Android SQLIte插入null而不是所需的值
根据评论人问题更新: 我试图在SQLite表中插入一个值,但当我获取该值时,似乎插入了null 插入该行并获取/记录其上方所有现有行的调用如下所示:Android SQLIte插入null而不是所需的值,android,sqlite,android-sqlite,Android,Sqlite,Android Sqlite,根据评论人问题更新: 我试图在SQLite表中插入一个值,但当我获取该值时,似乎插入了null 插入该行并获取/记录其上方所有现有行的调用如下所示: @Override public void onClick(View v) { Deck deck = new Deck(mDeckNameText.getText().toString()); dbHandler.addDeck(deck); List<Deck> allDecks = dbHandler.g
@Override
public void onClick(View v) {
Deck deck = new Deck(mDeckNameText.getText().toString());
dbHandler.addDeck(deck);
List<Deck> allDecks = dbHandler.getAllDecks();
Log.d("Get Decks", "Getting all decks");
for (Deck one_deck: allDecks){
int deck_id = one_deck.getDeckId();
String deck_id_string = ""+deck_id;
Log.d("ID: ", deck_id_string);
String deck_name = one_deck.getDeckName();
if (deck_name != null) {
Log.d("Name: ", deck_name);
}
else {
Log.d("Name: ", "null");
}
}
}
其中甲板等级定义为:
public class Deck {
int _deck_id;
String _deck_name;
public Deck(){
}
public Deck(String deck_name) {
this._deck_name = deck_name;
}
public Deck(int deck_id, String deck_name) {
this._deck_id = deck_id;
this._deck_name = deck_name;
}
//get deck_id
public int getDeckId(){
return this._deck_id;
}
//set deck_id
public void setDeckId(int deck_id){
this._deck_id = deck_id;
}
//get deck name
public String getDeckName(){
return this._deck_name;
}
//set deck name
public void setDeckName(String deck_name){
this._deck_name = deck_name;
}
}
包含组的表是通过以下方法创建的:
public void onCreate(SQLiteDatabase db) {
String CREATE_DECKS_TABLE = "CREATE TABLE "+TABLE_DECKS+"("
+KEY_DECK_ID+" INTEGER PRIMARY KEY, "+KEY_DECK_NAME
+" TEXT"+")";
db.execSQL(CREATE_DECKS_TABLE);
}
取牌方法如下:
void addDeck(Deck deck) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_DECK_NAME, deck.getDeckName());
db.insert(TABLE_DECKS,null,values);
}
//get single deck
public Deck getDeck(long deck_id) {
SQLiteDatabase db = this.getReadableDatabase();
String selectQuery = "SELECT * FROM " + TABLE_DECKS + " WHERE "
+ KEY_DECK_ID + " = " + deck_id;
Log.e(LOG, selectQuery);
Cursor c = db.rawQuery(selectQuery, null);
if (c != null)
c.moveToFirst();
Deck deck = new Deck();
deck.setDeckId(c.getInt(c.getColumnIndex(KEY_DECK_ID)));
return deck;
}
//get all decks
public List<Deck> getAllDecks() {
List<Deck> deck_list = new ArrayList<Deck>();
String selectQuery = "SELECT * FROM " + TABLE_DECKS;
Log.e(LOG, selectQuery);
SQLiteDatabase db = this.getReadableDatabase();
Cursor c = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (c.moveToFirst()) {
do {
Deck deck = new Deck();
deck.setDeckId(c.getInt((c.getColumnIndex(KEY_DECK_ID))));
// adding to decks
deck_list.add(deck);
} while (c.moveToNext());
}
return deck_list;
}
//获取单甲板
公共甲板(长甲板){
SQLiteDatabase db=this.getReadableDatabase();
String selectQuery=“SELECT*FROM”+表组+“WHERE”
+密钥组ID+“=”+组ID;
Log.e(Log,selectQuery);
游标c=db.rawQuery(selectQuery,null);
如果(c!=null)
c、 moveToFirst();
甲板=新甲板();
deck.setDeckId(c.getInt(c.getColumnIndex(KEY_deck_ID));
返回甲板;
}
//全副武装
公共列表getAllDecks(){
List deck_List=new ArrayList();
String selectQuery=“SELECT*FROM”+表格;
Log.e(Log,selectQuery);
SQLiteDatabase db=this.getReadableDatabase();
游标c=db.rawQuery(selectQuery,null);
//循环遍历所有行并添加到列表
if(c.moveToFirst()){
做{
甲板=新甲板();
deck.setDeckId(c.getInt((c.getColumnIndex(KEY_deck_ID)));
//添加到甲板
甲板列表。添加(甲板);
}而(c.moveToNext());
}
返回甲板清单;
}
从表中的行获取数据组ID和数据组名称时得到的日志输出如下所示(在第三次尝试插入数据组后):身份证:﹕ 1
D/姓名:﹕ 空
身份证:﹕ 2
D/姓名:﹕ 空
身份证:﹕ 3
D/姓名:﹕ 空的 你知道为什么这个名字是空的吗
提前感谢。您需要在获取代码中添加一行:
deck.setDeckName(c.getString((c.getColumnIndex(KEY_DECK_NAME))));
将其添加到getDeck语句的return前面
我凭记忆写作
希望能有帮助
如果是,请评分您用于从sqlite获取数据的代码在哪里?在您的onclick中,您正在实例化一个具有空deckname的新对象deckname未实例化为mDeckNameText.getText().toString()?我还更新了问题,以包含用于从sqlite获取数据的代码。再次感谢!添加deck.setDeckNAme(c.getString((c.getColumnIndex(KEY_deck_NAME)));祝你好运,谢谢!它奏效了,我非常感谢你的帮助。我不能投票,因为我没有足够的声望点数。当我这么做的时候,我会回来投票!非常感谢。谢谢你们,按回答打分总比追加投票好