Java 如何通过用户输入从sqlite检索数据
目前我正在开发一个小应用程序。我想通过用户输入从sqlite检索数据。我有两张桌子和两种食物。我想通过用户输入从这些表中检索数据。Java 如何通过用户输入从sqlite检索数据,java,android,android-layout,android-sqlite,Java,Android,Android Layout,Android Sqlite,目前我正在开发一个小应用程序。我想通过用户输入从sqlite检索数据。我有两张桌子和两种食物。我想通过用户输入从这些表中检索数据。 例如,应用程序将要求用户输入字段,例如年龄、性别,以根据这些字段显示数据。当用户插入输入时,应用程序将根据输入字段显示数据。有人能帮我吗?我如何编写代码来实现上述功能 public class DBClass extends SQLiteOpenHelper { private static final String dname= "NutritionD
例如,应用程序将要求用户输入字段,例如年龄、性别,以根据这些字段显示数据。当用户插入输入时,应用程序将根据输入字段显示数据。有人能帮我吗?我如何编写代码来实现上述功能
public class DBClass extends SQLiteOpenHelper {
private static final String dname= "NutritionDatabase";
private static final int version =4;
public DBClass(Context context){
super(context, dname,null, version);
}
@Override
public void onOpen(SQLiteDatabase db){
super.onOpen(db);
db.setForeignKeyConstraintsEnabled(true);
}
@Override
public void onCreate(SQLiteDatabase db) {
try {
String gender_cat = "CREATE TABLE gender_group" +
"(id INTEGER PRIMARY KEY," +
"name VARCHAR )";
db.execSQL(gender_cat);
String foodtbl = "CREATE TABLE Foods" +
"(id INTEGER PRIMARY KEY AUTOINCREMENT," +
"age VARCHAR ," +
"gender_cat INTEGER," +
"Food VARCHAR," +
"FOREIGN KEY (gender_cat) REFERENCES gender_group(id))";
db.execSQL(foodtbl);
InsertGenderCat(1,"Men",db);
InsertGenderCat(2,"Women",db);
InsertGenderCat(3,"Toddlers",db);
InsertGenderCat(4,"Olders",db);
insertFoods("12",2,"Calories Required \n 45 to 55 calories per kg.\n\n Protein \n 1 gram per kg. \n\n Breads or Starches. \n 1 bagel or muffin.\n 2 slices bread.\n 1/2 cup cooked cereal, pasta, potatoes, or rice. \n\n Fruits:\n 1/2 cup canned fruit or fruit juice. \n 1 piece fresh fruit, such as an apple, orange, peach, or pear. \n\n 15 to 20 grapes.\n\n Meat or Meat Substitutes:\n 1/2 cup cottage or ricotta cheese. \n 3/4 to 1 cup cooked dried beans or legumes. \n 1 egg.\n 2 to 3 ounces meat, fish, or poultry.\n\n Milk or Yogurt\n 1 cup milk or yogurt.\n\n Vegetables:\n 1/2 cup cooked or 1 cup raw vegetable. \n 2 cups salad greens. \n\n Fats\n 6 almonds or 10 peanuts.\n 2 Tbsps cream cheese, avocado, or low calorie salad dressing.\n\nSweets and Desserts .",db);
insertFoods("13",2,"Calories Required \n 45 to 55 calories per kg.\n\n Protein \n 1 gram per kg. \n\n Breads or Starches. \n 1 bagel or muffin.\n 2 slices bread.\n 1/2 cup cooked cereal, pasta, potatoes, or rice. \n\n Fruits:\n 1/2 cup canned fruit or fruit juice. \n 1 piece fresh fruit, such as an apple, orange, peach, or pear. \n\n 15 to 20 grapes.\n\n Meat or Meat Substitutes:\n 1/2 cup cottage or ricotta cheese. \n 3/4 to 1 cup cooked dried beans or legumes. \n 1 egg.\n 2 to 3 ounces meat, fish, or poultry.\n\n Milk or Yogurt\n 1 cup milk or yogurt.\n\n Vegetables:\n 1/2 cup cooked or 1 cup raw vegetable. \n 2 cups salad greens. \n\n Fats\n 6 almonds or 10 peanuts.\n 2 Tbsps cream cheese, avocado, or low calorie salad dressing.\n\nSweets and Desserts .",db);
insertFoods("14",2,"Calories Required \n 45 to 55 calories per kg.\n\n Protein \n 1 gram per kg. \n\n Breads or Starches. \n 1 bagel or muffin.\n 2 slices bread.\n 1/2 cup cooked cereal, pasta, potatoes, or rice. \n\n Fruits:\n 1/2 cup canned fruit or fruit juice. \n 1 piece fresh fruit, such as an apple, orange, peach, or pear. \n\n 15 to 20 grapes.\n\n Meat or Meat Substitutes:\n 1/2 cup cottage or ricotta cheese. \n 3/4 to 1 cup cooked dried beans or legumes. \n 1 egg.\n 2 to 3 ounces meat, fish, or poultry.\n\n Milk or Yogurt\n 1 cup milk or yogurt.\n\n Vegetables:\n 1/2 cup cooked or 1 cup raw vegetable. \n 2 cups salad greens. \n\n Fats\n 6 almonds or 10 peanuts.\n 2 Tbsps cream cheese, avocado, or low calorie salad dressing.\n\nSweets and Desserts .",db);
insertFoods("15",2,"Total Calories Required \n 40 to 45 calories per kg.\n\n Protein \n 0.9 grams per kg. \n\n Breads or Starches::1/2 cup cottage or ricotta cheese.3/4 to 1 cup cooked dried beans or legumes.\n 1 egg.2 to 3 ounces meat, fish, or poultry.\n Milk or Yogurt \n 1 cup milk or yogurt.\n\n Vegetables:\n 1/2 cup cooked or 1 cup raw vegetable.\n 2 cups salad greens.\n\n Fats\n 6 almonds or 10 peanuts.\n 2 Tbsps cream cheese, avocado, or low calorie salad dressing.\n\n Sweets and Desserts .",db);
insertFoods("16",2,"Total Calories Required \n 40 to 45 calories per kg.\n\n Protein \n 0.9 grams per kg. \n\n Breads or Starches::1/2 cup cottage or ricotta cheese.3/4 to 1 cup cooked dried beans or legumes.\n 1 egg.2 to 3 ounces meat, fish, or poultry.\n Milk or Yogurt \n 1 cup milk or yogurt.\n\n Vegetables:\n 1/2 cup cooked or 1 cup raw vegetable.\n 2 cups salad greens.\n\n Fats\n 6 almonds or 10 peanuts.\n 2 Tbsps cream cheese, avocado, or low calorie salad dressing.\n\n Sweets and Desserts .",db);
insertFoods("17",2,"Total Calories Required \n 40 to 45 calories per kg.\n\n Protein \n 0.9 grams per kg. \n\n Breads or Starches::1/2 cup cottage or ricotta cheese.3/4 to 1 cup cooked dried beans or legumes.\n 1 egg.2 to 3 ounces meat, fish, or poultry.\n Milk or Yogurt \n 1 cup milk or yogurt.\n\n Vegetables:\n 1/2 cup cooked or 1 cup raw vegetable.\n 2 cups salad greens.\n\n Fats\n 6 almonds or 10 peanuts.\n 2 Tbsps cream cheese, avocado, or low calorie salad dressing.\n\n Sweets and Desserts .",db);
}
catch (SQLException e){
e.printStackTrace();
}
}
private void InsertGenderCat(Integer id, String group, SQLiteDatabase db){
ContentValues values = new ContentValues();
values.put("id",id);
values.put("name",group);
db.insert("gender_group", null,values);
}
private void insertFoods(String age,Integer cat, String food, SQLiteDatabase db){
ContentValues values = new ContentValues();
values.put("age",age);
values.put("gender_cat",cat);
values.put("Food",food);
db.insert("Foods", null,values);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
String genderTbl ="DROP TABLE IF EXISTS gender_categories";
db.execSQL(genderTbl);
String foodsTbl ="DROP TABLE IF EXISTS Foods";
db.execSQL(foodsTbl);
}
}
布局文件
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:fitsSystemWindows="true"
android:orientation="vertical">
<TextView
android:id="@+id/txtBmr"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Fill The Field to Find Food"
android:textAlignment="center"
android:textColor="@color/colorAccent"
android:textSize="25dp" />
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:padding="5dp">
<TextView
android:id="@+id/food_gender_group"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:padding="18dp"
android:text="Gender Group :"
android:textColor="@color/colorAccent"
android:textSize="20dp"
android:textStyle="bold" />
<EditText
android:id="@+id/edt_gender_group"
android:layout_width="289dp"
android:layout_height="wrap_content"
android:padding="5dp" />
</LinearLayout>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:padding="5dp">
<TextView
android:id="@+id/txt_genderGroup_age"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:padding="18dp"
android:text="Enter Age :"
android:textColor="@color/colorAccent"
android:textSize="20dp"
android:textStyle="bold" />
<EditText
android:id="@+id/edt_genderGroup_age"
android:layout_width="289dp"
android:layout_height="wrap_content"
android:padding="5dp" />
</LinearLayout>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal">
</LinearLayout>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:padding="5dp"
android:weightSum="2">
<Button
android:id="@+id/btn_food"
android:textStyle="bold"
android:padding="5dp"
android:layout_width="wrap_content"
android:layout_marginLeft="23dp"
android:background="@android:color/black"
android:textColor="@android:color/white"
android:layout_height="wrap_content"
android:layout_marginRight="10dp"
android:textSize="18dp"
android:layout_weight="1"
android:text="Click to show Foods"/>
</LinearLayout>
</LinearLayout>
首先,单击按钮时获取两个
editText
值。然后将这两个值传递给readEntry
函数,该函数位于DBManager类中
btnFood.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Cursor cursor = dbManager.open().readEntry(genderGroup.getText().toString(), age.getText().toString());
if (cursor.moveToFirst()) {
do {
String value = cursor.getString(0);
Toast.makeText(getApplication(),value,Toast.LENGTH_SHORT).show();
} while (cursor.moveToNext());
}
}
});
在DBManager类中,在readEntry
函数中编写查询。我们可以使用Left join
query连接两个表
public class DBManager {
private DBClass dbhelper;
private Context context;
private SQLiteDatabase database;
public DBManager(Context c) {
context = c;
}
public DBManager open() throws SQLException {
dbhelper = new DBClass(context);
database = dbhelper.getWritableDatabase();
return this;
}
public void close() {
dbhelper.close();
}
public Cursor readEntry(String genderGroup, String age) {
return database.rawQuery("SELECT i.food FROM foods i LEFT JOIN gender_group w ON i.gender_cat = w.id WHERE w.name = ? AND i.age = ?", new String[]{genderGroup, age}, null);
}
}
输出将显示为Toast
您可以在这里获得完整的项目:您是否创建了一个包含
editText
的布局?是的。我创建了layoutI发布的布局文件代码请检查。请参考我检查过的@JohnJoe,但这对我没有帮助。。请分享一下和我的问题类似的来源,非常感谢。。请,您可以共享完整的代码吗?单击“显示食物”按钮时,将姓名和年龄传递给readEntry函数。您知道单击按钮时如何获取editText值吗?请将您的项目上载到github。如果我有空,我会帮忙的。我上传了,请检查一下。