Question

我的应用程序应该将数据保存在数据库中，然后将其显示在listView中。问题是listView没有显示任何内容。查看错误日志，似乎说它在保存数据方面存在问题。

提前致谢

将对DBAdapter

package se.welovecode.wdmmg;

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 DBAdapter {

    private static final String TAG = "DBAdapter"; //used for logging database version changes

    // Field Names:
    public static final String KEY_ROWID = "_id";
    public static final String KEY_TRANSACTIONS = "transactions";
    public static final String KEY_ITEM = "item";
    public static final String KEY_SUM = "sum";

    public static final String[] ALL_KEYS = new String[] {KEY_ROWID, KEY_TRANSACTIONS, KEY_ITEM, KEY_SUM,};

    // Column Numbers for each Field Name:
    public static final int COL_ROWID = 0;
    public static final int COL_TRANSACTIONS = 1;
    public static final int COL_ITEM = 2;
    public static final int COL_SUM = 3;

    // DataBase info:
    public static final String DATABASE_NAME = "db";
    public static final String DATABASE_TABLE = "mainTransactions";
    public static final int DATABASE_VERSION = 1; // The version number must be incremented each time a change to DB structure occurs.

    //SQL statement to create database
    private static final String DATABASE_CREATE_SQL =
            "CREATE TABLE " + DATABASE_TABLE
                    + " (" + KEY_ROWID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
                    + KEY_TRANSACTIONS + " TEXT NOT NULL, "
                    + KEY_ITEM + " TEXT NOT NULL, "
                    + KEY_SUM + " INTEGER"
                    + ");";

    private DatabaseHelper myDBHelper;
    private SQLiteDatabase db;


    public DBAdapter(Context ctx) {
        Context context = ctx;
        myDBHelper = new DatabaseHelper(context);
    }

    // Open the database connection.
    public DBAdapter open() {
        db = myDBHelper.getWritableDatabase();
        return this;
    }

    // Close the database connection.
    public void close() {
        myDBHelper.close();
    }

    // Add a new set of values to be inserted into the database.
    public long insertRow(String transactions) {
        ContentValues initialValues = new ContentValues();
        initialValues.put(KEY_TRANSACTIONS, transactions);

        // Insert the data into the database.
        return db.insert(DATABASE_TABLE, null, initialValues);
    }

    public long insertRow2(String item) {
        ContentValues initialValues = new ContentValues();
        initialValues.put(KEY_ITEM, item);

        // Insert the data into the database.
        return db.insert(DATABASE_TABLE, null, initialValues);
    }
    public long insertRow3(int sum) {
        ContentValues initialValues = new ContentValues();
        initialValues.put(KEY_SUM, sum);

        // Insert the data into the database.
        return db.insert(DATABASE_TABLE, null, initialValues);
    }

    // Delete a row from the database, by rowId (primary key)
    public boolean deleteRow(long rowId) {
        String where = KEY_ROWID + "=" + rowId;
        return db.delete(DATABASE_TABLE, where, null) != 0;
    }

    public void deleteAll() {
        Cursor c = getAllRows();
        long rowId = c.getColumnIndexOrThrow(KEY_ROWID);
        if (c.moveToFirst()) {
            do {
                deleteRow(c.getLong((int) rowId));
            } while (c.moveToNext());
        }
        c.close();
    }

    // Return all data in the database.
    public Cursor getAllRows() {
        String where = null;
        Cursor c =  db.query(true, DATABASE_TABLE, ALL_KEYS, where, null, null, null, null, null);
        if (c != null) {
            c.moveToFirst();
        }
        return c;
    }

    // Get a specific row (by rowId)
    public Cursor getRow(long rowId) {
        String where = KEY_ROWID + "=" + rowId;
        Cursor c =  db.query(true, DATABASE_TABLE, ALL_KEYS,
                where, null, null, null, null, null);
        if (c != null) {
            c.moveToFirst();
        }
        return c;
    }

    // Change an existing row to be equal to new data.
    public boolean updateRow(long rowId, String transaction, String item, String sum) {
        String where = KEY_ROWID + "=" + rowId;
        ContentValues newValues = new ContentValues();
        newValues.put(KEY_TRANSACTIONS, transaction);
        newValues.put(KEY_ITEM, item);
        newValues.put(KEY_SUM, sum);
        // Insert it into the database.
        return db.update(DATABASE_TABLE, newValues, where, null) != 0;
    }


    private static class DatabaseHelper extends SQLiteOpenHelper
    {
        DatabaseHelper(Context context) {
            super(context, DATABASE_NAME, null, DATABASE_VERSION);
        }

        @Override
        public void onCreate(SQLiteDatabase _db) {
            _db.execSQL(DATABASE_CREATE_SQL);
        }

        @Override
        public void onUpgrade(SQLiteDatabase _db, int oldVersion, int newVersion) {
            Log.w(TAG, "Upgrading application's database from version " + oldVersion
                    + " to " + newVersion + ", which will destroy all old data!");

            // Destroy old database:
            _db.execSQL("DROP TABLE IF EXISTS " + DATABASE_TABLE);

            // Recreate new database:
            onCreate(_db);
        }
    }
}

MainActivity

package se.welovecode.wdmmg;

import android.content.Intent;
import android.content.SharedPreferences;
import android.database.Cursor;
import android.preference.PreferenceManager;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.widget.ListView;
import android.widget.SimpleCursorAdapter;
import android.widget.TextView;

public class MainActivity extends ActionBarActivity {

    DBAdapter myDB;
    TextView Balance;
    Double value;
    ListView lwTransactions;

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

        Balance = (TextView) findViewById(R.id.tvBalance);
        refreshSum();
        openDB();
        populateListView();

    }

    @Override
    protected void onResume() {
        super.onResume();

        refreshSum();
        populateListView();

    }

    protected void onDestroy(){
        super.onDestroy();
        closeDb();

    }

    private void openDB(){
        myDB = new DBAdapter(this);
        myDB.open();

    }

    private void closeDb(){

        myDB.close();

    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu items for use in the action bar
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.menu_main, menu);
        return super.onCreateOptionsMenu(menu);

    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle presses on the action bar items
        switch (item.getItemId()) {
            case R.id.action_add:
                Intent intent = new Intent(MainActivity.this, AddTransaction.class);
                startActivity(intent);
            default:
                return super.onOptionsItemSelected(item);
        }
    }

    private void refreshSum(){
        SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
        value = (double) prefs.getFloat("KEY", 0f);
        Balance.setText(value.toString());
    }

    private void populateListView(){
        Cursor cursor = myDB.getAllRows();
        String[] fromFieldNames = new String[]{DBAdapter.KEY_ROWID, DBAdapter.KEY_TRANSACTIONS, DBAdapter.KEY_ITEM, DBAdapter.KEY_SUM,};
        int[] toViewIDs = new int[] {R.id.textViewRowID, R.id.textViewStore, R.id.textViewService, R.id.textViewCost};
        SimpleCursorAdapter myCursorAdapter;
        myCursorAdapter = new SimpleCursorAdapter(getBaseContext(),R.layout.item_layout, cursor, fromFieldNames,toViewIDs,0);
        lwTransactions = (ListView) findViewById(R.id.lwTransactions);
        lwTransactions.setAdapter(myCursorAdapter);
    }
}

错误日志

06-12 17:33:38.383  29168-29168/se.welovecode.wdmmg E/SQLiteLog﹕ (1299) abort at 7 in [INSERT INTO mainTransactions(transactions) VALUES (?)]: NOT NULL constraint failed: mainTransactions.item
06-12 17:33:38.383  29168-29168/se.welovecode.wdmmg E/SQLiteDatabase﹕ Error inserting transactions=hsns
    android.database.sqlite.SQLiteConstraintException: NOT NULL constraint failed: mainTransactions.item (code 1299)
            at android.database.sqlite.SQLiteConnection.nativeExecuteForLastInsertedRowId(Native Method)
            at android.database.sqlite.SQLiteConnection.executeForLastInsertedRowId(SQLiteConnection.java:952)
            at android.database.sqlite.SQLiteSession.executeForLastInsertedRowId(SQLiteSession.java:788)
            at android.database.sqlite.SQLiteStatement.executeInsert(SQLiteStatement.java:86)
            at android.database.sqlite.SQLiteDatabase.insertWithOnConflict(SQLiteDatabase.java:1595)
            at android.database.sqlite.SQLiteDatabase.insert(SQLiteDatabase.java:1465)
            at se.welovecode.wdmmg.DBAdapter.insertRow(DBAdapter.java:68)
            at se.welovecode.wdmmg.AddTransaction.onClick_AddTransaction(AddTransaction.java:55)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at android.view.View$1.onClick(View.java:4268)
            at android.view.View.performClick(View.java:5217)
            at android.view.View$PerformClick.run(View.java:20983)
            at android.os.Handler.handleCallback(Handler.java:739)
            at android.os.Handler.dispatchMessage(Handler.java:95)
            at android.os.Looper.loop(Looper.java:145)
            at android.app.ActivityThread.main(ActivityThread.java:6141)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1399)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1194)
06-12 17:33:38.393  29168-29168/se.welovecode.wdmmg E/SQLiteLog﹕ (1299) abort at 6 in [INSERT INTO mainTransactions(item) VALUES (?)]: NOT NULL constraint failed: mainTransactions.transactions
06-12 17:33:38.393  29168-29168/se.welovecode.wdmmg E/SQLiteDatabase﹕ Error inserting item=bsb
    android.database.sqlite.SQLiteConstraintException: NOT NULL constraint failed: mainTransactions.transactions (code 1299)
            at android.database.sqlite.SQLiteConnection.nativeExecuteForLastInsertedRowId(Native Method)
            at android.database.sqlite.SQLiteConnection.executeForLastInsertedRowId(SQLiteConnection.java:952)
            at android.database.sqlite.SQLiteSession.executeForLastInsertedRowId(SQLiteSession.java:788)
            at android.database.sqlite.SQLiteStatement.executeInsert(SQLiteStatement.java:86)
            at android.database.sqlite.SQLiteDatabase.insertWithOnConflict(SQLiteDatabase.java:1595)
            at android.database.sqlite.SQLiteDatabase.insert(SQLiteDatabase.java:1465)
            at se.welovecode.wdmmg.DBAdapter.insertRow2(DBAdapter.java:76)
            at se.welovecode.wdmmg.AddTransaction.onClick_AddTransaction(AddTransaction.java:58)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at android.view.View$1.onClick(View.java:4268)
            at android.view.View.performClick(View.java:5217)
            at android.view.View$PerformClick.run(View.java:20983)
            at android.os.Handler.handleCallback(Handler.java:739)
            at android.os.Handler.dispatchMessage(Handler.java:95)
            at android.os.Looper.loop(Looper.java:145)
            at android.app.ActivityThread.main(ActivityThread.java:6141)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1399)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1194)
06-12 17:33:38.393  29168-29168/se.welovecode.wdmmg E/SQLiteLog﹕ (1299) abort at 6 in [INSERT INTO mainTransactions(sum) VALUES (?)]: NOT NULL constraint failed: mainTransactions.transactions
06-12 17:33:38.393  29168-29168/se.welovecode.wdmmg E/SQLiteDatabase﹕ Error inserting sum=120
    android.database.sqlite.SQLiteConstraintException: NOT NULL constraint failed: mainTransactions.transactions (code 1299)
            at android.database.sqlite.SQLiteConnection.nativeExecuteForLastInsertedRowId(Native Method)
            at android.database.sqlite.SQLiteConnection.executeForLastInsertedRowId(SQLiteConnection.java:952)
            at android.database.sqlite.SQLiteSession.executeForLastInsertedRowId(SQLiteSession.java:788)
            at android.database.sqlite.SQLiteStatement.executeInsert(SQLiteStatement.java:86)
            at android.database.sqlite.SQLiteDatabase.insertWithOnConflict(SQLiteDatabase.java:1595)
            at android.database.sqlite.SQLiteDatabase.insert(SQLiteDatabase.java:1465)
            at se.welovecode.wdmmg.DBAdapter.insertRow3(DBAdapter.java:83)
            at se.welovecode.wdmmg.AddTransaction.onClick_AddTransaction(AddTransaction.java:61)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at android.view.View$1.onClick(View.java:4268)
            at android.view.View.performClick(View.java:5217)
            at android.view.View$PerformClick.run(View.java:20983)
            at android.os.Handler.handleCallback(Handler.java:739)
            at android.os.Handler.dispatchMessage(Handler.java:95)
            at android.os.Looper.loop(Looper.java:145)
            at android.app.ActivityThread.main(ActivityThread.java:6141)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1399)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1194)

Answer 1

你得到KEY_TRANSACTIONS TEXT NOT NULL而KEY_ITEM TEXT NOT NULL

但是你只在insertRow中传入KEY_TRANSACTION，但是你还需要把KEY_ITEM传递给

 public long insertRow(String transactions) {
    ContentValues initialValues = new ContentValues();
    initialValues.put(KEY_TRANSACTIONS, transactions);
    initialValues.put(KEY_ITEM, "some key item");

    // Insert the data into the database.
    return db.insert(DATABASE_TABLE, null, initialValues);
}

或从KEY_ITEM列约束中删除NOT NULL

应用程序未正确保存或显示数据

1 个答案: