detect if views are overlapping

Question

I have problem with drawing views on another size screens! I need method which has two parameters of View type. And return true if first view overlapping on second view, and false in another case!

and

Answer 1

You can also use Rect.intersect() to find overlapping views.

    int[] firstPosition = new int[2];
    int[] secondPosition = new int[2];

    firstView.getLocationOnScreen(firstPosition);
    secondView.getLocationOnScreen(secondPosition);

    // Rect constructor parameters: left, top, right, bottom
    Rect rectFirstView = new Rect(firstPosition[0], firstPosition[1],
            firstPosition[0] + firstView.getMeasuredWidth(), firstPosition[1] + firstView.getMeasuredHeight());
    Rect rectSecondView = new Rect(secondPosition[0], secondPosition[1],
            secondPosition[0] + secondView.getMeasuredWidth(), secondPosition[1] + secondView.getMeasuredHeight());
    return rectFirstView.intersect(rectSecondView);

Answer 2

Berserk thanks you for help! After some experiments I wrote method which detect view is overlapped or not for my case!

private boolean isViewOverlapping(View firstView, View secondView) {
        int[] firstPosition = new int[2];
        int[] secondPosition = new int[2];

        firstView.measure(View.MeasureSpec.UNSPECIFIED, View.MeasureSpec.UNSPECIFIED);
        firstView.getLocationOnScreen(firstPosition);
        secondView.getLocationOnScreen(secondPosition);

        int r = firstView.getMeasuredWidth() + firstPosition[0];
        int l = secondPosition[0];
        return r >= l && (r != 0 && l != 0);
    }

Answer 3

This is similar to the answer from Marcel Derks, but was written without the need for an additional import. It uses the basic code that forms Rect.intersect without creating the Rect objects.

private boolean isViewOverlapping(View firstView, View secondView) {
    int[] firstPosition = new int[2];
    int[] secondPosition = new int[2];

    firstView.measure(View.MeasureSpec.UNSPECIFIED, View.MeasureSpec.UNSPECIFIED);
    firstView.getLocationOnScreen(firstPosition);
    secondView.measure(View.MeasureSpec.UNSPECIFIED, View.MeasureSpec.UNSPECIFIED);
    secondView.getLocationOnScreen(secondPosition);

    return firstPosition[0] < secondPosition[0] + secondView.getMeasuredWidth()
            && firstPosition[0] + firstView.getMeasuredWidth() > secondPosition[0]
            && firstPosition[1] < secondPosition[1] + secondView.getMeasuredHeight()
            && firstPosition[1] + firstView.getMeasuredHeight() > secondPosition[1];
}

You are not required to force a view measurement, but it is done for good measure ;)

Answer 4

In Kotlin, you can use the View class extension. It turns out a more compact solution:

// Returns true if the view overlaps another view.
// Additionally checks whether another view will overlap if it is shifted to delta values.
fun View.isOverlap(other: View, deltaX: Int = 0, deltaY: Int = 0): Boolean {
    val thisXY  = IntArray(2).apply { getLocationOnScreen(this) }
    val otherXY = IntArray(2).apply {
        other.getLocationOnScreen(this)
        this[0] += deltaX
        this[1] += deltaY
    }
    return thisXY.let { Rect(it[0], it[1], it[0] + width, it[1] + height) }
        .intersect(otherXY.let { 
            Rect(it[0], it[1], it[0] + other.width, it[1] + other.height)
         })
}

// usage example:
if (myView.isOverlap(otherView)) {
    // do something ...
}