How to set the starting position of a ScrollView?

Question

I have been trying to set the initial position of a scroll View but have not found a way. Does anyone have any ideas? Also I have a GoogleMaps fragment as a children of the

Answer 1

The problem is that the ScrollView doesn't know its size before it been laid out. A solution is to save the scroll position unil onLayout has been called and then set the scroll position.

Here is an example (kotlin):

class MyScrollView constructor(context: Context, attrs: AttributeSet) : ScrollView(context, attrs) {

    private var hasStartPositionBeenSet = false
    var startPosition = 0

    override fun onLayout(changed: Boolean, l: Int, t: Int, r: Int, b: Int) {
        super.onLayout(changed, l, t, r, b)

        if(!hasStartPositionBeenSet) {
             scrollTo(0, startPosition)
             hasStartPositionBeenSet = true
        }
    }
}

class MyActivity: Activity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        /* ... */
        findViewById(R.id.scrollView).startPosition = scrollPosition
    }
}