Question

我想在我的UITextView中有一个占位符，我宁愿避免像拖出方法（重载代码）和子类化这样的复杂性。我只需要保留编辑。

我目前正在使用此方法在UITextView

中创建占位符

·H

@property (weak, nonatomic) IBOutlet UITextView *gcTextView;

的.m

@synthesize gcTextView;

将此添加到viewDidLoad:

self.gcTextView.text = @"placeholder text here";
self.gcTextView.textColor = [UIColor lightGrayColor];
gcTextView.layer.borderColor = [[UIColor whiteColor] CGColor];

然后使用此方法进行编辑 - ＆gt;

- (void) textViewDidBeginEditing:(UITextView *) textView
{
    [textView setText:@""];

    self.gcTextView.textColor = [UIColor blackColor];
}

问题：我需要添加到这种方式

1）如果已修改的文字返回nil或textView，我认为将占位符添加回@""。

2）在textView

上重新进入编辑模式时，不会删除所有用户的已修改文字

Answer 1

为了在UITextView中拥有占位符功能，我通常会这样做：

[self.gcTextView setText:@"placeholder"];
[self.gcTextView setTextColor:[UIColor lightGrayColor]];
[self.gcTextView setTag:100]; //start tag with default 100

- (void) textViewShouldBeginEditing:(UITextView *) textView
{
    if(textView.tag == 100) {
        [textView setTag:200];
        [textView setText:@""];
        [textView setTextColor:[UIColor blackColor];
    }
}

- (void) textViewDidEndEditing:(UITextView *) textView
{
    //handle text that has spaces as it's content (i.e. no characters)
    NSString *strStrippedText = [textView.text stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];

    if(strStrippedText.length == 0) {
        [textView setTag:100];
        [textView setText:@"Placeholder"];
        [textView setTextColor:[UIColor lightGrayColor];
    }
}

基本上，这都与我设置的标签有关

编辑：但是......

如果您将标签用于其他目的，那么这可能会破坏某些内容，因此您可以安全地修改bounces属性并将其用作个人使用的指示器。

[self.gcTextView setText:@"placeholder"];
[self.gcTextView setTextColor:[UIColor lightGrayColor]];
[self.gcTextView setBounces:NO]; //NO for placeholder text

- (void) textViewShouldBeginEditing:(UITextView *) textView
{
    if(textView.bounces == NO) {
        [textView setText:@""];
        [textView setTextColor:[UIColor blackColor];
        [textView setBounces:YES]; //YES for non-placeholder text
    }
}

- (void) textViewDidEndEditing:(UITextView *) textView
{
    //handle text that has spaces as it's content (i.e. no characters)
    NSString *strStrippedText = [textView.text stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];

    if(strStrippedText.length == 0) {
        [textView setText:@"Placeholder"];
        [textView setTextColor:[UIColor lightGrayColor];
        [textView setBounces:NO];
    }
}

Answer 2

我不得不将标签版本（IOS 9）更改为以下代码。

- (BOOL) textViewShouldBeginEditing:(UITextView *) textView //changed to bool
{
    if(textView.tag == 100) {
        [textView setTag:200];
        [textView setText:@""];
        [textView setTextColor:[UIColor blackColor]];
    }
    return YES; // added return value
}

- (void) textViewDidEndEditing:(UITextView *) textView
{
    //handle text that has spaces as it's content (i.e. no characters)
    NSString *strStrippedText = [textView.text stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];

    if(strStrippedText.length == 0) {
        [textView setText:UI_TEXT_HINT_BODY];
        [textView setTextColor:[UIColor lightGrayColor]];
        [textView setBounces:NO];
        [textView setTag:100]; // reset to hint mode
        }
}

使用UITextView占位符而不是在重新输入时清除文本

2 个答案:

编辑：但是......