动态刷新ListView

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要刷新ListView，只需要调用其适配器的notifyDataSetChanged()方法即可。

下面的例子是在“ListView的例子”的基础上演化而言，本文仅给出变化的部分。

布局文件：增加了一个按钮，动态增加一个学生记录。

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical" >        <TextView        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:text="@string/label_for_listview"/>        <ListView        android:id="@+id/list_view"        android:layout_width="fill_parent"        android:layout_height="wrap_content"/>        <Button         android:id="@+id/add_student"        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:text="@string/add_student"        /></LinearLayout>

Java代码：对之前的代码进行了重构，增加了Button的消息处理，即增加一个学生记录，然后刷新ListView：

package com.example.hellolistview;import java.util.ArrayList;import java.util.HashMap;import android.app.Activity;import android.content.Context;import android.os.Bundle;import android.view.LayoutInflater;import android.view.View;import android.view.View.OnClickListener;import android.view.ViewGroup;import android.widget.BaseAdapter;import android.widget.Button;import android.widget.ListView;import android.widget.SimpleAdapter;import android.widget.TextView;public class MainActivity extends Activity {private int student_item_id = R.layout.student_item;private String[] columnNames = new String[] { "name", "score" };private int[] ids = new int[] { R.id.student_name, R.id.student_score };private ArrayList<HashMap<String, Object>> students = new ArrayList<HashMap<String, Object>>();private int student_id = 0;private Context context = null;BaseAdapter adapter = null;    @Override    protected void onCreate(Bundle savedInstanceState) {            super.onCreate(savedInstanceState);        setContentView(R.layout.my_listview);        context = this;        student_id = 0;                ListView listView = (ListView) this.findViewById(R.id.list_view);        createStudents();                //adapter = new SimpleAdapter(this, students, student_item_id, columnNames, ids);        adapter = new AnotherAdapter();                listView.setAdapter(adapter);                Button addStudent = (Button) this.findViewById(R.id.add_student);        addStudent.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {addStudent();adapter.notifyDataSetChanged();}                });    }    private void createStudents() {for (int i = 1; i <= 10; i++) {addStudent();}    }        private void addStudent() {    HashMap<String, Object> map = null;map = new HashMap<String, Object>();map.put(columnNames[0], "student-" + student_id);map.put(columnNames[1], String.valueOf(student_id * 10));student_id++;students.add(map);}    public class AnotherAdapter extends BaseAdapter {@Overridepublic int getCount() {return students.size();}@Overridepublic Object getItem(int position) {return students.get(position);}@Overridepublic long getItemId(int position) {return position;}@Overridepublic View getView(int position, View convertView, ViewGroup parent) {if (convertView == null) {convertView = LayoutInflater.from(context).inflate(R.layout.student_item, null);}TextView studentName = (TextView) convertView.findViewById(ids[0]);TextView studentScore = (TextView) convertView.findViewById(ids[1]);studentName.setText((CharSequence) students.get(position).get(columnNames[0]));studentScore.setText((CharSequence) students.get(position).get(columnNames[1]));return convertView;}}}

运行效果：

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