我到处寻找这个问题的解决方案,我能找到的唯一答案似乎是“不要把一个ListView放入一个ScrollView”。不过,我还没有看到任何真正的解释。我能找到的唯一原因似乎是谷歌认为你不应该这么做。我知道,所以我做了。
问题是,如何将ListView放到ScrollView中而不缩到最小高度?
我到处寻找这个问题的解决方案,我能找到的唯一答案似乎是“不要把一个ListView放入一个ScrollView”。不过,我还没有看到任何真正的解释。我能找到的唯一原因似乎是谷歌认为你不应该这么做。我知道,所以我做了。
问题是,如何将ListView放到ScrollView中而不缩到最小高度?
当前回答
下面是我的计算列表视图总高度的代码版本。这个对我很有用:
public static void setListViewHeightBasedOnChildren(ListView listView) {
ListAdapter listAdapter = listView.getAdapter();
if (listAdapter == null || listAdapter.getCount() < 2) {
// pre-condition
return;
}
int totalHeight = 0;
int widthMeasureSpec = View.MeasureSpec.makeMeasureSpec(BCTDApp.getDisplaySize().width, View.MeasureSpec.AT_MOST);
int heightMeasureSpec = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
ViewGroup.LayoutParams lp = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);
for (int i = 0; i < listAdapter.getCount(); i++) {
View listItem = listAdapter.getView(i, null, listView);
if (listItem instanceof ViewGroup) listItem.setLayoutParams(lp);
listItem.measure(widthMeasureSpec, heightMeasureSpec);
totalHeight += listItem.getMeasuredHeight();
}
totalHeight += listView.getPaddingTop() + listView.getPaddingBottom();
totalHeight += (listView.getDividerHeight() * (listAdapter.getCount() - 1));
ViewGroup.LayoutParams params = listView.getLayoutParams();
params.height = totalHeight;
listView.setLayoutParams(params);
listView.requestLayout();
}
其他回答
虽然建议的setListViewHeightBasedOnChildren()方法在大多数情况下都可以工作,但在某些情况下,特别是对于许多项,我注意到最后一个元素不显示。所以我决定模仿一个简单版本的ListView行为,以便重用任何适配器代码,这里是ListView的替代方案:
import android.content.Context;
import android.database.DataSetObserver;
import android.util.AttributeSet;
import android.util.Log;
import android.view.View;
import android.widget.LinearLayout;
import android.widget.ListAdapter;
public class StretchedListView extends LinearLayout {
private final DataSetObserver dataSetObserver;
private ListAdapter adapter;
private OnItemClickListener onItemClickListener;
public StretchedListView(Context context, AttributeSet attrs) {
super(context, attrs);
setOrientation(LinearLayout.VERTICAL);
this.dataSetObserver = new DataSetObserver() {
@Override
public void onChanged() {
syncDataFromAdapter();
super.onChanged();
}
@Override
public void onInvalidated() {
syncDataFromAdapter();
super.onInvalidated();
}
};
}
public void setAdapter(ListAdapter adapter) {
ensureDataSetObserverIsUnregistered();
this.adapter = adapter;
if (this.adapter != null) {
this.adapter.registerDataSetObserver(dataSetObserver);
}
syncDataFromAdapter();
}
protected void ensureDataSetObserverIsUnregistered() {
if (this.adapter != null) {
this.adapter.unregisterDataSetObserver(dataSetObserver);
}
}
public Object getItemAtPosition(int position) {
return adapter != null ? adapter.getItem(position) : null;
}
public void setSelection(int i) {
getChildAt(i).setSelected(true);
}
public void setOnItemClickListener(OnItemClickListener onItemClickListener) {
this.onItemClickListener = onItemClickListener;
}
public ListAdapter getAdapter() {
return adapter;
}
public int getCount() {
return adapter != null ? adapter.getCount() : 0;
}
private void syncDataFromAdapter() {
removeAllViews();
if (adapter != null) {
int count = adapter.getCount();
for (int i = 0; i < count; i++) {
View view = adapter.getView(i, null, this);
boolean enabled = adapter.isEnabled(i);
if (enabled) {
final int position = i;
final long id = adapter.getItemId(position);
view.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (onItemClickListener != null) {
onItemClickListener.onItemClick(null, v, position, id);
}
}
});
}
addView(view);
}
}
}
}
这肯定会工作............ 你必须替换你的<ScrollView ></ScrollView>在布局XML文件与这个自定义ScrollView像<com.tmd.utils。VerticalScrollview > </com.tmd.utils。VerticalScrollview >
package com.tmd.utils;
import android.content.Context;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.widget.ScrollView;
public class VerticalScrollview extends ScrollView{
public VerticalScrollview(Context context) {
super(context);
}
public VerticalScrollview(Context context, AttributeSet attrs) {
super(context, attrs);
}
public VerticalScrollview(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
final int action = ev.getAction();
switch (action)
{
case MotionEvent.ACTION_DOWN:
Log.i("VerticalScrollview", "onInterceptTouchEvent: DOWN super false" );
super.onTouchEvent(ev);
break;
case MotionEvent.ACTION_MOVE:
return false; // redirect MotionEvents to ourself
case MotionEvent.ACTION_CANCEL:
Log.i("VerticalScrollview", "onInterceptTouchEvent: CANCEL super false" );
super.onTouchEvent(ev);
break;
case MotionEvent.ACTION_UP:
Log.i("VerticalScrollview", "onInterceptTouchEvent: UP super false" );
return false;
default: Log.i("VerticalScrollview", "onInterceptTouchEvent: " + action ); break;
}
return false;
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
super.onTouchEvent(ev);
Log.i("VerticalScrollview", "onTouchEvent. action: " + ev.getAction() );
return true;
}
}
你不应该把ListView放到ScrollView中因为ListView已经是一个ScrollView了。这就像把一个ScrollView放到一个ScrollView中。
你想要完成什么?
这是DougW、Good Guy Greg和Paul的答案组合。我发现当尝试使用自定义列表视图适配器和非标准列表项时,这都是需要的,否则列表视图会导致应用程序崩溃(也会导致Nex的答案崩溃):
public void setListViewHeightBasedOnChildren(ListView listView) {
ListAdapter listAdapter = listView.getAdapter();
if (listAdapter == null) {
return;
}
int totalHeight = listView.getPaddingTop() + listView.getPaddingBottom();
for (int i = 0; i < listAdapter.getCount(); i++) {
View listItem = listAdapter.getView(i, null, listView);
if (listItem instanceof ViewGroup)
listItem.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
listItem.measure(0, 0);
totalHeight += listItem.getMeasuredHeight();
}
ViewGroup.LayoutParams params = listView.getLayoutParams();
params.height = totalHeight + (listView.getDividerHeight() * (listAdapter.getCount() - 1));
listView.setLayoutParams(params);
}
我把@DougW的实用程序转换成c#(在Xamarin中使用)。下面的代码对于列表中固定高度的项目很有效,如果只有一些项目比标准项目稍大一点,那么大多数项目都将很好,或者至少是一个良好的开端。
// You will need to put this Utility class into a code file including various
// libraries, I found that I needed at least System, Linq, Android.Views and
// Android.Widget.
using System;
using System.Linq;
using Android.Views;
using Android.Widget;
namespace UtilityNamespace // whatever you like, obviously!
{
public class Utility
{
public static void setListViewHeightBasedOnChildren (ListView listView)
{
if (listView.Adapter == null) {
// pre-condition
return;
}
int totalHeight = listView.PaddingTop + listView.PaddingBottom;
for (int i = 0; i < listView.Count; i++) {
View listItem = listView.Adapter.GetView (i, null, listView);
if (listItem.GetType () == typeof(ViewGroup)) {
listItem.LayoutParameters = new LinearLayout.LayoutParams (ViewGroup.LayoutParams.MatchParent, ViewGroup.LayoutParams.WrapContent);
}
listItem.Measure (0, 0);
totalHeight += listItem.MeasuredHeight;
}
listView.LayoutParameters.Height = totalHeight + (listView.DividerHeight * (listView.Count - 1));
}
}
}
谢谢@DougW,当我不得不使用其他人的代码时,这让我摆脱了困境。: -)