android SQLite的CRUD

activity12.java

package com.wansha; import android.app.Activity; import android.content.ContentValues; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteOpenHelper; import android.os.Bundle; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import com.wansha.db.DatabaseHelper; public class Activity12 extends Activity { private Button createDatabase; private Button updateDatabase; private Button insert; private Button update; private Button read; private Button delete; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); this.createDatabase = (Button)this.findViewById(R.id.createDatabase); this.createDatabase.setOnClickListener(new CreateDatabaseListener()); this.updateDatabase = (Button)this.findViewById(R.id.updateDatabase); this.updateDatabase.setOnClickListener(new UpdateDatabaseListener()); this.insert = (Button)this.findViewById(R.id.insert); this.insert.setOnClickListener(new InsertListener()); this.update = (Button)this.findViewById(R.id.update); this.update.setOnClickListener(new UpdateListener()); this.read = (Button)this.findViewById(R.id.read); this.read.setOnClickListener(new ReadListener()); this.delete = (Button)this.findViewById(R.id.delete); this.delete.setOnClickListener(new DeleteListener()); } class CreateDatabaseListener implements OnClickListener{ @Override public void onClick(View v) { SQLiteOpenHelper sqlite = new DatabaseHelper(Activity12.this,"sharp"); sqlite.getReadableDatabase(); } } class UpdateDatabaseListener implements OnClickListener{ @Override public void onClick(View v) { System.out.println("UpdateDatabaseListener is invoked !!!"); SQLiteOpenHelper sqlite = new DatabaseHelper(Activity12.this,"sharp",2); sqlite.getReadableDatabase(); } } class InsertListener implements OnClickListener{ @Override public void onClick(View v) { SQLiteOpenHelper sqlite = new DatabaseHelper(Activity12.this,"sharp"); SQLiteDatabase database = sqlite.getWritableDatabase(); ContentValues values = new ContentValues(); values.put("username", "xiaopeng"); database.insert("sharp", null, values); } } class UpdateListener implements OnClickListener{ @Override public void onClick(View v) { SQLiteOpenHelper sqlite = new DatabaseHelper(Activity12.this,"sharp"); SQLiteDatabase database = sqlite.getWritableDatabase(); ContentValues values = new ContentValues(); values.put("username", "pengpeng"); database.update("sharp", values, "id=?", new String[]{"2"}); } } class ReadListener implements OnClickListener{ @Override public void onClick(View v) { SQLiteOpenHelper sqlite = new DatabaseHelper(Activity12.this,"sharp"); SQLiteDatabase database = sqlite.getWritableDatabase(); Cursor cursor = database.query("sharp", new String[]{"id","username"}, null, null, null, null, null); while(cursor.moveToNext()){ String username = cursor.getString(cursor.getColumnIndex("username")); System.out.println("username---->" + username); } } } class DeleteListener implements OnClickListener{ @Override public void onClick(View v) { SQLiteOpenHelper sqlite = new DatabaseHelper(Activity12.this,"sharp"); SQLiteDatabase database = sqlite.getWritableDatabase(); database.delete("sharp", "id=?", new String[]{"1"}); } } }
main.xml

<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical" > <Button android:id="@+id/createDatabase" android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="创建数据库" /> <Button android:id="@+id/updateDatabase" android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="更新数据库" /> <Button android:id="@+id/insert" android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="插入数据" /> <Button android:id="@+id/update" android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="更新数据" /> <Button android:id="@+id/read" android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="读取数据" /> <Button android:id="@+id/delete" android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="删除数据" /> </LinearLayout>

db.execSQL("create table sharp(id integer primary key autoincrement, username varchar(255))");

创建自增长ID

DatebaseHelper.java

package com.wansha.db; import android.content.Context; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteDatabase.CursorFactory; import android.database.sqlite.SQLiteOpenHelper; public class DatabaseHelper extends SQLiteOpenHelper{ private static final int VERSION = 1; public DatabaseHelper(Context context, String name, CursorFactory factory, int version) { super(context, name, factory, version); } public DatabaseHelper(Context context, String name,int version) { this(context, name, null, version); } public DatabaseHelper(Context context, String name) { this(context, name, VERSION); } @Override public void onCreate(SQLiteDatabase db) { System.out.println("create table is invoked !!!"); db.execSQL("create table sharp(id integer primary key autoincrement, username varchar(255))"); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { System.out.println("update table is invoked !!!"); } }