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本示例说明:
1.自定义listview条目样式,自定义listview显示列数的多少,灵活与数据库中字段绑定.
2.实现对DB的增删改查,并且操作后listview自动刷新.
3.响应用户操作点击事件,示例中展示单击时取出主键Id和其他内容.
4.响应用户操作长按事件,示例中展示长按时根据主键Id来编辑和删除数据.
5.表现层与数据处理层分开,不依赖于cursor(使用cursor不易表现和业务分离),支持接口编程.
6.使用数据库处理框架AHibernate灵活操作sqlite数据库,详见:
http://blog.csdn.net/lk_blog/article/details/7455992
本示例效果图:
列出主要代码:
1.list.xml:
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<?xml version="1.0" encoding="UTF-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/child"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#E3D25E"
android:orientation="horizontal" >
<!-- 若想隐藏id加入此属性: android:visibility="gone",这样做有点类似于Html中hidden域 -->
<TextView
android:id="@+id/idTo"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#ff0000" />
<TextView
android:id="@+id/nameTo"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:paddingBottom="5px"
android:paddingLeft="50px"
android:paddingTop="5px"
android:text="No data"
android:textColor="#0000ff"
android:textSize="20sp" />
<TextView
android:id="@+id/ageTo"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:paddingBottom="5px"
android:paddingLeft="50px"
android:paddingTop="5px"
android:text="No data"
android:textColor="#00ff00"
android:textSize="20sp" />
</LinearLayout> |
2.MainActivity.java:
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package com.tgb.lk.listview;
import java.util.List;
import java.util.Map;
import com.tgb.lk.demo.dao.StudentDao;
import com.tgb.lk.demo.dao.impl.StudentDaoImpl;
import com.tgb.lk.demo.model.Student;
import com.tgb.lk.listview.R;
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.ContextMenu;
import android.view.MenuItem;
import android.view.View;
import android.view.ContextMenu.ContextMenuInfo;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;
import android.widget.Toast;
import android.widget.AdapterView.AdapterContextMenuInfo;
import android.widget.AdapterView.OnItemClickListener;
/**
* 欢迎访问我的博客进行对代码交流: http://blog.csdn.net/lk_blog
* 数据库处理使用AHibernate框架,详见:http://blog.csdn.net/lk_blog/article/details/7455992
* @author likun
*/
public class MainActivity extends Activity {
private static final int ITEM_MODIFY = 1;
private static final int ITEM_DELETE = 2;
// 定义接口
private StudentDao dao = null;
private ListView lv = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// 添加
Button btnAdd = (Button) findViewById(R.id.btnAdd);
btnAdd.setOnClickListener(listener);
// 显示前3条数据
Button btnShow = (Button) findViewById(R.id.btnShow);
btnShow.setOnClickListener(listener);
// 删除数据
Button btnClear = (Button) findViewById(R.id.btnClear);
btnClear.setOnClickListener(listener);
lv = (ListView) findViewById(R.id.lvStudent);
// 设置在条目上单击监听器
lv.setOnItemClickListener(itemListener);
// 设置长按事件
registerForContextMenu(lv);
// 显示所有数据
showData(-1);
}
// 显示数据,num小于等于0时显示所有数据,num大于0时显示前N条.
private void showData(int num) {
dao = (dao == null ? new StudentDaoImpl(this) : dao);
List<Map<String, String>> data = null;
if (num <= 0) { // 显示所有学生,调用dao层接口
data = dao.queryAllStudent();
} else {// 显示前N个学生,调用dao层接口
data = dao.queryTopN(num);
}
SimpleAdapter adapter = buildListAdapter(this, data);
lv.setAdapter(adapter);
}
// 构建adapter.
public SimpleAdapter buildListAdapter(Context context,
List<Map<String, String>> data) {
SimpleAdapter adapter = new SimpleAdapter(context, data, R.layout.list,
new String[] { "_id", "name", "age" }, new int[] { R.id.idTo,
R.id.nameTo, R.id.ageTo });
return adapter;
}
// 初始化数据
OnClickListener listener = new OnClickListener() {
@Override
public void onClick(View v) {
dao = (dao == null ? new StudentDaoImpl(MainActivity.this) : dao);
switch (v.getId()) {
case R.id.btnAdd:
// 添加学生
Student student1 = new Student();
student1.setName("lk");
student1.setAge(26);
dao.insert(student1);
Student student2 = new Student();
student2.setName("cls");
student2.setAge(26);
dao.insert(student2);
Student student3 = new Student();
student3.setName("lb");
student3.setAge(27);
dao.insert(student3);
showData(-1);
break;
case R.id.btnShow:
// 显示前3条数据
showData(3);
break;
case R.id.btnClear:
// 删除所有数据
dao.deleteData();
// 显示所有数据
showData(-1);
break;
default:
break;
}
}
};
// 条目上单击处理方法.
OnItemClickListener itemListener = new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position,
long id) {
// 这里的view是我们在list.xml中定义的LinearLayout对象.
// 所以可以通过findViewById方法可以找到list.xml中定义的它的子对象,如下:
TextView stuId = (TextView) view.findViewById(R.id.idTo);
TextView stuName = (TextView) view.findViewById(R.id.nameTo);
TextView stuAge = (TextView) view.findViewById(R.id.ageTo);
toastShow("学号:" + stuId.getText().toString() + "; 姓名:"
+ stuName.getText().toString() + "; 年龄:"
+ stuAge.getText().toString());
}
};
// 封装Toast,一方面调用简单,另一方面调整显示时间只要改此一个地方即可.
public void toastShow(String text) {
Toast.makeText(MainActivity.this, text, 1000).show();
}
// 长按时显示的菜单
@Override
public void onCreateContextMenu(ContextMenu menu, View v,
ContextMenuInfo menuInfo) {
menu.setHeaderTitle("请选择操作");
menu.add(0, ITEM_MODIFY, 0, "编辑");
menu.add(0, ITEM_DELETE, 1, "删除");
}
// 响应编辑和删除事件处理
public boolean onContextItemSelected(MenuItem item) {
AdapterContextMenuInfo info = (AdapterContextMenuInfo) item
.getMenuInfo();
// info.targetView得到list.xml中的LinearLayout对象.
String stuId = ((TextView) info.targetView.findViewById(R.id.idTo))
.getText().toString();
if (!TextUtils.isEmpty(stuId)) {
int id = Integer.parseInt(stuId);
dao = (dao == null ? new StudentDaoImpl(this) : dao);
switch (item.getItemId()) {
case ITEM_MODIFY:
// 编辑数据
toastShow("编辑" + stuId);
// 此方法定义在AHibernate中.更多使用示例见http://blog.csdn.net/lk_blog/article/details/7455992
Student student = dao.get(id);
student.setName("李坤");
student.setAge(26);
dao.update(student); // 此方法定义在AHibernate中.
break;
case ITEM_DELETE:
// 删除数据
toastShow("删除" + stuId);
dao.delete(id);// 此方法定义在AHibernate中.
break;
default:
break;
}
}
showData(-1);
return false;
}
} |
3.数据库处理层:StudentDaoImpl.java:
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package com.tgb.lk.demo.dao.impl;
import java.util.List;
import java.util.Map;
import com.tgb.lk.ahibernate.dao.impl.BaseDaoImpl;
import com.tgb.lk.demo.dao.StudentDao;
import com.tgb.lk.demo.model.Student;
import com.tgb.lk.demo.util.DBHelper;
import android.content.Context;
//本文数据库处理引用jar包AHibernate处理.
//AHibernate的详细使用教程示例地址: http://blog.csdn.net/lk_blog/article/details/7455992
//AHibernate源码交流地址: http://blog.csdn.net/lk_blog/article/details/7456125
//AHibernate jar包下载及源代码下载地址: http://download.csdn.net/detail/lk_blog/4222048
public class StudentDaoImpl extends BaseDaoImpl<Student> implements StudentDao {
public StudentDaoImpl(Context context) {
super(new DBHelper(context));
}
// 返回一个List,List中的对象是以sql中的列的小写形式为key的Map.(本例中 _id,name,age为key)
public List<Map<String, String>> queryAllStudent() {
String sql = "select _id, name,age from t_student";
return super.query2MapList(sql, null);
}
// 返回一个List,List中的对象是以sql中的列的小写形式为key的Map.(本例中 _id,name,age为key)
public List<Map<String, String>> queryTopN(int num) {
String sql = "select _id, name,age from t_student limit ?";
return super.query2MapList(sql, new String[] { String.valueOf(num) });
}
public void deleteData() {
String sql = "delete from t_student";
super.execSql(sql, null);
}
} |
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