uislider - Linking stepper to Slider UIObject in C4 -

i new c4 please gentle...

if want link slider value label done nsstring stringwithformat... e.g.:

self.mylabel.text = [nsstring stringwithformat:@"%4.2f",slider.value]; 

i added stepper object well, , updates mylabel:

self.mylabel.text = [nsstring stringwithformat:@"%4.2f",stepper.value]; 

but intuitive if slider position follows label value when i'm using stepper. .value not available property in uilabel... how take mylabel.text property , push slider.value property without getting datatype mismatch error?

this question has 2 answers, how using c4 objects , how interface builder / uicontrols. i'll show both ways, ui first can compare c4 way afterwards.

uicontrol

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to uicontrols first set c4workspace.h header has following methods , properties:

@property (assign, nonatomic) iboutlet uilabel *mylabel; @property (assign, nonatomic) iboutlet uislider *myslider; @property (assign, nonatomic) iboutlet uistepper *mystepper;  -(ibaction)sliderwasupdated:(uislider *)slider; -(ibaction)stepperwasupdated:(uistepper *)stepper; 

then, in drag 3 components onto projects xib file (i.e. uislider, uilabel , uistepper). link action sliderwasupdated: slider using valuechanged option, , stepperwasupdated: action stepper using valuechanged option. step selecting c4canvas.xib project right-clicking on yellow cube, dragging actions listed in pop-up menu each of objects placed on canvas.

next, add following code c4workspace.m file:

@implementation c4workspace  -(void)setup {     self.mystepper.minimumvalue = 0.0f;     self.mystepper.maximumvalue = 10.0f;      self.myslider.minimumvalue = 0.0f;     self.myslider.maximumvalue = 10.0f; }  -(ibaction)sliderwasupdated:(uislider *)slider {     slider.value = [c4math round:slider.value];     self.mylabel.text = [nsstring stringwithformat:@"%4.2f",slider.value];     self.mystepper.value = slider.value;     [self.mylabel sizetofit]; }  -(ibaction)stepperwasupdated:(uistepper *)stepper {     self.mylabel.text = [nsstring stringwithformat:@"%4.2f",stepper.value];     self.myslider.value = stepper.value;     [self.mylabel sizetofit]; }  @end 

in setup make sure min/max values of both ui objects same (so can keep them matched up).

in stepperwaschanged: method 2 things:

1. we use stepper's value set label's text
2. we use stepper's value set slider's value!

in sliderwaschanged: method same thing, updating stepper, round value of slider increments in steps (just keep things tidy).

c4control

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to same c4 objects, instead of native ui objects, set things little differently. first, don't add our c4canvas.xib, instead we'll set objects manually.

in c4workspace.h file, add following lines of code:

@property (readwrite, nonatomic, strong) c4label *mylabel; @property (readwrite, nonatomic, strong) c4slider *myslider; @property (readwrite, nonatomic, strong) c4stepper *mystepper;  -(void)sliderwasupdated:(c4slider *)slider; -(void)stepperwasupdated:(c4stepper *)stepper; 

notice of same except we're using c4 instead of ui prefixes. also, call our methods -(void) instead of -(ibaction) because we're not using interface builder.

next, add following code c4workspace.m:

@implementation c4workspace  -(void)setup {     [self createaddobjects];     //calibrate min/max values     self.mystepper.minimumvalue = 0.0f;     self.mystepper.maximumvalue = 10.0f;      self.myslider.minimumvalue = 0.0f;     self.myslider.maximumvalue = 10.0f; }  -(void)sliderwasupdated:(c4slider *)slider {     slider.value = [c4math round:slider.value];     self.mylabel.text = [nsstring stringwithformat:@"%4.2f",slider.value];     self.mystepper.value = slider.value;     [self.mylabel sizetofit]; }  -(void)stepperwasupdated:(c4stepper *)stepper {     self.mylabel.text = [nsstring stringwithformat:@"%4.2f",stepper.value];     self.myslider.value = stepper.value;     [self.mylabel sizetofit]; }  -(void)createaddobjects {     //set objects     self.mylabel = [c4label labelwithtext:@"values"];     self.mystepper = [c4stepper stepper];     self.myslider = [c4slider slider:cgrectmake(0, 0, 192, 44)];      //position them     cgpoint centerpoint = cgpointmake(self.canvas.center.x,                                       self.canvas.center.y - 100);     self.mystepper.center = centerpoint;      centerpoint.y += 100;     self.mylabel.center = self.canvas.center;      centerpoint.y += 100;     self.myslider.center = centerpoint;      //set action bindings     [self.myslider runmethod:@"sliderwasupdated:"                       target:self                     forevent:valuechanged];     [self.mystepper runmethod:@"stepperwasupdated:"                        target:self                      forevent:valuechanged];      [self.canvas addobjects:@[self.mystepper,self.mylabel,self.myslider]]; }  @end 

differences

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the major difference between 2 approaches whether or not use interface builder. in c4 approach need add method called createaddobjects our project our slider, label , stepper added canvas.

this method contains methods binding actions of our c4uielements our code, happens in lines:

[self.myslider runmethod:@"sliderwasupdated:"                   target:self                 forevent:valuechanged]; [self.mystepper runmethod:@"stepperwasupdated:"                    target:self                  forevent:valuechanged]; 

once these set only difference specifying use of c4 objects instead of ui objects, like:

-(void)sliderwasupdated:(c4slider *)slider {...} 

instead of

-(ibaction)sliderwasupdated:(uislider *)slider {...}