android - How is the activity "adjustResize" attribute actually works -

these days learning when softkeyboard pop came, out how activity layout changed. wrote sample, , found strange.

here layout:

<linearlayout     xmlns:android="http://schemas.android.com/apk/res/android"     xmlns:tools="http://schemas.android.com/tools"     android:layout_width="match_parent"     android:layout_height="match_parent"     android:orientation="vertical"     tools:context="com.margi.inputbar.mainactivity">      <textview         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:text="hello world!" />       <linearlayout         android:layout_width="match_parent"         android:layout_height="0dp"         android:layout_weight="1"         android:orientation="vertical">          <textview             android:layout_width="match_parent"             android:layout_height="wrap_content"             android:layout_margintop="30dp"             android:text="1" />          <textview             android:layout_width="match_parent"             android:layout_height="wrap_content"             android:layout_margintop="30dp"             android:text="2" />         <textview             android:layout_width="match_parent"             android:layout_height="wrap_content"             android:layout_margintop="30dp"             android:text="3" />         <textview             android:layout_width="match_parent"             android:layout_height="wrap_content"             android:layout_margintop="30dp"             android:text="4" />         <textview             android:layout_width="match_parent"             android:layout_height="wrap_content"             android:layout_margintop="30dp"             android:text="5" />         <textview             android:layout_width="match_parent"             android:layout_height="wrap_content"             android:layout_margintop="30dp"             android:text="6" />         <textview             android:layout_width="match_parent"             android:layout_height="wrap_content"             android:layout_margintop="30dp"             android:text="7" />         <textview             android:layout_width="match_parent"             android:layout_height="wrap_content"             android:layout_margintop="30dp"             android:text="8" />        </linearlayout>   <include layout="@layout/layout_input" /> 

this manifest:

<application     android:allowbackup="true"     android:icon="@mipmap/ic_launcher"     android:label="@string/app_name"     android:supportsrtl="true"     android:theme="@style/apptheme">     <activity android:name=".mainactivity"         android:windowsoftinputmode="adjustresize">         <intent-filter>             <action android:name="android.intent.action.main" />              <category android:name="android.intent.category.launcher" />         </intent-filter>     </activity> </application> 

and use android studio ddms tool check layout state.

when hide softkeyboard layout is:

and xml layout is:

the linear layout has 8 child textviews.

and softkeyboard pop out:

the xml layout is:

the linearlayout has 4 child textviews

so, here 2 questions want find answers for:

(1) want know happened when softkeyboard shown, disappeared textview?

(2) there document, file or blog explain this? had read google's document google training, i'm still not clear this.