Android布局最大宽度或屏幕宽度？

Question

除非屏幕小于该宽度，否则可以将小孩的宽度设置为固定宽度吗？

即我想下面的CardView是400dp正常，除非它是一个小屏幕，此时应该是屏幕宽度（减去保证金）上...

<cdudigital.com.conjugator.MyLinearLayout 
    xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:tools="http://schemas.android.com/tools" 
    xmlns:app="http://schemas.android.com/apk/res-auto" 
    android:orientation="vertical" 
    android:paddingLeft="@dimen/activity_horizontal_margin" 
    android:paddingRight="@dimen/activity_horizontal_margin" 
    android:paddingTop="@dimen/activity_vertical_margin" 
    android:paddingBottom="@dimen/activity_vertical_margin" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:gravity="center" 
    tools:context=".GameActivity"> 
    <android.support.v7.widget.CardView 
     xmlns:card_view="http://schemas.android.com/apk/res-auto" 
     android:id="@+id/card_view" 
     android:layout_gravity="center" 
     android:gravity="center" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     card_view:cardCornerRadius="4dp" 
     card_view:cardElevation="3dp"> 
    </android.support.v7.widget.CardView> 
</cdudigital.com.conjugator.MyLinearLayout> 

Answer 1

获取屏幕的DP

DisplayMetrics displayMetrics = context.getResources().getDisplayMetrics(); 
float dpWidth = displayMetrics.widthPixels/displayMetrics.density; 

和检查，看看它是否小于400

if(dpWidth < 400){ 
    cardView.setLayoutParams(new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.MATCH_PARENT)); 
} else { 
    cardView.setLayoutParams(new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT,(400 * displayMetrics.density + 0.5f))); 
} 

还是在XML

android:layout_width="match_parent" 
android:maxWidth="400dp"