SQLiteDatabse提供意外錯誤

Question

我的SQLite軟件包下的所有文件都給出錯誤。 由於這些是預定義的類，不需要或不允許進行編輯，因此我很難編寫項目。

代碼太長，無法在此處發布。 例如，這些導入在SQLiteDatabase.java中以紅色顯示：

import android.database.sqlite.SQLiteDebug.DbStats;
import dalvik.system.CloseGuard;

而我的logcat顯示以下錯誤：

02-04 12:47:55.781 2666-2666/? E/AndroidRuntime: FATAL EXCEPTION: main
02-04 12:47:55.781 2666-2666/? E/AndroidRuntime: android.database.sqlite.SQLiteException: no such table: user (code 1): , while compiling: select * from user
02-04 12:47:55.781 2666-2666/? E/AndroidRuntime:     at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method)
02-04 12:47:55.781 2666-2666/? E/AndroidRuntime:     at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:889)
02-04 12:47:55.781 2666-2666/? E/AndroidRuntime:     at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:500)
02-04 12:47:55.781 2666-2666/? E/AndroidRuntime:     at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:588)
02-04 12:47:55.781 2666-2666/? E/AndroidRuntime:     at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:58)
02-04 12:47:55.781 2666-2666/? E/AndroidRuntime:     at android.database.sqlite.SQLiteQuery.<init>(SQLiteQuery.java:37)
02-04 12:47:55.781 2666-2666/? E/AndroidRuntime:     at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:44)
02-04 12:47:55.781 2666-2666/? E/AndroidRuntime:     at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1314)
02-04 12:47:55.781 2666-2666/? E/AndroidRuntime:     at android.database.sqlite.SQLiteDatabase.rawQuery(SQLiteDatabase.java:1253)
02-04 12:47:55.781 2666-2666/? E/AndroidRuntime:     at com.example.abcd.helloworld.DatabaseHelper.insertUser(DatabaseHelper.java:40)
02-04 12:47:55.781 2666-2666/? E/AndroidRuntime:     at com.example.abcd.helloworld.SignUp$1.onClick(SignUp.java:52)
02-04 12:47:55.781 2666-2666/? E/AndroidRuntime:     at android.view.View.performClick(View.java:4240)
02-04 12:47:55.781 2666-2666/? E/AndroidRuntime:     at android.view.View$PerformClick.run(View.java:17721)
02-04 12:47:55.781 2666-2666/? E/AndroidRuntime:     at android.os.Handler.handleCallback(Handler.java:730)
02-04 12:47:55.781 2666-2666/? E/AndroidRuntime:     at android.os.Handler.dispatchMessage(Handler.java:92)
02-04 12:47:55.781 2666-2666/? E/AndroidRuntime:     at android.os.Looper.loop(Looper.java:137)
02-04 12:47:55.781 2666-2666/? E/AndroidRuntime:     at android.app.ActivityThread.main(ActivityThread.java:5103)
02-04 12:47:55.781 2666-2666/? E/AndroidRuntime:     at java.lang.reflect.Method.invokeNative(Native Method)
02-04 12:47:55.781 2666-2666/? E/AndroidRuntime:     at java.lang.reflect.Method.invoke(Method.java:525)
02-04 12:47:55.781 2666-2666/? E/AndroidRuntime:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
02-04 12:47:55.781 2666-2666/? E/AndroidRuntime:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
02-04 12:47:55.781 2666-2666/? E/AndroidRuntime:     at dalvik.system.NativeStart.main(Native Method)

我所做的所有編碼似乎都是正確的。

用於創建表的代碼是：

public class DatabaseHelper extends SQLiteOpenHelper {
    private static final int DATABASE_VERSION = 1;
    private static final String DATABASE_NAME = "user.db";
    private static final String TABLE_NAME = "user";
    private static final String COLUMN_ID = "id";
    private static final String COLUMN_NAME = "name";
    private static final String COLUMN_EMAIL = "email";
    private static final String COLUMN_UNAME = "uname";
    private static final String COLUMN_PASS = "pass";
    SQLiteDatabase db;
    private static final String TABLE_CREATE = "create table user (id integer primary key autoincrement," +
            "name text, email text, uname text, pass text);";

    public DatabaseHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL(TABLE_CREATE);
        this.db = db;
    }

    public void insertUser(User u) {
        db = this.getWritableDatabase();
        ContentValues values = new ContentValues();

        String query = "select * from user";
        Cursor cursor = db.rawQuery(query, null);
        int count = cursor.getCount();
        values.put(COLUMN_ID, count);
        values.put(COLUMN_NAME, u.getName());
        values.put(COLUMN_EMAIL, u.getEmail());
        values.put(COLUMN_UNAME, u.getUname());
        values.put(COLUMN_PASS, u.getPass());

        db.insert(TABLE_NAME, null, values);

    }

    public String searchPass(String uname) {
        db = this.getReadableDatabase();
        String query = "select uname, pass from" + TABLE_NAME;
        Cursor cursor = db.rawQuery(query, null);
        String a, b;
        b = "not found";
        if (cursor.moveToFirst()) {
            do {
                a = cursor.getString(0);

                if (a.equals(uname)) {
                    b = cursor.getString(1);
                    break;
                }
            }
            while (cursor.moveToNext());
        }
        db.close();
        return b;

    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        String query = "DROP TABLE IF EXISTS" + TABLE_NAME;
        db.execSQL(query);
        this.OnCreate(db);
    }

    private void OnCreate(SQLiteDatabase db) {
        db.execSQL(TABLE_CREATE);
        this.db = db;
    }

}

Answer 1

您在代碼中兩次使用了onCreate方法。 刪除重復項。

試試下面的代碼：

public class DBHandler extends SQLiteOpenHelper {

    private static final int DATABASE_VERSION = 1;
    private static final String DATABASE_NAME = "user.db";

    public DBHandler(Context context) {
         super(context, DB_NAME, null, DB_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        String query = "create table user(" +
                "id integer primary key autoincrement, " +
                "name text, "+
                "email text, "+
                "uname text, "+
                "pass text"+
                ");";

        db.execSQL(query);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

        String query = "drop table if exists user";
        db.execSQL(query);

        onCreate(db);
    }

    /*

        Remaining code

        Please do not add onCreate and onUpgrade method anymore.

    */

}

Answer 2

您的代碼似乎還可以，請嘗試調試SQLite代碼。 在android代碼之外執行該語句。 打開終端並執行sql語句，然后執行.tables，此命令將向您顯示數據庫中存在的表。

有關更多信息，請參見http://www.tutorialspoint.com/sqlite/sqlite_create_table.htm