实现带标题的ListView

在一些项目中，往往有要求为ListView里的内容分类，比如按日期分类，就要把相同日期的项目放在一起。可以看一些示例图，会清楚一些：

以上根据标题来进行分类，实现代码如下：

首先是数据项的模型：

public class Data {    private String text1, text2, text3; //数据1 2 3    public Data(String text1, String text2, String text3) {        this.text1 = text1;        this.text2 = text2;        this.text3 = text3;    }    public String getText1() {        return text1;    }    public String getText2() {        return text2;    }    public String getText3() {        return text3;    }}

因为要分类，所以需要一些类来存标题和数据Data集合：

public class Type {    private String title;  //ListView头部显示的标题    private List<Data> mList; //头部对应的内容集合    public Type(String title) {        this.title = title;        mList = new ArrayList<>();    }    /**     * 添加项目     * @param data Data对象     */    public void addItem(Data data) {        mList.add(data);    }    /**     * 获取项目     * @param position 如果position为1就返回标题     * @return     */    public Object getItem(int position) {        if (position == 0) {            return title;        } else {            return mList.get(position - 1);        }    }    /**     * @return item数目，为集合大小+1     */    public int size() {        return mList.size() + 1;    }}

紧接着实现适配器Adapter,主要的逻辑设计在此部分:

public class MyAdapter extends BaseAdapter {    private static final int TYPE_HEADER = 0;  //代表标题    private static final int TYPE_ITEM = 1;    //代表项目item    private List<Type> mList;    private LayoutInflater inflater;    public MyAdapter(Context context, List<Type> list) {        mList = list;        inflater = LayoutInflater.from(context);    }    /**     *     * @return 所有项的总和     */    @Override    public int getCount() {        int count = 0;        if (mList != null) {            for (Type type : mList) {                count += type.size();            }        }        return count;    }    /**     * 根据position的不同返回不同的值     * @param position     * @return     */    @Override    public Object getItem(int position) {        int head = 0;  //标题位置        for (Type type : mList) {            int size = type.size();            int current = position - head;            if (current < size) {                //返回对应位置的值                return type.getItem(current);            }            head += size;        }        return null;    }    @Override    public long getItemId(int position) {        return position;    }    @Override    public View getView(int position, View convertView, ViewGroup parent) {        ViewHolder viewHolder;        switch (getItemViewType(position)) {            //分为两种情况加载item            case TYPE_HEADER: //加载标题布局                if (convertView == null) {                    viewHolder = new ViewHolder();                    convertView = inflater.inflate(R.layout.header, parent, false);                    viewHolder.title = (TextView) convertView.findViewById(R.id.date);                    convertView.setTag(viewHolder);                } else {                    viewHolder = (ViewHolder) convertView.getTag();                }                viewHolder.title.setText((CharSequence) getItem(position));                break;            case TYPE_ITEM: //加载数据项目布局                if (convertView == null) {                    viewHolder = new ViewHolder();                    convertView = inflater.inflate(R.layout.adapter, parent, false);                    viewHolder.tv1 = (TextView) convertView.findViewById(R.id.text1);                    viewHolder.tv2 = (TextView) convertView.findViewById(R.id.text2);                    viewHolder.tv3 = (TextView) convertView.findViewById(R.id.text3);                    convertView.setTag(viewHolder);                } else {                    viewHolder = (ViewHolder) convertView.getTag();                }                Data data = (Data) getItem(position);                viewHolder.tv1.setText(data.getText1());                viewHolder.tv2.setText(data.getText2());                viewHolder.tv3.setText(data.getText3());                break;        }        return convertView;    }    /**     *     * @return 返回item类型数目     */    @Override    public int getViewTypeCount() {        return 2;    }    /**     * 获取当前item的类型     * @param position     * @return     */    @Override    public int getItemViewType(int position) {        int head = 0;        for (Type type : mList) {            int size = type.size();            int current = position - head;            if (current == 0) {                return TYPE_HEADER;            }            head += size;        }        return TYPE_ITEM;    }    /**     * 判断当前的item是否可以点击     * @param position     * @return     */    @Override    public boolean isEnabled(int position) {        return getItemViewType(position) != TYPE_HEADER;    }    @Override    public boolean areAllItemsEnabled() {        return false;    }    private class ViewHolder {        TextView tv1, tv2, tv3, title;    }}

最后，简单写一个测试的Activity:

public class MainActivity extends AppCompatActivity {    private ListView listView;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        listView = (ListView) findViewById(R.id.list);        List<Type> list = new ArrayList<>();        for (int i = 1; i <= 5; i++) {            Type type = new Type("标题" + i);            for (int j = 0; j < Math.random() * 6; j++) {                Data data = new Data("数据1", "数据2", "数据3");                type.addItem(data);            }            list.add(type);        }        MyAdapter adapter = new MyAdapter(this, list);        listView.setAdapter(adapter);    }}

附上两个所需的XML：
adapter.xml

<?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">    <LinearLayout        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:orientation="horizontal"        >        <ImageView            android:layout_width="70dp"            android:layout_height="70dp"            android:src="@android:drawable/btn_star_big_on"            android:scaleType="centerCrop"            />        <TextView            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:layout_marginLeft="20dp"            android:id="@+id/text1"            android:text="text"            android:textSize="17sp"            android:layout_gravity="center_vertical"            />        <TextView            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:layout_marginLeft="20dp"            android:id="@+id/text2"            android:text="text"            android:textSize="17sp"            android:layout_gravity="center_vertical"            />        <TextView            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:layout_marginLeft="20dp"            android:id="@+id/text3"            android:text="text"            android:textSize="17sp"            android:layout_gravity="center_vertical"            />    </LinearLayout></LinearLayout>

header.xml

<?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">    <TextView        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:textSize="25sp"        android:id="@+id/date"        android:background="@android:color/holo_purple"        /></LinearLayout>