将文本居中放置在UITextView中,垂直和水平 [英] Center the text in a UITextView, vertically and horizontally
问题描述
我有一个单元格的分组表视图。在这个单元格中,我在 cellForRowAtIndexPath:
中放置一个 UITextView
,我立即使第一个响应者。
I have a grouped table view with one cell. In this cell I'm putting a UITextView
in cellForRowAtIndexPath:
, and I instantly make this first Responder.
我的问题是:当我开始输入时,文本是左对齐的,不是水平和垂直居中我想要的。
My problem is: When I start typing, the text is left-justified, not centered horizontally and vertically as I want. This is on iOS 7.
推荐答案
我通过观察UITextView的contentsize来解决这个问题,当contentSize有任何变化时,更新contentOffset。
I resolve this issue by observing the contentsize of UITextView, when there is any change in the contentSize, update the contentOffset.
添加观察者如下:
[textview addObserver:self forKeyPath:@"contentSize" options:(NSKeyValueObservingOptionNew) context:NULL];
处理观察者操作,如下所示:
Handle the observer action as follows:
-(void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
UITextView *txtview = object;
CGFloat topoffset = ([txtview bounds].size.height - [txtview contentSize].height * [txtview zoomScale])/2.0;
topoffset = ( topoffset < 0.0 ? 0.0 : topoffset );
txtview.contentOffset = (CGPoint){.x = 0, .y = -topoffset};
}
要使textview文本水平居中,从.xib类中选择textview,去图书馆,在那个集合对齐作为中心。
To make the textview text horizontally center, select the textview from .xib class and go to the library and in that set Alignment as center.
享受。 :)
这篇关于将文本居中放置在UITextView中,垂直和水平的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!