android:digits

在Android开发中，经常要设置EditText为密码显示，但是通常要求密码只能是 **字母和数字 . _ **的组合，此时就可以用该属性进行过滤

<EditText
android:layout_width="match_parent" 
android:layout_height="wrap_content" 
android:digits="0123456789abcdefghigklmnopqrstuvwxyzQWERTYUIOPASDFGHJKLZXCVBNM._" 
/>

android:duplicateParentState="true"

该属性可以让子View跟随其Parent的状态。常见的使用场景是某个按钮特别小，为了设置点击事件，给其包裹一层Parent布局，将点击事件写到Parent上，如果希望被包裹按钮的点击效果对应的Selector继续生效的话，就可以使用它了，来个有说服力的测试案例。

<RelativeLayout 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" 
tools:context=".MainActivity">
   <RelativeLayout 
    android:id="@+id/content" android:layout_width="300dp" 
    android:layout_height="300dp" 
    android:layout_centerInParent="true" 
    android:background="@drawable/selector_back">
     <Button android:layout_width="50dp" 
        android:layout_height="50dp" 
        android:layout_alignParentBottom="true" 
        android:background="@drawable/selector" 
        android:duplicateParentState="true" />
     </RelativeLayout>
</RelativeLayout>

Toolbar属性

<style name="ToolbarBaseStyle">
    <item name="android:background">？attr/colorPrimary</item>   
    <item name="android:textColorPrimary">?android:attr/textColorPrimary</item>  
    <item name="titleTextAppearance">@style/ActionBarTitle</item> 
    <item name="navigationIcon">@drawable/ic_back</item>  
    <item name="logo">@drawable/ic_title_divider</item>    
    <item name="titleMarginStart">16dp</item><!--标题距离Logo距离-->
    <item name="android:fitsSystemWindows">true</item><!--沉浸式必备-->
</style>

<style name="ActionBarTitle" parent="TextAppearance.Widget.AppCompat.Toolbar.Title"> 
    <item name="android:textSize">16sp</item>   
    <item name="android:textColor">@color/white</item>
</style>

<!-- App theme here. -->
<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">   
     <!-- Customize your theme here. -->   
    <item name="colorPrimary">@color/primary</item><!---沉浸式颜色->
    <item name="colorPrimaryDark">@color/primary</item>  
    <item name="colorAccent">@color/primary</item>   
    <item name="android:windowBackground">@color/grey6</item>
    <item name="toolbarNavigationButtonStyle">@style/ToolbarNavigationButtonStyle</item>
    <item name="actionMenuTextAppearance">@style/ToolbarMenuTextSize</item>
    <item name="toolbarStyle">@style/ToolbarStyle</item><item name="actionButtonStyle">@style/MyActionButtonStyle</item>
</style>

<style name="ToolbarNavigationButtonStyle" parent="@style/Widget.AppCompat.Toolbar.Button.Navigation">
    <item name="android:minWidth">56dp</item><!--返回按钮最小宽度-->
</style>

<style name="MyActionButtonStyle">  
    <item name="android:background">?attr/actionBarItemBackground</item>   
    <item name="android:scaleType">center</item>   
    <item name="android:gravity">center</item>    
    <item name="android:maxLines">2</item>  
    <item name="android:minWidth">0dp</item> 
    <item name="android:padding">15dp</item>
</style>

<style name="ToolbarStyle" parent="@style/Widget.AppCompat.Toolbar">
    <item name="titleMargin">0dp</item>  
    <item name="contentInsetStart">0dp</item>    
    <item name="contentInsetStartWithNavigation">0dp</item>   
    <item name="titleTextAppearance">@style/ActionBarTitle</item>
</style>

<!-- toolbar菜单文字尺寸 -->
<style name="ToolbarMenuTextSize" parent="@style/TextAppearance.AppCompat.Menu">  
  <item name="android:textSize">14sp</item>
</style>