LayoutUtil.java

package xyz.selfenrichment.robertotomas.popularmovies.lib;
// Created by RobertoTomás on 0004, 4, 4, 2016.

import android.content.Context;
import android.content.res.Configuration;
import android.content.res.Resources;
import android.util.DisplayMetrics;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ListAdapter;
import android.widget.ListView;

/**
 * Utility functions for programmatic layout. 
 */
public class LayoutUtil {
    /* Singleton Pattern */
    private final String LOG_TAG = LayoutUtil.class.getSimpleName();

    private static LayoutUtil mInstance = null;

    private LayoutUtil(){
        mInstance = new LayoutUtil();
    }

    @SuppressWarnings("SynchronizationOnLocalVariableOrMethodParameter")
    public static LayoutUtil getInstance() {
        if (mInstance == null) {
            Class clazz = LayoutUtil.class;
            synchronized (clazz) {
                mInstance = new LayoutUtil();
            }
        }
        return mInstance;
    }
    /* /endSingleton Pattern */

    /**
     * A handy getter for display metric width and height.
     * @param c - Context
     * @return float[] of dpWidth, dpHeight
     */
    public static float[] getScreen(Context c){
        DisplayMetrics displayMetrics = c.getResources().getDisplayMetrics();

        float dpHeight = displayMetrics.heightPixels / displayMetrics.density;
        float dpWidth = displayMetrics.widthPixels / displayMetrics.density;

        return new float[] {dpWidth, dpHeight};
        //Log.d(LayoutUtil.getInstance().LOG_TAG, String.format("%f x %f ", dpWidth, dpHeight));
    }

    public static Boolean twoPanes(Context c){
        Configuration conf = c.getResources().getConfiguration();
        return (Configuration.ORIENTATION_LANDSCAPE == conf.orientation) &&
                (600 <= conf.smallestScreenWidthDp);
    }

    public static Boolean isTablet(Context c){
        Configuration conf = c.getResources().getConfiguration();
        return (600 <= conf.smallestScreenWidthDp);
    }

    /**
     * A helper function returning the pixels-per-display-pixel
     * @param dp - density-indendent pixels
     * @param context - this probably could even be getApplicationContext
     * @return - pixels for your dp
     */
    public static int convertDPtoPixels(float dp, Context context) {
        Resources resources = context.getResources();
        DisplayMetrics metrics = resources.getDisplayMetrics();
        return (int) (dp * (metrics.densityDpi / 160f));
    }

    /**
     * Helper method to determine if the device has an extra-large screen. For
     * example, 10" tablets are extra-large.
     */
    private static boolean isXLargeTablet(Context context) {
        return (context.getResources().getConfiguration().screenLayout
                & Configuration.SCREENLAYOUT_SIZE_MASK) >= Configuration.SCREENLAYOUT_SIZE_XLARGE;
    }

    public boolean isMultiPane(Context c) {
        return isXLargeTablet(c);
    }

    public static void setListViewHeightBasedOnChildren(ListView listView) {
        ListAdapter listAdapter = listView.getAdapter();
        if (listAdapter == null) {
            // pre-condition
            return;
        }

        int totalHeight = 0;
        for (int i = 0; i < listAdapter.getCount(); i++) {
            View listItem = listAdapter.getView(i, null, listView);
            listItem.measure(0, 0);
            totalHeight += listItem.getMeasuredHeight();
        }

        ViewGroup.LayoutParams params = listView.getLayoutParams();
        params.height = totalHeight + (listView.getDividerHeight() * (listAdapter.getCount() - 1));
        listView.setLayoutParams(params);
        listView.requestLayout();
    }
}

This is a utility lib I wrote for my popular movies app. A couple of the methods were from the default preferences activity from the activity creator. I posted it here so I would have easy access to it after finding I wanted it for my next project, a coffee roasting app. Rather than being tempted to load the whole project again to get it, next time I can just come here.