Question

我正在尝试更新我的数据库，并且已经传递了内容值，包括ID，我需要检索更新语句的ID。

 public int updateEntryById(ContentValues diaryValues) {
    ContentValues updateValues = new ContentValues();

    String diaryID = updateValues.getAsString(Diary.DiaryItem.COLUMN_NAME_ID);
    Log.i(TAG, "ID" + diaryID);
    String  updateWhere = Diary.DiaryItem.COLUMN_NAME_ID + " = " + diaryID;
    Log.i(TAG, "UpdateWhere query values" + updateWhere);
    SQLiteDatabase db = diaryDbHelper.getWritableDatabase();

我创建了一个内容值的实例，并将id作为要传递的字符串。

但是logcat给了我id = null

更新条目有更多代码，但具体问题与ID有关。

任何想法？

public class UpdateActivity extends Activity implements LocationListener {

    private TextView mID;
    private EditText mTitle;
    private EditText mDate;
    private EditText mTime;
    private EditText mEntry;
    private TextView mLat;
    private TextView mLong;
    private ImageButton mSaveButton;
    private DAO getDAO;

    private int mYear;
    private int mMonth;
    private int mDay;
    private int mHour;
    private int mMinute;

    static final int DATE_DIALOG_ID = 0;
    static final int TIME_DIALOG_ID = 1;

    private final String TAG ="UpdateActivity";

     private TextView latituteField;
      private TextView longitudeField;
      private LocationManager locationManager;
      private String provider;


    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.update_entry); //Sets the view for Diary Entry 

        /**References to the fields where data is inputted**/

        mTitle = (EditText) findViewById(R.id.diaryform_et_title); 
        mDate= (EditText) findViewById(R.id.diaryform_et_date);
        mTime= (EditText) findViewById(R.id.diaryform_et_time);
        mEntry= (EditText) findViewById(R.id.diaryform_et_entry);
        mLat= (TextView) findViewById(R.id.diaryform_tv_lat);
        mLong= (TextView) findViewById(R.id.diaryform_tv_long);
        mID = (TextView) findViewById(R.id.diaryform_tv_ID);

        final Calendar c = Calendar.getInstance();
        mYear = c.get(Calendar.YEAR);
        mMonth = c.get(Calendar.MONTH);
        mDay = c.get(Calendar.DAY_OF_MONTH);
        mHour = c.get(Calendar.HOUR_OF_DAY);
        mMinute = c.get(Calendar.MINUTE);

        updateDateDisplay();
        updateTimeDisplay();


        mSaveButton = (ImageButton) findViewById(R.id.diaryform_ib_save); //Reference to the save button is stored in mSaveButton


        Intent showTitle = getIntent();
        String fieldTitle = showTitle.getStringExtra(Constants.DIARY_TITLE);
        mTitle.setText(fieldTitle);
        Log.i(TAG,"Field title 2: "+ fieldTitle);



    protected void saveDiaryItem() {
        ContentValues saveValues = new ContentValues();

        saveValues.put(Diary.DiaryItem.COLUMN_NAME_ID, mID.getText().toString());
        saveValues.put(Diary.DiaryItem.COLUMN_NAME_DIARY_TITLE, mTitle.getText().toString());
        saveValues.put(Diary.DiaryItem.COLUMN_NAME_DIARY_DATE, mDate.getText().toString());
        saveValues.put(Diary.DiaryItem.COLUMN_NAME_DIARY_TIME, mTime.getText().toString());
        saveValues.put(Diary.DiaryItem.COLUMN_NAME_DIARY_ENTRY, mEntry.getText().toString());
        saveValues.put(Diary.DiaryItem.COLUMN_NAME_DIARY_LAT, mLat.getText().toString());
        saveValues.put(Diary.DiaryItem.COLUMN_NAME_DIARY_LONG, mLong.getText().toString());

        Log.i(TAG, "About to insert data" + saveValues);
        DAO diarySave = new DAO(getBaseContext());

        diarySave.updateEntryById(saveValues);
        Log.i(TAG, "IM BACK!"); 
    }

Answer 1

public int updateEntryById(ContentValues diaryValues) {
    ContentValues updateValues = new ContentValues();

    String diaryID = updateValues.getAsString(Diary.DiaryItem.COLUMN_NAME_ID);

您正在尝试从刚创建的空updateValues对象中获取ID。也许你的意思是diaryValues.getAsString()。

更新数据库无法运行... android

1 个答案: