Android ListView rows in ScrollView not fully disp

问题:

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>   

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> 

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;
        }
    }

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.

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

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?

Clipped list:

回答1:

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 :)

回答2:

Use this method created by https://stackoverflow.com/users/205192/dougw

 public static void setListViewHeightBasedOnChildren(ListView listView) {
        ListAdapter listAdapter = listView.getAdapter(); 
        if (listAdapter == null) {
            // pre-condition
            return;
        }

        int totalHeight = 0;
        for (int i = 0; i < listAdapter.getCount(); i++) {
            View listItem = listAdapter.getView(i, null, listView);
            listItem.measure(0, 0);
            totalHeight += listItem.getMeasuredHeight();
        }

        ViewGroup.LayoutParams params = listView.getLayoutParams();
        params.height = totalHeight + (listView.getDividerHeight() * (listAdapter.getCount() - 1));
        listView.setLayoutParams(params);
    }

回答3:

Here resource of main layout with ScrollView:

<ScrollView android:layout_height="fill_parent" android:layout_width="fill_parent">
<LinearLayout android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" android:id="@+id/parentLayout"/>
</ScrollView>

Here the code to insert items:

parentLayout.removeAllViews();
LayoutInflater inflater = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
for (int i = comments.size() - 1; i >= 0; i--) {
CommentInfo comment = comments.get(i);
View view = inflater.inflate(your_resource_id, null, false);

TextView commentsContent =(TextView)view.findViewById(R.id.commentContent);
if (commentsContent != null) {
    String data = String.format("%s (by %s, %s)",  comment.getCommentText(), comment.getUserName(),
        commentsContent.setTextSize(st.getTextSize());
    commentsContent.setText(data);

}

parentLayout.addView(view, 0);

}       

回答4:

I had the same problem in my project.You need to create simple LinearLayout inside ScrollView. After that you need create new View with your listview item xml using LayoutInflater. After creation put all data in new View and add to LinearLayout as child view:

linearLayot.addView(newView, position_you_need).

Hope it would help you!

回答5:

I took the recommendation of not using a ListView element inside a ScrollView to heart and decided to use a slightly brute force method to achieve what I need. Since there is a constant number of up to five list rows that need to be displayed I removed the ListView instantiation from the xml file and replaced it with five instances of rows:

<include android:id="@+id/info_comment_1" layout="@layout/chat_single_message" />
<include android:id="@+id/info_comment_2" layout="@layout/chat_single_message" />
<include android:id="@+id/info_comment_3" layout="@layout/chat_single_message" />
<include android:id="@+id/info_comment_4" layout="@layout/chat_single_message" />
<include android:id="@+id/info_comment_5" layout="@layout/chat_single_message" />

In the Activity class I declare five placeholders for these views:

private RelativeLayout mChatMessages[] = new RelativeLayout[COMMENTS_NUMBER];

and initialize them with:

mChatMessages[0] = (RelativeLayout) mMoreInfoLayout.findViewById(R.id.info_comment_1);
mChatMessages[1] = (RelativeLayout) mMoreInfoLayout.findViewById(R.id.info_comment_2);
mChatMessages[2] = (RelativeLayout) mMoreInfoLayout.findViewById(R.id.info_comment_3);
mChatMessages[3] = (RelativeLayout) mMoreInfoLayout.findViewById(R.id.info_comment_4);
mChatMessages[4] = (RelativeLayout) mMoreInfoLayout.findViewById(R.id.info_comment_5);

Then, whenever a new message is received I use the ChatAdapter (the same I used for the ListView previously) and call its getView() method:

protected void updateChatMessages() {
  int msgCount = mChatAdapter.getCount();
  for (int i = 0; i < COMMENTS_NUMBER; i++) {
    if (msgCount <= i) {
      mChatMessages[i].setVisibility(View.GONE);
    } else {
      mChatMessages[i] = (RelativeLayout) mChatAdapter.getView(i, mChatMessages[i], null); 
      mChatMessages[i].setVisibility(View.VISIBLE);
    }   
  }
}

I don't inflate the pariculat views ever again since the only thing that changes is the content of each row, not the layout. This means there is no performance penalty here.

This is basically a manual implementation of a ListView with a limited maximum number of elements. This time, however, ScrollView is able to fit them nicely and nothing gets clipped.

For a dynamic number of rows the approach suggested by Layko could be employed with the views being instantiated programatically and added to the LinearLayout inside the ScrollView.

回答6:

I can see the ListView is inside a ViewPager; one other simple approach to resolving this issue is to add app:layout_behavior="@string/appbar_scrolling_view_behavior" to the ViewPager in your layout xml as seen below.

<android.support.v4.view.ViewPager
    android:id="@+id/viewpager"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"/>

To prevent the same behavior at the bottom of the list, you can also add android:layout_marginBottom="?attr/actionBarSize" to the ViewPager like so

<android.support.v4.view.ViewPager
    android:id="@+id/viewpager"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    android:layout_marginBottom="?attr/actionBarSize"/>

This is coming late, but I hope it helps any other person.

回答7:

try it.. after create all view add bellow line for ScrollView location on screen (x,y)

  ScrollView scrollView = (ScrollView)findViewById(R.id.scrollView);

  scrollView.smoothScrollTo(0,0);// top location zero index

回答8:

I had a similar problem. I have a

RelativeLayout
  listView
  includeLayout  

where I include some bottom nav beneath the listView with this

<include
    android:id="@+id/includeLayout"
    layout="@layout/bottom_nav_bar"

and my listView was clipped - not taking the full height available between the header and bottom nav. I tried various xml settings suggested in this and other threads, but what worked for me was to add

android:layout_alignBottom="@+id/includeLayout"

to my listView. That seemed to pull the listView down to the top of the bottom nav, so that the listView is now using the full available height (and it scrolls as needed).

回答9:

This works for me

<RelativeLayout                                          xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"

    android:padding="@dimen/activity_vertical_margin">

    <TextView
        android:id="@+id/tv_status"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:textSize="17sp"
        android:text="@string/text_list_devices" />

    <ListView
        android:id="@+id/lv_paired"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="@dimen/activity_vertical_margin"
        android:cacheColorHint="#00000000"
        android:layout_above="@+id/signup_t"
        android:layout_below="@id/tv_status"
        />

    <Button

        android:id="@+id/signup_t"
        style="?android:textAppearanceSmall"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="20dp"
        android:textColor="@android:color/white"
        android:layout_alignParentBottom="true"
        android:text="Print All Records"
        android:typeface="sans"
        android:layout_marginLeft="45dp"
        android:layout_marginRight="45dp"
        android:textSize="24sp"
        android:background="@drawable/selector_for_button"
        android:textStyle="bold" />
</RelativeLayout>