Android HeightResizableLinearLayoutManager

HeightResizableLinearLayoutManager.java

package com.oostaa.app.widgets;

import android.content.Context;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.view.ViewGroup;

import java.util.List;

/**
 * Created by Hani on 9/8/15.
 *
 * All childes should have unique height.
 * Set layout_height to wrap_content.
 * RecyclerView
 */
public class HeightResizableLinearLayoutManager<T> extends LinearLayoutManager {

    private int heightMeasure;
    private List<T> dataSet;

    public HeightResizableLinearLayoutManager(Context context, List<T> dataSet) {
        super(context);
        this.dataSet = dataSet;
    }

    @Override
    public void onMeasure(RecyclerView.Recycler recycler, RecyclerView.State state,
                          int widthSpec, int heightSpec) {
        measureScrapChild(recycler);
        setMeasuredDimension(widthSpec, heightMeasure);
    }

    private void measureScrapChild(RecyclerView.Recycler recycler) {

        if (dataSet.size() == 0) {
            heightMeasure = 0;
            return;
        }

        View view = recycler.getViewForPosition(0);
        RecyclerView.LayoutParams p = (RecyclerView.LayoutParams) view.getLayoutParams();
        int childWidthSpec = ViewGroup.getChildMeasureSpec(0,
                getPaddingLeft() + getPaddingRight(), p.width);
        int childHeightSpec = ViewGroup.getChildMeasureSpec(0,
                getPaddingTop() + getPaddingBottom(), p.height);
        view.measure(childWidthSpec, childHeightSpec);
        heightMeasure = view.getMeasuredHeight() * dataSet.size();
        recycler.recycleView(view);
    }
}