android sql语句博客,通过SQL语句查询
在main.xml中:
encoding="utf-8"?>
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/mylayout"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:gravity="center_horizontal">
android:id="@+id/findBut"
android:layout_marginTop="8dp"
android:background="#0066ff"
android:textColor="#ffffff"
android:layout_width="100dp"
android:layout_height="40dp"
android:text="查詢?nèi)繑?shù)據(jù)" />
在MyDatabaseHelper.java類中:
package com.li.sqlite;
//數(shù)據(jù)庫的輔助操作類
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class MyDatabaseHelper extends SQLiteOpenHelper {
private static final String DATABASENAME =
"liyewen.db" ;
private static final int DATABASERVERSION = 1
;?// 設(shè)置數(shù)據(jù)庫的版本
private static final String TABLENAME =
"mytab" ;
public MyDatabaseHelper(Context context)
{?// 用戶最關(guān)心的也肯定只是Context
super(context, DATABASENAME, null, DATABASERVERSION);
}
@Override
public void onCreate(SQLiteDatabase db) { //
創(chuàng)建數(shù)據(jù)表
String sql = "CREATE TABLE " + TABLENAME + "("
+ "id?INTEGER?PRIMARY KEY ," ?// 在SQLite中設(shè)置為Integer、PRIMARY
KEY則ID自動增長
+ "name ?VARCHAR(50) ?NOT NULL
,"
+ "birthday DATE NOT ?NULL" +
")";
db.execSQL(sql) ;?// 執(zhí)行SQL
System.out.println("****************** 創(chuàng)建:onCreate()。");
}
@Override
public void onUpgrade(SQLiteDatabase db, int
oldVersion, int newVersion) {
String sql = "DROP TABLE IF EXISTS " + TABLENAME ;
db.execSQL(sql) ;
System.out.println("****************** 更新:onUpgrade()。");
this.onCreate(db) ;
}
}
在MytabCursor.java類中:
package com.li.sqlite;
import java.util.ArrayList;
import java.util.List;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
public class MytabCursor {
private static final String TABLENAME =
"mytab" ;
private SQLiteDatabase db = null ;
public MytabCursor(SQLiteDatabase db) {
this.db = db ;
}
public
List find(){
List all = new
ArrayList() ; //
此時只是String
String sql = "SELECT id,name,birthday FROM " + TABLENAME ;
Cursor result = this.db.rawQuery(sql, null); // 執(zhí)行查詢語句
for (result.moveToFirst(); !result.isAfterLast();
result.moveToNext()) { // 采用循環(huán)的方式檢索數(shù)據(jù)
all.add("【" + result.getInt(0) + "】" + " " +
result.getString(1)
+ "," + result.getString(2));
}
this.db.close() ;
return all ;
}
}
在MySQLiteDemo.java中:
package com.li.sqlite;
import android.app.Activity;
import android.database.sqlite.SQLiteOpenHelper;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.ListView;
public class MySQLiteDemo extends Activity {
private Button findBut = null;
private SQLiteOpenHelper helper = null;
private LinearLayout mylayout = null;
@Override
public void onCreate(Bundle
savedInstanceState) {
super.onCreate(savedInstanceState);
super.setContentView(R.layout.main);
this.findBut = (Button)super.findViewById(R.id.findBut);
this.mylayout =
(LinearLayout)super.findViewById(R.id.mylayout);
this.findBut.setOnClickListener(new OnClickListenerImpl());
}
private class OnClickListenerImpl implements
OnClickListener{
public void onClick(View v) {
MySQLiteDemo.this.helper = new
MyDatabaseHelper(MySQLiteDemo.this);
ListView listView = new ListView(MySQLiteDemo.this);
listView.setAdapter( //設(shè)置數(shù)據(jù)
new
ArrayAdapter?//所有的數(shù)據(jù)是字符串
(MySQLiteDemo.this,?//上下文
android.R.layout.simple_list_item_1, //列表顯示的布局
new
MytabCursor(?//實例化查詢
MySQLiteDemo.this.helper.getReadableDatabase())?//取得SQLiteDatabase對象
.find()));?//調(diào)用find()方法,返回List
MySQLiteDemo.this.mylayout.addView(listView);
}
}
}
總結(jié)
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