AndroidSQLite增、删、查、改操作源码资源-CSDN文库

共34个文件

class：16个

xml：5个

java：4个

Android

SQLite

增、删、查、改操作源码

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在Android开发中，SQLite是一个非常重要的组件，它是一个轻量级的数据库系统，用于存储应用程序中的结构化数据。SQLite数据库支持基本的SQL语法，包括增（Insert）、删（Delete）、查（Select）和改（Update）等操作。下面将详细讲解Android中如何使用SQLite进行这些操作，并提供相关的源码解析。 1. **创建SQLite数据库** 在Android中，我们通常通过`SQLiteOpenHelper`的子类来创建和管理SQLite数据库。我们需要在子类中重写`onCreate()`方法，用于创建数据库表结构。例如： ```java public class DatabaseHelper extends SQLiteOpenHelper { // 数据库版本号 private static final int DATABASE_VERSION = 1; // 数据库名称 private static final String DATABASE_NAME = "MyDatabase.db"; public DatabaseHelper(Context context) { super(context, DATABASE_NAME, null, DATABASE_VERSION); } @Override public void onCreate(SQLiteDatabase db) { String CREATE_TABLE = "CREATE TABLE IF NOT EXISTS MyTable ( \ _id INTEGER PRIMARY KEY AUTOINCREMENT, \ name TEXT, \ age INTEGER)"; db.execSQL(CREATE_TABLE); } } ``` 2. **插入数据（Insert）** 插入数据使用`SQLiteDatabase`的`insert()`方法。以下代码展示了如何插入一条新的记录： ```java SQLiteDatabase db = new DatabaseHelper(context).getWritableDatabase(); ContentValues contentValues = new ContentValues(); contentValues.put("name", "John"); contentValues.put("age", 25); long insertedId = db.insert("MyTable", null, contentValues); db.close(); ``` 3. **查询数据（Select）** 查询数据使用`query()`方法，可以根据条件进行选择性查询。以下代码展示了如何查询所有记录： ```java db = new DatabaseHelper(context).getReadableDatabase(); Cursor cursor = db.query("MyTable", null, null, null, null, null, null); while (cursor.moveToNext()) { int id = cursor.getInt(cursor.getColumnIndex("_id")); String name = cursor.getString(cursor.getColumnIndex("name")); int age = cursor.getInt(cursor.getColumnIndex("age")); Log.d("Data", "ID: " + id + ", Name: " + name + ", Age: " + age); } cursor.close(); db.close(); ``` 4. **更新数据（Update）** 更新数据使用`update()`方法，同样需要指定更新的条件。以下代码展示了如何根据ID更新一条记录： ```java contentValues.clear(); contentValues.put("age", 30); int updatedRows = db.update("MyTable", contentValues, "_id = ?", new String[]{"1"}); db.close(); ``` 5. **删除数据（Delete）** 删除数据使用`delete()`方法，可以按条件删除。以下代码展示了如何删除ID为1的记录： ```java int deletedRows = db.delete("MyTable", "_id = ?", new String[]{"1"}); db.close(); ``` 以上就是Android中SQLite数据库的基本操作，包括创建、插入、查询、更新和删除。这些操作通常与用户交互或在应用程序的后台运行，以处理和存储应用程序的数据。在实际项目中，为了提高效率和减少错误，通常会封装成DAO（Data Access Object）类，提供更抽象的接口供其他组件调用。通过理解这些源码，你可以更好地掌握Android应用中的数据管理。

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Android SQLite 增、删、查、改操作源码.zip （34个子文件）

Android SQLite 增、删、查、改操作源码

SQLTest

AndroidManifest.xml 670B

res

layout

listview.xml 813B

main.xml 2KB

drawable-ldpi

icon.png 2KB

drawable-mdpi

icon.png 3KB

drawable-hdpi

icon.png 4KB

values

strings.xml 425B

array.xml 210B

src

com

test

CityBean.java 593B

SQLDemo.java 8KB

SQLiteHelper.java 1KB

bin

com

test

SQLDemo$ListAdapter$1.class 2KB

SQLDemo$1.class 1KB

R.class 499B

CityBean.class 973B

R$layout.class 396B

R$attr.class 310B

SQLDemo.class 5KB

R$id.class 663B

R$array.class 362B

SQLDemo$2.class 2KB

SQLDemo$3.class 3KB

R$string.class 569B

SQLiteHelper.class 2KB

R$drawable.class 370B

SQLDemo$ListAdapter.class 2KB

SQLDemo$4.class 2KB

classes.dex 13KB

SQLTest.apk 20KB

resources.ap_ 12KB

.classpath 273B

assets

default.properties 449B

.project 810B

gen

com

test

R.java 2KB

package com.test; import java.util.ArrayList; import java.util.List; import android.app.Activity; import android.content.ContentValues; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.os.Bundle; import android.view.View; import android.view.ViewGroup; import android.widget.AdapterView; import android.widget.BaseAdapter; import android.widget.Button; import android.widget.EditText; import android.widget.ListView; import android.widget.TextView; /** * 本例实现SQLite数据库增加、删除、修改、模糊查询操作。这里不是最好的实现方法, * 如想研究SQL如何封装，请详细查看SQLiteDatebase类. * 查看SQL语句：String sql = SQLiteQueryBuilder.buildQueryString(); * 希望机友们多交流心得! * @author ytm0220@163.com */ public class SQLDemo extends Activity { private static String DB_NAME = "mycity.db"; private static int DB_VERSION = 1; private static int POSTION; private ListView listview; private Cursor cursor; private SQLiteDatabase db; private SQLiteHelper dbHelper; private ListAdapter listAdapter; private EditText etCity; private EditText etCode; private Button bt_add; private Button bt_modify; private Button bt_query; private List<CityBean> cityList = new ArrayList<CityBean>(); /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); etCity = (EditText) findViewById(R.id.etCity); etCode = (EditText) findViewById(R.id.etCode); bt_add = (Button) findViewById(R.id.bt_add); bt_modify = (Button) findViewById(R.id.bt_modify); bt_query = (Button) findViewById(R.id.bt_query); try{ /* 初始化并创建数据库 */ dbHelper = new SQLiteHelper(this, DB_NAME, null, DB_VERSION); /* 创建表 */ db = dbHelper.getWritableDatabase(); //调用SQLiteHelper.OnCreate() /* 查询表，得到cursor对象 */ cursor = db.query(SQLiteHelper.TB_NAME, null, null, null, null, null, CityBean.CODE + " DESC"); cursor.moveToFirst(); while(!cursor.isAfterLast() && (cursor.getString(1) != null)){ CityBean city = new CityBean(); city.setId(cursor.getString(0)); city.setCity(cursor.getString(1)); city.setCode(cursor.getString(2)); cityList.add(city); cursor.moveToNext(); } }catch(IllegalArgumentException e){ //当用SimpleCursorAdapter装载数据时，表ID列必须是_id，否则报错column '_id' does not exist e.printStackTrace(); //当版本变更时会调用SQLiteHelper.onUpgrade()方法重建表注：表以前数据将丢失 ++ DB_VERSION; dbHelper.onUpgrade(db, --DB_VERSION, DB_VERSION); // dbHelper.updateColumn(db, SQLiteHelper.ID, "_"+SQLiteHelper.ID, "integer"); } listview = (ListView)findViewById(R.id.listView); listAdapter = new ListAdapter(); listview.setAdapter(listAdapter); listview.setOnItemClickListener(new ListView.OnItemClickListener(){ @Override public void onItemClick(AdapterView<?> parent, View view, int postion, long arg3) { setSelectedValues(postion); } }); /* 插入表数据并ListView显示更新 */ bt_add.setOnClickListener(new Button.OnClickListener(){ @Override public void onClick(View arg0) { if(etCity.getText().length() > 1 && etCode.getText().length() >1){ ContentValues values = new ContentValues(); values.put(CityBean.CITY, etCity.getText().toString().trim()); values.put(CityBean.CODE, etCode.getText().toString().trim()); //插入数据用ContentValues对象也即HashMap操作,并返回ID号 Long cityID = db.insert(SQLiteHelper.TB_NAME, CityBean.ID, values); CityBean city = new CityBean(); city.setId(""+cityID); city.setCity(etCity.getText().toString().trim()); city.setCode(etCode.getText().toString().trim()); cityList.add(city); listview.setAdapter(new ListAdapter()); resetForm(); } } }); /* 查询表，模糊条件查询 */ bt_query.setOnClickListener(new Button.OnClickListener(){ @Override public void onClick(View view) { cityList.removeAll(cityList); String sql = null; String sqlCity = etCity.getText().length() > 0 ? CityBean.CITY + " like '%" + etCity.getText().toString().trim() + "%'" : ""; String sqlCode = etCode.getText().length() > 0 ? CityBean.CITY + " like '%" + etCity.getText().toString().trim() + "%'" : ""; if( (!"".equals(sqlCity)) && (!"".equals(sqlCode)) ){ sql = sqlCity + " and" + sqlCode; }else if(!"".equals(sqlCity)){ sql = sqlCity; }else if(!"".equals(sqlCode)){ sql = sqlCode; } cursor = db.query(true, SQLiteHelper.TB_NAME, new String[]{CityBean.ID, CityBean.CITY, CityBean.CODE}, sql, null, null, null, null, null); cursor.moveToFirst(); while(!cursor.isAfterLast() && (cursor.getString(1) != null)){ CityBean city = new CityBean(); city.setId(cursor.getString(0)); city.setCity(cursor.getString(1)); city.setCode(cursor.getString(2)); cityList.add(city); cursor.moveToNext(); } listview.setAdapter(new ListAdapter()); resetForm(); } }); /* 修改表数据 */ bt_modify.setOnClickListener(new Button.OnClickListener(){ @Override public void onClick(View arg0) { ContentValues values = new ContentValues(); values.put(CityBean.CITY, etCity.getText().toString().trim()); values.put(CityBean.CODE, etCode.getText().toString().trim()); db.update(SQLiteHelper.TB_NAME, values, CityBean.ID + "=" + cityList.get(POSTION).getId(), null); cityList.get(POSTION).setCity(etCity.getText().toString().trim()); cityList.get(POSTION).setCode(etCode.getText().toString().trim()); listview.setAdapter(new ListAdapter()); resetForm(); } }); } /* 设置选中ListView的值 */ public void setSelectedValues(int postion){ POSTION = postion; etCity.setText(cityList.get(postion).getCity()); etCode.setText(cityList.get(postion).getCode()); } /* 重值form */ public void resetForm(){ etCity.setText(""); etCode.setText(""); } @Override protected void onDestroy() { db.delete(SQLiteHelper.TB_NAME, null, null); super.onDestroy(); } private class ListAdapter extends BaseAdapter{ public ListAdapter(){ super(); } @Override public int getCount() { // TODO Auto-generated method stub return cityList.size(); } @Override public Object getItem(int postion) { // TODO Auto-generated method stub return postion; } @Override public long getItemId(int postion) { // TODO Auto-generated method stub return postion; } @Override public View getView(final int postion, View view, ViewGroup parent) { view = getLayoutInflater().inflate(R.layout.listview, null); TextView tv = (TextView) view.findViewById(R.id.tvCity); tv.setText("" + cityList.get(postion).getCity()); TextView bu = (TextView) view.findViewById(R.id.btRemove); bu.setText(R.string.delete); bu.setId(Integer.parseInt(cityList.get(postion).getId())); /* 删除表数据 */ bu.setOnClickListener(new Button.OnClickListener(){ @Override public void onClick(View view) { try{ db.delete(SQLiteHelper.TB_NAME, CityBean.ID + "=" + view.getId(), null); cityList.remove(postion); listview.setAdapter(new ListAdapter()); }catch(Exception e){ e.printStackTrace(); } } }); return view; } } }

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