ChangelogDialog.java

package com.afollestad.materialdialogssample;

import android.annotation.SuppressLint;
import android.app.Dialog;
import android.graphics.Color;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.v4.app.DialogFragment;
import android.view.InflateException;
import android.view.LayoutInflater;
import android.view.View;
import android.webkit.WebView;

import com.afollestad.materialdialogs.MaterialDialog;
import com.afollestad.materialdialogs.Theme;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;

/** @author Aidan Follestad (afollestad) */
public class ChangelogDialog extends DialogFragment {

  public static ChangelogDialog create(boolean darkTheme, int accentColor) {
    ChangelogDialog dialog = new ChangelogDialog();
    Bundle args = new Bundle();
    args.putBoolean("dark_theme", darkTheme);
    args.putInt("accent_color", accentColor);
    dialog.setArguments(args);
    return dialog;
  }

  @SuppressLint("InflateParams")
  @NonNull
  @Override
  public Dialog onCreateDialog(Bundle savedInstanceState) {
    final View customView;
    try {
      customView = LayoutInflater.from(getActivity()).inflate(R.layout.dialog_webview, null);
    } catch (InflateException e) {
      throw new IllegalStateException("This device does not support Web Views.");
    }
    MaterialDialog dialog =
        new MaterialDialog.Builder(getActivity())
            .theme(getArguments().getBoolean("dark_theme") ? Theme.DARK : Theme.LIGHT)
            .title(R.string.changelog)
            .customView(customView, false)
            .positiveText(android.R.string.ok)
            .build();

    final WebView webView = (WebView) customView.findViewById(R.id.webview);
    try {
      // Load from changelog.html in the assets folder
      StringBuilder buf = new StringBuilder();
      InputStream json = getActivity().getAssets().open("changelog.html");
      BufferedReader in = new BufferedReader(new InputStreamReader(json, "UTF-8"));
      String str;
      while ((str = in.readLine()) != null) {
        buf.append(str);
      }
      in.close();

      // Inject color values for WebView body background and links
      final int accentColor = getArguments().getInt("accent_color");
      webView.loadData(
          buf.toString()
              .replace(
                  "{style-placeholder}",
                  getArguments().getBoolean("dark_theme")
                      ? "body { background-color: #444444; color: #fff; }"
                      : "body { background-color: #fff; color: #000; }")
              .replace("{link-color}", colorToHex(shiftColor(accentColor, true)))
              .replace("{link-color-active}", colorToHex(accentColor)),
          "text/html",
          "UTF-8");
    } catch (Throwable e) {
      webView.loadData(
          "<h1>Unable to load</h1><p>" + e.getLocalizedMessage() + "</p>", "text/html", "UTF-8");
    }
    return dialog;
  }

  private String colorToHex(int color) {
    return Integer.toHexString(color).substring(2);
  }

  private int shiftColor(int color, boolean up) {
    float[] hsv = new float[3];
    Color.colorToHSV(color, hsv);
    hsv[2] *= (up ? 1.1f : 0.9f); // value component
    return Color.HSVToColor(hsv);
  }
}