Question

我正在开发一个应用程序，其中我需要一个ListView，其行包含TextView，2 CheckBox和Spinner。

但是，我遇到了Spinner onItemSelected()的问题，因为每次为每行显示时都会调用它。在这个方法中，我正在使用所选选项更新数据库记录，但是当Android自动调用它时，每次项目都会重置，因为Android会将其调用位置0，这是数据库中更新的值。

我已经阅读了很多与onItemSelected()和一些黑客有关的问题的链接，但所有这些链接都是在没有ListView的情况下使用的。这里有什么要点吗？

我试图在列表中跟踪哪些位置实际显示以使其工作但却没有。我认为这是因为Android中的回收导致了已经显示的Spinners的故障排除方法！

所以重点是：如何在显示微调器时从Android调用中选择用户，从而区分真实的onItemSelected()来电？

以下是我的适配器的代码，它扩展了SimpleCursorAdapter。

提前非常感谢你。

public ParticipationAdapter(Context context, int layout, Cursor c, String[] from, int[] to) {
    super(context, layout, c, from, to);
    mActivity = (Activity)context;
    ParticipationComment.ParticipationCommentManager commentManager = new ParticipationComment.ParticipationCommentManager(mActivity);
    mParticipationCommentsCursor = commentManager.get();
    mActivity.startManagingCursor(mParticipationCommentsCursor);
    commentManager.detach();
    mPositionsOfCursorIds = getPositionsOfCursorIds(mParticipationCommentsCursor);
    mSpinnerPositionsDisplayed = new ArrayList<Integer>();
}

@Override
public View getView(final int participationPosition, View convertView, ViewGroup parent) {
    final Cursor participationsCursor = getCursor();
    mActivity.startManagingCursor(participationsCursor);
    participationsCursor.moveToPosition(participationPosition);
    View participationRow;
    if (convertView == null) {
        participationRow = LayoutInflater.from(mActivity).inflate(R.layout.participation_row_student, null);
    } else {
        mSpinnerPositionsDisplayed.remove((Integer)convertView.getTag());
        participationRow = convertView;
    }
    participationRow.setTag(participationPosition);
    Spinner commentSpinner = (Spinner)participationRow.findViewById(R.id.participation_comment_id_spinner);
    SimpleCursorAdapter commentSpinnerAdapter = new SimpleCursorAdapter(
            mActivity,
            android.R.layout.simple_spinner_item,
            mParticipationCommentsCursor,
            new String[] {DatabaseManager.NAME},
            new int[] {android.R.id.text1}
    );
    commentSpinnerAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    commentSpinner.setAdapter(commentSpinnerAdapter);
    long participationCommentId = participationsCursor.getLong(participationsCursor.getColumnIndex(DatabaseManager.PARTICIPATION_COMMENT_ID));
    if (participationCommentId != 0) {
        commentSpinner.setSelection(mPositionsOfCursorIds.get(participationCommentId));
    }
    commentSpinner.setOnItemSelectedListener(new OnItemSelectedListener() {
        @Override
        public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
            participationsCursor.moveToPosition(participationPosition);
            if (!mSpinnerPositionsDisplayed.contains(participationPosition)) {
                // Android calls this method the first time a Spinner is displayed,
                // to differentiate from a real user click we check if the current Spinner's position
                // in the ListView is being shown
                mSpinnerPositionsDisplayed.add(participationPosition);
            } else {
                ParticipationComment participationComment = new ParticipationComment((Cursor)parent.getItemAtPosition(position));
                Participation.ParticipationManager participationManager = new Participation.ParticipationManager(mActivity);
                Participation participation = new Participation(participationsCursor);
                participation.setConnectionProfileParticipationCommentId(participationComment.getConnectionProfileId());
                participation.setParticipationCommentId(participationComment.getIdOpenErp());
                participation.setChanged(true);
                participationManager.update(participation);
                participationManager.detach();
            }
        }

        @Override
        public void onNothingSelected(AdapterView<?> parent) {
            // Not used
        }
    });
    TextView studentName = (TextView)participationRow.findViewById(R.id.participation_student_name);
    studentName.setText(participationsCursor.getString(participationsCursor.getColumnIndex(DatabaseManager.NAME)));
    CheckBox expectedPresent = (CheckBox)participationRow.findViewById(R.id.participation_expected_present_value);
    expectedPresent.setChecked(participationsCursor.getInt(participationsCursor.getColumnIndex(DatabaseManager.EXPECTED_PRESENT)) == 1);
    CheckBox present = (CheckBox)participationRow.findViewById(R.id.participation_present_value);
    present.setChecked(participationsCursor.getInt(participationsCursor.getColumnIndex(DatabaseManager.PRESENT)) == 1);
    return participationRow;
}

Answer 1

更好的方法是使用AlertDialog Variant ..如this ..并创建一个按钮，该按钮最初将第一个选择作为其Text并根据AlertDialog选项进行更改。

Answer 2

如何使用小标志来放弃第一次调用ItemSelected？

如何让ListView中的Spinner在Android中运行？

2 个答案: