Save settings and configurations.

Data Persistance

5 different ways of data persistance:

• onSavedInstanceState(): store state of views in k-v pairs (Bundles), used when screen rotates / app killed by system, temperary.
• SharedPreferences: save k-v pairs to a file, can save primitive types.
• SQLite database: complicated data types
• Internal / External Storage: save …

Android kills background apps !!

→ onCreate() → Created →onStart() → Visible(can be seen on screen) → onResume() → Active(get focus, can interact with)

Active → onPause() → Paused(lose focus — same thing as Visible?) → onStop() → Stopped(disappeared) → onDestroy() → Destroyed(lifecycle ends)

when rotate screen, the function calling is:

onPause --> onStop --> onDestroy --> onCreate --> onStart --> onResume

note …

logging

https://developer.android.com/reference/android/util/Log.html

• 5 log levels: error/warning/info/debug/verbose
• error/warning/info are preserved in the release of app
• use class name as tag: MyClass.class.getSimpleName()

the Resources folder

https://developer.android.com/guide/topics/resources/providing-resources.html

working with …

Recycler View, Adaper, ViewHolder

rather than creating list items as we scroll, keep them in a queue (recycling bin) → when scrolling, the list items are recycled and re-bind to new content. RecyclerView is better version of ListView.

Adaper: bind data from data source, and provide the RecyclerView with new views …

So far: single screen with a single activity.

start activity from another activity: use Intents.

Explicit intent: start a new activity

toy app: type some text, press button, and a new activity will appear with the typed words.

create activity in android studio: new → activity

call startActivity with an …

1 create project sunshine

Created 星期一 06 二月 2017

minSDK vs targetSDK

The minSDK is the lowest SDK level that your app can run on. You can choose what level of devices to support.

By comparison, the targetSDK is NOT a high pass filter -- it’s used …

INF422的TD2, 这节TD是要做一个多线程筛选质数的程序, 关于java的多线程, 以前用过但是不知道啥意思, 在这里总结下.

创建进程

为了实现多线程, 需要定义一个新的class, 有两种方法 …

这学期INF422, 第一节课就是android安装调试环境的搭建(居然要一节课?), 这里总结一下.

第一步: 下载bundle

下载ADT-Bundle 解压缩以后啥都有了, 包含一个eclipse...

第二步: 修 …

S01E02: 开发环境搭建

• 直接去 developer.android.com/sdk/ 下载bundle解压即可, 里面包含eclipse
• 新建一个模拟器: 内部存储一般64MB足矣:

S01E03: android项目目录结构

第一个android程序

new-->android application

目录结构

• com …