下面是最原始的方法,用SQL语句操作数据库。后面的“Android中SQLite数据库操作(2)——SQLiteOpenHelper类”将介绍一种常用的android封装操作SQLite的工具类。
MainActivity.java
package com.example.sqlitetest; import android.app.Activity; import android.database.Cursor; import android.database.SQLException; import android.database.sqlite.SQLiteDatabase; import android.os.Bundle; import android.support.v4.widget.CursorAdapter; import android.support.v4.widget.SimpleCursorAdapter; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.EditText; import android.widget.ListView; public class MainActivity extends Activity { SQLiteDatabase db; Button bn = null; ListView listView; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); //创建或打开数据库 //如果my.db3存在则打开该数据库,如果不存在先创建my.db3文件再打开 /* SQLite数据库只是一个文件 从本质上来看,SQLite的数据库操作方式是对文件的操作。 */ db = SQLiteDatabase.openOrCreateDatabase(this.getFilesDir().toString() + "my.db3", null); listView = (ListView) findViewById(R.id.show); bn = (Button) findViewById(R.id.ok); bn.setOnClickListener(new OnClickListener() { @Override public void onClick(View source) { //获取用户输入 EditText titleEdit = (EditText) findViewById(R.id.title); EditText contentEdit = (EditText) findViewById(R.id.content); String title = titleEdit.getText().toString(); String content = contentEdit.getText().toString(); try { insertData(db, title, content); Cursor cursor = db.rawQuery("select * from news_inf", null); inflateList(cursor); } catch (SQLException se) { //执行DDL创建数据表 db.execSQL("create table news_inf(_id integer" + " primary key autoincrement," + " news_title varchar(50)," + " news_content varchar(255))"); //执行insert语句插入数据 insertData(db, title, content); //执行查询 Cursor cursor = db.rawQuery("select * from news_inf", null); inflateList(cursor); } } }); } private void insertData(SQLiteDatabase db, String title, String content){ //执行插入语句 db.execSQL("insert into news_inf values(null, ?, ?)", new String[]{title, content}); } private void inflateList(Cursor cursor){ //填充SimpleCursorAdapter SimpleCursorAdapter adapter = new SimpleCursorAdapter(MainActivity.this, R.layout.line, cursor, new String[]{"news_title", "news_content"}, new int[]{R.id.my_title, R.id.my_content}, CursorAdapter.FLAG_REGISTER_CONTENT_OBSERVER); listView.setAdapter(adapter); } @Override protected void onDestroy() { super.onDestroy(); //退出程序时关闭SQLiteDatabase if(db != null && db.isOpen()){ db.close(); } } }
string.xml
<?xml version="1.0" encoding="utf-8"?> <resources> <string name="hello">Hello World, DBTest!</string> <string name="app_name">数据库访问测试</string> <string name="insert">插入</string> </resources>
main.xml
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" > <EditText android:id="@+id/title" android:layout_width="fill_parent" android:layout_height="wrap_content" /> <EditText android:id="@+id/content" android:layout_width="fill_parent" android:layout_height="wrap_content" android:lines="2" /> <Button android:id="@+id/ok" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/insert" /> <ListView android:id="@+id/show" android:layout_width="fill_parent" android:layout_height="fill_parent" /> </LinearLayout>
line.xml
<?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" > <EditText android:id="@+id/my_title" android:layout_width="wrap_content" android:layout_height="wrap_content" android:width="120px" /> <EditText android:id="@+id/my_content" android:layout_width="fill_parent" android:layout_height="wrap_content" /> </LinearLayout>
运行中出现了错误
有错误日志可以看到是创建表时有问题,发现是字段之间忘了空格。
最后的运行结果
有关SQLite部分知识可以参考:http://blog.csdn.net/dawanganban/article/details/9832883
源代码下载:http://download.csdn.net/detail/lxq_xsyu/5890745