未知文字長度的動態標籤框架

有時我們必須根據文字長度未知的動態內容調整 UILabel 的大小。在這個例子中，UILabel 的寬度固定為 280 點，高度是無限的，比方說 9999.估計相對於文字樣式和 maximumLabelSize 的幀。

Objective-C 的

UILabel * label = [[UILabel alloc] init];

NSString *message = @"Some dynamic text for label";

//set the text and style if any.
label.text = message;

label.numberOfLines = 0;

CGSize maximumLabelSize = CGSizeMake(280, 9999); //280:max width of label and 9999-max height of label.

// use font information from the UILabel to calculate the size
CGSize expectedLabelSize = [label sizeThatFits:maximumLabelSize];

//Deprecated in iOS 7.0
//CGSize expectedLabelSize = [message sizeWithFont:label.font constrainedToSize:maximumLabelSize lineBreakMode:NSLineBreakByWordWrapping];

// create a frame that is filled with the UILabel frame data
CGRect newFrame = label.frame;

// resizing the frame to calculated size
newFrame.size.height = expectedLabelSize.height;

// put calculated frame into UILabel frame
label.frame = newFrame;

迅速

var message: String = "Some dynamic text for label"
//set the text and style if any.
label.text = message
label.numberOfLines = 0
var maximumLabelSize: CGSize = CGSize(width: 280, height: 9999)
var expectedLabelSize: CGSize = label.sizeThatFits(maximumLabelSize)
// create a frame that is filled with the UILabel frame data
var newFrame: CGRect = label.frame
// resizing the frame to calculated size
newFrame.size.height = expectedLabelSize.height
// put calculated frame into UILabel frame
label.frame = newFrame