android 雜項3

 

android SDK and AVD manager 

after install SDK ,we can install other package .

 

DataSetObservable

getDropDownView

AdapterDataSetObserver , data change to notify view to re layout cache 

TrafficStats

 ThumbnailUtils 

 

System.out.println( value); null 報錯,的確重寫了java code

 

0x7f020000 資源 按照順序處理

按照字母順序，可以自己計算得到編譯後int 

 

子目錄裏面定義resource無效

 

2.3 guide add web application divelop 

3.0 add action bar ,fragment load etc 

 

MarginLayoutParams is parent of all other layout 

total 12 gravity , every direction has 5 , left right center ,fill and clip_h . add two direction center and fill all .

 

wrap + fill  = wrap

child layout gravity is high level than parent gravity 

 

android:layout_gravity="right"

判斷 visible

activity 狀態自己判斷

onWindowVisibilityChanged (int visibility)

onVisibilityChanged (View changedView, int visibility)

 

fade ，drawable ，selector ，transform ,animation 

hint

View has min but no max size

TextView has maxWidth

TextView has drawable left 

 

 

ImageView的scaletype

fitStart 拉昇

center 不拉昇 

centercrop 拉昇填充全圖，中部截圖

centerInside 小圖居中，大圖

default is fitCenter

 

 

<action android:name="android.intent.action.VIEW" />

<data android:scheme="javUserInfo" />

<category android:name="android.intent.category.DEFAULT"/>

<category android:name="android.intent.category.BROWSABLE"/>

 

List select

android:listSelector="@drawable/border"  />

boder use shape 

<stroke  android:width="2dp"  android:color="#FF000000" />