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/*
* Copyright (C) 2013 The Android Open Source Project
*
* 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.
*/
package com.android.gallery3d.filtershow.history;
import android.graphics.drawable.Drawable;
import android.view.MenuItem;
import java.util.Vector;
public class HistoryManager {
private static final String LOGTAG = "HistoryManager";
private Vector<HistoryItem> mHistoryItems = new Vector<HistoryItem>();
private int mCurrentPresetPosition = 0;
private MenuItem mUndoMenuItem = null;
private MenuItem mRedoMenuItem = null;
private MenuItem mResetMenuItem = null;
public void setMenuItems(MenuItem undoItem, MenuItem redoItem, MenuItem resetItem) {
mUndoMenuItem = undoItem;
mRedoMenuItem = redoItem;
mResetMenuItem = resetItem;
updateMenuItems();
}
private int getCount() {
return mHistoryItems.size();
}
public HistoryItem getItem(int position) {
if (position > mHistoryItems.size() - 1) {
return null;
}
return mHistoryItems.elementAt(position);
}
private void clear() {
mHistoryItems.clear();
}
private void add(HistoryItem item) {
mHistoryItems.add(item);
}
private void notifyDataSetChanged() {
// TODO
}
public boolean canReset() {
if (getCount() <= 0) {
return false;
}
return true;
}
public boolean canUndo() {
if (mCurrentPresetPosition == getCount() - 1) {
return false;
}
return true;
}
public boolean canRedo() {
if (mCurrentPresetPosition == 0) {
return false;
}
return true;
}
public void updateMenuItems() {
if (mUndoMenuItem != null) {
setEnabled(mUndoMenuItem, canUndo());
}
if (mRedoMenuItem != null) {
setEnabled(mRedoMenuItem, canRedo());
}
if (mResetMenuItem != null) {
setEnabled(mResetMenuItem, canReset());
}
}
private void setEnabled(MenuItem item, boolean enabled) {
item.setEnabled(enabled);
Drawable drawable = item.getIcon();
if (drawable != null) {
drawable.setAlpha(enabled ? 255 : 80);
}
}
public void setCurrentPreset(int n) {
mCurrentPresetPosition = n;
updateMenuItems();
notifyDataSetChanged();
}
public void reset() {
if (getCount() == 0) {
return;
}
clear();
updateMenuItems();
}
public HistoryItem getLast() {
if (getCount() == 0) {
return null;
}
return getItem(0);
}
public HistoryItem getCurrent() {
return getItem(mCurrentPresetPosition);
}
public void addHistoryItem(HistoryItem preset) {
insert(preset, 0);
updateMenuItems();
}
private void insert(HistoryItem preset, int position) {
if (mCurrentPresetPosition != 0) {
// in this case, let's discount the presets before the current one
Vector<HistoryItem> oldItems = new Vector<HistoryItem>();
for (int i = mCurrentPresetPosition; i < getCount(); i++) {
oldItems.add(getItem(i));
}
clear();
for (int i = 0; i < oldItems.size(); i++) {
add(oldItems.elementAt(i));
}
mCurrentPresetPosition = position;
notifyDataSetChanged();
}
mHistoryItems.insertElementAt(preset, position);
mCurrentPresetPosition = position;
notifyDataSetChanged();
}
public int redo() {
mCurrentPresetPosition--;
if (mCurrentPresetPosition < 0) {
mCurrentPresetPosition = 0;
}
notifyDataSetChanged();
updateMenuItems();
return mCurrentPresetPosition;
}
public int undo() {
mCurrentPresetPosition++;
if (mCurrentPresetPosition >= getCount()) {
mCurrentPresetPosition = getCount() - 1;
}
notifyDataSetChanged();
updateMenuItems();
return mCurrentPresetPosition;
}
}
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