android中的Section ListView

前几天，和ios开发的同事扯淡时发现iphone里有个section listview，分章节的列表。android中的联系人也有这种效果，首字母相同的联系人会被分在一个章节中。

后来搜了一下，android做起来也很easy。下面记录一下方便以后参考(大家改一下包名)

首先复写一下BaseAdapter:

package com.test.activity;

import java.util.LinkedHashMap;
import java.util.Map;
import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Adapter;
import android.widget.ArrayAdapter;
import android.widget.BaseAdapter;

public class SeparatedListAdapter extends BaseAdapter {

    public final Map<String, Adapter> sections = new LinkedHashMap<String, Adapter>();
    public final ArrayAdapter<String> headers;
    public final static int TYPE_SECTION_HEADER = 0;

    public SeparatedListAdapter(Context context) {
        headers = new ArrayAdapter<String>(context, R.layout.list_header);
    }

    public void addSection(String section, Adapter adapter) {
        this.headers.add(section);
        this.sections.put(section, adapter);
    }

    public Object getItem(int position) {
        for (Object section : this.sections.keySet()) {
            Adapter adapter = sections.get(section);
            int size = adapter.getCount() + 1;

            // check if position inside this section
            if (position == 0)
                return section;
            if (position < size)
                return adapter.getItem(position - 1);

            // otherwise jump into next section
            position -= size;
        }
        return null;
    }

    public int getCount() {
        // total together all sections, plus one for each section header
        int total = 0;
        for (Adapter adapter : this.sections.values())
            total += adapter.getCount() + 1;
        return total;
    }

    public int getViewTypeCount() {
        // assume that headers count as one, then total all sections
        int total = 1;
        for (Adapter adapter : this.sections.values())
            total += adapter.getViewTypeCount();
        return total;
    }

    public int getItemViewType(int position) {
        int type = 1;
        for (Object section : this.sections.keySet()) {
            Adapter adapter = sections.get(section);
            int size = adapter.getCount() + 1;

            // check if position inside this section
            if (position == 0)
                return TYPE_SECTION_HEADER;
            if (position < size)
                return type + adapter.getItemViewType(position - 1);

            // otherwise jump into next section
            position -= size;
            type += adapter.getViewTypeCount();
        }
        return -1;
    }

    public boolean areAllItemsSelectable() {
        return false;
    }

    public boolean isEnabled(int position) {
        return (getItemViewType(position) != TYPE_SECTION_HEADER);
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        int sectionnum = 0;
        for (Object section : this.sections.keySet()) {
            Adapter adapter = sections.get(section);
            int size = adapter.getCount() + 1;

            // check if position inside this section
            if (position == 0)
                return headers.getView(sectionnum, convertView, parent);
            if (position < size)
                return adapter.getView(position - 1, convertView, parent);

            // otherwise jump into next section
            position -= size;
            sectionnum++;
        }
        return null;
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

}

然后开始写主Act，用listview适配一下上面的adapter

package com.test.activity;

import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import android.app.Activity;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;

public class ListSample extends Activity {

    public final static String ITEM_TITLE = "title";
    public final static String ITEM_CAPTION = "caption";

    public Map<String, ?> createItem(String title, String caption) {
        Map<String, String> item = new HashMap<String, String>();
        item.put(ITEM_TITLE, title);
        item.put(ITEM_CAPTION, caption);
        return item;
    }

    @Override
    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);

        List<Map<String, ?>> security = new LinkedList<Map<String, ?>>();
        security.add(createItem("Remember passwords",
                "Save usernames and passwords for Web sites"));
        security.add(createItem("Clear passwords",
                "Save usernames and passwords for Web sites"));
        security.add(createItem("Show security warnings",
                "Show warning if there is a problem with a site's security"));

        // create our list and custom adapter
        SeparatedListAdapter adapter = new SeparatedListAdapter(this);
        adapter.addSection("Array test", new ArrayAdapter<String>(this,
                R.layout.list_item, new String[] { "First item", "Item two" }));
        adapter.addSection("Security", new SimpleAdapter(this, security,
                R.layout.list_complex,
                new String[] { ITEM_TITLE, ITEM_CAPTION }, new int[] {
                        R.id.list_complex_title, R.id.list_complex_caption }));
        ListView list = new ListView(this);
        list.setAdapter(adapter);
        this.setContentView(list);
    }
}

这样java代码就写完了。。

最后把xml布局文件粘贴一下就可以跑起来了

<!-- list_complex.xml -->
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    android:paddingTop="10dip"
    android:paddingBottom="10dip"
    android:paddingLeft="15dip"
    >
    <TextView
        android:id="@+id/list_complex_title"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceLarge"
        />
    <TextView
        android:id="@+id/list_complex_caption"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceSmall"
        />
</LinearLayout>

<!-- list_header.xml -->
<TextView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/list_header_title"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:paddingTop="2dip"
    android:paddingBottom="2dip"
    android:paddingLeft="5dip"
    style="?android:attr/listSeparatorTextViewStyle" />

<!-- list_item.xml -->
<TextView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/list_item_title"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:paddingTop="10dip"
    android:paddingBottom="10dip"
    android:paddingLeft="15dip"
    android:textAppearance="?android:attr/textAppearanceLarge"
    />