Btukfyl

I'm trying to move a custom view (a small circle) over the whole application layout by using proportional x and y values. Let's say for example, that I want to move the circle to exactly the middle of the screen, so I'll send (0.5f, 0.5f) and then multiply each value by my current screen width and height respectively. But for some reason the circle ends up somewhere else, like (0.5, 0.5) ending up at the bottom right of the screen, just as if I where using wrong and larger resolution values, which I'm not, since I've even hardcoded my device resolution to make sure that's not the problem.

Here is my custom view current implementation:

class CirclePointer(context: Context, attrs: AttributeSet) :View(context, attrs){



 override fun onDraw(canvas: Canvas?) {

     super.onDraw(canvas)



     canvas.apply {

         this!!.drawCircle(x, y, 5f, mCirclePointerPaint)

     }

 }



 private val mCirclePointerPaint = Paint().apply {

 }



 fun move(newX: Float, newY: Float){

     x = newX * 1280// hardcoded width

     y = newY * 720// hardcoded height



     invalidate()

     requestLayout()

 }// end of move



 override fun onSizeChanged(w: Int, h: Int, oldw: Int, oldh: Int) {

     super.onSizeChanged(w, h, oldw, oldh)

 }



}

And my activity xml:

<?xml version="1.0" encoding="utf-8"?>

    <RelativeLayout 

    xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:app="http://schemas.android.com/apk/res-auto"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:background="@color/heading"

    android:orientation="vertical">



    <my.package.annotation_views.CirclePointer

    android:id="@+id/circlePointer"

    android:layout_width="wrap_content"

    android:layout_height="wrap_content" />



</RelativeLayout>

I've just leant how to implement my own custom View so I'm pretty sure I'm missing something. So any help would be appreciated.

What I've tried

• Setting my CirclePointer width and height to match_parent instead of wrap_content

Observations

I'm using Android Studio 3.2 and macOS Mojave

Thanks in advance.

making the x and y of the circle in the half of your screen width and height respectively will not work because your circle's x and y are the top left of your circle not the center of the circle. The solution is to subtract half of the width from the x, and half of height from y such as:

int left = screenWidth / 2 - circleWidth / 2

int top = screenHeight / 2 - circleHeight / 2

yourCircle.setX(left);

yourCircle.setY(top);