Google Developers Study Jam

Android for Beginners. Final Projects

Constantine MarsCo-Organizer @ GDG Dnipropetrovs’kSenior Developer @ DataArt

constantine.mars@gmail.com+ConstantineMars

Agenda

● Summary● Common mistakes and issues● Best examples ● Certificates ceremony● Group photo :)

Stats

Started Jam: 62Final projects completed: 22Discussion projects: 8

Common mistakes

UX

● Mixing different languages (i.e. English + Latin)● Mixing color styles● Making too many elements in UI● Adding extra controls

XML

● Auto-indent, rearrange code before commit● Don’t left empty tags● Don’t mix +id and onClick method name in the same tag● Keep single color and size style for icons● Don’t use Layout.background to display images, use ImageView with ScaleType● Use Styles

Code duplication, copy-paste

Thing thing = new Thing();thing.setPrice(20);thing.setColor(RED);Thing thing2 = new Thing();thing2.setPrice(25);thing.setColor(GREEN);

Better:Thing thing = new Thing(20, RED);Thing thing2 = new Thing(25, GREEN);

OrThing thing = Thing.newInstance(20, RED);Thing thing2 = Thing.newInstance(25, GREEN);

Long chain of calls

adapter.addFragment(SomeFragment.newInstance(list.get(i)),list.get(i).getName());

Better:

adapter.addFragment( SomeFragment.newInstance(list.get(i)), list.get(i).getName());

*use:● Spaces● New line● Auto-indent● Rearrange code

Usage of design patterns

public class ClassicSingleton { private static ClassicSingleton instance = null; protected ClassicSingleton() { // Exists only to defeat instantiation. } public static ClassicSingleton getInstance() { if(instance == null) { instance = new ClassicSingleton(); } return instance; }}

Fragments

● Pattern Fragment.newInstance()● .onCreateView() - don’t load assets here● Interaction with Activity - get callback in .onAttach()● Flexible UI, master-detail

Common sense

● Unused folders, “test”, “androidTest”● Don’t put apk to github code, use Github Release feature● Don’t put different projects in one repo

Best examples

Good practices

● Spanned text, Html.fromHtml()● Menu.setShadowLayer()● Fragments● RecyclerView with CardView● Animations with alpha, translate● Real names for .apk● Be on Discussion Forum● Getting Real - making cool app, using only what you really know

Cool design, true OOP, ViewPager

OOP, Design, Database, ORM

Transparent, original design

RecyclerView withCardView

Good OOP and Design

First in discussion

San Francisco

AnimationWith alpha

Getting RealDiscussion, simple, but robust

И еще много проектов, которые мы не успеем сегодня посмотреть и обсудить...

Но они наверняка будут скоро на Discussion

- И их увидит весь мир :)

Certificates

Let’s take photo :)+ConstantineMars