MemoController.java

/*
 * MemoController.java
 *
 * Copyright � 1998-2011 Research In Motion Limited
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * Note: For the sake of simplicity, this sample application may not leverage
 * resource bundles and resource strings.  However, it is STRONGLY recommended
 * that application developers make use of the localization features available
 * within the BlackBerry development platform to ensure a seamless application
 * experience across a variety of languages and geographies.  For more information
 * on localizing your application, please refer to the BlackBerry Java Development
 * Environment Development Guide associated with this release.
 */

package com.rim.samples.device.memoapidemo;

import javax.microedition.pim.PIMException;
import javax.microedition.pim.PIMList;

import net.rim.blackberry.api.pdap.BlackBerryMemo;
import net.rim.device.api.ui.Field;
import net.rim.device.api.ui.component.BasicEditField;
import net.rim.device.api.ui.component.LabelField;

/**
 * Provides access to a memo's data via fields that can be displayed on a
 * screen.
 */
public final class MemoController {
    static final int FOR_VIEW = 0;
    static final int FOR_EDIT = 1;
    static final int FOR_TITLE = 2;
    static final int FOR_ADD = 3;

    private final BlackBerryMemo _memo;
    private final BasicEditField _titleField;
    private final BasicEditField _uidField;
    private final BasicEditField _notesField;

    /**
     * Constructor. Creates the displayable fields and populates them with all
     * available data from the provided memo.
     * 
     * @param memo
     *            The memo being "controlled".
     */
    public MemoController(final BlackBerryMemo memo) {
        _memo = memo;

        final PIMList list = memo.getPIMList();

        _uidField =
                new BasicEditField(list.getFieldLabel(BlackBerryMemo.UID)
                        + ": ", "", 128, BasicEditField.FILTER_INTEGER);
        _titleField =
                new BasicEditField(list.getFieldLabel(BlackBerryMemo.TITLE)
                        + ": ", "");
        _notesField =
                new BasicEditField(list.getFieldLabel(BlackBerryMemo.NOTE)
                        + ": ", "");

        // Populate the fields with all available data.
        if (_memo.countValues(BlackBerryMemo.TITLE) > 0) {
            final String title = _memo.getString(BlackBerryMemo.TITLE, 0);
            _titleField.setText(title);
        }

        if (_memo.countValues(BlackBerryMemo.UID) > 0) {
            final String uid = _memo.getString(BlackBerryMemo.UID, 0);
            _uidField.setText(uid);
        }

        if (_memo.countValues(BlackBerryMemo.NOTE) > 0) {
            final String notes = _memo.getString(BlackBerryMemo.NOTE, 0);
            _notesField.setText(notes);
        }
    }

    /**
     * Provides displayable fields containing the memo's data. Fields may be
     * editable or non-editable depending on the type of rendering requested.
     * 
     * @param type
     *            Type of rendering. One of the FOR_* constants.
     * @return Single LabelField if a title is being rendered; otherwise an
     *         array of Fields.
     * @throws IllegalArgumentException
     *             if the provided type is not one of the FOR_* constants.
     */
    /* package */Object render(final int type) {
        switch (type) {
        case FOR_TITLE:
            return new LabelField(_titleField.getText());

        case FOR_ADD:
            setEditable(true);

            return new Field[] { _titleField, _notesField };

        case FOR_EDIT:
            setEditable(true);
            _uidField.setEditable(false); // UID cannot be changed once a memo
                                          // has been committed.

            return new Field[] { _titleField, _notesField };

        case FOR_VIEW:
            setEditable(false);

            return new Field[] { _uidField, _notesField };

        default:
            throw new IllegalArgumentException();
        }
    }

    /**
     * Updates the memos with the data contained in the fields.
     */
    void updateMemo() {
        String s;

        if (_uidField.isEditable()) {
            // UID cannot be changed once a memo has been committed.
            s = _uidField.getText();

            if (_memo.countValues(BlackBerryMemo.UID) > 0) {
                _memo.setString(BlackBerryMemo.UID, 0, 0, s);
            } else {
                _memo.addString(BlackBerryMemo.UID, 0, s);
            }
        }

        s = _titleField.getText();

        if (_memo.countValues(BlackBerryMemo.TITLE) > 0) {
            _memo.setString(BlackBerryMemo.TITLE, 0, 0, s);
        } else {
            _memo.addString(BlackBerryMemo.TITLE, 0, s);
        }

        s = _notesField.getText();

        if (_memo.countValues(BlackBerryMemo.NOTE) > 0) {
            _memo.setString(BlackBerryMemo.NOTE, 0, 0, s);
        } else {
            _memo.addString(BlackBerryMemo.NOTE, 0, s);
        }
    }

    /**
     * Commits the memo to persistent storage.
     * 
     * @return True if the commit was successful; otherwise false.
     */
    boolean commitMemo() {
        try {
            _memo.commit();

            return true;
        } catch (final PIMException e) {
            MemoApiDemo.errorDialog("BlackBerryMemo#commit() threw "
                    + e.toString());
            return false;
        }
    }

    /**
     * Retrieves this controller's memo.
     * 
     * @return This controller's memo.
     */
    BlackBerryMemo getMemo() {
        return _memo;
    }

    /**
     * Sets this controller's fields to be editable or non-editable.
     * 
     * @param editable
     *            True if fields should be editable; false otherwise.
     */
    private void setEditable(final boolean editable) {
        _uidField.setEditable(editable);
        _titleField.setEditable(editable);
        _notesField.setEditable(editable);
    }
}