Android-线性布局权重在Listview项中无法正常工作 [英] Android - Linear layout weight not working properly in listview items
问题描述
在Android Studio中看似正确，但在手机上执行时不起作用.
我使用的是一个简单的线性布局(水平)，其中包含两个线性布局(垂直)容器，每个容器应占用列表视图中行的50％的空间.这是代码:
Looks right in Android Studio, but doesn't work when executed on my phone.
I'm using a simple linear layout (horizontal) with two linear layout (vertical) containers inside, which should each take up 50% of the space of the row in the listview. Here's the code:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal" android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:weightSum="1">
<LinearLayout
android:orientation="vertical"
android:layout_width="0dp"
android:layout_height="fill_parent"
android:layout_weight="0.5">
<LinearLayout
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="wrap_content">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceMedium"
android:text="001"
android:id="@+id/pokemonNumber"
android:layout_marginLeft="5dp" />
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceMedium"
android:text="Bulbasaur"
android:id="@+id/pokemonName"
android:layout_marginLeft="10dp" />
</LinearLayout>
<LinearLayout
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceSmall"
android:text="Grass"
android:id="@+id/pokemonTypes"
android:layout_marginLeft="50dp" />
</LinearLayout>
</LinearLayout>
<LinearLayout
android:orientation="vertical"
android:layout_width="0dp"
android:layout_height="fill_parent"
android:layout_weight="0.5">
<ImageView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="@+id/pokemonImage"
android:src="#ff65ff4f" />
</LinearLayout>
</LinearLayout>
如果您需要视觉参考，我可以上传图片，但是基本上它应该是两个线性布局，每个线性布局分别占其父级线性布局的50％.有任何想法为什么这行不通吗?
I can upload pictures if you need a visual reference, but basically it should just be two linear layouts taking up 50% each of their parent linear layout, horizontally. Any ideas why this isn't working?
为清晰起见，附上图片:
attached pictures for clarity:
在Android Studio中的外观(正确): http://i.stack.imgur. com/bxhxi.png
How it looks in Android Studio (correct): http://i.stack.imgur.com/bxhxi.png
它的实际外观(不正确): http://i.stack.imgur.com/jPXCW.png
How it actually looks (incorrect): http://i.stack.imgur.com/jPXCW.png
这是列表视图的行布局
this is a row layout for a listview
使用此布局的代码:
public class DexListAdapter extends BaseAdapter {
private LayoutInflater mInflater;
private List<Pokemon> mPokes;
private String mRowLayout = "pokemon_list_item";
private Context mContext;
public DexListAdapter(Context context, List<Pokemon> pokes) {
mInflater = LayoutInflater.from(context);
mPokes = pokes;
mContext = context;
}
@Override
public int getCount() {
return mPokes.size();
}
@Override
public Object getItem(int position) {
return mPokes.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View view;
ViewHolder holder;
if(convertView == null) {
int resID = mContext.getResources().getIdentifier(mRowLayout, "layout", mContext.getPackageName());
view = mInflater.inflate(resID, parent, false);
holder = new ViewHolder();
holder.number = (TextView)view.findViewById(R.id.pokemonNumber);
holder.name = (TextView)view.findViewById(R.id.pokemonName);
holder.types = (TextView)view.findViewById(R.id.pokemonTypes);
holder.image = (ImageView)view.findViewById(R.id.pokemonImage);
view.setTag(holder);
} else {
view = convertView;
holder = (ViewHolder)view.getTag();
}
Pokemon poke = mPokes.get(position);
//Set info from pokemon object to listview item
holder.number.setText(poke.getStringNumber());
holder.name.setText(poke.getName());
holder.types.setText(poke.getTypeOne() + " " + poke.getTypeTwo());
return view;
}
private class ViewHolder {
public TextView number, name, types;
public ImageView image;
}
}
在此处调用的代码上方(作为导航抽屉活动中使用的片段的一部分):
Above code called here (as part of fragment used in navigation drawer activity):
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_pokelist, container, false);
ListView l1=(ListView)rootView.findViewById(R.id.pokeList);
l1.setAdapter(new DexListAdapter(c,pokemonList));
return rootView;
}
列表视图的代码
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<ListView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/pokeList" />
</LinearLayout>
推荐答案
问题是ListView在wrap_content上具有宽度，这不允许LinearLayout使用其权重属性.因此解决方案如下所示:
The problem was that the ListView had it's width on wrap_content which didn't allow the LinearLayout to use it's weight properties. So the solution is as shown below:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<ListView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/pokeList" />
</LinearLayout>
我在这里的一个问题中也读过它(不幸的是找不到链接)，给ListView wrap_content作为高度不是很好，总是要像match_parent一样具体或使用其他约束，以便它知道之前的高度任何孩子都被添加.
I also read it in a question here (Can't find the link unfortunately) that it's not good to give a ListView wrap_content as height, always try to be specific, like match_parent or use other constraints so it knows it's height before any children are added.
这篇关于Android-线性布局权重在Listview项中无法正常工作的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
