Methods for datasource are not called for this custom view - ios

Question

I would like to implement this sort of thing :
1- So first, I have implemented this view : UnitSliderView :
using this code :
#import "UnitSliderView.h"
#implementation UnitSliderView
-(id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self != nil)
{
//initialization
self.backgroundColor = [UIColor grayColor];
[self initViews];
[self initConstraints];
}
return self;
}
-(void)initViews
{
_leftLabel = [[UILabel alloc] init];
_leftLabel.textColor = [UIColor whiteColor];
//self.leftLabel.text = #"John";
[self addSubview:_leftLabel];
_rightLabel = [[UILabel alloc] init];
_rightLabel.textColor = [UIColor whiteColor];
//self.rightLabel.text = #"20%";
[self addSubview:self.rightLabel];
_slider = [[UISlider alloc] init];
_slider.value = 0.6;
[self addSubview:_slider];
}
-(void)initConstraints
{
self.rightLabel.translatesAutoresizingMaskIntoConstraints = NO;
self.leftLabel.translatesAutoresizingMaskIntoConstraints = NO;
self.slider.translatesAutoresizingMaskIntoConstraints = NO;
id views = #{
#"leftLabel": self.leftLabel,
#"slider": self.slider,
#"rightLabel": self.rightLabel,
};
[self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:#"H:|-[leftLabel(==90)]-5-[slider(==120)]-[rightLabel(==50)]-|" options:0 metrics:nil views:views]];
[self addConstraint:[NSLayoutConstraint constraintWithItem:self.slider attribute:NSLayoutAttributeCenterY relatedBy:NSLayoutRelationEqual toItem:self attribute:NSLayoutAttributeCenterY multiplier:1.0 constant:0.0]];
[self addConstraint:[NSLayoutConstraint constraintWithItem:self.leftLabel attribute:NSLayoutAttributeCenterY relatedBy:NSLayoutRelationEqual toItem:self attribute:NSLayoutAttributeCenterY multiplier:1.0 constant:0.0]];
[self addConstraint:[NSLayoutConstraint constraintWithItem:self.rightLabel attribute:NSLayoutAttributeCenterY relatedBy:NSLayoutRelationEqual toItem:self attribute:NSLayoutAttributeCenterY multiplier:1.0 constant:0.0]];
}
#end
2- Then, I have created this view, named MultiSliderView, which use the precedent View (UnitSliderView):
#import "MultiSliderView.h"
#import "UnitSliderView.h"
static const int kUnitsCount = 3;
#implementation MultiSliderView
-(id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self != nil)
{
//initialization
self.backgroundColor = [UIColor clearColor];
[self initViews];
}
return self;
}
- (void)initViews {
float totalHeight = self.frame.size.height;
float spacingRatio = 0.1;
float heightPerUnit = totalHeight/(kUnitsCount+spacingRatio*(kUnitsCount));
for (int i = 0; i < kUnitsCount; i++)
{
double percentage = [self.dataSource valueForSliderAtIndex:i];
NSString *leftString = [self.dataSource stringForLeftLabelAtIndex:i];
NSString *rightString = [self.dataSource stringForRightLabelAtIndex:i];
UnitSliderView *unit = [[UnitSliderView alloc] initWithFrame:CGRectMake(0, i*heightPerUnit + (i)*heightPerUnit*spacingRatio, self.frame.size.width, heightPerUnit)];
unit.slider.value = percentage;
unit.leftLabel.text = leftString;
unit.rightLabel.text = rightString;
[self addSubview:unit];
}
}
#end
3 - problem : when I init a MultiSlidersView in a viewController, the datasource methods that I have implemented in this same view controller are not called, thus the labels are not shown, and the slider values are 0.
I think there some of my code is not in the right place, but I can't find how to do it differently.

Answer 1

You should define the dataSource of the created class before you call the init function. You should define a method initWithFrame:(CGRect)frame andDataSource:(id <MultiSliderViewDataSource> ) dataSource and use it to initialize your view.

Answer 2

I assume you want to get an action called whenever the slide value changes. Since you implemented everything in code, you can do this in code using e.g.
[youSlider addTarget:self action:#selector(sliderValueChanged:) forControlEvents:UIControlEventValueChanged];