android - 无法在 ListView 中显示数据库

Question

我正在尝试让我的应用程序显示我在数据库中设置的表中的信息。据我所知，数据库设置正确并且代码正确，但我不知道是什么导致了错误。我将发布所有代码，看看这里是否有人可以帮助我解决问题。

进度类:

public class WorkoutProgress extends ListActivity {
   private DataBaseHelper datasource;
   TextView goal;
   @Override
   public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      requestWindowFeature(Window.FEATURE_NO_TITLE);
      getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);
      setContentView(R.layout.progress);
      goal = (TextView)findViewById(R.id.goal);
      datasource = new DataBaseHelper(this);
      datasource.open();
      fillData();
      datasource.close();
  }
  private void fillData() {
    Cursor c = datasource.getAllActs();
    startManagingCursor(c);
    String[] from = new String[] {DataBaseHelper.KEY_DATE,  
    DataBaseHelper.KEY_STEPS,DataBaseHelper.KEY_CALs };
    int[] to = { R.id.code, R.id.Days, R.id.BMI };
    SimpleCursorAdapter notes = new SimpleCursorAdapter (this, R.layout.notes_row, c,  from, to);
    setListAdapter(notes);               
  }
}

数据库助手:

public class DataBaseHelper
{
    public static final String KEY_ROWID = "_id";
    public static final String KEY_GOAL = "goal";
    public static final String KEY_Current = "cweight";
    public static final String KEY_Target = "nweight"; 

    public static final String KEY_ROWID2 = "_id";

    public static final String KEY_DATE = "date";
    public static final String KEY_STEPS = "steps";
    public static final String KEY_CALs = "calories";
    public static final String KEY_CALID = "_id";
    public static final String KEY_TOTALCALS = "totalcals";    
    private static final String TAG = "DBAdapter";
    private static final String DATABASE_NAME = "workout";
    private static final String DATABASE_TABLE = "goals";
    private static final String DATATABLE = "acts";
    private static final String CALTABLE = "cals";
    private static final int DATABASE_VERSION = 1;
    private static final String DATABASE_CREATE =
     "create table goals (_id integer primary key autoincrement, "
     + "goal text not null, cweight number not null, " 
     + "nweight number not null);";
    private static final String DATABASE_CREATE2 =
        "create table acts (_id integer primary key autoincrement, "
                + "date text not null, steps text not null, " 
                + "calories number not null);"
    private final Context context; 
    private DatabaseHelper DBHelper;
    private SQLiteDatabase db;
    public DataBaseHelper(Context ctx) 
    {
        this.context = ctx;
        DBHelper = new DatabaseHelper(context);
    }

    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);
            db.execSQL(DATABASE_CREATE2);
        }
        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, 
        int newVersion) 
        {
            Log.w(TAG, "Upgrading database from version " + oldVersion 
                + " to "
                + newVersion + ", which will destroy all old data");
            db.execSQL("DROP TABLE IF EXISTS titles");
            onCreate(db);
        }
    }    
    public DataBaseHelper open() throws SQLException 
    {
        db = DBHelper.getWritableDatabase();
        return this;
    }
    public void close() 
    {
        DBHelper.close();
    }
    public long insertTitle(String goal, int current, int target) 
    {
        ContentValues initialValues = new ContentValues();
        initialValues.put(KEY_GOAL, goal);
        initialValues.put(KEY_Current, current);
        initialValues.put(KEY_Target, target);
        return db.insert(DATABASE_TABLE, null, initialValues);
    }

    public long insertActivity(String date, String steps, double Calories) 
    {
        ContentValues initialValues = new ContentValues();
        initialValues.put(KEY_DATE, date);
        initialValues.put(KEY_STEPS, steps);
        initialValues.put(KEY_CALs, Calories);
        return db.insert(DATATABLE, null, initialValues);
    }
    public boolean deleteTitle(long rowId) 
    {
        return db.delete(DATABASE_TABLE, KEY_ROWID + 
            "=" + rowId, null) > 0;
    }
    public void deleteFirst()
    {
        Cursor cursor = db.query(DATABASE_TABLE, null, null, null, null, null, null); 
        if(cursor.moveToFirst()) {
        long rowId = cursor.getLong(cursor.getColumnIndex(KEY_ROWID)); 
        db.delete(DATABASE_TABLE, KEY_ROWID +  "=" + rowId, null);
   }
}

public boolean deleteAct(long rowId) 
{
    return db.delete(DATATABLE, KEY_ROWID + 
            "=" + rowId, null) > 0;
}
//---retrieves all the titles---
public Cursor getAllGoals() 
{
    return db.query(DATABASE_TABLE, new String[] {
            KEY_ROWID, 
            KEY_GOAL,
            KEY_Current,
            KEY_Target}, 
            null, 
            null, 
            null, 
            null, 
            null);
}
public Cursor getAllActs() 
{
    return db.query(DATATABLE, new String[] {

            KEY_ROWID2, 

            KEY_DATE,
            KEY_STEPS,
            KEY_CALs}, 
            null, 
            null, 
            null, 
            null, 
            null);
}

//---retrieves a particular title---
public Cursor getGoal
(long rowId) throws SQLException 
{
    Cursor mCursor =
            db.query(true, DATABASE_TABLE, new String[] {
                    KEY_ROWID,
                    KEY_GOAL, 
                    KEY_Current,
                    KEY_Target
                    }, 
                    KEY_ROWID + "=" + rowId, 
                    null,
                    null, 
                    null, 
                    null, 
                    null);
    if (mCursor != null) {
        mCursor.moveToFirst();
    }
    return mCursor;
}
public Cursor getAct(long rowId) throws SQLException 
{
    Cursor mCursor =
            db.query(true, DATATABLE, new String[] {
                    KEY_ROWID2,
                    KEY_DATE, 
                    KEY_STEPS,
                    KEY_CALs
                    }, 
                    KEY_ROWID2 + "=" + rowId, 
                    null,
                    null, 
                    null, 
                    null, 
                    null);
    if (mCursor != null) {
        mCursor.moveToFirst();
    }
    return mCursor;
}
public boolean updateAct(long rowId, String date, 
        String steps, String cals) 
        {
            ContentValues args = new ContentValues();
            args.put(KEY_DATE, date);
            args.put(KEY_STEPS, steps);
            args.put(KEY_CALs, cals);
            return db.update(DATATABLE, args, 
                             KEY_ROWID2 + "=" + rowId, null) > 0;
        }
/*public boolean updateCals(long rowId, double cals) 
        {
            ContentValues args = new ContentValues();
            args.put(KEY_TOTALCALS, cals);
            return db.update(CALTABLE, args, 
                             KEY_CALID + "=" + rowId, null) > 0;
        }*/

//---updates a title---
public boolean updateTitle(long rowId, String isbn, 
String title, String publisher) 
{
    ContentValues args = new ContentValues();
    args.put(KEY_GOAL, isbn);
    args.put(KEY_Current, title);
    args.put(KEY_Target, publisher);
    return db.update(DATABASE_TABLE, args, 
                     KEY_ROWID + "=" + rowId, null) > 0;
} 
}

日志:

05-26 14:42:03.895: E/AndroidRuntime(345): FATAL EXCEPTION: main
05-26 14:42:03.895: E/AndroidRuntime(345): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.b00348312.workout/com.b00348312.workout.WorkoutProgress}: android.database.sqlite.SQLiteException: no such column: _id: , while compiling: SELECT _id, date, steps, calories FROM acts
05-26 14:42:03.895: E/AndroidRuntime(345):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
05-26 14:42:03.895: E/AndroidRuntime(345):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
05-26 14:42:03.895: E/AndroidRuntime(345):  at android.app.ActivityThread.access$2300(ActivityThread.java:125)
05-26 14:42:03.895: E/AndroidRuntime(345):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
05-26 14:42:03.895: E/AndroidRuntime(345):  at android.os.Handler.dispatchMessage(Handler.java:99)
05-26 14:42:03.895: E/AndroidRuntime(345):  at android.os.Looper.loop(Looper.java:123)
05-26 14:42:03.895: E/AndroidRuntime(345):  at android.app.ActivityThread.main(ActivityThread.java:4627)
05-26 14:42:03.895: E/AndroidRuntime(345):  at java.lang.reflect.Method.invokeNative(Native Method)
05-26 14:42:03.895: E/AndroidRuntime(345):  at java.lang.reflect.Method.invoke(Method.java:521)
05-26 14:42:03.895: E/AndroidRuntime(345):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
05-26 14:42:03.895: E/AndroidRuntime(345):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
05-26 14:42:03.895: E/AndroidRuntime(345):  at dalvik.system.NativeStart.main(Native Method)
05-26 14:42:03.895: E/AndroidRuntime(345): Caused by: android.database.sqlite.SQLiteException: no such column: _id: , while compiling: SELECT _id, date, steps, calories FROM acts
05-26 14:42:03.895: E/AndroidRuntime(345):  at android.database.sqlite.SQLiteCompiledSql.native_compile(Native Method)
05-26 14:42:03.895: E/AndroidRuntime(345):  at android.database.sqlite.SQLiteCompiledSql.compile(SQLiteCompiledSql.java:91)
05-26 14:42:03.895: E/AndroidRuntime(345):  at android.database.sqlite.SQLiteCompiledSql.<init>(SQLiteCompiledSql.java:64)
05-26 14:42:03.895: E/AndroidRuntime(345):  at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:80)
05-26 14:42:03.895: E/AndroidRuntime(345):  at android.database.sqlite.SQLiteQuery.<init>(SQLiteQuery.java:46)
05-26 14:42:03.895: E/AndroidRuntime(345):  at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:42)
05-26 14:42:03.895: E/AndroidRuntime(345):  at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1345)
05-26 14:42:03.895: E/AndroidRuntime(345):  at android.database.sqlite.SQLiteDatabase.queryWithFactory(SQLiteDatabase.java:1229)
05-26 14:42:03.895: E/AndroidRuntime(345):  at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1184)
05-26 14:42:03.895: E/AndroidRuntime(345):  at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1264)
05-26 14:42:03.895: E/AndroidRuntime(345):  at com.b00348312.workout.DataBaseHelper.getAllActs(DataBaseHelper.java:168)
05-26 14:42:03.895: E/AndroidRuntime(345):  at com.b00348312.workout.WorkoutProgress.fillData(WorkoutProgress.java:30)
05-26 14:42:03.895: E/AndroidRuntime(345):  at com.b00348312.workout.WorkoutProgress.onCreate(WorkoutProgress.java:25)
05-26 14:42:03.895: E/AndroidRuntime(345):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
05-26 14:42:03.895: E/AndroidRuntime(345):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
05-26 14:42:03.895: E/AndroidRuntime(345):  ... 11 more

查看 logcat，它似乎告诉我我缺少列 "_id" 但我修改了数据库以包含此列，您可以在上面的数据库帮助程序代码中看到它。我错过了什么吗？

Answer 1

您可能已经修改了数据库以包含所需的列，但是直到再次调用方法 onCreate 或您在 onUpgrade 中实现更改后，此更改才会真正在数据库中实现 方法并修改数据库的版本。

尝试卸载应用程序，然后在模拟器/手机上再次安装该应用程序，以便再次调用 SQLiteOpenHelper 实现的 onCreate 方法。