iojsioi 发表于 2016-11-29 07:48:23

android SQLite查询

1.package com.eoeAndroid.SQLite;   
import android.app.Activity;   
import android.content.Context;   
import android.database.Cursor;   
import android.database.SQLException;   
import android.database.sqlite.SQLiteDatabase;   
import android.database.sqlite.SQLiteOpenHelper;   
import android.os.Bundle;   
import android.util.Log;   
import android.view.View;   
import android.view.View.OnClickListener;   
import android.widget.Button;   
public class ActivityMain extends Activity {   
OnClickListener listener1 = null;   
OnClickListener listener2 = null;   
OnClickListener listener3 = null;   
OnClickListener listener4 = null;   
OnClickListener listener5 = null;   
Button button1;   
Button button2;   
Button button3;   
Button button4;   
Button button5;   
DatabaseHelper mOpenHelper;   
private static final String DATABASE_NAME = "dbForTest.db";   
private static final int DATABASE_VERSION = 1;   
private static final String TABLE_NAME = "diary";   
private static final String TITLE = "title";   
private static final String BODY = "body";   
private static class DatabaseHelper extends SQLiteOpenHelper {   
DatabaseHelper(Context context) {   
super(context, DATABASE_NAME, null, DATABASE_VERSION);   
}   
@Override
public void onCreate(SQLiteDatabase db) {   
String sql = "CREATE TABLE " + TABLE_NAME + " (" + TITLE   
+ " text not null, " + BODY + " text not null " + ");";   
Log.i("haiyang:createDB=", sql);   
Log.v("lunzi", sql);   
db.execSQL(sql);   
}   
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {   
}   
}   
@Override
public void onCreate(Bundle savedInstanceState) {   
super.onCreate(savedInstanceState);   
setContentView(R.layout.main);   
prepareListener();   
initLayout();   
mOpenHelper = new DatabaseHelper(this);   
}   
private void initLayout() {   
button1 = (Button) findViewById(R.id.button1);   
button1.setOnClickListener(listener1);   
button2 = (Button) findViewById(R.id.button2);   
button2.setOnClickListener(listener2);   
button3 = (Button) findViewById(R.id.button3);   
button3.setOnClickListener(listener3);   
button4 = (Button) findViewById(R.id.button4);   
button4.setOnClickListener(listener4);   
button5 = (Button) findViewById(R.id.button5);   
button5.setOnClickListener(listener5);   
}   
private void prepareListener() {   
listener1 = new OnClickListener() {   
public void onClick(View v) {   
CreateTable();   
}   
};   
listener2 = new OnClickListener() {   
public void onClick(View v) {   
dropTable();   
}   
};   
listener3 = new OnClickListener() {   
public void onClick(View v) {   
insertItem();   
}   
};   
listener4 = new OnClickListener() {   
public void onClick(View v) {   
deleteItem();   
}   
};   
listener5 = new OnClickListener() {   
public void onClick(View v) {   
showItems();   
}   
};   
}   
/*
* 重新建立数据表
*/
private void CreateTable() {   
SQLiteDatabase db = mOpenHelper.getWritableDatabase();   
String sql = "CREATE TABLE " + TABLE_NAME + " (" + TITLE   
+ " text not null, " + BODY + " text not null " + ");";   
Log.i("haiyang:createDB=", sql);   
Log.v("lunzi", sql);   
try {   
db.execSQL("DROP TABLE IF EXISTS diary");   
db.execSQL(sql);   
setTitle("数据表成功重建");   
} catch (SQLException e) {   
setTitle("数据表重建错误");   
}   
}   
/*
* 删除数据表
*/
private void dropTable() {   
SQLiteDatabase db = mOpenHelper.getWritableDatabase();   
String sql = "drop table " + TABLE_NAME;   
Log.v("lunzi", sql);   
try {   
db.execSQL(sql);   
setTitle("数据表成功删除:" + sql);   
} catch (SQLException e) {   
setTitle("数据表删除错误");   
}   
}   
/*
* 插入两条数据
*/
private void insertItem() {   
SQLiteDatabase db = mOpenHelper.getWritableDatabase();   
String sql1 = "insert into " + TABLE_NAME + " (" + TITLE + ", " + BODY   
+ ") values('haiyang', 'android的发展真是迅速啊');";   
String sql2 = "insert into " + TABLE_NAME + " (" + TITLE + ", " + BODY   
+ ") values('icesky', 'android的发展真是迅速啊');";   
try {   
Log.i("haiyang:sql1=", sql1);   
Log.v("lunzi", sql1);   
Log.i("haiyang:sql2=", sql2);   
Log.v("lunzi", sql2);   
db.execSQL(sql1);   
db.execSQL(sql2);   
setTitle("插入两条数据成功");   
} catch (SQLException e) {   
setTitle("插入两条数据失败");   
}   
}   
/*
* 删除其中的一条数据
*/
private void deleteItem() {   
try {   
SQLiteDatabase db = mOpenHelper.getWritableDatabase();   
db.delete(TABLE_NAME, " title = 'haiyang'", null);   
setTitle("删除title为haiyang的一条记录");   
} catch (SQLException e) {   
}   
}   
/*
* 在屏幕的title区域显示当前数据表当中的数据的条数。
*/
private void showItems() {   
SQLiteDatabase db = mOpenHelper.getReadableDatabase();   
String col[] = { TITLE, BODY };   
Cursor cur = db.query(TABLE_NAME, col, null, null, null, null, null);   
Integer num = cur.getCount();   
cur.moveToFirst();   
while (!cur.isAfterLast()) {   
Log.v("lunzi", "cols:"+cur.getString(0)+"-"+cur.getString(1));   
System.out.println("cols:"+cur.getString(0)+"-"+cur.getString(1));   
cur.moveToNext();   
}   
db.close();   
/*for (int i=0;i<num;i++) {
Log.v("lunzi", cur.getString(i));
}*/
setTitle(Integer.toString(num) + " 条记录");   
}   
}
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