用户点击ListView中的item时,有的时候我们想要选中的item高亮显示,以便提醒用户。原本以为只需要简单设置就能实现,但是并非如此。下面我们来介绍如何让选中的item高亮显示。
方法一:简单实现
此方法的思路就是在ListView的 OnItemClickListener 中,得到当前点击的View ,将其保存在Tag信息中,设置背景色为红色;如果tag信息存在的话,说明用户又单击了其他的View,这个时候将背景色取消即可,代码如下:
//item绑定菜品列表单击监听器
listDishes.setOnItemClickListener(new OnItemClickListener(){
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
if (((ListView)parent).getTag() != null){
((View)((ListView)parent).getTag()).setBackgroundDrawable(null);
}
((ListView)parent).setTag(view);
view.setBackgroundColor(Color.RED);
}
});
优点:实现简单
缺点:无法外部调用,比如我们想要实现点击按钮,listview自动选中下一个item
方法二: 为ListView实现自定义的适配器
1.我们需要为ListView实现一个自定义的适配器,复写其中的getView方法。如果你不知道怎么做,推荐你先好好阅读一下这里:Android开发之ListView 适配器(Adapter)优化
2.适配器中有一个成员变量,用于接收从外部传进来位置信息
3.在适配器的getView方法中,将用户点击position位置处的View背景设置为屎黄色
参考代码如下:
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import tgb.com.R;
import android.app.Activity;
import android.content.Context;
import android.graphics.Color;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.AdapterView.OnItemClickListener;
public class DemoActivity extends Activity {
//显示具体菜品
private ListView listDishes = null;
//具体菜品listview适配器
private MyAdapter myAdapter;
//列表,用来存放类别下的菜品
List<HashMap<String, String>> data;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.menu);
//取得所有的菜品
data = this.getDishes();
myAdapter = new MyAdapter(this);
//寻找菜类别控件
listDishes = (ListView)findViewById(R.id.listDishes);
//设置适配器
listDishes.setAdapter(myAdapter);
//绑定菜品列表单击监听器
listDishes.setOnItemClickListener(new OnItemClickListener(){
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
myAdapter.setSelectItem(5);
myAdapter.notifyDataSetInvalidated();
}
});
}
/**
* 获得菜品名称
* @return
*/
public List<HashMap<String, String>> getDishes() {
//声明一个哈希数组
ArrayList<HashMap<String, String>> list = new ArrayList<HashMap<String, String>>();
HashMap<String, String> map1 = new HashMap<String, String>();
HashMap<String, String> map2 = new HashMap<String, String>();
HashMap<String, String> map3 = new HashMap<String, String>();
HashMap<String, String> map4 = new HashMap<String, String>();
HashMap<String, String> map5 = new HashMap<String, String>();
HashMap<String, String> map6 = new HashMap<String, String>();
HashMap<String, String> map7 = new HashMap<String, String>();
HashMap<String, String> map8 = new HashMap<String, String>();
//加载菜品信息
map1.put("dish_name", "鱼香肉丝");
map1.put("dish_price", "5元");
map2.put("dish_name", "麻婆豆腐");
map2.put("dish_price", "6元");
map3.put("dish_name", "茅台十五年");
map3.put("dish_price", "2580元");
map4.put("dish_name", "考利干白");
map4.put("dish_price", "168元");
map5.put("dish_name", "汉诺香槟");
map5.put("dish_price", "568元");
map6.put("dish_name", "张裕香槟");
map6.put("dish_price", "168元");
map7.put("dish_name", "杰克丹尼");
map7.put("dish_price", "35元/杯");
map8.put("dish_name", "伏特加");
map8.put("dish_price", "50元/杯");
//添加进列表中
list.add(map1);
list.add(map2);
list.add(map3);
list.add(map4);
list.add(map5);
list.add(map6);
list.add(map7);
list.add(map8);
return list;
}
/**
* 静态类,用于ListView中存放菜品名称和单价
* @author abing
*
*/
static class ViewHolder {
TextView textDishName;
TextView textDishPrice;
}
/**
* ListView适配器,实现有自己布局的Listview
* @author abing
*
*/
public class MyAdapter extends BaseAdapter {
private LayoutInflater mInflater;
private int selectItem=-1;
public MyAdapter(Context context) {
this.mInflater = LayoutInflater.from(context);
}
public int getCount() {
// TODO Auto-generated method stub
return data.size();
}
public Object getItem(int arg0) {
// TODO Auto-generated method stub
return data.get(arg0);
}
public long getItemId(int arg0) {
// TODO Auto-generated method stub
return arg0;
}
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder;
if (convertView == null) {
holder = new ViewHolder();
//此处布局文件详见文章最后
convertView = mInflater.inflate(R.layout.list_dishes_detail, null);
holder.textDishName = (TextView) convertView.findViewById(R.id.dish_name);
holder.textDishPrice = (TextView) convertView.findViewById(R.id.dish_price);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
holder.textDishName.setText(data.get(position).get("dish_name"));
holder.textDishPrice.setText(data.get(position).get("dish_price"));
//如果位置相同则设置背景为黄色
if (position == selectItem) {
convertView.setBackgroundColor(Color.YELLOW);
}
else {
convertView.setBackgroundColor(Color.TRANSPARENT);
}
return convertView;
}
public void setSelectItem(int selectItem) {
this.selectItem = selectItem;
}
}
}
R.layout.list_dishes_detail 布局文件如下
<?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="fill_parent"
android:paddingTop="1dip"
android:paddingBottom="1dip"
android:paddingLeft="10dip"
android:paddingRight="10dip"
>
<TextView
android:id="@+id/dish_name"
android:layout_width="100dip"
android:layout_height="30dip"
android:textSize="11pt"
android:singleLine="true"
/>
<TextView
android:id="@+id/dish_price"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:gravity="right"
android:textSize="11pt"
android:singleLine="true"
/>
</LinearLayout>
优点:功能强大,灵活
缺点:实现较为复杂,新手需要耐心调试
最终效果如图: