[英]How to add UIviews programmatically using auto-layouts parogramatically?
[英]How can we Growing UITextview size based on data programmatically using Auto-layouts
嗨,我是iOS的目標初學者,我正在嘗試以編程方式在UIViewController
上添加UITextView
,在這里我想根據數據大小來增長UItextview,我已經嘗試了一些代碼,但是它不起作用,請幫我一個
#import "AUIAutoGrowingTextView.h"
@interface AUIAutoGrowingTextView()
@property (strong, nonatomic) NSLayoutConstraint *heightConstraint;
@property (strong, nonatomic) NSLayoutConstraint *maxHeightConstraint;
@property (strong, nonatomic) NSLayoutConstraint *minHeightConstraint;
@end
@implementation AUIAutoGrowingTextView
-(id) initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
[self commonInit];
}
return self;
}
-(void) awakeFromNib
{
[self commonInit];
}
-(void) commonInit
{
// If we are using auto layouts, than get a handler to the height constraint.
for (NSLayoutConstraint *constraint in self.constraints) {
if (constraint.firstAttribute == NSLayoutAttributeHeight) {
self.heightConstraint = constraint;
break;
}
}
if (!self.heightConstraint) {
// TODO: We might use auto layouts but set the height of the textView by using a top + bottom constraints. In this case we would want to manually create a height constraint
}
}
- (void) layoutSubviews
{
[super layoutSubviews];
if (self.heightConstraint) {
[self handleLayoutWithAutoLayouts];
}
else {
[self handleLayoutWithoutAutoLayouts];
}
// Center vertically
// We're supposed to have a maximum height contstarint in code for the text view which will makes the intrinsicSide eventually higher then the height of the text view - if we had enough text.
// This code only center vertically the text view while the context size is smaller/equal to the text view frame.
if (self.intrinsicContentSize.height <= self.bounds.size.height) {
CGFloat topCorrect = (self.bounds.size.height - self.contentSize.height * [self zoomScale])/2.0;
topCorrect = ( topCorrect < 0.0 ? 0.0 : topCorrect );
self.contentOffset = (CGPoint){.x = 0, .y = -topCorrect};
}
}
-(void) handleLayoutWithAutoLayouts
{
CGSize intrinsicSize = self.intrinsicContentSize;
if (self.minHeight) {
intrinsicSize.height = MAX(intrinsicSize.height, self.minHeight);
}
if (self.maxHeight) {
intrinsicSize.height = MIN(intrinsicSize.height, self.maxHeight);
}
self.heightConstraint.constant = intrinsicSize.height;
}
-(void) handleLayoutWithoutAutoLayouts
{
// TODO:
}
- (CGSize)intrinsicContentSize
{
CGSize intrinsicContentSize = self.contentSize;
if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 7.0) {
intrinsicContentSize.width += (self.textContainerInset.left + self.textContainerInset.right ) / 2.0f;
intrinsicContentSize.height += (self.textContainerInset.top + self.textContainerInset.bottom) / 2.0f;
}
return intrinsicContentSize;
}
@end
#import "ViewController.h"
#import "AUIAutoGrowingTextView.h"
@interface ViewController ()
{
AUIAutoGrowingTextView * growingTextView;
}
@end
@implementation ViewController
- (void)viewDidLoad
{
[super viewDidLoad];
growingTextView = [AUIAutoGrowingTextView new];
growingTextView = [[AUIAutoGrowingTextView alloc]init];
growingTextView.translatesAutoresizingMaskIntoConstraints = NO;
growingTextView.backgroundColor = [UIColor colorWithRed:0.95 green:0.47 blue:0.48 alpha:1.0];
growingTextView.maxHeight = 200;
[self.view addSubview:growingTextView];
NSLayoutConstraint * constraint2 = [NSLayoutConstraint constraintWithItem:growingTextView attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem: self.view attribute:NSLayoutAttributeTop multiplier:1.0f constant:20.0f];
[self.view addConstraint:constraint2];
constraint2 = [NSLayoutConstraint constraintWithItem:growingTextView attribute:NSLayoutAttributeLeading relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeLeading multiplier:1.0f constant:5.0f];
[self.view addConstraint:constraint2];
constraint2 = [NSLayoutConstraint constraintWithItem:growingTextView attribute:NSLayoutAttributeTrailing relatedBy:NSLayoutRelationEqual toItem:self.view attribute:NSLayoutAttributeTrailing multiplier:1.0f constant:-5.0f];
[self.view addConstraint:constraint2];
constraint2 = [NSLayoutConstraint constraintWithItem:growingTextView attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationEqual toItem: nil attribute:NSLayoutAttributeNotAnAttribute multiplier:1.0f constant:50.0f];
[self.view addConstraint:constraint2];
}
@end
我認為您想以編程方式添加自定義UITextView
。
var textView:AUIAutoGrowingTextView?
override func viewDidLoad() {
super.viewDidLoad()
self.textView = AUIAutoGrowingTextView()
self.textView?.text = "Hello"
self.textView?.frame = self.view.frame // set frame as per your need.
self.view.addSubview(self.textView!)
// Do any additional setup after loading the view, typically from a nib.
}
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