当 UISearchBar 处于活动状态时如何展开它 [英] How to expand a UISearchBar when it becomes active

问题描述

我有一个 UISearchBar 需要压缩(见截图)，然后在它被触摸或处于活动状态时扩展到更大的尺寸.

I have a UISearchBar that needs to be compressed (see screenshot) and then expand to a larger size when it is touched or isActive.

我该怎么做?目前我的搜索栏通过 IB 放置在视图中.

How would I go about doing this? Currently my search bar is placed in the view via IB.

谢谢

推荐答案

我建议为键盘显示/隐藏通知添加一个 NSNotifcation 侦听器，并基于此调整 UISearchBar 框架:

I would suggest adding a NSNotifcation listener for the keyboard showing/hiding notifications and based on this adjust the UISearchBar frame:

- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];

    NSNotificationCenter *nc = [NSNotificationCenter defaultCenter];
    [nc addObserver:self selector:@selector(adjustFrame:) name:UIKeyboardWillShowNotification object:nil];
    [nc addObserver:self selector:@selector(adjustFrame:) name:UIKeyboardWillHideNotification object:nil];
}

当视图即将消失时，我们需要移除监听器:

We need to remove the listener when the view is going to disappear:

- (void)viewWillDisappear:(BOOL)animated {
    [super viewWillDisappear:animated];

    NSNotificationCenter *nc = [NSNotificationCenter defaultCenter];
    [nc removeObserver:self name:UIKeyboardWillShowNotification object:nil];
    [nc removeObserver:self name:UIKeyboardWillHideNotification object:nil];
}

现在我们需要 2 个自定义函数来调整框架:

And now we need the 2 custom functions to adjust the frame:

- (void)adjustFrame:(NSNotification *) notification {
    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationDuration:0.3];
    [UIView setAnimationBeginsFromCurrentState:YES];

    if ([[notification name] isEqual:UIKeyboardWillHideNotification]) {
        // revert back to the normal state.
        self.searchBar.frame = CGRectMake (100,50,100,self.searchBar.frame.size.Height);
    } 
    else  {
        //resize search bar
        self.searchBar.frame = CGRectMake (10,50,200,self.searchBar.frame.size.Height);    
}

    [UIView commitAnimations];
}

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