Hi all, few months ago I started working on Xamarin Android apps.
It takes a little time because we need to code in C# instead of java, there are few syntactical changes when compared to Native android development. Eg : Few Methods are converted to attributes and handling click events using delegates and stuff like that.
The first thing I did was to develop a sample project to read all the packages installed and display on a custom ListView.
This way we learn :
1. Creating and accessing the views in Xamarin.
2. Creating a custom List Adapter for our Activity.
3. Writing the Activity Class and registering events.
4. Displaying a simple Toast Message.
However creating the Android Project, Deploying the apk on device is all as same as Native Android and IDE gives similar options which feels familiar. I use the Visual Studio for developing this app.
Lets Start :
It takes a little time because we need to code in C# instead of java, there are few syntactical changes when compared to Native android development. Eg : Few Methods are converted to attributes and handling click events using delegates and stuff like that.
The first thing I did was to develop a sample project to read all the packages installed and display on a custom ListView.
This way we learn :
1. Creating and accessing the views in Xamarin.
2. Creating a custom List Adapter for our Activity.
3. Writing the Activity Class and registering events.
4. Displaying a simple Toast Message.
However creating the Android Project, Deploying the apk on device is all as same as Native Android and IDE gives similar options which feels familiar. I use the Visual Studio for developing this app.
Lets Start :
Create an Activity Class MainActivty.cs
The class has following methods :
1. getInstalledApplicationsList - Reads and adds the package name to an ArrayList.
2. importInstalledAppsData - Read app name and app icon from individual packages.
3. successCallBack - Populate the Listview with the retrieved list and register On item click of the list to display the package name as a Toast message.
using System;
using System.Collections;
using System.Collections.Generic;
using Android.App;
using Android.Content;
using Android.Content.PM;
using Android.Graphics.Drawables;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Android.OS;
using PackageName.Src;
namespace PackageName
{
[Activity(Label = "PackageName", MainLauncher = true, Icon = "@drawable/icon")]
public class MainActivity : Activity
{
int count = 1;
List<AppDao> appList = new List<AppDao>();
ArrayList packageName = new ArrayList();
private ListView lvApps;
private PackageAdapter packageAdapter;
private Context mContext;
private ProgressDialog _progressDialog;
protected override void OnCreate(Bundle bundle)
{
base.OnCreate(bundle);
mContext = this;
// Set our view from the "main" layout resource
SetContentView(Resource.Layout.Main);
lvApps = FindViewById<ListView>(Resource.Id.lv_apps);
_progressDialog = new ProgressDialog(this);
_progressDialog.SetMessage("Fetching apps list");
_progressDialog.SetTitle("Please wait...");
_progressDialog.SetCancelable(false);
_progressDialog.Show();
new GetAppsTask(this).Execute();
}
public IList<ApplicationInfo> getInstalledApplicationsList(PackageManager pm)
{
IList<ApplicationInfo> packages = pm.GetInstalledApplications(PackageInfoFlags.MetaData);
foreach (var value in packages)
{
packageName.Add(value.PackageName);
}
return packages;
}
public void importInstalledAppsData()
{
PackageManager pkgManager = this.ApplicationContext.PackageManager;
IList<ApplicationInfo> packages = getInstalledApplicationsList(pkgManager);
int count = 0;
foreach (ApplicationInfo packageInfo in packages)
{
AppDao appDao = new AppDao();
appDao.AppName = (String)pkgManager.GetApplicationLabel(packageInfo);
appDao.AppIcon = (Drawable) pkgManager.GetApplicationIcon(packageInfo);
appList.Add(appDao);
count++;
}
}
public void successCallBack()
{
packageAdapter = new PackageAdapter(this, appList);
lvApps.Adapter = packageAdapter;
lvApps.ItemClick += delegate(object sender, AdapterView.ItemClickEventArgs e)
{
Toast.MakeText(this, packageName[e.Position].ToString(), ToastLength.Short).Show();
};
_progressDialog.Hide();
}
}
}
Create an AsyncTask to Fetch all package names
The Task is called from the main activity and once completes the successCallBack of MainActivity is called
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Android.App;
using Android.Content;
using Android.OS;
using Android.Runtime;
using Android.Views;
using Android.Widget;
namespace PackageName.Src
{
class GetAppsTask : AsyncTask
{
private MainActivity _context;
public GetAppsTask(MainActivity context)
{
_context = context;
}
protected override void OnPreExecute()
{
base.OnPreExecute();
}
protected override Java.Lang.Object DoInBackground(params Java.Lang.Object[] @params)
{
_context.importInstalledAppsData();
return true;
}
protected override void OnPostExecute(Java.Lang.Object result)
{
base.OnPostExecute(result);
_context.successCallBack();
}
}
}
Create an Model class
The model has two attributes app icon and app name.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Android.App;
using Android.Content;
using Android.Graphics.Drawables;
using Android.OS;
using Android.Runtime;
using Android.Views;
using Android.Widget;
namespace PackageName
{
class AppDao
{
public string AppName { get; set; }
public Drawable AppIcon { get; set; }
}
}
Create an Custom List Adapter class
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Android.App;
using Android.Content;
using Android.OS;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Object = Java.Lang.Object;
namespace PackageName
{
class PackageAdapter : BaseAdapter
{
List<AppDao> _appsList = new List<AppDao>();
Activity _activity;
public PackageAdapter(Activity activity, List<AppDao> appsList)
{
this._activity = activity;
foreach (var value in appsList)
{
_appsList.Add(value);
}
}
public override Object GetItem(int position)
{
return (Object) _appsList[position].ToString();
}
public override long GetItemId(int position)
{
return position;
}
public override View GetView(int position, View convertView, ViewGroup parent)
{
var view = convertView ?? _activity.LayoutInflater.Inflate(
Resource.Layout.List_row, parent, false);
var appName = view.FindViewById<TextView>(Resource.Id.tv_appName);
var appImage = view.FindViewById<ImageView>(Resource.Id.iv_app);
appName.Text = _appsList[position].AppName;
appImage.SetImageDrawable(_appsList[position].AppIcon);
return view;
}
public override int Count
{
get { return _appsList.Count; }
}
}
}
Create Layout files
The main layout and the row to be inflated in listview.
Main.axml
