我在我的sqlite数据库中插入图片时遇到了困难。我的代码中没有语法错误。运行后,应用程序会自动强制停止。 logcat显示:
Caused by: java.lang.IllegalStateException: Couldn't read row 0, col 3 from CursorWindow. Make sure the Cursor is initialized correctly before accessing data from it.
at com.synergy88studios.catalogapp.DatabaseHandler.getAllItemsInList(DatabaseHandler.java:86)
at com.synergy88studios.catalogapp.MainActivity.onCreate(MainActivity.java:56)
这是我的DatabaseHandler.class中的getAllItemsInList中的方法
public List<Item> getAllItemsInList() {
List<Item> itemList = new ArrayList<Item>();
// Select All Query
String selectQuery = "SELECT * FROM " + TABLE_ITEMS;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
Item item = new Item();
item.set_id(Integer.parseInt(cursor.getString(0)));
item.set_name(cursor.getString(1));
item.set_description(cursor.getString(2));
item.set_image(cursor.getBlob(3));
// Adding contact to list
itemList.add(item);
} while (cursor.moveToNext());
}
// return item list
return itemList;
}
在我的MainActivity中,我只是调用该方法。
items = db.getAllItemsInList();
修改
DatabaseHandler.class
public class DatabaseHandler extends SQLiteOpenHelper{
public static final int DATABASE_VERSION = 1;
public static final String DATABASE_NAME = "CatalogItems";
public static final String TABLE_ITEMS = "Items";
public static final String KEY_ID = "_id";
public static final String KEY_NAME = "name";
public static final String KEY_DESC = "description";
public static final String KEY_IMAGE = "image";
public static final String[] ALL_KEYS = new String[] {KEY_ID, KEY_NAME, KEY_DESC};
//private static final String KEY_IMAGE = "image";
public DatabaseHandler(Context context){
super(context,DATABASE_NAME,null,DATABASE_VERSION);
}
public void onCreate(SQLiteDatabase db){
String CREATE_ITEMS_TABLE = "CREATE TABLE " + TABLE_ITEMS + "( "
+ KEY_ID + " INTEGER PRIMARY KEY," + KEY_NAME + " TEXT,"
+ KEY_DESC + " TEXT, " + KEY_IMAGE + " BLOB" + ")";
db.execSQL(CREATE_ITEMS_TABLE);
}
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion){
db.execSQL("DROP TABLE IF EXISTS "+ TABLE_ITEMS);
onCreate(db);
}
public void addItems(Item item){
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_NAME, item.get_name());
values.put(KEY_DESC, item.get_description());
values.put(KEY_IMAGE, item.get_image());
db.insert(TABLE_ITEMS, null ,values);
db.close();
}
Item getItem(int id){
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.query(TABLE_ITEMS, new String[] { KEY_ID,
KEY_NAME, KEY_DESC , KEY_IMAGE}, KEY_ID + "=?",
new String[] { String.valueOf(id) }, null, null, null, null);
Item item = new Item(Integer.parseInt(cursor.getString(0)),
cursor.getString(1), cursor.getString(2), cursor.getBlob(3));
return item;
}
void deleteAllItems() {
SQLiteDatabase db = this.getWritableDatabase();
db.execSQL("DELETE FROM "+ TABLE_ITEMS);
}
public List<Item> getAllItemsInList() {
List<Item> itemList = new ArrayList<Item>();
// Select All Query
String selectQuery = "SELECT * FROM " + TABLE_ITEMS;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
Item item = new Item();
item.set_id(Integer.parseInt(cursor.getString(0)));
item.set_name(cursor.getString(1));
item.set_description(cursor.getString(2));
item.set_image(cursor.getBlob(3));
// Adding contact to list
itemList.add(item);
} while (cursor.moveToNext());
}
// return item list
return itemList;
}
public Cursor getAllRows() {
SQLiteDatabase db = this.getWritableDatabase();
String where = null;
Cursor c = db.query(true, TABLE_ITEMS, ALL_KEYS,
where, null, null, null, null, null);
if (c != null) {
c.moveToFirst();
}
return c;
}
public int getItemsCount(){
String countQuery = "SELECT * FROM " + TABLE_ITEMS;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(countQuery, null);
return cursor.getCount();
}
public int updateItem(Item item) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_NAME, item.get_name());
values.put(KEY_DESC, item.get_description());
values.put(KEY_IMAGE, item.get_image());
// updating row
return db.update(TABLE_ITEMS, values, KEY_ID + " = ?",
new String[] { String.valueOf(item.get_id()) });
}
public void deleteContact(Item item) {
SQLiteDatabase db = this.getWritableDatabase();
db.delete(TABLE_ITEMS, KEY_ID + " = ?",
new String[] { String.valueOf(item.get_id()) });
db.close();
}
}
我希望有人可以向我解释会发生什么。我可以发布我的其他课程作为参考。
答案 0 :(得分:2)
不要在Android sqlite表中存储大数据。特别是,CursorWindow
仅支持最大2MB的行数据。如果您的行较大,则无法访问它。
相反,将blob存储为文件系统中的文件,并仅存储数据库中的路径。