Binary XML file line #14: Error inflating custom ViewGroup class

Question

Problem with inflating custom ViewGroup.

Unable to start activity Binary XML file line #14: Binary XML file line #14: Error inflating class com.example.interactiveplatform.view.GraphLayout.

I searched about this problem and there is something wrong with constructors.

<LinearLayout
    android:id="@+id/graph"
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal"
    tools:context=".MainActivity">

    <com.example.interactiveplatform.view.GraphLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">
    </com.example.interactiveplatform.view.GraphLayout>

</LinearLayout>



class GraphLayout(context: Context, attrs: AttributeSet, var chapterAdapter: ChapterAdapter) : ViewGroup(context, attrs) {

    private val detector: GestureDetector
    private val mMoveAndScaleHandler: MoveAndScaleHandler
    private val myListener: GestureDetector.SimpleOnGestureListener
    private var spacing = 0

    init {
        myListener = object : GestureDetector.SimpleOnGestureListener() {
            override fun onDown(e: MotionEvent?): Boolean {
                return true
            }
        }

        detector = GestureDetector(context, myListener)
        mMoveAndScaleHandler = MoveAndScaleHandler(context, this, chapterAdapter)
    }


    override fun onLayout(p0: Boolean, p1: Int, p2: Int, p3: Int, p4: Int) {
        for(i in 0 until childCount){
            val v = getChildAt(i)
            v.layout(v.left, v.top, v.right, v.bottom)
        }
    }


    override fun onTouchEvent(event: MotionEvent): Boolean {

        detector.onTouchEvent(event)
        invalidate()
        return mMoveAndScaleHandler.onTouchEvent(event)
    }


    override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {
        setMeasuredDimension(400 * chapterAdapter.numberChapters,chapterAdapter.heightScreen)
    }


}

Answer 1

When you instantiate your custom view via XML you cannot pass custom constructor parameters like chapterAdapter. Also, you have to support all Android's view constructors. For example, you can do it like this:

class GraphLayout @JvmOverloads constructor(
        context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0
) : ViewGroup(context, attrs, defStyleAttr)