ScrollView 中的 Android ListView 行未完全显示 - 已剪辑 [英] Android ListView rows in ScrollView not fully displayed - clipped

问题描述

我在 ScrollView 中嵌入 ListView 时遇到了问题，或者至少这是我猜问题的来源.ListView 元素是一个相当简单的元素:

I encountered a problem when embedding a ListView inside a ScrollView, or at least that's where I guess the problem comes from. The ListView element is a fairly simple one:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/item_root"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@drawable/general_background_list_middle" 
    android:paddingTop="4dp"
    android:paddingBottom="4dp"
    android:paddingRight="0dp"
    android:paddingLeft="0dp">

    <ImageView
        android:id="@+id/chat_friends_avatar"       
        android:layout_width="45dp"
        android:layout_height="45dp"
        android:layout_marginLeft="7dp"
        android:layout_marginRight="8dp"
        android:paddingRight="0dp" 
        android:paddingLeft="0dp"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:src="@drawable/friends_icon_avatar_default"/>

    <TextView
        android:id="@+id/chat_message_text"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_toRightOf="@id/chat_friends_avatar"
        android:layout_alignParentTop="true"
        android:layout_marginRight="35dp"
        android:maxLines="10"
        android:textSize="12dp"/>

    <TextView
        android:id="@+id/chat_friend_name"
        android:layout_width="140dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="3dp"
        style="@style/SubText"
        android:layout_toRightOf="@id/chat_friends_avatar"      
        android:layout_below="@id/chat_message_text" />

    <TextView
        android:id="@+id/chat_message_time"
        android:layout_width="80dp"
        android:layout_height="wrap_content"
        android:layout_marginRight="8dp"
        android:layout_marginTop="3dp"
        style="@style/SubText"
        android:layout_alignParentRight="true"
        android:layout_below="@id/chat_message_text" />

</RelativeLayout>   

但是，当我在 ScrollView 中嵌入此类元素的列表时，在其他一些元素之间，行未完全显示，如果文本被换行，它们将被剪裁(见下图).ListView在ScrollView中实例化如下:

However, when I embed a list of such elements in a ScrollView, in between some other elements, the rows are not fully displayed, they are clipped (see image below) if the text is wrapped. The ListView is instantiated as follows in the ScrollView:

<ListView
android:id="@+id/info_chat_listview"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="center"
android:cacheColorHint="@color/frame_background_color"
android:clickable="false"
android:divider="@null"
android:footerDividersEnabled="false"
android:focusable="false" >
</ListView> 

如果 ListView 的高度设置为wrap_content"，则仅显示第一个元素.这就是为什么我使用一种方法来计算列表行的高度:

If the height of the ListView is set to "wrap_content" only the first element is shown. That's why I'm using a method to calculate the height of the rows of the list:

private int getCommentsListHeight() {
        if (mChatAdapter != null && mChatAdapter.getCount() != 0) {
            if (mChatList != null) {// && mCommentsListItemHeight == 0) {
                mCommentsListItemHeight = 0;
                for (int i = 0; i < mChatAdapter.getCount(); i++) {
                    // Get view item height
                    View viewItem = mChatAdapter
                            .getView(i, new View(OnAirActivity.this), mChatList);
                    viewItem.measure(0, 0);
                    Logger.d(LOGTAG, "View " + i + " measured height = " + viewItem.getMeasuredHeight());
                    mCommentsListItemHeight += viewItem.getMeasuredHeight();
                }
            }
            //return mChatAdapter.getCount() * mCommentsListItemHeight;
            return mCommentsListItemHeight;
        } else {
            return 0;
        }
    }

不幸的是，万一TextView里面的文本被换行，即使是多行，getMeasuredHeight()方法返回的行元素的高度也是恒定的.即使文本被换行，在行元素内的 TextView 上调用的 getLineCount() 也会返回 1.

Unfortunately, in case when the text inside the TextView is wrapped, even over several lines, the height of the row element returned by the getMeasuredHeight() method is constant. Also the getLineCount() called on the TextView inside the row element returns 1 even if the text is wrapped.

另一方面，如果此 ListView 嵌入到 LinearLayout 中，则一切正常，并且显示完整列表而不会被剪裁.

On the other hand, if this ListView is embedded in a LinearLayout, everything works fine and the full list is displayed with no clipping.

您对这里可能出现的问题有什么建议吗?我真的不喜欢手动测量列表元素高度的想法，它显然不起作用，但为什么 android 不能很好地拉伸 ScrollView 内的 ListView 以适应它?

Do you have any suggestions as to what might be wrong here? I really don't like the idea of manually measuring the height of the list elements and it apparently doesn't work but why can't android nicely stretch the ListView inside the ScrollView to fit it all in there?

剪辑列表:

推荐答案

将 ListView 封装在 ScrollView 中是一种BAD 做法，因为 ListView本身包含滚动功能.您应该实现一个不包含这种视图层次结构的解决方案，我希望它会发挥作用:)

It's a BAD practice to encapsulate ListView within a ScrollView because ListView itself contains scrolling capabilities. You should implement a solution that does not contain such hierarchy of views and I hope it will do the magic :)

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