Question

你好我对android编程很新，并且因为错误而被困了好几个小时。应该发生的是，在它加载了我的表中的所有引号之后，如果我点击一个我的它应该将id传递给一个新的片段并将其再次加载到一个片段上。但最终发生的是当我点击引号时，我收到一个错误，它指向我的DatabaseHelper类中的getItemID方法。我得到的错误是我一直在 -

android.database.sqlite.SQLiteException: near "SELECTIDFROMQuote_TableWHEREQuote": syntax error (code 1): , while compiling: SELECTIDFROMQuote_TableWHEREQuote = 'Play it, Sam. Play 'As Time Goes By.'

然后指向 - getItemID（DatabaseHelper.java:78）

任何帮助都会有所帮助。

（这是包含listFragments和favoriteFragment的活动）

import android.support.v4.app.FragmentTransaction;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;

public class FavoriteActivity extends AppCompatActivity {


final String LOG_TAG = FavoriteActivity.class.getSimpleName();

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_favorite);


    Log.e(LOG_TAG, "youre now in FavoriteActivity ");


    FavoriteListFragment newFragment = new FavoriteListFragment();
    FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
    transaction.replace(R.id.favorite_Container, newFragment);
    // Commit the transaction
    transaction.commit();


}

}

（这是点击listview引用后加载的片段）（这是我在ID中遇到问题的地方）

public class FavoriteFragment extends Fragment {

DatabaseHelper mDatabaseHelper;
private String selectedQuote;
private int selectedID;
private TextView savedQuoteView;
final String LOG_TAG = FavoriteFragment.class.getSimpleName();

public FavoriteFragment() {
    // Required empty public constructor
}


@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    Log.e(LOG_TAG, "youre now in FavoriteFragment ");

    Bundle openBundle = getArguments();
    selectedID = openBundle.getInt("ID", -1);
    String selectedQuote = openBundle.getString("quote", "empty");
    mDatabaseHelper = new DatabaseHelper(getActivity());
    View view = inflater.inflate(R.layout.fragment_favorite, container, false);
    Button deleteBtn = (Button) view.findViewById(R.id.deleteButton);

    deleteBtn.setOnClickListener(new AdapterView.OnClickListener() {

        @Override
        public void onClick(View v) {
            // Log.e(LOG_TAG, "selectedID : " + selectedID + " selectedQuote : " + selectedQuote);
            mDatabaseHelper.deleteQuote(selectedID, selectedQuote);
            savedQuoteView.setText("");
            FavoriteListFragment favoriteListFragment = new FavoriteListFragment();
            FragmentTransaction transaction = getFragmentManager().beginTransaction();
            transaction.replace(R.id.favorite_Container, favoriteListFragment);
            // Commit the transaction
            transaction.commit();
            Toast.makeText(getActivity(), "removed from database", Toast.LENGTH_SHORT).show();

        }
    });

    savedQuoteView = (TextView) view.findViewById(R.id.savedQuote);
    savedQuoteView.setText(selectedQuote);

    return view;
}}

（这是显示我的表的listFragment）

import android.database.Cursor;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentTransaction;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.Toast;
import java.util.ArrayList;


public class FavoriteListFragment extends Fragment {

private static final String LOG_TAG = "FavoriteListFragment";
private ListView listView;
DatabaseHelper mDatabaseHelper;

public FavoriteListFragment() {
}

@Override
public void onCreate(Bundle savedInstanceState) {
    // final String LOG_TAG = FavoriteActivity.class.getSimpleName();
    super.onCreate(savedInstanceState);
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.fragment_favorite_list, container, false);
    listView = view.findViewById(android.R.id.list);
    mDatabaseHelper = new DatabaseHelper(getActivity());
    //Log.e(LOG_TAG, "mDataBaseHelper: " + mDatabaseHelper);
    Log.e(LOG_TAG, "you're now in FavoriteListFragment ");
    // Log.e(LOG_TAG, "this is your list view " + listView);
    populateListView();
    return view;
}

private void populateListView() {
    Log.d(LOG_TAG, "youre in populateListView");

    //get the data and append to a list
    Cursor data = mDatabaseHelper.getAllQuotes();
    ArrayList<String> listData = new ArrayList<>();
    while (data.moveToNext()) {
        //get the value from the database in column 1
        //then add it to the ArrayList
        listData.add(data.getString(1));
    }


    //create the list adapter and set the adapter
    ListAdapter adapter = new ArrayAdapter<>(getActivity(), android.R.layout.simple_list_item_1, listData);
    listView.setAdapter(adapter);

    //set an onItemClickListener to the ListView
    listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {

            String quote = adapterView.getItemAtPosition(i).toString();

            Cursor data = mDatabaseHelper.getItemID(quote); //get the id associated with that name
            int itemID = -1;
            while (data.moveToNext()) {
                itemID = data.getInt(0);
                Log.d(LOG_TAG, "onItemClick: You Clicked on " + quote);
            }
            if (itemID > -1) {

                Log.d(LOG_TAG, "onItemClick: The ID is: " + itemID);
                FavoriteFragment newFragment = new FavoriteFragment();

                Bundle args = new Bundle();
                args.putInt("ID", itemID);
                args.putString("quote", quote);
                newFragment.setArguments(args);

                FragmentTransaction transaction = getFragmentManager().beginTransaction();
                transaction.replace(R.id.favorite_Container, newFragment);
                transaction.commit();

            } else {
                Toast toast = Toast.makeText(getActivity(), "No ID associated with that name", Toast.LENGTH_SHORT);
                toast.show();
            }
        }
    });
}
}

（这是我正在使用的处理程序）

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;

public class DatabaseHelper extends SQLiteOpenHelper {

private static final String LOG_TAG = "DatabaseHelper";
private static final String TABLE_NAME = "Quote_Table";
private static final String COL0 = "ID";
private static final String COL1 = "Quote";


public DatabaseHelper(Context context) {
    super(context, TABLE_NAME, null, 1);
}

@Override
public void onCreate(SQLiteDatabase db) {
    db.execSQL("CREATE TABLE " + TABLE_NAME + " (ID INTEGER PRIMARY KEY AUTOINCREMENT, " +
            COL1 + " TEXT)");
}

@Override
public void onUpgrade(SQLiteDatabase db, int v1, int v2) {
    db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME);
    onCreate(db);
}

public boolean addData(String item) {
    SQLiteDatabase dataBase = this.getWritableDatabase();
    ContentValues values = new ContentValues();
    values.put(COL1, item);

    long result = dataBase.insert(TABLE_NAME, null, values);

    //if date as inserted incorrectly it will return -1
    if (result == -1) {
        return false;
    } else {
        return true;
    }
}

/**
 * Returns all the data from database
 */
public Cursor getAllQuotes() {
    SQLiteDatabase db = this.getWritableDatabase();
    String query = "SELECT * FROM " + TABLE_NAME;
    Cursor data = db.rawQuery(query, null);
    return data;
}

/**
 * Returns only the ID that matches the name passed in
 */

public Cursor getItemID(String quote) {
    SQLiteDatabase db = this.getWritableDatabase();
    String query = "SELECT " + COL0 + " FROM " + TABLE_NAME +
            " WHERE " + COL1 + " = '" + quote + "'";
    Cursor data = db.rawQuery(query, null);
    return data;
}

/**
 * Delete from database
 *
 * @param id
 * @param quote
 */
public void deleteQuote(int id, String quote) {
    SQLiteDatabase db = this.getWritableDatabase();
    String query = "DELETE FROM " + TABLE_NAME + " WHERE "
            + COL0 + " = '" + id + "'" + " AND " + COL1 + " = '" + quote + "'";
    Log.d(LOG_TAG, "deleteName: query: " + query);
    Log.d(LOG_TAG, "deleteName: Deleting " + quote + " from database.");
    db.execSQL(query);
}

}

（如果你想看到logcat说的话）：

  randomquote.hfad.com.randomquote.DatabaseHelper.getItemID(DatabaseHelper.java:71)
     at 

 randomquote.hfad.com.randomquote.FavoriteListFragment$1.onItemClick(FavoriteListFragment.java:72)

Answer 1

我的猜测是，引号包含未正确转义的字符（猜测时引用）。我建议尝试使用为您逃避的查询便捷方法。

因此尝试使用以下内容： -

public Cursor getItemID(String quote) {
    SQLiteDatabase db = this.getWritableDatabase();

    String[] columns = new String[]{COL0};
    String whereclause = COL1+"=?";
    String[] whereargs = new String[]{quote};

    return db.query(TABLE_NAME,columns,whereclause,whereargs,null,null,null);

}

请注意，这是原则上的代码，尚未经过测试，因此可能包含错误。

当我试图获取id＆＃34; android.database.sqlite.SQLiteException：near＆＃34;

1 个答案: