐藏和取消隐藏。请帮忙！！

Answer 1

您可以对所有三个 textview 使用相同的委托方法，例如

-(void)textViewDidBeginEditing:(UITextView *)textView {
  if (textView == textview1) {
    // Code for textview1
  }
  else if (textView == textview2) {
    // Code for textview2
  }
  else if (textView == textview3) {
    // Code for textview3
  }
}

所以你的方法会是这样的：

- (void)textViewDidEndEditing:(UITextView *)textView
{
    if(textView == textview1 && textview1.text.length == 0)
    {
        textviewlbl1.hidden=NO;
    }
    if(textView == textview2  && textview2.text.length == 0)
    {
        textviewlbl2.hidden=NO;
    }
    if(textView == textview3  && textview3.text.length == 0)
    {
        textviewlbl3.hidden=NO;
    }
}

这样你就可以访问 textview 的所有委托方法了。只需按其对象区分 textview 即可。其他一些委托方法是：

- (void)textViewDidChange:(UITextView *)textView;
- (void)textViewDidChangeSelection:(UITextView *)textView;
- (void)textViewDidEndEditing:(UITextView *)textView;
- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text;
- (BOOL)textView:(UITextView *)textView shouldInteractWithURL:(NSURL *)URL inRange:(NSRange)characterRange;
- (BOOL)textView:(UITextView *)textView shouldInteractWithTextAttachment:(NSTextAttachment *)textAttachment inRange:(NSRange)range;

Answer 2

试试下面的代码

- (void)textViewDidEndEditing:(UITextView *)textView
 {
    if(textView.text.length == 0)
    {
       textView.hidden=NO;
    }
}

Answer 3

委托对象是每个委托调用的参数，在您的情况下为textView：

- (void)textViewDidEndEditing:(UITextView *)textView { if (textView == textview1) { // work with textview1 here } else if (textView == textview2) { // work with textview2 here } }

Answer 4

像这样使用if-condition，

- (void)textViewDidBeginEditing:(UITextView *)textView
{
      if (textView == textView1) {
       }
     if (textView == textView2) {

       }
       // and so on
}

Answer 5

您可以通过将tag 设置为UITextView 来做到这一点

在您的viewDidLoad 方法集标记中：

textview1.tag=1;
textview2.tag=2;
textview3.tag=3;

现在您可以通过if-else 条件隐藏和显示占位符标签

- (void)textViewDidBeginEditing:(UITextView *)textView
{
    if (textView.tag==1)
    {
        textviewlbl1.hidden=YES;
    }
    else if (textView.tag==2)
    {
        textviewlbl2.hidden=YES;
    }
    else if (textView.tag==3)
    {
        textviewlbl3.hidden=YES;
    }
}
- (void)textViewDidEndEditing:(UITextView *)textView
{
    if (textView.tag==1)
    {
        if(textview1.text.length == 0)
        {
            textviewlbl1.hidden=NO;
        }
    }
    else if (textView.tag==2)
    {
        if(textview2.text.length == 0)
        {
            textviewlbl2.hidden=NO;
        }
    }
    else if (textView.tag==3)
    {
        if(textview3.text.length == 0)
        {
            textviewlbl3.hidden=NO;
        }
    }
}

Answer 6

textview1.tag=1;
textview2.tag=2;
textview3.tag=3;

给这三个textview一个标签，标识不同的textview。