Android IQs

Android IQs.md

Android IQs

Intent

• <intent-filter>: action, category, data
• Pending intent, NotificationManager

Activity

• Activity lifecycle
• Intent flags/launchMode：standard, singleTop, singleTask, singleInstance
• best practices for Acti.. and Frag..: use Acti.. to manage Frag...

Fragment

• lifecycle
• Fragment transaction

Service

• IntentService
• startService, bindService

Background

• Knowledge of AsyncTask: its dark sides: lifecycle/view reference
• Looper(message loop)
• Handler(Looper) -> handleMessage(Message…), obtainMessage(…)
• handle message on main thread: new Handler(Looper.getMainLooper()) {handleMessage}
• HandlerThread.getLooper
• Runnable

UI

• View: onDraw
• Layout: onMeasure: setMeasuredDimension, onLayout
• <declare-stylable>, Context. obtainStyledAttributes
• onTouchEvent, onInterceptTouchEvent
• MotionEvent, GestureDetector , OverScroller
• ValueAnimator, ObjectAnimator
• RelativeLayout: evenly spacing, what if children is ImageButton
• Auto complete: AutoCompleteTextView + Loader

Drawable

• selector: states, fade duration
• shape: round corder, stroke, solid ...
• Animation: <set>, <objectAnimator>, <animator>, AnimationUtils.loadAnimation, View.startAnimation

res/layout

• dp, dip, px, sp(scale independant, for fonts)
• mdpi : hdpi : xhdpi : xxhdpi : xxxhdpi :: 1 : 1.5 : 2 : 3 : 4
• launcher icon : 48dp on mobile, 512px on Play store

Style and Themes

• define style: res/values : <resources> <style name="" parent=“”><item …>…
• apply theme to application : <application android:theme=“”>…
• Select theme based on platform: use resource filters: e.g. values-v21

Performance

• Reuse layout with <include>
• use <merge> tag
• in favor of RelativeLayout vs LinearLayout
• Avoid deep hierarchy
• Smooth Scrolling: use ViewHolder, use background thread
• StrictMode
• ANR: how to avoid

Test

• Unit tests: Robolectric
• UI tests: Robotium

Misc

• Http client: OKhttp
• EventBus
• Realm
• Retrofit for JSON
• Gson: TypeAdapter
• 65K limitation
• Crash report: fabric...
• Projects, github, stackoverflow

Real World

• How to implement a Activity/Fragment open-splitting/swipe-back transition animation.