Kotlin Android DialogFragment with ListView tutorial.

We want to see how to open a DialogFragment when a simple button is clicked. The dialogFragment will comprise of a title and a listview.

We infact inflate it via the LayoutInflater class from an xml layout specification.

When the user clicks a ListView item we show it in a Toast. When the user clicks outside the DialogFragment, we dismiss it(the DialogFragment).

Let's go.

This is an android horizontal datetimepicker tutorial and example.

We see how to create a horizontally scrolling datetime picker. You can easily scroll to a certain date.

The selected date gets shown in a Toast message.

We will be using HorizontalPicker Library.

HorizontalPicker is a custom-build Android View used for choosing dates (similar to the native date picker) but draws horizontally into a vertically narrow container. It allows easy day picking using the horizontal pan gesture.

A DialogFragment is a fragment that displays a dialog window, floating on top of its activity's window.

This fragment contains a Dialog object, which it displays as appropriate based on the fragment's state. Control of the dialog (deciding when to show, hide, dismiss it) should be done through the API here, not with direct calls on the dialog.

We do inherit from this class(android.support.v4.app.DialogFragment) then implement the Fragment.onCreateView(LayoutInflater, ViewGroup, Bundle) to supply the content of the dialogfragment.

You can also override onCreateDialog(Bundle) to create an entirely custom dialog, such as an AlertDialog, with its own content.

This is a flutter ListView tutorial.

A ListView is a scrollable list of widgets arranged linearly.

As the names suggests it's responsibility is list items. These items can then scrolled. ListView isn't the only scrolling view. There are others like gridview, however ListView is the most commonly used.

ListView will display its children one after another in the scroll direction. In the cross axis, the children are required to fill the ListView.

Here's a simple infinite listview:

new ListView.builder(
  padding: new EdgeInsets.all(8.0),
  itemExtent: 20.0,
  itemBuilder: (BuildContext context, int index) {
    return new Text('entry $index');

Bioinformatics is the application of mathematical and information-science techniques to biology.

You can imagine this is a difficult task given the complexity within living organisms with regards to the interaction between different chemical processes.

However alot of research has been ongoing i...

This is a Flutter Android SnackBar Tutorial and Example.

SnackBar is a lightweight message with an optional action which briefly displays at the bottom of the screen.

SnakBars are important as they allows us show quick notifications for a short period of time without requiring user intervention.

However uses can also act by clicking the action button which can be rendered in the SnackBar.

Displaying a snackbar is easy. You simply invoke the Scaffold.of(context).showSnackBar(), passing an instance of SnackBar that describes the message.

You can also provide your own custom duration for displaying the SnackBar.

A SnackBar with an action will not time out when TalkBack or VoiceOver are enabled. This is controlled by AccessibilityFeatures.accessibleNavigation.

BuildContext is an abstract class acting as a handle to the location of a widget in the widget tree.

abstract class BuildContext

It's defined in the flutter package.

It's role as an abstract class is to hold a set of methods. These methods can be used from StatelessWidget.build methods and from methods on State objects.

Normally when you are using widget builder functions like the build() method of the StatelessWidget class.

For instance here's a BuildContext object being passed to the build() method of a StatelessWidget subclass:

  Widget build(BuildContext context) {
    return MaterialApp()

A StatelessWidget is a widget that does not require mutable state.

StatelessWidget describes part of the user interface by building a constellation of other widgets that describe the user interface more concretely.

Here's the api definition of StatelessWidget:

abstract class StatelessWidge...

Android Studio is the official Integrated Develepment Environment(IDE) for android.

Google recommends it for android development and it will make your job much easier instead of using other tools like Eclipse or basic Text Editor.

Android Studio comes bundled with the Android SDK Manager, which is a tool that allows us download the Android SDK components required to develop android applications.