I am trying to make a UISlider that has a fat track. I tried this, and it almost works. However, when the UISlider is first displayed, the track bar is normal. Only when it gets a touch event does it get thicker.
Here is the code I added to my subclass of UISlider, as recommended:
- (CGRect)trackRectForBounds:(CGRect)bounds
{
return bounds;
}
I don't understand how this works, so I can't figure out why it isn't working perfectly. Here are my questions:
How does this work?
How can I control how thick it makes the track?
How can I make it affect the track when the UISlider is first drawn?
Of course, the third question is the most important, though the others will help me in my understanding.
One other thing to consider: when it is first displayed, I hide the thumb:
[slider setThumbImage:[[UIImage alloc] init] forState:UIControlStateNormal];
When the user touches the slider, I display the thumb like this:
[slider setThumbImage:nil forState:UIControlStateNormal];
I mention this because I wonder if that is somehow interfering with the trackRectForBounds magic.
Thanks!
Question 1. From the docs:
If you want to customize the track rectangle, you can override this
method and return a different rectangle. The returned rectangle is
used to scale the track and thumb images during drawing.
The default implementation of this method returns a smaller rectangle than the one it is passed. Yours simply returns what it's passed, instead of shrinking it first.
Question 2. Return a larger or smaller CGRect, for example:
return CGRectMake(0, 0, 500, 200);
Question 3. I think the method only gets called if you don't set a custom image, which is why it has no effect until you set the image to nil. If you want to override the image, try overriding the slider images with actual images that look the way you want.
Related
I am currently working on a drawing application in swift. So far I have implemented buttons that will change the colour of the drawings. I now have a UISlider and want to change the width of the drawings being made. Does anyone know
how this could be implemented, as in what code can I use for the IBAction function in the view controller?
You can use Value changed event.
Inside value changed event you can get the slider.value assign this value to the width factor.
-(IBAction)SliderValueChanged:(id)sender
{
UISlider * slider = (UISlider*)sender;
self.drawingWidth = slider.value;
//redraw with the new value
}
I think you have overrided touchesBegan drawLineFrom touchesMoved methods of the drawing view.
I came accross a well explained example for you. It explains how to control coloring, opacity and brush sizes as well.
Have a lok at this example
I've followed this answer to create an animated circle, and it works just fine. In addition to the path, I draw a text in the center of the view with drawInRect. I would like that text to change during the animation, to reflect the percentage of the path that is visible at each moment. How can I achieve that?
Thanks.
The most promising post would likely be this one. It describes creating a new CALayer that keeps track of the progress, which can then fire a call back.
Otherwise you'll likely need to wangle something together by observing your view's presentationLayer.
I'm creating UIItableview. For the first cell I want to have a user Image with a button to allow him to change the image. (not so complicated).
Somehow I have a strange problem: When I set setMasksToBounds:NO the [self.userTable.layer setCornerRadius:20.0]; is simply get disabled.
I am attaching a code with output example:
//Initiate UserTable
//[self.userTable setClipsToBounds:NO];//from the documentation this line is set by default
[self.userTable.layer setCornerRadius:20.0];
[self.view addSubview:self.userTable];
later in cellForRowAtIndexPath: I add:
[myCellView.contentView addSubview:photo]; //My photo is UImageview
If I uncomment the line [self.userTable setClipsToBounds:NO] I get:
but my corners are not rounded any more......
I read the following questions
this and this and still cant figure that out?
Did someone had this problem and can provide a fix which will not force me to change all my code? and also how the 2 options are related to each other?
Thanks a lot.
Calling setCornerRadius applies a mask to your CALayer, which is then used to mask the bounds and create the rounded corner effect.
By calling setMasksToBounds:NO, you are disabling the mechanism used to round the corners.
In short, you can't have it both ways.
Consider making that row in the tableview taller, or using a custom view instead of a standard UITableViewCell.
It was necessary to create a subclass of UIButton, lets call it subButton. These subButtons are instantiated one by one and dynamically added to an UIScrollView object.
Unfortunately the subButtons aren't reacting as expected. After scrolling away from the first dynamic generated subButtons and then returning back to them. They loose their reactivity to single tapping. I can not explain this behaviour. Can somebody explain why its behaving this way?
Many thanks.
Source code
self.subButton = [[SubButton alloc]initWithFrame:CGRectMake(69.5, y, 201, 114)];
[self.subButton setBackgroundColor:[UIColor blueColor]];
self.subButton.imageData = imageData;
self.subButton.videoPath = videoPath;
self.subButton.vidIndex = _indexVideo +1;
[self.subButton drawVidPreview];
[self.subButton setTag:(_indexVideo +1)];
[self.subButton addTarget:self action:#selector(handleSingleTap:) forControlEvents:UIControlEventTouchUpInside];
[self.videoScroll addSubview:self.subButton];
[_videoPreviews addObject:self.subButton];
The subButton method drawVidPreview adds some subviews to itself.
Do the buttons not respond at all, or just not to single-tap? That might help us help you.
If they don't respond at all, I would check your view hierarchy to make sure no other view (perhaps invisible) are sitting above your buttons. Or, perhaps are the buttons not being added to the parent view you think?
Please make sure you are not adding the same UIGestureRecognizer instance to all of the UIButtons, instead for each UIButton you need to add a separate instance, however all gesture instance can point to the same target.
At last, i could solve the problem. The reason why the first subButtons did not respond to single tapping with UIControlEventTouchDown is because the uiScrollview content offset was set to a negative y value. This first of all was not necessary and was done out of pure laziness. I corrected it by giving it a positive value.
So my conclusion is, if you do not set the content offset or content size of the scrollView correctly, some dynamically added buttons to the scrollView might not respond to tapping appropriately. This is even the case if all Buttons are placed completely on a uiScrollview object.
This I could confirm by playing around with the content size of the uiScrollview instance too. I changed size of the y value of uiScrollviews instance just by few points and then some of the last buttons did not respond to tapping anymore.
Just by increasing the content size of the y value again, made the buttons responsive again.
I'm trying to use my own images on a C4Stepper. I'm setting it up like this
#implementation C4WorkSpace{
C4Stepper *theStepper;
C4Image *stepperBackground;
C4Image *stepperPlus;
}
-(void)setup {
//load backgroundimage
stepperBackground=[C4Image imageNamed:#"icon_zoom.png"];
stepperBackground.width=100;
//load incrementImage
stepperPlus=[C4Image imageNamed:#"icon_zoom_plus.png"];
stepperPlus.width=stepperBackground.width/2;
//setup stepper
theStepper=[C4Stepper stepper];
[theStepper setBackgroundImage:stepperBackground forState:NORMAL];
[theStepper setIncrementImage:stepperPlus forState:NORMAL];
theStepper.center=self.canvas.center;
[self.canvas addSubview:theStepper];
}
The 2 icons look like this:
Strangely, what appears on the canvas looks something like this: !
Are there any special requirements for the zoomStepperImages? A certain size or something?
There are special requirements.
The background image used is "stretchable", so you have to design a button image that can be stretched if needed. If you have a look at any of the button images (incl. in the Media.xcassets folder) you'll see that they are generic. For example, the selected button background image looks like:
Similarly, the increment / decrement images are themselves independent of the background images. The incrementNormal image included in the same folder looks like:
You can see how the default values of the C4Stepper class are initialized in C4AppDelegate.m:
...
[C4Stepper defaultStyle].style = basicStyle;
[C4Stepper defaultStyle].tintColor = [UIColor colorWithPatternImage:[UIImage imageNamed:#"lightGrayPattern"]];
[[C4Stepper defaultStyle] setDecrementImage:[C4Image imageNamed:#"decrementDisabled"] forState:DISABLED];
[[C4Stepper defaultStyle] setDecrementImage:[C4Image imageNamed:#"decrementNormal"] forState:NORMAL];
[[C4Stepper defaultStyle] setIncrementImage:[C4Image imageNamed:#"incrementDisabled"] forState:DISABLED];
[[C4Stepper defaultStyle] setIncrementImage:[C4Image imageNamed:#"incrementNormal"] forState:NORMAL];
So, what you want to do is create an image for your background (mine is stretchable because the stuff in the middle are straight lines that can be stretched horizontally without looking stretched. You also want to create independent + - images for increment / decrement sides of the button.
Just as a note, when I was creating the C4Button class, I had to play around with the various images I was creating to get them to "look" right... In the end, I had to do a lot of tweaking and experimenting to learn how they were rendered. The difficulty I had in figuring this out was that the rendering mechanism of UIButton itself was a bit strange and I had to learn how to fit things into the button so that they rendered properly.