Android Studio 搜索现有的 sqlite 数据库
Android Studio search existing sqlite db
所以我正在开发一个应用程序，我希望用户在我的数据库中搜索食品，然后 return 使用符合搜索条件的所有食品名称的列表视图进行编辑。我已经创建了 slqite 数据库并将其添加到资产文件夹中。数据库名为foodDatabase.db
我已经像这样创建了数据库助手：
package com.example.codebind.databasedemo;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
/**
* Created by tom on 15/03/2018.
*/
public class FoodDatabaseHelper extends SQLiteOpenHelper{
public static final String DATABASE_NAME = "FoodDatabase.db";
public static final String TABLE_NAME = "dataset";
public static final String COL_1 = "ID";
public static final String COL_2 = "Food";
public static final String COL_3 = "Description";
public static final String COL_4 = "Protein";
public static final String COL_5 = "Fat";
public static final String COL_6 = "Carbohydrate";
public static final String COL_7 = "Energy";
public static final String COL_8 = "Starch";
public static final String COL_9 = "Sugar";
public static final String COL_10 = "Cholesterol";
public FoodDatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, 1);
SQLiteDatabase sqLiteDatabase = this.getWritableDatabase();
}
@Override
public void onCreate(SQLiteDatabase sqLiteDatabase) {
sqLiteDatabase.execSQL("create table " + TABLE_NAME +" (ID INTEGER
PRIMARY KEY AUTOINCREMENT,FOOD TEXT,DESCRIPTION TEXT,PROTEIN BLOB,FAT
BLOB,CARBOHYDRATE BLOB,ENERGY BLOB,STARCH BLOB,SUGAR BLOB,CHOLESTEROL BLOB)
");
}
@Override
public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {
sqLiteDatabase.execSQL("DROP TABLE IF EXISTS " +TABLE_NAME);
onCreate(sqLiteDatabase);
}
}
目前我的 MainActivity.java 是干净的。我还没接触过
我正在寻求有关如何添加侦听器的指导，以便当用户输入食物名称时，该应用程序将 return foodDatabase.db 中满足搜索查询的所有食物。
谢谢
您的搜索基础将是基于 FOOD 列的查询（我相信）。
例如SELECT * FROM dataset WHERE FOOD LIKE '%your_food%'
例如，假设您的数据库具有如下数据（请注意只有 food 和 id 列已填充数据）：-
然后查询 SELECT * FROM dataset WHERE FOOD LIKE '%mash%' 将导致：-
- 即id 为 2 和 3 的食物包含食物 mash
您可以 运行 使用 SQLiteDatabase query 方法进行此查询。 query 方法 returns 带有提取数据的 Cursor。所以你的 DatabaseHelper 中的一个方法可以是：-
public Cursor getFoodsWithProvidedFood(String provided_food) {
return this.getWritableDatabase().query(
TABLE_NAME,
null,
COL_2 + " LIKE '%" + provided_food + "%' ",
null,
null,
null,
null
);
}
将其转换为一个完整但非常基本的应用程序，您可以拥有：-
数据库助手 - FoodDatabaseHelper.java
public class FoodDatabaseHelper extends SQLiteOpenHelper {
public static final String DATABASE_NAME = "FoodDatabase.db";
public static final String TABLE_NAME = "dataset";
public static final String COL_1 = "ID";
public static final String COL_2 = "Food";
public static final String COL_3 = "Description";
public static final String COL_4 = "Protein";
public static final String COL_5 = "Fat";
public static final String COL_6 = "Carbohydrate";
public static final String COL_7 = "Energy";
public static final String COL_8 = "Starch";
public static final String COL_9 = "Sugar";
public static final String COL_10 = "Cholesterol";
SQLiteDatabase sqLiteDatabase; //<<<< Added
public FoodDatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, 1);
sqLiteDatabase = this.getWritableDatabase(); //<<<< Amended
}
//@Override
public void onNotRecommendedCreate(SQLiteDatabase sqLiteDatabase) {
sqLiteDatabase.execSQL("create table " + TABLE_NAME +
" (ID INTEGER PRIMARY KEY AUTOINCREMENT," +
"FOOD TEXT," +
"DESCRIPTION TEXT," +
"PROTEIN BLOB," +
"FAT BLOB," +
"CARBOHYDRATE BLOB," +
"ENERGY BLOB," +
"STARCH BLOB," +
"SUGAR BLOB," +
"CHOLESTEROL BLOB)");
}
@Override
public void onCreate(SQLiteDatabase db) {
String crtsql = "CREATE TABLE IF NOT EXISTS " + TABLE_NAME +
"(" +
COL_1 + " INTEGER PRIMARY KEY, " +
COL_2 + " TEXT, " +
COL_3 + " TEXT, " +
COL_4 + " BLOB, " +
COL_5 + " BLOB, " +
COL_6 + " BLOB, " +
COL_7 + " BLOB, " +
COL_8 + " BLOB, " +
COL_9 + " BLOB, " +
COL_10 + " BLOB " +
")";
db.execSQL(crtsql);
}
@Override
public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {
sqLiteDatabase.execSQL("DROP TABLE IF EXISTS " +TABLE_NAME);
onCreate(sqLiteDatabase);
}
public void insertFood(
String food,
String description,
byte[] protien,
byte[] fat,
byte[] carbohydrate,
byte[] energy,
byte[] starch,
byte[] sugar,
byte[] cholesterol) {
ContentValues cv = new ContentValues();
cv.put(COL_2,food);
cv.put(COL_3,description);
cv.put(COL_4,protien);
cv.put(COL_5,fat);
cv.put(COL_6,carbohydrate);
cv.put(COL_7,energy);
cv.put(COL_8,starch);
cv.put(COL_9,sugar);
cv.put(COL_10,cholesterol);
SQLiteDatabase db = this.getWritableDatabase();
db.insert(TABLE_NAME,null,cv);
}
public Cursor getFoodsWithProvidedFood(String provided_food) {
return this.getWritableDatabase().query(
TABLE_NAME,
null,
COL_2 + " LIKE '%" + provided_food + "%' ",
null,
null,
null,
null
);
}
}
- 备注
如果您只在一处定义 table 和列名，问题可能会更少。
- 因此更改了 onCreate
- 尽管 SQLite 中的列名是 case-insensitive，但 Cursor 的
getColumnIndex 方法（在主 activity 中使用）是 case-sensitive (IMO a错误）.
AUTOINCREMENT 并没有按照它的意思去做，而是 INTEGER PRIMARY KEY 本身创建了一个递增的列，添加 AUTOINCREMENT 是一种特殊情况，它确保 id 在间接费用。因此 AUTOINCREMENT 已被删除。
已添加两个额外的方法
insertFood 将数据插入（添加）到 数据集 table.getFoodsWithProvidedFood 如上所述。
Activity - MainActivity.java
public class MainActivity extends AppCompatActivity {
FoodDatabaseHelper foodDBHlpr;
Cursor mCsr;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
foodDBHlpr = new FoodDatabaseHelper(this);
byte[] dummy = new byte[]{0,1,2,3,4,5,6,7,8,9};
// Add some data oif none exists
if (DatabaseUtils.queryNumEntries(foodDBHlpr.getWritableDatabase(),FoodDatabaseHelper.TABLE_NAME) < 1) {
foodDBHlpr.insertFood("Fish and Chips", "The English Seaside meal",
dummy, dummy, dummy, dummy, dummy, dummy, dummy);
foodDBHlpr.insertFood("Bangers and Mash", "Yummy!!",
dummy, dummy, dummy, dummy, dummy, dummy, dummy);
foodDBHlpr.insertFood("Mashed Potatoe", "Boring",
dummy, dummy, dummy, dummy, dummy, dummy, dummy);
}
// get a Cursor with the extracted foods
mCsr = foodDBHlpr.getFoodsWithProvidedFood("Mash");
// Loop Through the Cursor
while (mCsr.moveToNext()) {
Log.d("FOODFOUND","You found the food called - " + mCsr.getString(mCsr.getColumnIndex(FoodDatabaseHelper.COL_2)));
}
if (mCsr.getCount() < 1) {
Log.d("FOODFOUND","No foods found that match the search criteria.");
}
mCsr.close(); //<<<< Should always close Cursors when done with them
}
}
日志中的结果：-
03-15 21:48:21.170 1702-1702/foodsdb.so49307874_foodsdb D/FOODFOUND: You found the food called - Bangers and Mash
03-15 21:48:21.170 1702-1702/foodsdb.so49307874_foodsdb D/FOODFOUND: You found the food called - Mashed Potatoe
所以我正在开发一个应用程序，我希望用户在我的数据库中搜索食品，然后 return 使用符合搜索条件的所有食品名称的列表视图进行编辑。我已经创建了 slqite 数据库并将其添加到资产文件夹中。数据库名为foodDatabase.db
我已经像这样创建了数据库助手：
package com.example.codebind.databasedemo;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
/**
* Created by tom on 15/03/2018.
*/
public class FoodDatabaseHelper extends SQLiteOpenHelper{
public static final String DATABASE_NAME = "FoodDatabase.db";
public static final String TABLE_NAME = "dataset";
public static final String COL_1 = "ID";
public static final String COL_2 = "Food";
public static final String COL_3 = "Description";
public static final String COL_4 = "Protein";
public static final String COL_5 = "Fat";
public static final String COL_6 = "Carbohydrate";
public static final String COL_7 = "Energy";
public static final String COL_8 = "Starch";
public static final String COL_9 = "Sugar";
public static final String COL_10 = "Cholesterol";
public FoodDatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, 1);
SQLiteDatabase sqLiteDatabase = this.getWritableDatabase();
}
@Override
public void onCreate(SQLiteDatabase sqLiteDatabase) {
sqLiteDatabase.execSQL("create table " + TABLE_NAME +" (ID INTEGER
PRIMARY KEY AUTOINCREMENT,FOOD TEXT,DESCRIPTION TEXT,PROTEIN BLOB,FAT
BLOB,CARBOHYDRATE BLOB,ENERGY BLOB,STARCH BLOB,SUGAR BLOB,CHOLESTEROL BLOB)
");
}
@Override
public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {
sqLiteDatabase.execSQL("DROP TABLE IF EXISTS " +TABLE_NAME);
onCreate(sqLiteDatabase);
}
}
目前我的 MainActivity.java 是干净的。我还没接触过
我正在寻求有关如何添加侦听器的指导，以便当用户输入食物名称时，该应用程序将 return foodDatabase.db 中满足搜索查询的所有食物。
谢谢
您的搜索基础将是基于 FOOD 列的查询（我相信）。
例如SELECT * FROM dataset WHERE FOOD LIKE '%your_food%'
例如，假设您的数据库具有如下数据（请注意只有 food 和 id 列已填充数据）：-
然后查询 SELECT * FROM dataset WHERE FOOD LIKE '%mash%' 将导致：-
- 即id 为 2 和 3 的食物包含食物 mash
您可以 运行 使用 SQLiteDatabase query 方法进行此查询。 query 方法 returns 带有提取数据的 Cursor。所以你的 DatabaseHelper 中的一个方法可以是：-
public Cursor getFoodsWithProvidedFood(String provided_food) {
return this.getWritableDatabase().query(
TABLE_NAME,
null,
COL_2 + " LIKE '%" + provided_food + "%' ",
null,
null,
null,
null
);
}
将其转换为一个完整但非常基本的应用程序，您可以拥有：-
数据库助手 - FoodDatabaseHelper.java
public class FoodDatabaseHelper extends SQLiteOpenHelper {
public static final String DATABASE_NAME = "FoodDatabase.db";
public static final String TABLE_NAME = "dataset";
public static final String COL_1 = "ID";
public static final String COL_2 = "Food";
public static final String COL_3 = "Description";
public static final String COL_4 = "Protein";
public static final String COL_5 = "Fat";
public static final String COL_6 = "Carbohydrate";
public static final String COL_7 = "Energy";
public static final String COL_8 = "Starch";
public static final String COL_9 = "Sugar";
public static final String COL_10 = "Cholesterol";
SQLiteDatabase sqLiteDatabase; //<<<< Added
public FoodDatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, 1);
sqLiteDatabase = this.getWritableDatabase(); //<<<< Amended
}
//@Override
public void onNotRecommendedCreate(SQLiteDatabase sqLiteDatabase) {
sqLiteDatabase.execSQL("create table " + TABLE_NAME +
" (ID INTEGER PRIMARY KEY AUTOINCREMENT," +
"FOOD TEXT," +
"DESCRIPTION TEXT," +
"PROTEIN BLOB," +
"FAT BLOB," +
"CARBOHYDRATE BLOB," +
"ENERGY BLOB," +
"STARCH BLOB," +
"SUGAR BLOB," +
"CHOLESTEROL BLOB)");
}
@Override
public void onCreate(SQLiteDatabase db) {
String crtsql = "CREATE TABLE IF NOT EXISTS " + TABLE_NAME +
"(" +
COL_1 + " INTEGER PRIMARY KEY, " +
COL_2 + " TEXT, " +
COL_3 + " TEXT, " +
COL_4 + " BLOB, " +
COL_5 + " BLOB, " +
COL_6 + " BLOB, " +
COL_7 + " BLOB, " +
COL_8 + " BLOB, " +
COL_9 + " BLOB, " +
COL_10 + " BLOB " +
")";
db.execSQL(crtsql);
}
@Override
public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {
sqLiteDatabase.execSQL("DROP TABLE IF EXISTS " +TABLE_NAME);
onCreate(sqLiteDatabase);
}
public void insertFood(
String food,
String description,
byte[] protien,
byte[] fat,
byte[] carbohydrate,
byte[] energy,
byte[] starch,
byte[] sugar,
byte[] cholesterol) {
ContentValues cv = new ContentValues();
cv.put(COL_2,food);
cv.put(COL_3,description);
cv.put(COL_4,protien);
cv.put(COL_5,fat);
cv.put(COL_6,carbohydrate);
cv.put(COL_7,energy);
cv.put(COL_8,starch);
cv.put(COL_9,sugar);
cv.put(COL_10,cholesterol);
SQLiteDatabase db = this.getWritableDatabase();
db.insert(TABLE_NAME,null,cv);
}
public Cursor getFoodsWithProvidedFood(String provided_food) {
return this.getWritableDatabase().query(
TABLE_NAME,
null,
COL_2 + " LIKE '%" + provided_food + "%' ",
null,
null,
null,
null
);
}
}
- 备注
如果您只在一处定义 table 和列名，问题可能会更少。
- 因此更改了 onCreate
- 尽管 SQLite 中的列名是 case-insensitive，但 Cursor 的
getColumnIndex方法（在主 activity 中使用）是 case-sensitive (IMO a错误）. AUTOINCREMENT并没有按照它的意思去做，而是INTEGER PRIMARY KEY本身创建了一个递增的列，添加AUTOINCREMENT是一种特殊情况，它确保 id 在间接费用。因此AUTOINCREMENT已被删除。
已添加两个额外的方法
insertFood将数据插入（添加）到 数据集 table.getFoodsWithProvidedFood如上所述。
Activity - MainActivity.java
public class MainActivity extends AppCompatActivity {
FoodDatabaseHelper foodDBHlpr;
Cursor mCsr;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
foodDBHlpr = new FoodDatabaseHelper(this);
byte[] dummy = new byte[]{0,1,2,3,4,5,6,7,8,9};
// Add some data oif none exists
if (DatabaseUtils.queryNumEntries(foodDBHlpr.getWritableDatabase(),FoodDatabaseHelper.TABLE_NAME) < 1) {
foodDBHlpr.insertFood("Fish and Chips", "The English Seaside meal",
dummy, dummy, dummy, dummy, dummy, dummy, dummy);
foodDBHlpr.insertFood("Bangers and Mash", "Yummy!!",
dummy, dummy, dummy, dummy, dummy, dummy, dummy);
foodDBHlpr.insertFood("Mashed Potatoe", "Boring",
dummy, dummy, dummy, dummy, dummy, dummy, dummy);
}
// get a Cursor with the extracted foods
mCsr = foodDBHlpr.getFoodsWithProvidedFood("Mash");
// Loop Through the Cursor
while (mCsr.moveToNext()) {
Log.d("FOODFOUND","You found the food called - " + mCsr.getString(mCsr.getColumnIndex(FoodDatabaseHelper.COL_2)));
}
if (mCsr.getCount() < 1) {
Log.d("FOODFOUND","No foods found that match the search criteria.");
}
mCsr.close(); //<<<< Should always close Cursors when done with them
}
}
日志中的结果：-
03-15 21:48:21.170 1702-1702/foodsdb.so49307874_foodsdb D/FOODFOUND: You found the food called - Bangers and Mash
03-15 21:48:21.170 1702-1702/foodsdb.so49307874_foodsdb D/FOODFOUND: You found the food called - Mashed Potatoe