我们在真实项目中通常会遇到ListView或者GridView嵌套在ScrollView中问题。但是做的时候会发现，一旦两者进行嵌套，即会发生冲突。得不到我们希望的效果。由于ListView和GridView本身都继承于ScrollView，一旦在ScrollView中嵌套ScrollView，那么里面的ScrollView高度计算就会出现问题。我们也就无法得到想要的效果。下面进入正题，我们将分别讨论ScrollView中嵌套ListView和FGridView的情况：
核心解决方案： 重写ListView或者GridView的OnMesure 方法：
[java]
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
// TODO Auto-generated method stub
int expandSpec = MeasureSpec.makeMeasureSpec(
Integer.MAX_VALUE >> 2, MeasureSpec.AT_MOST);
super.onMeasure(widthMeasureSpec, expandSpec);
}
一、ScrollView中嵌套ListView
BlogScrollViewActivity.java代码：
[java]
package com.csdn.blog.scrollview;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.ScrollView;
import android.widget.LinearLayout.LayoutParams;
import android.widget.TextView;
public class BlogScrollViewActivity extends Activity {
// MyGridView grid;
ImageView image;
ScrollView scroll;
String[] texts=new String[]{“无线”,”通话设置”,”声音”,”显示”,”位置”,
“应用”,”账户”,”隐私权”,”存储”,”语言”,”游戏”,”娱乐”,”电影”,”音乐”,
“辅助功能”,”日期”};
TestListView list;
LinearLayout.LayoutParams lp;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
init();
}
void init(){
list=(TestListView)findViewById(R.id.list);
image=(ImageView)findViewById(R.id.image);
list.setAdapter(new GridAdapter(this));
scroll=(ScrollView)findViewById(R.id.scroll);
scroll.requestChildFocus(image, null);
}
private class GridAdapter extends BaseAdapter{
Activity context;
public GridAdapter(Activity context){
this.context=context;
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return texts.length;
}
@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return null;
}
@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return 0;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
ViewHolder holder=null;
if(convertView==null){
convertView=context.getLayoutInflater().inflate(R.layout.item, null);
holder=new ViewHolder();
holder.text=(TextView)convertView.findViewById(R.id.grid_text);
convertView.setTag(holder);
}
else{
holder=(ViewHolder)convertView.getTag();
}
holder.text.setText(texts[position]);
return convertView;
}
class ViewHolder {
TextView text;
}
}
}
TestListView.java代码如下：
[java]
package com.csdn.blog.scrollview;
import android.content.Context;
import android.util.AttributeSet;
import android.view.View.MeasureSpec;
import android.widget.ListView;
public class TestListView extends ListView{
public TestListView(Context context) {
super(context);
// TODO Auto-generated constructor stub
}
public TestListView(Context context, AttributeSet attrs) {
super(context, attrs);
// TODO Auto-generated constructor stub
}
public TestListView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
// TODO Auto-generated constructor stub
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
// TODO Auto-generated method stub
int expandSpec = MeasureSpec.makeMeasureSpec(
Integer.MAX_VALUE >> 2, MeasureSpec.AT_MOST);
super.onMeasure(widthMeasureSpec, expandSpec);
}
}
main.xml代码：
[html]
<p><?xml version=”1.0″ encoding=”utf-8″?>
<LinearLayout xmlns:android=”<a href=”http://schemas.android.com/apk/res/android”>http://schemas.android.com/apk/res/android</a>”
android:layout_width=”fill_parent”
android:layout_height=”fill_parent”
android:orientation=”vertical”
android:background=”#FFFFFF”
>
<ScrollView
android:layout_height=”fill_parent”
android:layout_width=”fill_parent”
android:fadingEdgeLength=”0dp”
android:scrollbars=”none”
android:id=”@+id/scroll”>
<LinearLayout
android:layout_height=”fill_parent”
android:layout_width=”fill_parent”
android:orientation=”vertical”
>
<ImageView
android:id=”@+id/image”
android:layout_height=”150dp”
android:layout_width=”fill_parent”
android:padding=”2dp”
android:scaleType=”centerCrop”
android:src=”@drawable/fruit”</p><p> />
<com.csdn.blog.scrollview.TestListView
android:id=”@+id/list”
android:layout_height=”fill_parent”
android:layout_width=”fill_parent”
android:fadingEdgeLength=”0dp”
android:scrollbars=”none”
/>
</LinearLayout>
</ScrollView></p><p></LinearLayout></p>
效果图如下：
这里我的布局方式是上面一张图片，下面放置listView。
对于此种布局方式，可以通过另外一种方式避免此问题。由于ListView有addHeadView()方法，那么我们可以直接将上面想加入的View通过 getLayoutInflater().inflate(this,R.layout.***) 加入到ListView的顶部即可。
二、ScrollView中嵌套GridView的解决方案。
ScrollView中嵌套GridView ，最简单的方法就是重写GridView方法，使其在绘制时重新计算GridView高度
MyGridView.java代码如下：
[java]
package com.csdn.blog.scrollview;
import android.content.Context;
import android.util.AttributeSet;
import android.widget.GridView;
public class MyGridView extends GridView{
public MyGridView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
// TODO Auto-generated constructor stub
}
public MyGridView(Context context, AttributeSet attrs) {
super(context, attrs);
// TODO Auto-generated constructor stub
}
public MyGridView(Context context) {
super(context);
// TODO Auto-generated constructor stub
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
// TODO Auto-generated method stub
int expandSpec = MeasureSpec.makeMeasureSpec(
Integer.MAX_VALUE >> 2, MeasureSpec.AT_MOST);
super.onMeasure(widthMeasureSpec, expandSpec);
}
}
main.xml代码如下：
[java]
<?xml version=”1.0″ encoding=”utf-8″?>
<LinearLayout xmlns:android=”http://schemas.android.com/apk/res/android”
android:layout_width=”fill_parent”
android:layout_height=”fill_parent”
android:orientation=”vertical”
android:background=”#FFFFFF”
>
<ScrollView
android:layout_height=”fill_parent”
android:layout_width=”fill_parent”
android:fadingEdgeLength=”0dp”
android:scrollbars=”none”
android:id=”@+id/scroll”>
<LinearLayout
android:layout_height=”fill_parent”
android:layout_width=”fill_parent”
android:orientation=”vertical”
>
<ImageView
android:id=”@+id/image”
android:layout_height=”150dp”
android:layout_width=”fill_parent”
android:padding=”2dp”
android:scaleType=”centerCrop”
android:src=”@drawable/fruit”
/>
<com.csdn.blog.scrollview.MyGridView
android:layout_marginTop=”10dp”
android:id=”@+id/grid”
android:layout_height=”fill_parent”
android:layout_width=”fill_parent”
android:fadingEdgeLength=”0dp”
android:scrollbars=”none”
android:numColumns=”3″
/>
</LinearLayout>
</ScrollView>
</LinearLayout>
主类主要就是GridVIew数据绑定。简单贴下代码：
[java]
package com.csdn.blog.scrollview;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.ScrollView;
import android.widget.LinearLayout.LayoutParams;
import android.widget.TextView;
public class BlogScrollViewActivity extends Activity {
MyGridView grid;
ImageView image;
ScrollView scroll;
String[] texts=new String[]{“无线”,”通话设置”,”声音”,”显示”,”位置”,
“应用”,”账户”,”隐私权”,”存储”,”语言”,”游戏”,”娱乐”,”电影”,”音乐”,
“辅助功能”,”日期”};
ArrayAdapter<String> adapter;
LinearLayout.LayoutParams lp;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
init();
}
void init(){
image=(ImageView)findViewById(R.id.image);
grid=(MyGridView)findViewById(R.id.grid);
grid.setAdapter(new GridAdapter(this));
scroll=(ScrollView)findViewById(R.id.scroll);
scroll.requestChildFocus(image, null);
}
private class GridAdapter extends BaseAdapter{
Activity context;
public GridAdapter(Activity context){
this.context=context;
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return texts.length;
}
@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return null;
}
@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return 0;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
ViewHolder holder=null;
if(convertView==null){
convertView=context.getLayoutInflater().inflate(R.layout.item, null);
holder=new ViewHolder();
holder.image=(ImageView)convertView.findViewById(R.id.grid_image);
holder.text=(TextView)convertView.findViewById(R.id.grid_text);
convertView.setTag(holder);
}
else{
holder=(ViewHolder)convertView.getTag();
}
holder.image.setImageResource(R.drawable.meinv);
holder.text.setText(texts[position]);
return convertView;
}
class ViewHolder {
ImageView image;
TextView text;
}
}
}
上述代码中 scroll.requestChildFocus(image, null); 此句主要是修复了程序进入时GridView会滑动到顶端的小bug。
