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

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

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:

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();
				}
			}
			
		});
	}
}