Android ListView 处理滚动事件以将其展开全屏

Question

我有一个由 MapView 和 Listview 50-50 组成的布局(下面的图片链接)

http://imgur.com/uRIS9AN

我想处理 ListView 的滚动事件，在滚动列表元素之前将其展开为全屏。

布局:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="0dp"
    android:layout_weight="1">
<com.google.android.gms.maps.MapView
    android:id="@+id/mapView"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:clickable="true" />
</LinearLayout>
<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="0dp"
    android:layout_weight="1">
<ListView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/fortress_listview">
</ListView>
</LinearLayout>
</LinearLayout>

Answer 1

看看我在这里使用的代码，在 xml 类中使用它:

<NestedListView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/fortress_listview">

在您的应用程序包中添加此嵌套 ListView 类:

public class NestedListView extends ListView implements View.OnTouchListener, AbsListView.OnScrollListener {

private int listViewTouchAction;
private static final int MAXIMUM_LIST_ITEMS_VIEWABLE = 99;

public NestedListView(Context context, AttributeSet attrs) {
    super(context, attrs);
    listViewTouchAction = -1;
    setOnScrollListener(this);
    setOnTouchListener(this);
}

@Override
public void onScroll(AbsListView view, int firstVisibleItem,
                     int visibleItemCount, int totalItemCount) {
    if (getAdapter() != null && getAdapter().getCount() > MAXIMUM_LIST_ITEMS_VIEWABLE) {
        if (listViewTouchAction == MotionEvent.ACTION_MOVE) {
            scrollBy(0, -1);
        }
    }
}

@Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);

    int newHeight = 0;
    final int heightMode = MeasureSpec.getMode(heightMeasureSpec);
    int heightSize = MeasureSpec.getSize(heightMeasureSpec);
    if (heightMode != MeasureSpec.EXACTLY) {
        ListAdapter listAdapter = getAdapter();
        if (listAdapter != null && !listAdapter.isEmpty()) {
            int listPosition = 0;
            for (listPosition = 0; listPosition < listAdapter.getCount()
                    && listPosition < MAXIMUM_LIST_ITEMS_VIEWABLE; listPosition++) {
                View listItem = listAdapter.getView(listPosition, null, this);
                //now it will not throw a NPE if listItem is a ViewGroup instance
                if (listItem instanceof ViewGroup) {
                    listItem.setLayoutParams(new LayoutParams(
                            LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
                }
                listItem.measure(widthMeasureSpec, heightMeasureSpec);
                newHeight += listItem.getMeasuredHeight();
            }
            newHeight += getDividerHeight() * listPosition;
        }
        if ((heightMode == MeasureSpec.AT_MOST) && (newHeight > heightSize)) {
            if (newHeight > heightSize) {
                newHeight = heightSize;
            }
        }
    } else {
        newHeight = getMeasuredHeight();
    }
    setMeasuredDimension(getMeasuredWidth(), newHeight);
}

@Override
public boolean onTouch(View v, MotionEvent event) {
    if (getAdapter() != null && getAdapter().getCount() > MAXIMUM_LIST_ITEMS_VIEWABLE) {
        if (listViewTouchAction == MotionEvent.ACTION_MOVE) {
            scrollBy(0, 1);
        }
    }
    return false;
}