Implementation of a firebase Admob banner in flutter

history_fragment.dart

import 'package:firebase_admob/firebase_admob.dart';
import 'package:flutter/material.dart';
import 'package:sabnzbdplusrewrite/main.dart';
import 'package:sabnzbdplusrewrite/retrofit/models/history.dart';
import 'package:sabnzbdplusrewrite/screens/history_item_activity.dart';
import 'package:sabnzbdplusrewrite/utils/banner_util.dart';
import 'dart:io' show Platform;
import 'package:sabnzbdplusrewrite/consts/admob.dart';


class HistoryFragment extends StatefulWidget {
  @override
  State<StatefulWidget> createState() => _HistoryFragmentState();
}

class _HistoryFragmentState extends State<HistoryFragment> {
  int _currentIndex = 0;
  GlobalKey mKey;
  RenderBox mRenderBox;
  Offset mUpperBotNavBarOffset;
  BannerAd historyBanner;

  @override
  void initState() {
    try {
      mHistory = HistoryModel().getHistoryData();
    } catch (Exception) {}

    mKey = new GlobalKey();

    super.initState();

    WidgetsBinding.instance.addPostFrameCallback(
      (_) {
        populateBox(context);
        // historyBanner = doBanner(
        //     context, historyBanner, targetingInfo, BannerAd.testAdUnitId, 2);

        if (Platform.isAndroid) {
          // Android-specific code
          historyBanner = doBanner(
            context, historyBanner, targetingInfo, getAndroidAdUnit("history-banner"), 2);
        } else if (Platform.isIOS) {
          // iOS-specific code
          historyBanner = doBanner(
            context, historyBanner, targetingInfo, getiOsAdUnit("history-banner"), 2);
        } else {
          historyBanner = doBanner(
            context, historyBanner, targetingInfo, BannerAd.testAdUnitId, 2);
        }
      },
    );
  }

  void populateBox(BuildContext context) {
    mRenderBox = mKey.currentContext.findRenderObject();
    mUpperBotNavBarOffset = mRenderBox.localToGlobal(Offset.zero);
    upperBotNavCoordinateX = mUpperBotNavBarOffset.dx;
    upperBotNavCoordinateY = mUpperBotNavBarOffset.dy;
  }

  @override
  void dispose() {
    disposeBanner(historyBanner);
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    double w = MediaQuery.of(context).size.width;
    double w2 = w * 0.25;
    double w3 = w * 0.65;
    double w4 = w2 * 0.25;
    return Center(
      child: RefreshIndicator(
        child: Scaffold(
          body: Center(
            child: FutureBuilder<History>(
              future: mHistory,
              builder: (context, snapshot) {
                if (snapshot.hasData) {
                  // Assign to main
                  mHistoryData = snapshot.data;

                  return Padding(
                    child: Column(
                      children: <Widget>[
                        Expanded(
                          child: new ListView.builder(
                            itemCount: snapshot.data.slots.length,
                            itemBuilder: (BuildContext ctxt, int index) {
                              return Card(
                                child: InkWell(
                                  splashColor: Colors.deepOrange.withAlpha(30),
                                  onTap: () {
                                    _navigateToDownloadedItem(context, index);
                                  },
                                  child: Row(
                                    children: <Widget>[
                                      Container(
                                        width: w4 * 2,
                                        height: w4,
                                        child: _buildImage(snapshot
                                                    .data.slots[index].status ==
                                                Status.QUEUED ||
                                            snapshot.data.slots[index].status ==
                                                Status.COMPLETED ||
                                            snapshot.data.slots[index].status ==
                                                Status.DOWNLOADING),
                                      ),
                                      Container(
                                          margin: EdgeInsets.only(
                                              right: 10, left: 10),
                                          height: 80,
                                          width: w3,
                                          child: Align(
                                              alignment: Alignment.centerLeft,
                                              child: Text(
                                                  '${snapshot.data.slots[index].name}'))),
                                    ],
                                  ),
                                ),
                              );
                            },
                          ),
                        )
                      ],
                    ),
                    padding: EdgeInsets.only(
                      bottom: 50.0,
                    ),
                  );
                } else if (snapshot.hasError) {
                  return Text("${snapshot.error}");
                }

                // By default, show a loading spinner.
                return CircularProgressIndicator();
              },
            ),
          ),
          bottomNavigationBar: BottomNavigationBar(
            key: mKey,
            onTap: onTabTapped, // new
            currentIndex: _currentIndex, // new
            items: [
              new BottomNavigationBarItem(
                icon: new Icon(Icons.skip_previous),
                title: new Text('Previous Page'),
                backgroundColor: Colors.orangeAccent,
              ),
              new BottomNavigationBarItem(
                icon: new Icon(Icons.delete),
                title: new Text('Clear History'),
                backgroundColor: Colors.orangeAccent,
              ),
              new BottomNavigationBarItem(
                  icon: Icon(Icons.skip_next),
                  backgroundColor: Colors.orangeAccent,
                  title: Text('Next Page')),
            ],
          ),
        ),
        onRefresh: () {
          setState(
            () {
              mHistory = HistoryModel().getHistoryData();
            },
          );
          return mHistory;
        },
      ),
    );
  }

  void onTabTapped(int index) {
    setState(
      () {
        _currentIndex = index;
      },
    );
  }

  _navigateToDownloadedItem(BuildContext context, int index) async {
    // Navigator.push returns a Future that completes after calling
    // Navigator.pop on the Selection Screen.
    disposeBannerBlock(historyBanner);
    await Navigator.of(context).push(
      MaterialPageRoute(
        builder: (context) => HistoryItemActivity(
          itemIdx: index,
        ),
      ),
    );

    setState(
      () {
        mHistory = HistoryModel().getHistoryData();
        // historyBanner = doBanner(
        //     context, historyBanner, targetingInfo, BannerAd.testAdUnitId, 2);

        if (Platform.isAndroid) {
          // Android-specific code
          historyBanner = doBanner(
            context, historyBanner, targetingInfo, getAndroidAdUnit("history-banner"), 2);
        } else if (Platform.isIOS) {
          // iOS-specific code
          historyBanner = doBanner(
            context, historyBanner, targetingInfo, getiOsAdUnit("history-banner"), 2);
        } else {
          historyBanner = doBanner(
            context, historyBanner, targetingInfo, BannerAd.testAdUnitId, 2);
        }
      },
    );
  }
}

Widget _buildImage(bool success) {
  if (success) {
    return Image(
      image: AssetImage('assets/icons/circle_green_alpha.png'),
      height: 30,
      width: 30,
    );
  }
  return Image(
    image: AssetImage('assets/icons/circle_red_alpha.png'),
    height: 30,
    width: 30,
  );
}