Is it possible to give different alpha values to the same view at the same time?
I want to display color in a uiview, but it should faded out to a direction. Means I want to change its alpha value within increasing its x coordinate value.
Yes you can achieve this, but you have to remember that the range alpha value is from 0-1. So in this case you can define you can define change according to the width ie
float changeInAlphaPerX = 1/self.frame.width;
And where you are getting changed x value, you can do..
view.alpha = changeInAlphaPerX * x;
Hope it helps..
Related
I want two independent rows to have the same width and scroll simultaneously. I have tried to achieve this in this way:
#Composable
fun TwoRows() {
val scrollState = rememberScrollState()
Column(Modifier.fillMaxWidth()) {
Row(Modifier.fillMaxWidth().horizontalScroll(scrollState)) {
for (i in 0 until 100) {
Box(Modifier.width(10.dp).height(10.dp).background(Color.Red))
Spacer(Modifier.width(90.dp))
}
}
Row(Modifier.fillMaxWidth().horizontalScroll(scrollState)) {
for (i in 0 until 100) {
Box(Modifier.width(100.dp).height(10.dp).background(Color.Green))
}
}
}
}
The first row consists of 10 dp width red rectangles and 90 dp width spacers. The second row consists of only 100 dp width green rectangles. I'm expecting these rows to have the same width but the layout inspector shows they're not:
Because of this the elements do not match expecting positions:
How can I fix it?
This is happening because each of .size(), width(), .height() modifiers transform incoming value into pixel just in time it applied. I.e. they apply independently - the first modifier converts its value to pixels, and then the second, and so on. There is no guarantee that you get the same dp value after transforming it to px and back because of rounding. Here is how dp->px->dp transformation works for your case:
dp = 10.dp // Incoming dp value
density = 2.625 // Screen density scale value of your emulator
unrounded_px = 10 * density = 26.25
px = 26
restored_dp = 26 / density = 9.904762.dp
Most likely that the LayoutInspector doesn't round computed dp value to the nearest integer, but simply discards the fractional part. I think this is the reason why it shows different value. Such behavior is especially likely to occur when you work with relatively small views on low pixel density screens.
You can achieve desired behavior wrapping your red Box and Spacer into the Box with specified size:
Box(Modifier.width(100.dp).height(10.dp)) {
Box(Modifier.width(10.dp).height(10.dp).background(Color.Red))
Spacer(Modifier.width(90.dp))
}
In widget iOS14, I want to show values in graphical form using bar chart.
I have used this library "https://github.com/dawigr/BarChart" to draw bar chart.
But in Xcode12+, it's not showing negative values and considering negative value as 0 and throwing warning as shown in screen shot.
"[SwiftUI] Invalid frame dimension (negative or non-finite)"
You could try to normalise your input Values to prevent getting errors like this.
e.g.: if your data set contains values from -10 to 100, your min normalised value would be 0 and your max normalised value 1. This only works if your numbers are CGFloat, Double or something like this, numbers in Int format would be rounded up.
This could be done by using an extension like this:
extension Array where Element == Double {
var noramlized: [Double] {
if let min = self.min(), let max = self.max() {
return self.map{ ($0 - min) / (max - min) }
}
return []
}
}
I don't no how you get your values for the frame exactly, but I think you did something like this:
// normalise your data set:
let data : [Double] = [Double]()
youChart(inputData: data.noramlized)
// get values for the frame
let height = data.noramlized.max()
// if your normalised value is too small for your purpose (your max will always be 1.0 but in relation to the rest it might fit), you can scale it up like height * 20.
// the width might be a non changing value that you will enter manually or it will append on the count of bars in your chart.
How can I connect the position of slider's value with label's position? I want, that when slider change its value, the label move with slider's value too. please help me. I can't write this code.
You need to add this inside the slider change value action
// calculate current space available for movement
let factor = ( self.view.frame.width - self.label.frame.width ) / maxSliderValue
// apply the change according to slider value assuming in x axis
self.label.frame.origin.x = factor * slider.value
In UISlider Control if I set "MinimumValue = 0" & "MaximimValue=2000" then I am not able to set the exact value. On release of slider thumb image it changes the value to + or - 5 to10. My slider width = 225px.
For example:- if I try to set the slider value to 100 then on release of slider thumb it shows me result like 105 or 95.
Code
IBOutlet UISlider * slider;
//"Slider" Object attached using XIB(.NIB)
slider.minimumValue = 0;
slider.maximumValue = 100;
//Attached Below Method Using XIB(.NIB) with "value Changed" event.
-(IBAction)slider_Change:(id)sender;
{
//Assigning value to UITextField
textFiled.text = [NSString stringWithFormat:#"%d",(((int) (slider.value)) * 20)];
}
Because you have set your slider range to be so large each pixel on the screen is equivalent to 8.888.
2000 / 255 = 8.8888888889
To get graduations of 1 you'll need to move the slider 1/8 of a pixel (this is impossible).
Alternatives are:
Make the slider longer
Reduce the slider range
Use a different control UIStepper
In addition to the answer by #rjstelling, it seems as if you are trying to convert the value of the slider to become an integer value. I believe that the default of the slider is a double value, this would cause the value to become rounded as it is increasing, since there will not be decimal values. Unless it is a requirement, see if you can use double.
textFiled.text = [NSString stringWithFormat:#"%f",(slider.value * 20.0)];
or if for some reason you'd want to restrict the level of decimal places you could go, you could do:
textField.text = [NSString stringWithFormat:#"%.1f", slider.value * 20.0];
This will give you the result of a decimal like 1.5 as your answer.
You could do anything with the decimal or even do something like %1.2f, %4.3f, or even %10.4f,
those will produce results like: 0.34, 0012.446, and something extreme like 000000345.1111
Hope this helps
Now i have a working Joystick, but I want to increase the characters speed.
I´m using this one at the moment: http://roadtonerdvana.wordpress.com/2013/09/20/jcinput-a-simple-joystick-for-sprite-kit/
I attached an Imagefile as the moving object, but it´s way too slow for my purpose.
Where and how can I change the speed?
If you read the post you'll know that the joystick returns a x and y value, each ranging from -1 to 1.
Every time you move the joystick, the properties x and y of it change accordingly, the maximum value is 1 and the minimum is -1.
In the update method, you could do something like this to adjust the speed :
-(void)update:(CFTimeInterval)currentTime {
// I'm using the magic number of 5 as an example of how to magnify the speed x5
float speedX = 5 * self.joystick.x;
float speedY = 5 * self.joystick.y;
[self.myLabel setPosition:CGPointMake(self.myLabel.position.x+speedX, self.myLabel.position.y+speedY)];
}