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>