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 报错,的确重写了java code
0x7f020000 资源 按照顺序处理
按照字母顺序，可以自己计算得到编译后int
子目录里面定义resource无效
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"
判断 visible
activity 状态自己判断
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 拉升
center 不拉升
centercrop 拉升填充全图，中部截图
centerInside 小图居中，大图
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" />
