Android ListView 多种布局--初步

AndroidWidget 2015-07

提出问题

先看下面这个ListView

该如何实现上面这个需求？

解决问题

我们知道ListView数据绑定类BaseAdapter有个getItemViewType，这个方法完全满足上面的要求，下面写个简单的Demo实现上面的需求。

• 定义主UI R.layout.activity_listview_type

<?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="match_parent"
            android:id="@+id/list_view"
            android:divider="@color/list_view_divider_color"
            android:dividerHeight="1dp" />
</LinearLayout>

• 定义其中一种Item UI R.layout.item_listview_type_title

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              xmlns:tools="http://schemas.android.com/tools"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_height="match_parent">
    <TextView
            android:id="@+id/item_list_view_type_title"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_vertical"
            android:gravity="center"
            android:textColor="@android:color/black"
            android:textSize="@dimen/item_list_view_type_title_size"
            android:padding="8dp"
            tools:ignore="RtlHardcoded,RtlSymmetry" />
</LinearLayout>

• 定义另外一种Item UI R.layout.item_listview_type_content

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
          xmlns:tools="http://schemas.android.com/tools"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:gravity="center"
          android:textColor="@android:color/black"
          android:textSize="@dimen/item_list_view_type_title_size"
          android:padding="8dp"
          android:drawablePadding="10dp"
          android:drawableRight="@mipmap/ic_launcher"
          android:id="@+id/item_list_view_type_content"
          tools:ignore="RtlHardcoded">
</TextView>

• 最后写UI主类

import android.app.Activity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ListView;
import android.widget.TextView;
import java.util.ArrayList;
import java.util.List;
public class ListViewTypeActivity extends Activity
{
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_listview_type);
        initView();
    }
    private void initView()
    {
        ListView listView = (ListView) findViewById(R.id.list_view);
        List<ItemFeed> data = new ArrayList<>();
        for (int i = 0; i < 20; i++)
        {
            ItemFeed feed = new ItemFeed();
            if (i % 5 == 0)
            {
                feed.setItemType(ItemType.TITLE);
                feed.setText("TypeListView_Item: Title" + i);
            }
            else
            {
                feed.setItemType(ItemType.CONTENT);
                feed.setText("TypeListView_Item: Content" + i);
            }
            data.add(feed);
        }
        BaseAdapter listAdapter = new TypedListAdapter(data);
        listView.setAdapter(listAdapter);
    }
    private class TypedListAdapter extends BaseAdapter
    {
        private List<ItemFeed> data;
        public TypedListAdapter(List<ItemFeed> datas)
        {
            this.data = datas;
        }
        @Override
        public int getViewTypeCount()
        {
            return 2;
        }
        @Override
        public int getItemViewType(int position)
        {
            final ItemFeed feed = data.get(position);
            if (feed != null)
            {
                return feed.getItemType().getValue();
            }
            return super.getItemViewType(position);
        }
        @Override
        public int getCount()
        {
            return data == null ? 0 : data.size();
        }
        @Override
        public Object getItem(int position)
        {
            return data == null ? null : data.get(position);
        }
        @Override
        public long getItemId(int position)
        {
            return position;
        }
        @Override
        public View getView(int position, View convertView, ViewGroup parent)
        {
            final ItemFeed feed = data.get(position);
            final LayoutInflater inflater = LayoutInflater.from(ListViewTypeActivity.this);
            ItemTitleHolder titleHolder;
            ItemContentHolder contentHolder;
            int type = getItemViewType(position);
            switch (type)
            {
                case 0:
                    if (convertView == null)
                    {
                        convertView = inflater.inflate(R.layout.item_listview_type_title, parent, false);
                        titleHolder = new ItemTitleHolder(convertView);
                        convertView.setTag(titleHolder);
                    }
                    else
                    {
                        titleHolder = (ItemTitleHolder) convertView.getTag();
                    }
                    titleHolder.refreshUI(feed);
                    break;
                case 1:
                    if (convertView == null)
                    {
                        convertView = inflater.inflate(R.layout.item_listview_type_content, parent, false);
                        contentHolder = new ItemContentHolder(convertView);
                        convertView.setTag(contentHolder);
                    }
                    else
                    {
                        contentHolder = (ItemContentHolder) convertView.getTag();
                    }
                    contentHolder.refreshUI(feed);
                    break;
            }
            return convertView;
        }
    }
    private class ItemTitleHolder
    {
        private TextView title;
        public ItemTitleHolder(View convertView)
        {
            if (convertView != null)
            {
                title = (TextView) convertView.findViewById(R.id.item_list_view_type_title);
            }
        }
        public void refreshUI(ItemFeed feed)
        {
            if (title != null && feed != null)
            {
                title.setText(feed.getText());
            }
        }
    }
    private class ItemContentHolder
    {
        private TextView content;
        public ItemContentHolder(final View convertView)
        {
            if (convertView != null)
            {
                content = (TextView) convertView.findViewById(R.id.item_list_view_type_content);
            }
        }
        public void refreshUI(ItemFeed feed)
        {
            if (content != null && feed != null)
            {
                content.setText(feed.getText());
            }
        }
    }
    private class ItemFeed
    {
        public ItemType getItemType()
        {
            return itemType;
        }
        public void setItemType(ItemType itemType)
        {
            this.itemType = itemType;
        }
        public String getText()
        {
            return text;
        }
        public void setText(String text)
        {
            this.text = text;
        }
        private ItemType itemType;
        private String text;
    }
    private enum ItemType
    {
        TITLE(0),
        CONTENT(1);
        public int getValue()
        {
            return value;
        }
        private int value;
        ItemType(int value)
        {
            this.value = value;
        }
    }
}

运行结果