[英]CursorAdapter java.lang.IllegalArgumentException: column '_id' does not exist
[英]java.lang.IllegalArgumentException: column '_id' does not exist
我正在嘗試在真實設備上調試我的應用程序,但出現此錯誤:
錯誤/AndroidRuntime(981):原因:java.lang.IllegalArgumentException:列“_id”不存在
當我在模擬器上測試時,錯誤不會出現。 錯誤在以下代碼的最后一行給出:
adapter = new SimpleCursorAdapter(this, R.layout.list_item, c, new String[] {
DataHandlerDB.CONTACT_NAME_COL,
DataHandlerDB.CONTACT_NUMBER_COL,
DataHandlerDB.CONTACT_DURATION_COL,
DataHandlerDB.CONTACT_DATE_COL }, new int[] {
R.id.contact_name, R.id.phone_number, R.id.duration, R.id.date });
這是我的活動:
public class MyActivity extends Activity {
private static final String LOG_TAG = "MyActivity";
private ListView listview;
private SimpleCursorAdapter adapter;
private DataHandlerDB handler;
private SQLiteDatabase db;
private OpenHelper helper;
private Cursor c;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
helper = new OpenHelper(this);
db = helper.getWritableDatabase();
helper.onCreate(db);
setBasicContent();
c.close();
}
@Override
public void onDestroy(){
super.onDestroy();
DataHandlerDB.makeTheSelection(this).close();
db.close();
helper.close();
}
@Override
public void onPause(){
super.onPause();
DataHandlerDB.makeTheSelection(this).close();
db.close();
helper.close();
}
@Override
public void onStop(){
super.onStop();
DataHandlerDB.makeTheSelection(this).close();
db.close();
helper.close();
}
@Override
protected void onResume(){
super.onResume();
setBasicContent();
}
public void setBasicContent() {
listview = (ListView) findViewById(R.id.list_view);
Log.i(LOG_TAG, "listview " + listview);
c = DataHandlerDB.makeTheSelection(this);
c.moveToFirst();
if(db.isOpen())
Log.i(LOG_TAG, "db is opened");
Log.i(LOG_TAG, "cursor: " + c.getCount());
startManagingCursor(c);
adapter = new SimpleCursorAdapter(this, R.layout.list_item, c, new String[] {
DataHandlerDB.CONTACT_NAME_COL,
DataHandlerDB.CONTACT_NUMBER_COL,
DataHandlerDB.CONTACT_DURATION_COL,
DataHandlerDB.CONTACT_DATE_COL }, new int[] {
R.id.contact_name, R.id.phone_number, R.id.duration, R.id.date });
Log.i(LOG_TAG, "before setAdapter");
Toast.makeText(this, "Before setAdapter", Toast.LENGTH_SHORT).show();
listview.setAdapter(adapter);
db.close();
if(db.isOpen()){
Log.i(LOG_TAG, "db is opened.");
}
if(!c.isClosed()){
Log.i(LOG_TAG, "cursor is opened");
}
}
}
查詢並返回 Cursor 的Cursor
位於 class DataHandlerDB
中:
public class DataHandlerDB {
private static final String DATABASE_NAME = "calls.db";
private static final int DATABASE_VERSION = 1;
protected static String CONTACT_NAME_COL = "contact_name";
protected static String CONTACT_NUMBER_COL = "contact_number";
protected static String CONTACT_DURATION_COL = "duration";
protected static String CONTACT_DATE_COL = "date";
protected static String CONTACT_MONTH_COL = "month";
// create the DB
public static SQLiteDatabase createDB(Context ctx) {
OpenHelper helper = new OpenHelper(ctx);
SQLiteDatabase db = helper.getWritableDatabase();
helper.onCreate(db);
helper.onOpen(db);
db.close();
return db;
}
public static Cursor makeTheSelection(Context ctx) {
OpenHelper helper = new OpenHelper(ctx);
SQLiteDatabase db = helper.getWritableDatabase();
Cursor cursor = db.query(TABLE_NAME_2, null, null, null, null, null,
"duration desc");
cursor.moveToFirst();
db.close();
return cursor;
}
// class OpenHelper
public static class OpenHelper extends SQLiteOpenHelper {
private final Context mContext;
OpenHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
this.mContext = context;
}
@Override
public void onCreate(SQLiteDatabase db) {
Log.i(LOG_TAG, "entrou no onCreate");
String[] sql = mContext.getString(
R.string.MyAppDatabase_OnCreate).split("\n");
db.beginTransaction();
try {
execMultipleSQL(db, sql);
db.setTransactionSuccessful();
} catch (SQLException e) {
Log.e("Error creating tables and debug data", e.toString());
throw e;
} finally {
db.endTransaction();
}
}
private void execMultipleSQL(SQLiteDatabase db, String[] sql) {
for (String s : sql) {
if (s.trim().length() > 0) {
db.execSQL(s);
}
}
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
Log.w("MyDB Database",
"Upgrading database, this will drop tables and recreate.");
db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME); onCreate(db);
}
@Override
public void onOpen(SQLiteDatabase db) {
super.onOpen(db);
}
}
}
這是帶有 SQL 命令的 XML 文件:
<string name="MyAppDatabase_OnCreate">
"CREATE TABLE IF NOT EXISTS contact_data(_id INTEGER PRIMARY KEY AUTOINCREMENT, contact_id INTEGER, contact_name VARCHAR(50), number_type VARCHAR(50), contact_number VARCHAR(50), duration TIME, duration_sum TIME, date DATE, current_time TIME, cont INTEGER, type VARCHAR, month VARCHAR(50), day VARCHAR(50), year VARCHAR(50));"
</string>
我認為應用程序在首次啟動時並未創建數據庫。 我認為是這樣,因為它可以找到列_id
,但它明確地寫在 XML 代碼中以使用_id
列創建它。 我還認為,因為我已經明確地寫了SELECT
方法中的列,包括_id
。 我是這樣做的:
Cursor cursor = db.query(TABLE_NAME_2,
new String[]{
"_id",
"contact_id",
"contact_name",
"number_type",
"contact_number",
"duration",
"duration_sum",
"date",
"current_time",
"cont", "type",
"month",
"day",
"year"}, null, null, null, null,
"duration desc");
在這種情況下,我收到的錯誤幾乎相同:
Caused by: android.database.sqlite.SQLiteException: no such column: _id: , while compiling: SELECT _id, contact_id, contact_name, number_type, contact_number, duration, duration_sum, date, current_time, cont, type, month, day, year FROM contact_data ORDER BY 持續時間 desc
我已經像這樣記錄了數據庫的第一列:
Log.i(LOG_TAG, "Cursor(0)" + cursor.getColumnName(0));
它打印id
,而不是_id
。 如您所見,語句中寫有_id
。 關於如何解決這個問題的任何建議?
您正在嘗試使用需要名為 _id 的列的cursor 。 它就像編輯您的表創建語句並添加一個名為 _id 的列一樣簡單。
它的聲明看起來像這樣:
_id INTEGER PRIMARY KEY AUTOINCREMENT
添加這個,然后你就可以使用它了。 我相信這是使用 SimpleCursorAdapter 所必需的要求。
更新
"CREATE TABLE IF NOT EXISTS contact_data( _id INTEGER PRIMARY KEY AUTOINCREMENT, contact_id INTEGER, contact_name VARCHAR(50), number_type VARCHAR(50), contact_number VARCHAR(50), duration TIME, duration_sum TIME, date DATE, current_time TIME, cont INTEGER, type VARCHAR, month VARCHAR(50), day VARCHAR(50), year VARCHAR(50));"
解決方法:在左括號'('和_id之間加一個空格
我遇到了類似的問題,因為我沒有將_id列添加到投影參數,因此將_id添加到查詢的投影參數是解決方案。 ( @nobugs 評論)
例子:
String[] projections = {"_id", "name", "age"};
Cursor cursor = db.query(domainClass.getSimpleName(), projections,
null, null, null, null, null);
首先卸載應用程序,然后執行以下步驟:
CursorAdapter 始終需要存在_id
列。 因此,在用於創建 Cursor 的投影列表中,您需要添加_id
列。
我這樣做並解決了我的問題。
前
SELECT id
后
SELECT id as _id
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