android SQLite数据库使用实例

创建数据库帮助类DbHelper.java:

package com.example.db;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;

public class DbHelper extends SQLiteOpenHelper {

public DbHelper(Context context, String name, CursorFactory factory,
int version) {
super(context, name, factory, version);
// TODO Auto-generated constructor stub
}

@Override
public void onCreate(SQLiteDatabase db) {

db.execSQL("create table if not exists tb_people"+
"(_id integer primary key autoincrement,"+
"name varchar(20),"+
"phone varchar(12),"+
"mobile varchar(12),"+
"email varchar(30))");
}

@Override
public void onUpgrade(SQLiteDatabase arg0, int arg1, int arg2) {
// TODO Auto-generated method stub

}

}

主布局文件：

ch9_sqlmain.xml

<?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="所有联系人:"
android:textSize="15px"/>
<LinearLayout android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="wrap_content">
<TextView android:layout_width="40px"
android:layout_height="wrap_content"
android:text="编号"/>
<TextView android:layout_width="50px"
android:layout_height="wrap_content"
android:text="姓名"/>
<TextView android:layout_width="80px"
android:layout_height="wrap_content"
android:text="电话"/>
<TextView android:layout_width="80px"
android:layout_height="wrap_content"
android:text="手机"/>
<TextView android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="电子信箱"/>
</LinearLayout>
<ListView android:layout_width="wrap_content"
android:layout_height="fill_parent"
android:id="@+id/list_people"/>

</LinearLayout>

编写ListView的Item显示布局文件ch9_peoplelist.xml:

<?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="horizontal" >
<TextView android:id="@+id/id"
android:layout_width="40px"
android:layout_height="wrap_content"/>
<TextView android:id="@+id/name"
android:layout_width="50px"
android:layout_height="wrap_content"/>
<TextView android:id="@+id/phone"
android:layout_width="80px"
android:layout_height="wrap_content"/>
<TextView android:id="@+id/mobile"
android:layout_width="80px"
android:layout_height="wrap_content"/>
<TextView android:id="@+id/email"
android:layout_width="fill_parent"
android:layout_height="wrap_content"/>

</LinearLayout>

主活动类SqlMainActivity.java：

package com.example.ch9;

import com.example.baseexample.R;
import com.example.db.DbHelper;

import android.app.Activity;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.ContextMenu;
import android.view.ContextMenu.ContextMenuInfo;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView.AdapterContextMenuInfo;
import android.widget.ListView;
import android.widget.SimpleCursorAdapter;
import android.widget.TextView;

public class SqlMainActivity extends Activity {
private ListView list_people;
private DbHelper dbhelper;
private SQLiteDatabase db;

public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.ch9_sqlmain);

list_people = (ListView)findViewById(R.id.list_people);

dbhelper = new DbHelper(this, "Db_People", null, 1);

db = dbhelper.getReadableDatabase();
Cursor c = db.query("tb_people", new String[]{"_id","name","phone","mobile","email"}, null, null, null, null, null);
SimpleCursorAdapter adapter = new SimpleCursorAdapter(this, R.layout.ch9_peoplelist, c, new String[]{"_id","name","phone","mobile","email"}, new int[]{R.id.id,R.id.name,R.id.phone,R.id.mobile,R.id.email});

this.list_people.setAdapter(adapter);
this.registerForContextMenu(list_people);
}

public boolean onCreateOptionsMenu(Menu menu){
menu.add(Menu.NONE,Menu.FIRST+1,1,"添加").setIcon(android.R.drawable.ic_menu_add);
menu.add(Menu.NONE,Menu.FIRST+1,2,"退出").setIcon(android.R.drawable.ic_menu_delete);
return true;
}

public boolean onOptionsItemSelected(MenuItem item){
switch(item.getItemId()){
case Menu.FIRST+1:
Intent intent = new Intent();
intent.setClass(SqlMainActivity.this, AddPeopleActivity.class);
startActivity(intent);
break;
case Menu.FIRST+2:finish();
break;
}
return super.onOptionsItemSelected(item);
}

public void onCreateContextMenu(ContextMenu menu,View v,ContextMenuInfo menuInfo){
menu.setHeaderIcon(R.drawable.ic_launcher);
menu.add(0,3,0,"修改");
menu.add(0, 4, 0, "删除");
}

public boolean onContextItemSelected(MenuItem item){
AdapterContextMenuInfo menuInfo = (AdapterContextMenuInfo)item.getMenuInfo();
switch(item.getItemId()){
case 3:
String name=((TextView)menuInfo.targetView.findViewById(R.id.name)).getText().toString();
String phone=((TextView)menuInfo.targetView.findViewById(R.id.phone)).getText().toString();
String mobile=((TextView)menuInfo.targetView.findViewById(R.id.mobile)).getText().toString();
String email=((TextView)menuInfo.targetView.findViewById(R.id.email)).getText().toString();
Intent intent = new Intent();
intent.setClass(SqlMainActivity.this, AddPeopleActivity.class);
Bundle bundle = new Bundle();
bundle.putLong("id", menuInfo.id);
bundle.putString("name", name);
bundle.putString("phone", phone);
bundle.putString("mobile", mobile);
bundle.putString("email", email);
intent.putExtras(bundle);
startActivity(intent);
break;
case 4:
dbhelper = new DbHelper(this,"Db_People",null,1);
db = dbhelper.getWritableDatabase();
db.delete("tb_people", "_id=?", new String[]{menuInfo.id+""});
break;
}

return true;
}

}

布局文件ch9_addpeople.xml:

<?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" >
<LinearLayout android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<TextView android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="用户名"
android:layout_weight="2"/>
<EditText android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="@+id/edt_name"
android:layout_weight="1"/>
</LinearLayout>
<LinearLayout android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<TextView android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="联系电话"
android:layout_weight="2"/>
<EditText android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="@+id/edt_phone"
android:layout_weight="1"/>
</LinearLayout>
<LinearLayout android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<TextView android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="手机"
android:layout_weight="2"/>
<EditText android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="@+id/edt_mobile"
android:layout_weight="1"/>
</LinearLayout>
<LinearLayout android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<TextView android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="电子信箱"
android:layout_weight="2"/>
<EditText android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="@+id/edt_email"
android:layout_weight="1"/>
</LinearLayout>
<LinearLayout android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<Button android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="@+id/bt_save"
android:text="保存"
android:layout_weight="1"/>
<Button android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="@+id/bt_cancel"
android:text="取消"
android:layout_weight="1"/>
</LinearLayout>

</LinearLayout>

创建活动AddPeopleActivity.java：

package com.example.ch9;

import com.example.baseexample.R;
import com.example.db.DbHelper;

import android.app.Activity;
import android.content.ContentValues;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class AddPeopleActivity extends Activity {
private EditText edt_name;
private EditText edt_phone;
private EditText edt_mobile;
private EditText edt_email;
private Button bt_save;
String name,phone,mobile,email;
DbHelper dbhelper;
SQLiteDatabase db;
Bundle bundle;
protected void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.ch9_addpeople);

edt_name=(EditText)findViewById(R.id.edt_name);
edt_phone=(EditText)findViewById(R.id.edt_phone);
edt_mobile=(EditText)findViewById(R.id.edt_mobile);
edt_email=(EditText)findViewById(R.id.edt_email);
bt_save = (Button)findViewById(R.id.bt_save);

bundle = this.getIntent().getExtras();
if(bundle!=null){
edt_name.setText(bundle.getString("name"));
edt_phone.setText(bundle.getString("phone"));
edt_mobile.setText(bundle.getString("mobile"));
edt_email.setText(bundle.getString("email"));
}

bt_save.setOnClickListener(new Button.OnClickListener(){

@Override
public void onClick(View v) {
name = edt_name.getText().toString();
phone = edt_phone.getText().toString();
mobile = edt_mobile.getText().toString();
email = edt_email.getText().toString();

ContentValues value = new ContentValues();
value.put("name", name);
value.put("phone", phone);
value.put("mobile", mobile);
value.put("email", email);

DbHelper dbhelper = new DbHelper(AddPeopleActivity.this,"Db_People",null,1);
SQLiteDatabase db = dbhelper.getWritableDatabase();
long status;
if(bundle!=null){
status = db.update("tb_people", value, "_id=?", new String[]{bundle.getLong("id")+""});
}else{
status = db.insert("tb_people", null, value);
}
if(status!=-1){
Toast.makeText(AddPeopleActivity.this, "保存成功", Toast.LENGTH_LONG).show();
}else{
Toast.makeText(AddPeopleActivity.this, "保存失败", Toast.LENGTH_LONG).show();
}
}

});
}
}