com.thehayro.view.InfinitePagerAdapter Maven / Gradle / Ivy
/*
* Copyright (C) 2013 Onur-Hayri Bakici
*
* 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.thehayro.view;
import static com.thehayro.internal.Constants.PAGE_COUNT;
import com.thehayro.internal.Constants;
import com.thehayro.internal.PageModel;
import android.support.v4.view.PagerAdapter;
import android.util.Log;
import android.view.View;
import android.view.ViewGroup;
/**
* Base class providing the adapter to populate inside of a {@link com.thehayro.view.InfiniteViewPager}.
* The indication for each page is up the implementation. Meaning that it is up to the implementation what the next
* and previous page indication is. This is more generic than the regular PagerAdapter
* implementation, where the pages are indicated by its index and accessed through
* {@link android.support.v4.view.ViewPager#setCurrentItem(int, boolean)}.
*
*
* When you implement an adapter you must implement the following methods:
*
* - {@link com.thehayro.view.InfinitePagerAdapter#instantiateItem(Object)}
* - {@link InfinitePagerAdapter#getNextIndicator()}
* - {@link InfinitePagerAdapter#getPreviousIndicator()}
*
* @param an indicator datatype to distinguish the pages.
*/
public abstract class InfinitePagerAdapter extends PagerAdapter {
private PageModel[] mPageModels;
private T mCurrentIndicator;
/**
* Standard constructor.
* @param initValue the initial indicator value the ViewPager should start with.
*/
public InfinitePagerAdapter(T initValue) {
mCurrentIndicator = initValue;
mPageModels = new PageModel[PAGE_COUNT];
}
/**
* This method is only called, when this pagerAdapter is initialized.
*/
@Override
public final Object instantiateItem(final ViewGroup container, final int position) {
if (Constants.DEBUG) {
Log.i("InfiniteViewPager", String.format("instantiating position %s", position));
}
final PageModel model = createPageModel(position);
mPageModels[position] = model;
container.addView(model.getParentView());
return model;
}
/**
* fills the page on index {@code position}.
* @param position the page index to fill the page.
*/
void fillPage(final int position) {
if (Constants.DEBUG) {
Log.d("InfiniteViewPager", "setup Page " + position);
printPageModels("before newPage");
}
final PageModel oldModel = mPageModels[position];
final PageModel newModel = createPageModel(position);
if (oldModel == null || newModel == null) {
Log.w(Constants.LOG_TAG, "fillPage no model found " + oldModel + " " + newModel);
return;
}
// moving the new created views to the page of the viewpager
oldModel.removeAllChildren();
for (final View newChild : newModel.getChildren()) {
newModel.removeViewFromParent(newChild);
oldModel.addChild(newChild);
}
mPageModels[position].setIndicator(newModel.getIndicator());
}
/**
* Creates the internal page model. This method calls the {@link #instantiateItem(Object)} method
* that creates the page content.
* @param pagePosition the position in the pageModel array between [0..2]
* @return a new instance of a page model.
*/
private PageModel createPageModel(final int pagePosition) {
final T indicator = getIndicatorFromPagePosition(pagePosition);
final ViewGroup view = instantiateItem(indicator);
return new PageModel(view, indicator);
}
protected final T getCurrentIndicator() {
return mCurrentIndicator;
}
private T getIndicatorFromPagePosition(final int pagePosition) {
T indicator = null;
switch (pagePosition) {
case Constants.PAGE_POSITION_LEFT:
indicator = getPreviousIndicator();
break;
case Constants.PAGE_POSITION_CENTER:
indicator = getCurrentIndicator();
break;
case Constants.PAGE_POSITION_RIGHT:
indicator = getNextIndicator();
break;
}
return indicator;
}
/**
* Package internal. Moves contents from page index {@code from} to page index {@code to}.
* @param from page index to move contents from.
* @param to page index to move contents to.
*/
void movePageContents(final int from, final int to) {
final PageModel fromModel = mPageModels[from];
final PageModel toModel = mPageModels[to];
if (fromModel == null || toModel == null) {
Log.w(Constants.LOG_TAG, "fillPage no model found " + fromModel + " " + toModel);
return;
}
if (Constants.DEBUG) {
Log.d("InfiniteViewPager",
String.format("Moving page %s to %s, indicator from %s to %s", from, to,
fromModel.getIndicator(), toModel.getIndicator()));
printPageModels("before");
}
toModel.removeAllChildren();
for (View view : fromModel.getChildren()) {
fromModel.removeViewFromParent(view);
toModel.addChild(view);
}
if (Constants.DEBUG) {
printPageModels("transfer");
}
mPageModels[to].setIndicator(fromModel.getIndicator());
if (Constants.DEBUG) {
printPageModels("after");
}
}
void reset() {
for (PageModel pageModel : mPageModels) {
pageModel.removeAllChildren();
}
}
/**
* Sets {@code indicator} as the current visible indicator.
* @param indicator a indicator value.
*/
void setCurrentIndicator(final T indicator) {
mCurrentIndicator = indicator;
}
/**
*
* @return the next indicator.
*/
public abstract T getNextIndicator();
/**
*
* @return the previous indicator.
*/
public abstract T getPreviousIndicator();
/**
* Instantiates a page.
* @param indicator the indicator the page should be instantiated with.
* @return a ViewGroup containing the page layout.
*/
public abstract ViewGroup instantiateItem(T indicator);
/**
*
* @param currentIndicator the current value of the indicator.
* @return a string representation of the current indicator.
* @see #convertToIndicator(String)
*/
public String getStringRepresentation(final T currentIndicator) {
return "";
}
/**
* Convert the represented string back to its indicator
* @param representation the string representation of the current indicator.
* @return the indicator.
*/
public T convertToIndicator(final String representation) {
return getCurrentIndicator();
}
@Override
public final int getCount() {
return PAGE_COUNT;
}
@Override
public void destroyItem(final ViewGroup container, final int position, final Object object) {
final PageModel model = (PageModel) object;
container.removeView(model.getParentView());
}
@Override
public final boolean isViewFromObject(final View view, final Object o) {
return view == ((PageModel)o).getParentView();
}
// Debug related methods
private void printPageModels(final String tag) {
for (int i = 0; i < PAGE_COUNT; i++) {
printPageModel(tag, mPageModels[i], i);
}
}
private void printPageModel(final String tag, final PageModel model, int modelPos) {
final String builder = String.format("%s: ModelPos %s, indicator %s, " +
"Childcount %s viewChildCount %s tag %s",
tag, modelPos,
model.getIndicator(), model.getChildren().size(), model.getParentView().getChildCount(),
model.getParentView().getTag());
Log.d("InfiniteViewPager", builder);
}
}
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