这是我的类首先将SQLite表中的项数据显示到EditText，之后我尝试通过单击EditText按钮将这些addFavorites数据保存到收藏夹表中没有什么可以保存的善意帮助
以下是代码：
public class ItemListDetail extends AppCompatActivity {
EditText catID , itemID , itemName , itemDescription, unit , price ;
Button addFavorites;
DBhelper dBhelper;
//int fav;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_item_list_detail);
dBhelper = new DBhelper(this);
catID = findViewById(R.id.edCID);
itemID = findViewById(R.id.edIID);
itemName = findViewById(R.id.edName);
itemDescription = findViewById(R.id.edDescription);
unit = findViewById(R.id.edUnit);
price = findViewById(R.id.edPrice);
Items item = (Items) getIntent().getExtras().getSerializable("ITEMS");
// fav = Integer.parseInt(item.getItemId());
//fav = item.getItemId();
catID.setText("CategoryID : " + item.getCategoryId());
itemID.setText("ItemID : " +item.getItemId());
itemName.setText("ItemName : " +item.getItemName());
itemDescription.setText("Description : " +item.getItemDescription());
unit.setText("Unit : " +item.getUnit());
price.setText("Price : " +item.getPrice());
}
public void saveFavorites(View view) {
String iID = itemID.getText().toString();
String fID = itemID.getText().toString();
Fav fav = new Fav(iID ,fID);
int result =dBhelper.saveFavorites(fav);
if(result > 0){
Toast.makeText(this, "Favorites Added", Toast.LENGTH_SHORT).show();
}else {
Toast.makeText(this, "Not Added", Toast.LENGTH_SHORT).show();
}
}
}
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="wrap_content"
tools:context="com.example.bhb.vu_mcs.ItemListDetail">
<Button
android:id="@+id/addFavorites"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="0.2"
android:text="Add Favorites"
android:onClick="saveFavorites"
/>
<EditText
android:id="@+id/edIID"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="0.2"
android:ems="10"
android:inputType="textPersonName"
android:text="Name" />
<EditText
android:id="@+id/edCID"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="0.2"
android:editable="false"
android:ems="10"
android:inputType="textPersonName"
android:text="Name" />
<EditText
android:id="@+id/edPrice"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="0.2"
android:ems="10"
android:inputType="textPersonName"
android:text="Name" />
<EditText
android:id="@+id/edName"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="0.2"
android:ems="10"
android:inputType="textPersonName"
android:text="Name" />
<EditText
android:id="@+id/edDescription"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:ems="10"
android:inputType="textMultiLine|textPersonName"
android:text="Name" />
<EditText
android:id="@+id/edUnit"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="0.2"
android:ems="10"
android:inputType="textPersonName"
android:text="Name" />
</LinearLayout>
package com.example.bhb.vu_mcs;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import java.util.ArrayList;
import java.util.List;
/**
* Created by bhb on 1/30/2018.
*/
public class DBhelper extends SQLiteOpenHelper {
private static final String DATABASE_NAME = "MyDB.db";
private static final int DATABASE_VERSION = 2;
private static final String KEY_CAT_TABLE = "CATEGORY";
private static final String KEY_CAT_ID = "categoryId";
private static final String KEY_CAT_NAME = "categoryName";
private static final String KEY_CAT_DESCRIPTION = "categoryDescription";
private static final String CREATE_CATEGORY_TABLE = "CREATE TABLE " + KEY_CAT_TABLE + "( "+ KEY_CAT_ID + " INTEGER PRIMARY KEY,"
+ KEY_CAT_NAME + " TEXT NOT NULL,"
+ KEY_CAT_DESCRIPTION + " TEXT NOT NULL )";
private static final String KEY_ITEM_TABLE = "ITEMS";
private static final String KEY_ITEM_ID = "itemId";
// private static final String COL3 = "categoryId";
private static final String KEY_ITEM_NAME = "itemName";
private static final String KEY_ITEM_DESCRIPTION = "itemDescription";
private static final String KEY_ITEM_UNIT = "unit";
private static final String KEY_ITEM_PRICE = "price";
private static final String CREATE_ITEMS_TABLE = "CREATE TABLE " + KEY_ITEM_TABLE + "( "+ KEY_ITEM_ID + " INTEGER PRIMARY KEY,"
+ KEY_CAT_ID + " INTEGER,"
+ KEY_ITEM_NAME + " TEXT NOT NULL,"
+ KEY_ITEM_DESCRIPTION + " TEXT NOT NULL,"
+ KEY_ITEM_UNIT + " TEXT NOT NULL,"
+ KEY_ITEM_PRICE + " TEXT NOT NULL )";
////////////this part is for favrities/////////////////////
private static final String KEY_FAVORITES_TABLE = "FAVORITES";
private static final String KEY_FAVORITES_ID = "favritesId";
private static final String CREATE_FAVORITES_TABLE = "CREATE TABLE " + KEY_FAVORITES_TABLE + "( "+ KEY_FAVORITES_ID + " INTEGER TEXT NOT NULL,"
+ KEY_ITEM_ID + " INTEGER PRIMARY KEY )";
///////////////////////
public DBhelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(CREATE_CATEGORY_TABLE);
db.execSQL(CREATE_ITEMS_TABLE);
db.execSQL(CREATE_FAVORITES_TABLE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int i, int i1) {
db.execSQL(" DROP TABLE IF EXISTS " + KEY_CAT_TABLE);
db.execSQL(" DROP TABLE IF EXISTS " + KEY_ITEM_TABLE);
db.execSQL(" DROP TABLE IF EXISTS " + KEY_FAVORITES_TABLE);
onCreate( db);
}
public List<Items> getItemsForCategory(int catID) {
List<Items> myitems = new ArrayList<>();
SQLiteDatabase db = getReadableDatabase();
Cursor cursor = db.rawQuery("SELECT * FROM " + KEY_ITEM_TABLE + " WHERE categoryId = " + catID , null);
if(cursor.moveToNext())
{
do{
String itemId = cursor.getString(0);
String categoryId = cursor.getString(1);
String itemName = cursor.getString(2);
String itemDescription = cursor.getString(3);
String unit = cursor.getString(4);
String price = cursor.getString(5);
Items items = new Items(itemId, categoryId, itemName, itemDescription, unit, price);
myitems.add(items);
}while (cursor.moveToNext());
}
return myitems;
}
public List<Fav> getFavorities() {
List<Fav> myFav = new ArrayList<>();
SQLiteDatabase db = getReadableDatabase();
Cursor cursor = db.rawQuery("SELECT * FROM " + KEY_FAVORITES_TABLE, null );
if(cursor.moveToNext()){
do{
String fid = cursor.getString(0);
String iid = cursor.getString(1);
Fav favrities = new Fav(fid , iid);
myFav.add(favrities);
}while (cursor.moveToNext());
}
return myFav;
}
public int saveFavorites(Fav fav) {
SQLiteDatabase db = getReadableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_ITEM_ID , fav.getItemId());
values.put(KEY_FAVORITES_ID , fav.favId);
//return db.update("FAVORITES" , values, "id=?", new String[]{fav.getItemId()} );
long temp = db.insert("FAVORITES" , null, values);
db.close();
return (int) temp;
}
}
答案 0 :(得分：0)
我建议你这样做。使用getWritableDatabase（）而不是getReadableDatabase（）。
public int saveFavorites(Fav fav) {
SQLiteDatabase db = getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_ITEM_ID , fav.getItemId());
values.put(KEY_FAVORITES_ID , fav.favId);
//return db.update("FAVORITES" , values, "id=?", new String[]{fav.getItemId()} );
long temp = db.insert("FAVORITES" , null, values);
db.close();
return (int) temp;
}
答案 1 :(得分：0)
我相信你发的是你要么
不知道无法确定的实际值。
在SQLite中，任何列都可以使用ONE EXCEPTION保存任何类型的值，并且该列是 rowid 的别名。 rowid 是默认存在的特殊隐藏列（WITHOUT ROWID可用于指定没有rowid的表）。包含特殊关键字INTEGER PRIMARY KEY（或附加AUTOINCREMENT）的列是 rowid 的别名。只能在没有指定值或整数的情况下插入这样的列，并且该值必须是唯一的。
因此，特别是可能从KEY_ITEM_ID派生的FAVORITES表的String fID = itemID.getText().toString();（itemId）列不能是等于整数的字符串（可能是它）。此外，价值必须是独一无二的。
KEY_ITEM_ID（itemId）似乎是引用ITEMS表中的Item。因此，您可能只需指定INTEGER或INTEGER NOT NULL作为列类型。
虽然问题不是KEY_FAVORITES_ID（favritesId）列定义为INTEGER TEXT NOT NULL，但您应该将其更改为INTEGER NOT NULL。
因此我相信你应该改变： -
private static final String CREATE_FAVORITES_TABLE = "CREATE TABLE " + KEY_FAVORITES_TABLE + "( "+ KEY_FAVORITES_ID + " INTEGER TEXT NOT NULL,"
+ KEY_ITEM_ID + " INTEGER PRIMARY KEY )";
： -
private static final String CREATE_FAVORITES_TABLE = "CREATE TABLE " + KEY_FAVORITES_TABLE + "( "+ KEY_FAVORITES_ID + " INTEGER NOT NULL,"
+ KEY_ITEM_ID + " INTEGER NOT NULL )";
请注意！要实现上述功能，您需要DROP并重新创建FAVORITES。如果丢失所有数据不是问题，那么您可以执行以下操作之一;