Android 开发笔记___SQLite__基本用法
SQLiteOpenHelper
package com.example.alimjan.hello_world.dataBase; import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log; import com.example.alimjan.hello_world.bean.UserInfo; import java.util.ArrayList; public class UserDBHelper extends SQLiteOpenHelper {
private static final String TAG = "UserDBHelper";
private static final String DB_NAME = "user.db";
private static final int DB_VERSION = 1;
private static UserDBHelper mHelper = null;
private SQLiteDatabase mDB = null;
private static final String TABLE_NAME = "user_info"; private UserDBHelper(Context context) {
super(context, DB_NAME, null, DB_VERSION);
} private UserDBHelper(Context context, int version) {
super(context, DB_NAME, null, version);
} public static UserDBHelper getInstance(Context context, int version) {
if (version > 0 && mHelper == null) {
mHelper = new UserDBHelper(context, version);
} else if (mHelper == null) {
mHelper = new UserDBHelper(context);
}
return mHelper;
} public SQLiteDatabase openReadLink() {
if (mDB == null || mDB.isOpen() != true) {
mDB = mHelper.getReadableDatabase();
}
return mDB;
} public SQLiteDatabase openWriteLink() {
if (mDB == null || mDB.isOpen() != true) {
mDB = mHelper.getWritableDatabase();
}
return mDB;
} public void closeLink() {
if (mDB != null && mDB.isOpen() == true) {
mDB.close();
mDB = null;
}
} public String getDBName() {
if (mHelper != null) {
return mHelper.getDatabaseName();
} else {
return DB_NAME;
}
} @Override
public void onCreate(SQLiteDatabase db) {
Log.d(TAG, "onCreate");
String drop_sql = "DROP TABLE IF EXISTS " + TABLE_NAME + ";";
Log.d(TAG, "drop_sql:" + drop_sql);
db.execSQL(drop_sql);
String create_sql = "CREATE TABLE IF NOT EXISTS " + TABLE_NAME + " ("
+ "_id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,"
+ "name VARCHAR NOT NULL," + "age INTEGER NOT NULL,"
+ "height LONG NOT NULL," + "weight FLOAT NOT NULL,"
+ "married INTEGER NOT NULL," + "update_time VARCHAR NOT NULL"
//演示数据库升级时要先把下面这行注释
+ ",phone VARCHAR" + ",password VARCHAR"
+ ");";
Log.d(TAG, "create_sql:" + create_sql);
db.execSQL(create_sql);
} @Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
Log.d(TAG, "onUpgrade oldVersion="+oldVersion+", newVersion="+newVersion);
if (newVersion > 1) {
//Android的ALTER命令不支持一次添加多列，只能分多次添加
String alter_sql = "ALTER TABLE " + TABLE_NAME + " ADD COLUMN " + "phone VARCHAR;";
Log.d(TAG, "alter_sql:" + alter_sql);
db.execSQL(alter_sql);
alter_sql = "ALTER TABLE " + TABLE_NAME + " ADD COLUMN " + "password VARCHAR;";
Log.d(TAG, "alter_sql:" + alter_sql);
db.execSQL(alter_sql);
}
} public int delete(String condition) {
int count = mDB.delete(TABLE_NAME, condition, null);
return count;
} public int deleteAll() {
int count = mDB.delete(TABLE_NAME, "1=1", null);
return count;
} public long insert(UserInfo info) {
ArrayList<UserInfo> infoArray = new ArrayList<UserInfo>();
infoArray.add(info);
return insert(infoArray);
} public long insert(ArrayList<UserInfo> infoArray) {
long result = -1;
for (int i = 0; i < infoArray.size(); i++) {
UserInfo info = infoArray.get(i);
ArrayList<UserInfo> tempArray = new ArrayList<UserInfo>();
// 如果存在同名记录，则更新记录
// 注意条件语句的等号后面要用单引号括起来
if (info.name!=null && info.name.length()>0) {
String condition = String.format("name='%s'", info.name);
tempArray = query(condition);
if (tempArray.size() > 0) {
update(info, condition);
result = tempArray.get(0).rowid;
continue;
}
}
// 如果存在同样的手机号码，则更新记录
if (info.phone!=null && info.phone.length()>0) {
String condition = String.format("phone='%s'", info.phone);
tempArray = query(condition);
if (tempArray.size() > 0) {
update(info, condition);
result = tempArray.get(0).rowid;
continue;
}
}
// 不存在唯一性重复的记录，则插入新记录
ContentValues cv = new ContentValues();
cv.put("name", info.name);
cv.put("age", info.age);
cv.put("height", info.height);
cv.put("weight", info.weight);
cv.put("married", info.married);
cv.put("update_time", info.update_time);
cv.put("phone", info.phone);
cv.put("password", info.password);
result = mDB.insert(TABLE_NAME, "", cv);
// 添加成功后返回行号，失败后返回-1
if (result == -1) {
return result;
}
}
return result;
} public int update(UserInfo info, String condition) {
ContentValues cv = new ContentValues();
cv.put("name", info.name);
cv.put("age", info.age);
cv.put("height", info.height);
cv.put("weight", info.weight);
cv.put("married", info.married);
cv.put("update_time", info.update_time);
cv.put("phone", info.phone);
cv.put("password", info.password);
int count = mDB.update(TABLE_NAME, cv, condition, null);
return count;
} public int update(UserInfo info) {
return update(info, "rowid="+info.rowid);
} public ArrayList<UserInfo> query(String condition) {
String sql = String.format("select rowid,_id,name,age,height,weight,married,update_time," +
"phone,password from %s where %s;", TABLE_NAME, condition);
Log.d(TAG, "query sql: "+sql);
ArrayList<UserInfo> infoArray = new ArrayList<UserInfo>();
Cursor cursor = mDB.rawQuery(sql, null);
if (cursor.moveToFirst()) {
for (;; cursor.moveToNext()) {
UserInfo info = new UserInfo();
info.rowid = cursor.getLong(0);
info.xuhao = cursor.getInt(1);
info.name = cursor.getString(2);
info.age = cursor.getInt(3);
info.height = cursor.getLong(4);
info.weight = cursor.getFloat(5);
//SQLite没有布尔型，用0表示false，用1表示true
info.married = (cursor.getInt(6)==0)?false:true;
info.update_time = cursor.getString(7);
info.phone = cursor.getString(8);
info.password = cursor.getString(9);
infoArray.add(info);
if (cursor.isLast() == true) {
break;
}
}
}
cursor.close();
return infoArray;
} public UserInfo queryByPhone(String phone) {
UserInfo info = null;
ArrayList<UserInfo> infoArray = query(String.format("phone='%s'", phone));
if (infoArray.size() > 0) {
info = infoArray.get(0);
}
return info;
} }
package com.example.alimjan.hello_world.bean;
public class UserInfo {
public long rowid;
public int xuhao;
public String name;
public int age;
public long height;
public float weight;
public boolean married;
public String update_time;
public String phone;
public String password;
public UserInfo() {
rowid = 0l;
xuhao = 0;
name = "";
age = 0;
height = 0l;
weight = 0.0f;
married = false;
update_time = "";
phone = "";
password = "";
}
}
write
package com.example.alimjan.hello_world; /**
* Created by alimjan on 7/4/2017.
*/ import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.Toast;
import android.widget.AdapterView.OnItemSelectedListener; import com.example.alimjan.hello_world.bean.UserInfo;
import com.example.alimjan.hello_world.dataBase.UserDBHelper;
import com.example.alimjan.hello_world.Utils.DateUtil; public class class_4_2_2_1_write extends AppCompatActivity implements OnClickListener { private UserDBHelper mHelper;
private EditText et_name;
private EditText et_age;
private EditText et_height;
private EditText et_weight;
private boolean bMarried = false; @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.code_4_2_2_1);
et_name = (EditText) findViewById(R.id.et_name);
et_age = (EditText) findViewById(R.id.et_age);
et_height = (EditText) findViewById(R.id.et_height);
et_weight = (EditText) findViewById(R.id.et_weight);
findViewById(R.id.btn_save).setOnClickListener(this); ArrayAdapter<String> typeAdapter = new ArrayAdapter<String>(this,
R.layout.item_select, typeArray);
typeAdapter.setDropDownViewResource(R.layout.item_dropdown);
Spinner sp_married = (Spinner) findViewById(R.id.sp_married);
sp_married.setPrompt("请选择婚姻状况");
sp_married.setAdapter(typeAdapter);
sp_married.setSelection(0);
sp_married.setOnItemSelectedListener(new TypeSelectedListener()); } private String[] typeArray = {"未婚", "已婚"};
class TypeSelectedListener implements OnItemSelectedListener {
public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
bMarried = (arg2==0)?false:true;
} public void onNothingSelected(AdapterView<?> arg0) {
}
} @Override
protected void onStart() {
super.onStart();
mHelper = UserDBHelper.getInstance(this, 2);
mHelper.openWriteLink();
} @Override
protected void onStop() {
super.onStop();
mHelper.closeLink();
} @Override
public void onClick(View v) {
if (v.getId() == R.id.btn_save) {
String name = et_name.getText().toString();
String age = et_age.getText().toString();
String height = et_height.getText().toString();
String weight = et_weight.getText().toString();
if (name==null || name.length()<=0) {
showToast("请先填写姓名");
return;
}
if (age==null || age.length()<=0) {
showToast("请先填写年龄");
return;
}
if (height==null || height.length()<=0) {
showToast("请先填写身高");
return;
}
if (weight==null || weight.length()<=0) {
showToast("请先填写体重");
return;
} UserInfo info = new UserInfo();
info.name = name;
info.age = Integer.parseInt(age);
info.height = Long.parseLong(height);
info.weight = Float.parseFloat(weight);
info.married = bMarried;
info.update_time = DateUtil.getCurDateStr("yyyy-MM-dd HH:mm:ss");
mHelper.insert(info);
showToast("数据已写入SQLite数据库");
}
} private void showToast(String desc) {
Toast.makeText(this, desc, Toast.LENGTH_SHORT).show();
} public static void startHome(Context mContext) {
Intent intent = new Intent(mContext, class_4_2_2_1_write.class);
mContext.startActivity(intent);
} }
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:focusable="true"
android:focusableInTouchMode="true"
android:orientation="vertical"
android:padding="10dp" > <RelativeLayout
android:layout_width="match_parent"
android:layout_height="50dp" > <TextView
android:id="@+id/tv_name"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_alignParentLeft="true"
android:gravity="center"
android:text="姓名："
android:textColor="@color/black"
android:textSize="17sp" /> <EditText
android:id="@+id/et_name"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginBottom="5dp"
android:layout_marginTop="5dp"
android:layout_toRightOf="@+id/tv_name"
android:background="@drawable/editext_selector"
android:gravity="left|center"
android:hint="请输入姓名"
android:inputType="text"
android:maxLength="12"
android:textColor="@color/black"
android:textColorHint="@color/grey"
android:textCursorDrawable="@drawable/text_cursor"
android:textSize="17sp" />
</RelativeLayout> <RelativeLayout
android:layout_width="match_parent"
android:layout_height="50dp" > <TextView
android:id="@+id/tv_age"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_alignParentLeft="true"
android:gravity="center"
android:text="年龄："
android:textColor="@color/black"
android:textSize="17sp" /> <EditText
android:id="@+id/et_age"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginBottom="5dp"
android:layout_marginTop="5dp"
android:layout_toRightOf="@+id/tv_age"
android:background="@drawable/editext_selector"
android:gravity="left|center"
android:hint="请输入年龄"
android:inputType="number"
android:maxLength="2"
android:textColor="@color/black"
android:textColorHint="@color/grey"
android:textCursorDrawable="@drawable/text_cursor"
android:textSize="17sp" />
</RelativeLayout> <RelativeLayout
android:layout_width="match_parent"
android:layout_height="50dp" > <TextView
android:id="@+id/tv_height"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_alignParentLeft="true"
android:gravity="center"
android:text="身高："
android:textColor="@color/black"
android:textSize="17sp" /> <EditText
android:id="@+id/et_height"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginBottom="5dp"
android:layout_marginTop="5dp"
android:layout_toRightOf="@+id/tv_height"
android:background="@drawable/editext_selector"
android:gravity="left|center"
android:hint="请输入身高"
android:inputType="number"
android:maxLength="3"
android:textColor="@color/black"
android:textColorHint="@color/grey"
android:textCursorDrawable="@drawable/text_cursor"
android:textSize="17sp" />
</RelativeLayout> <RelativeLayout
android:layout_width="match_parent"
android:layout_height="50dp" > <TextView
android:id="@+id/tv_weight"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_alignParentLeft="true"
android:gravity="center"
android:text="体重："
android:textColor="@color/black"
android:textSize="17sp" /> <EditText
android:id="@+id/et_weight"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginBottom="5dp"
android:layout_marginTop="5dp"
android:layout_toRightOf="@+id/tv_weight"
android:background="@drawable/editext_selector"
android:gravity="left|center"
android:hint="请输入体重"
android:inputType="numberDecimal"
android:maxLength="5"
android:textColor="@color/black"
android:textColorHint="@color/grey"
android:textCursorDrawable="@drawable/text_cursor"
android:textSize="17sp" />
</RelativeLayout> <RelativeLayout
android:layout_width="match_parent"
android:layout_height="50dp" > <TextView
android:id="@+id/tv_married"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_alignParentLeft="true"
android:gravity="center"
android:text="婚否："
android:textColor="@color/black"
android:textSize="17sp" /> <Spinner
android:id="@+id/sp_married"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_toRightOf="@+id/tv_married"
android:gravity="left|center"
android:spinnerMode="dialog" />
</RelativeLayout> <Button
android:id="@+id/btn_save"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="保存到数据库"
android:textColor="@color/black"
android:textSize="20sp" /> </LinearLayout>
Read
package com.example.alimjan.hello_world; /**
* Created by alimjan on 7/4/2017.
*/ import java.util.ArrayList; import com.example.alimjan.hello_world.bean.UserInfo;
import com.example.alimjan.hello_world.dataBase.UserDBHelper; import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.TextView;
import android.widget.Toast; public class class_4_2_2 extends AppCompatActivity implements OnClickListener { private UserDBHelper mHelper;
private TextView tv_sqlite; @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.code_4_2_2);
tv_sqlite = (TextView) findViewById(R.id.tv_sqlite);
findViewById(R.id.btn_delete).setOnClickListener(this);
} private void readSQLite() {
if (mHelper == null) {
showToast("数据库连接为空");
return;
}
ArrayList<UserInfo> userArray = mHelper.query("1=1");
String desc = String.format("数据库查询到%d条记录，详情如下：", userArray.size());
for (int i=0; i<userArray.size(); i++) {
UserInfo info = userArray.get(i);
desc = String.format("%s\n第%d条记录信息如下：", desc, i+1);
desc = String.format("%s\n 姓名为%s", desc, info.name);
desc = String.format("%s\n 年龄为%d", desc, info.age);
desc = String.format("%s\n 身高为%d", desc, info.height);
desc = String.format("%s\n 体重为%f", desc, info.weight);
desc = String.format("%s\n 婚否为%b", desc, info.married);
desc = String.format("%s\n 更新时间为%s", desc, info.update_time);
}
if (userArray==null || userArray.size()<=0) {
desc = "数据库查询到的记录为空";
}
tv_sqlite.setText(desc);
} @Override
protected void onStart() {
super.onStart();
mHelper = UserDBHelper.getInstance(this, 2);
mHelper.openReadLink();
readSQLite();
} @Override
protected void onStop() {
super.onStop();
mHelper.closeLink();
} @Override
public void onClick(View v) {
if (v.getId() == R.id.btn_delete) {
//删除所有记录
mHelper.closeLink();
mHelper.openWriteLink();
mHelper.deleteAll();
//重新读取数据库
mHelper.closeLink();
mHelper.openReadLink();
readSQLite();
}
} private void showToast(String desc) {
Toast.makeText(this, desc, Toast.LENGTH_SHORT).show();
} public static void startHome(Context mContext) {
Intent intent = new Intent(mContext, class_4_2_2.class);
mContext.startActivity(intent);
} }
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:focusable="true"
android:focusableInTouchMode="true"
android:orientation="vertical"
android:padding="10dp" > <Button
android:id="@+id/btn_delete"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="删除所有记录"
android:textColor="@color/black"
android:textSize="20sp" /> <TextView
android:id="@+id/tv_sqlite"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingTop="10dp"
android:textColor="@color/black"
android:textSize="17sp" /> </LinearLayout>
Android 开发笔记___SQLite__基本用法的更多相关文章
- Android 开发笔记___SQLite__优化记住密码功能
package com.example.alimjan.hello_world; /** * Created by alimjan on 7/4/2017. */ import com.example ...
- 【转】Android开发笔记（序）写在前面的目录
原文:http://blog.csdn.net/aqi00/article/details/50012511 知识点分类 一方面写写自己走过的弯路掉进去的坑,避免以后再犯:另一方面希望通过分享自己的经 ...
- 【转】Android开发笔记——圆角和边框们
原文地址:http://blog.xianqu.org/2012/04/android-borders-and-radius-corners/ Android开发笔记——圆角和边框们 在做Androi ...
- [置顶] Android开发笔记(成长轨迹)
分类: 开发学习笔记2013-06-21 09:44 26043人阅读 评论(5) 收藏 Android开发笔记 1.控制台输出:called unimplemented OpenGL ES API ...
- Android开发笔记：打包数据库
对于数据比较多的控制一般会加入SQLite数据库进行数据存储,在打包时这些数据库是不自动打包到apk中的,如何创建数据库呢 方法1:将创建数据库的sql语句在SQLiteHelper继承类中实现,在第 ...
- Android开发笔记--hello world 和目录结构
原文:Android开发笔记--hello world 和目录结构 每接触一个新东西 都有一个hello world的例子. 1.新建项目 2.配置AVD AVD 没有要新建个,如果不能创建 运行SD ...
- [APP] Android 开发笔记 003-使用Ant Release 打包与keystore加密说明
接上节 [APP] Android 开发笔记 002 5. 使用ant release 打包 1)制作 密钥文件 release.keystore (*.keystore) keytool -genk ...
- [APP] Android 开发笔记 002-命令行创建默认项目结构说明
接上节:[APP] Android 开发笔记 001 4. 默认项目结构说明: 这里我使用Sublime Text 进行加载.
- Android开发笔记——以Volley图片加载、缓存、请求及展示为例理解Volley架构设计
Volley是由Google开源的.用于Android平台上的网络通信库.Volley通过优化Android的网络请求流程,形成了以Request-RequestQueue-Response为主线的网 ...
随机推荐
- JSP内置对象的实验报告，页面登陆设计
JSP内置对象的实验报告 一.实验目的: 本实验的目的是让学生掌握怎样在JSP中使用内置对象request.page.response等. 二.实验要求: 编写四个JSP 页面login.jsp.Re ...
- 使用LayUI展示数据
LayUI是一款免费,开源,轻量级的前端cms框架,适用于企业后端,能快速上手开发,集成了常用的组件,还有完善的文档和社区. 点击查看 文档地址 下载框架 使用: 1.把这个5个文件项都拷贝到项目中 ...
- HIT 1917 Peaceful Commission
这道题题意就是给你n对人,一对中编号为x,x+1,给你m对矛盾,表示这两个人不能同时选. 然后就是Two-Sat的模板题了,就是根据对称性,连边,加缩点,最后拓扑排序,求出一组可行解就可以了. #in ...
- 渣渣学QT
初学QT,自己的一些小总结,错误之处,望大神指点一二: 1,添加资源文件时想应用在界面的背景,但是发现用不了,后来才知道是没有"构建"?应该是要在构建之后才将所添加的资源文件真正的 ...
- 解决VMware下安装Ubuntu 16.04 不支持1920X1080分辨率的问题
解决方法: flashmx@ubuntu:~$ cvt # 192.07M9) hsync: 67.16 kHz; pclk: 173.00 MHz Modeline -hsync +vsync fl ...
- FPGA在AD采集中的应用
AD转换,也叫模数转换,是将模拟信号转换为数字信号.目前包括电脑CPU,ARM,FPGA,处理的信号都只能是数字信号,所以数据信号在进入处理芯片前必须要进行AD转换. 在高速的AD转换中,FPGA以其 ...
- IDL 矩阵运算
矩阵相乘,A#B表示A的列乘以B的行,要求A的行数必须跟B的列数一致 IDL> A=[[0,1,2],[3,4,5]] IDL> B=[[0,1],[2,3],[4,5]] IDL> ...
- cocos2dx - 环境配置，项目创建
准备工具 cocos2dx当前最新版本:v3.9 官网下载地址: http://www.cocos.com/download/ python 2.7x最新版本:2.7.11 官 ...
- 数组去重方法(ES6)
let arrayBefore = [1,3,3,2,1,5,2,1]; //去重之前的数组 Array.prototype.dedupe = function (){ //去重函数 返回去重后的数组 ...
- 深入浅出Diffie–Hellman
一.作者 这个密钥交换方法,由惠特菲尔德·迪菲(Bailey Whitfield Diffie).马丁·赫尔曼(Martin Edward Hellman)于1976年发表. 二.说明 它是一种安全协 ...