ScrollView中只能放一个控件,一般都放LinearLayout,orientation属性值为vertical。在LinearLayout中放需要呈现的内容。ListView也在其中,ListView的高度设为适应自身内容(wrap_content)。但是为啥在scrollview中嵌套listview会出现只显示第一条listitem的高度呢,原因是:scrollview的ontach方法的滚动事件消费处理,ListView控件的高度设定问题
从谷歌那里找到的ScrollView嵌套ListView只显示一行的解决办法相信很多人都遇到过,然后大部分都是用这位博主的办法解决的吧
刚开始我也是用这个办法解决的,首先感谢这位哥的大私奉献,贴上地址
http://blog.csdn.net/p106786860/article/details/10461015
2、解决的核心代码
- public void setListViewHeightBasedOnChildren(ListView listView) {
- // 获取ListView对应的Adapter
- ListAdapter listAdapter = listView.getAdapter();
- if (listAdapter == null) {
- return;
- }
- int totalHeight = 0;
- for (int i = 0, len = listAdapter.getCount(); i < len; i++) {
- // listAdapter.getCount()返回数据项的数目
- View listItem = listAdapter.getView(i, null, listView);
- // 计算子项View 的宽高
- listItem.measure(0, 0);
- // 统计所有子项的总高度
- totalHeight += listItem.getMeasuredHeight();
- }
- ViewGroup.LayoutParams params = listView.getLayoutParams();
- params.height = totalHeight+ (listView.getDividerHeight() * (listAdapter.getCount() - 1));
- // listView.getDividerHeight()获取子项间分隔符占用的高度
- // params.height最后得到整个ListView完整显示需要的高度
- listView.setLayoutParams(params);
- }
但是这个代码里面有一个问题,就是这个当你的ListView里面有多行的TextView的话,ListView的高度就会计算错误,它只算到了一行TextView的高度,
这个问题在so上的概述为以下:
http://stackoverflow.com/questions/14386584/getmeasuredheight-of-textview-with-wrapped-text
3、终极解决办法
这个问题头疼了一阵后,查找了一下,应该重写一个TextView的onMeasure方法比较好解决
代码有
- @Override
- protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
- super.onMeasure(widthMeasureSpec, heightMeasureSpec);
- Layout layout = getLayout();
- if (layout != null) {
- int height = (int)FloatMath.ceil(getMaxLineHeight(this.getText().toString()))
- + getCompoundPaddingTop() + getCompoundPaddingBottom();
- int width = getMeasuredWidth();
- setMeasuredDimension(width, height);
- }
- }
- private float getMaxLineHeight(String str) {
- float height = 0.0f;
- float screenW = ((Activity)context).getWindowManager().getDefaultDisplay().getWidth();
- float paddingLeft = ((LinearLayout)this.getParent()).getPaddingLeft();
- float paddingReft = ((LinearLayout)this.getParent()).getPaddingRight();
- //这里具体this.getPaint()要注意使用,要看你的TextView在什么位置,这个是拿TextView父控件的Padding的,为了更准确的算出换行
- int line = (int) Math.ceil( (this.getPaint().measureText(str)/(screenW-paddingLeft-paddingReft))); height = (this.getPaint().getFontMetrics().descent-this.getPaint().getFontMetrics().ascent)*line; return height;}
上面的代码完成更能为,在ListView开始测量时,测量到TextView时,就调用我们的onMeasure方法,我们就可以测量字体的总宽度除与去掉边距的屏幕的大小,就可以算出文字要几行来显示,然后测量字体的高度*行数可以得到字体的总高度,然后在加上上下边距就是TextView真正的高度,然后setMeasuredDimension进去就可以计算出正确的值出来。
完整大代码我贴出来
public class MyListView2 extends LinearLayout {
private BaseAdapter adapter;
private MyOnItemClickListener onItemClickListener;
boolean footerViewAttached = false;
private View footerview;
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
// TODO Auto-generated method stub
super.onLayout(changed, l, t, r, b);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int expandSpec = MeasureSpec.makeMeasureSpec(Integer.MAX_VALUE >> 2,
MeasureSpec.AT_MOST);
super.onMeasure(widthMeasureSpec, expandSpec);
}
public void notifyChange() {
int count = getChildCount();
if (footerViewAttached) {
count--;
}
LayoutParams params = new LayoutParams(LayoutParams.FILL_PARENT,
LayoutParams.WRAP_CONTENT);
for (int i = count; i < adapter.getCount(); i++) {
final int index = i;
final LinearLayout layout = new LinearLayout(getContext());
layout.setLayoutParams(params);
layout.setOrientation(VERTICAL);
View v = adapter.getView(i, null, null);
v.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
if (onItemClickListener != null) {
onItemClickListener.onItemClick(MyListView2.this,
layout, index, adapter.getItem(index));
}
}
});
ImageView imageView = new ImageView(getContext());
imageView.setLayoutParams(params);
layout.addView(v);
layout.addView(imageView);
addView(layout, index);
}
}
public MyListView2(Context context) {
super(context);
initAttr(null);
}
public MyListView2(Context context, AttributeSet attrs) {
super(context, attrs);
initAttr(attrs);
}
public void initAttr(AttributeSet attrs) {
setOrientation(VERTICAL);
}
public void initFooterView(final View footerView) {
this.footerview = footerView;
}
public void setFooterViewListener(OnClickListener onClickListener) {
this.footerview.setOnClickListener(onClickListener);
}
public BaseAdapter getAdapter() {
return adapter;
}
public void setAdapter(BaseAdapter adpater) {
this.adapter = adpater;
removeAllViews();
if (footerViewAttached)
addView(footerview);
notifyChange();
}
public void setOnItemClickListener(MyOnItemClickListener onClickListener) {
this.onItemClickListener = onClickListener;
}
public void noMorePages() {
if (footerview != null && footerViewAttached) {
removeView(footerview);
footerViewAttached = false;
}
}
public void mayHaveMorePages() {
if (!footerViewAttached && footerview != null) {
addView(footerview);
footerViewAttached = true;
}
}
public static interface MyOnItemClickListener {
public void onItemClick(ViewGroup parent, View view, int position,
Object o);
}
}
这个adapter就是你获取数据后设置的,也就是上面两点的综合