问题
I have SQLite database file and UILabel, and I set text for label from database on the number of characters after convert String to Characters, and I added extension its name (length), its job counts the number of characters.
My problem in this picture is : The UILabels are not organized in sizes and positions in per devices I want them to have their positions in the center of X-Axis
Questions:
1) How to set the label into center and set spaces right and left of screen for labels (per device) ??
2) How to set width for labels if device is iPhone 7/6S/6 plus width = 50, if device is iPhone 7/6S/6 width = 45 and if device is iPhone SE/5S/5C/5 width = 38 ??
3) Finally, how does the label become smaller by 10 if the number of characters is more than 8 ?
This my code :
func createTarget(id: Int) {
listdata = dbHelpr.getDatabase(rowId: id)
for data in listdata {
let lengthOfChar : CGFloat = data.ans.length
let yAxis : CGFloat = (self.view.frame.height) * 60%
let width: CGFloat = view.frame.size.width - 40 // frame width
var targetWidth: CGFloat = (width - (lengthOfChar - 1) * 5) / lengthOfChar
let targetHeigt : CGFloat = 5
if lengthOfChar >= 8 {
targetWidth = 40
} else {
targetWidth = 50
}
let totalWidth: CGFloat = (targetWidth * lengthOfChar) + ((lengthOfChar - 5) * 5)
for (indexTar, tar) in data.ans.characters.enumerated() {
let x : CGFloat = (width / 2) - (totalWidth / 2)
let xx : CGFloat = (CGFloat(indexTar) * targetWidth) + (CGFloat(indexTar) * 5) + 20
var xAxis : CGFloat = (x + xx)
xAxis = width - xAxis
let targetLabel = UILabel(frame: CGRect(x: xAxis, y: yAxis, width: targetWidth, height: targetHeigt))
targetLabel.backgroundColor = .white
targetLabel.layer.masksToBounds = true
targetLabel.layer.cornerRadius = 5
targetLabel.text = String(describing: tar)
targetLabel.textAlignment = .center
targetLabel.textColor = .white
self.view.addSubview(targetLabel)
}
}
}
回答1:
In order to position your labels you need a few things things:
- Label container to keep everything centered and with margins from the screen sides
- Constraints between your labels depending on the device sizes etc..
- If you need to break lines - you need to handle it manually as well
To identify device kinds and have different logics, you can check this posts: iOS: How to determine the current iPhone/device model in Swift?
In order to fill your view with labels, here is a sample code to achieve this:
self.view.backgroundColor = UIColor.black
let labelContainerView : UIView = UIView(frame: CGRect(x: 0, y: 0, width: 10, height: 10))
labelContainerView.translatesAutoresizingMaskIntoConstraints = false
let containerLeftConstraint : NSLayoutConstraint = NSLayoutConstraint(item: self.view, attribute: .left, relatedBy: .greaterThanOrEqual, toItem: labelContainerView, attribute: .left, multiplier: 1, constant: 8)
let containerRightConstraint : NSLayoutConstraint = NSLayoutConstraint(item: self.view, attribute: .right, relatedBy: .greaterThanOrEqual, toItem: labelContainerView, attribute: .right, multiplier: 1, constant: 8)
let containerCenterX : NSLayoutConstraint = NSLayoutConstraint(item: labelContainerView, attribute: .centerX, relatedBy: .equal, toItem: self.view, attribute: .centerX, multiplier: 1, constant: 0)
let containerCenterY : NSLayoutConstraint = NSLayoutConstraint(item: labelContainerView, attribute: .centerY, relatedBy: .equal, toItem: self.view, attribute: .centerY, multiplier: 1, constant: 0)
self.view.addSubview(labelContainerView)
self.view.addConstraints([ containerLeftConstraint, containerRightConstraint, containerCenterX, containerCenterY ])
// Add some labels
let totalLabels : Int = 10
var lastAddedLabel : UILabel? = nil
for labelAt : Int in 1 ... totalLabels
{
var addedConstraint : [NSLayoutConstraint] = [NSLayoutConstraint]()
let label : UILabel = UILabel(frame: CGRect.zero)
label.translatesAutoresizingMaskIntoConstraints = false
label.text = "_"
label.textColor = UIColor.white
label.textAlignment = .center
label.adjustsFontSizeToFitWidth = true
if (lastAddedLabel != nil)
{
// Add left constraint to previous label
let leftConstraint : NSLayoutConstraint = NSLayoutConstraint(item: label, attribute: .left, relatedBy: .equal, toItem: lastAddedLabel!, attribute: .right, multiplier: 1, constant: 8)
let equalWidth : NSLayoutConstraint = NSLayoutConstraint(item: label, attribute: .width, relatedBy: .equal, toItem: lastAddedLabel!, attribute: .width, multiplier: 1, constant: 0)
addedConstraint.append(contentsOf: [ leftConstraint, equalWidth ])
}
else
{
// Add left constraint to super view
let leftConstraint : NSLayoutConstraint = NSLayoutConstraint(item: labelContainerView, attribute: .left, relatedBy: .equal, toItem: label, attribute: .left, multiplier: 1, constant: 0)
addedConstraint.append(leftConstraint)
}
// Add top bottom constraint
let topConstraint : NSLayoutConstraint = NSLayoutConstraint(item: labelContainerView, attribute: .top, relatedBy: .equal, toItem: label, attribute: .top, multiplier: 1, constant: 0)
let bottomConstraint : NSLayoutConstraint = NSLayoutConstraint(item: labelContainerView, attribute: .bottom, relatedBy: .equal, toItem: label, attribute: .bottom, multiplier: 1, constant: 0)
addedConstraint.append(contentsOf: [ topConstraint, bottomConstraint ])
// Add right constraint if this is the last label
if (labelAt == totalLabels)
{
let rightConstraint : NSLayoutConstraint = NSLayoutConstraint(item: labelContainerView, attribute: .right, relatedBy: .equal, toItem: label, attribute: .right, multiplier: 1, constant: 0)
addedConstraint.append(rightConstraint)
}
labelContainerView.addSubview(label)
labelContainerView.addConstraints(addedConstraint)
lastAddedLabel = label
}
self.view.layoutIfNeeded()
This gives out the output:
Changes you might need to make:
- Change the "totalLabels" number depending on your requirement
- Maybe adding another width constraint to the first generated label in order to define a specific with for all labels - the rest of the labels keep the same width as the first
- Adjust the containing view margins from both sides for different devices
- Handle new lines manually by pre-calculating the width the labels might use.
Good luck
回答2:
I solved my problem and this answer :
func createTarget(id: Int) {
listdata = dbHelpr.getDatabase(rowId: id)
var targetHeigt = CGFloat()
let viewWidth = self.view.frame.size.width
if viewWidth == 320 {
targetHeigt = 2.5
} else {
targetHeigt = 5
}
for data in listdata {
let yAxis : CGFloat = (self.view.frame.height) * 60%
let i = data.ans.length
// char count
let width: Int = Int(view.frame.size.width) - 40
// frame width
var targetWidth: Int = (width - (i - 1) * 5) / i
if targetWidth > 50 {
targetWidth = 50
}
let totalWidth: Int = (targetWidth * i) + ((i - 1) * 5)
for x in 0..<i {
let currentWidth: Int = (width / 2) - (totalWidth / 2) + (x * targetWidth) + (x * 5) + 20
let targetLabel = UILabel(frame: CGRect(x: CGFloat(currentWidth), y: yAxis, width: CGFloat(targetWidth), height: targetHeigt))
targetLabel.backgroundColor = .white
targetLabel.layer.masksToBounds = true
targetLabel.layer.cornerRadius = 5
targetLabel.textAlignment = .center
targetLabel.textColor = .white
for i in listdata {
let tar = data.ans.characters.map{String($0)}
targetLabel.text = String(describing: tar)
}
self.view.addSubview(targetLabel)
}
}
}
来源：https://stackoverflow.com/questions/45544072/organize-and-adjust-the-uilabel-position-per-devices-swift-3