Android ListView在片段不滚动

Question

我有一个listView里面的一个自定义ArrayAdapter呈现的MainActivity的片段。问题是由于某种原因，listview无法滚动。

我的XML MainActivity：

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout 
    xmlns:android="http://schemas.android.com/apk/res/android" 
xmlns:tools="http://schemas.android.com/tools" 
xmlns:design="http://schemas.android.com/apk/res-auto" 
android:id="@+id/activity_main" 
android:layout_width="match_parent" 
android:layout_height="match_parent" 
android:orientation="vertical" 
android:screenOrientation="portrait" 
tools:context=".MainActivity"> 

<FrameLayout 
    android:id="@+id/container" 
    android:layout_width="match_parent" 
    android:layout_height="0dp" 
    android:layout_weight="1" 
    android:background="#f1f1f1"> 

</FrameLayout> 

<android.support.design.widget.BottomNavigationView 
    android:id="@+id/navigation" 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" 
    design:menu="@menu/navigation" /> 
</LinearLayout> 

我的XML片段：

<android.support.constraint.ConstraintLayout 
    xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:app="http://schemas.android.com/apk/res-auto" 
    xmlns:tools="http://schemas.android.com/tools" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:screenOrientation="portrait" 
    tools:context=".Friends"> 


<Button 
    android:id="@+id/newfriendbutton" 
    android:layout_width="0dp" 
    android:layout_height="66dp" 
    android:text="@string/new_friend" 
    tools:layout_constraintTop_creator="1" 
    tools:layout_constraintRight_creator="1" 
    android:layout_marginStart="8dp" 
    android:layout_marginEnd="8dp" 
    app:layout_constraintRight_toRightOf="parent" 
    tools:layout_constraintLeft_creator="1" 
    app:layout_constraintLeft_toLeftOf="parent" 
    app:layout_constraintTop_toTopOf="parent" /> 

<TextView 
    android:id="@+id/textView6" 
    android:layout_width="395dp" 
    android:layout_height="wrap_content" 
    android:text="@string/instruct" 
    android:textAlignment="center" 
    app:layout_constraintTop_toBottomOf="@+id/newfriendbutton" 
    tools:ignore="MissingConstraints" 
    tools:layout_editor_absoluteX="8dp" /> 

<ListView 
    android:id="@+id/friendListView" 
    android:layout_width="match_parent" 
    android:layout_height="592dp" 
    android:layout_marginEnd="8dp" 
    android:layout_marginStart="8dp" 
    app:layout_constraintLeft_toLeftOf="parent" 
    app:layout_constraintRight_toRightOf="parent" 
    app:layout_constraintTop_toBottomOf="@+id/textView6" 
    tools:ignore="MissingConstraints" 
    tools:layout_constraintLeft_creator="1" 
    tools:layout_constraintRight_creator="1" /> 
</android.support.constraint.ConstraintLayout> 

Answer 1

你确定ListView控件是满了吗？它只会让你滚动，如果你在视图中有更多的选择，而不是适合给定约束的东西。在这种情况下，最好使用RelativeLayout。

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout 
    xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:app="http://schemas.android.com/apk/res-auto" 
    xmlns:tools="http://schemas.android.com/tools" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:screenOrientation="portrait" 
    tools:context=".Friends"> 


    <Button 
     android:id="@+id/newfriendbutton" 
     android:layout_height="66dp" 
     android:text="@string/new_friend" 
     android:layout_width="match_parent" 
     android:layout_marginStart="8dp" 
     android:layout_marginEnd="8dp" 
     android:layout_marginLeft="8dp" 
     android:layout_marginRight="8dp" /> 

    <TextView 
     android:id="@+id/textView6" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:text="@string/instruct" 
     android:textAlignment="center" 
     android:layout_centerHorizontal="true" 
     android:layout_below="@+id/newfriendbutton"/> 

    <ListView 
     android:id="@+id/friendListView" 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     android:layout_below="@+id/textView6" 
     android:layout_marginEnd="8dp" 
     android:layout_marginStart="8dp"/> 
</RelativeLayout>