Java tutorial
/* * Copyright (c) 2012 Wireless Designs, LLC * * Permission is hereby granted, free of charge, to any person obtaining * a copy of this software and associated documentation files (the * "Software"), to deal in the Software without restriction, including * without limitation the rights to use, copy, modify, merge, publish, * distribute, sublicense, and/or sell copies of the Software, and to * permit persons to whom the Software is furnished to do so, subject to * the following conditions: * * The above copyright notice and this permission notice shall be * included in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ package com.medhdj.pagergallery; import android.content.Context; import android.graphics.Point; import android.graphics.drawable.TransitionDrawable; import android.support.v4.view.ViewPager; import android.util.AttributeSet; import android.view.MotionEvent; import android.view.View; import android.widget.FrameLayout; /** * PagerContainer: A layout that displays a ViewPager with its children that are * outside the typical pager bounds. */ public class PagerGalleryContainer extends FrameLayout implements ViewPager.OnPageChangeListener { private ViewPager mPager; boolean mNeedsRedraw = false; private Point mCenter = new Point(); private Point mInitialTouch = new Point(); private int mPreviousSelectedPosition; private OnItemChangedListener mOnItemChangedListener; public PagerGalleryContainer(Context context) { super(context); init(); } public PagerGalleryContainer(Context context, AttributeSet attrs) { super(context, attrs); init(); } public PagerGalleryContainer(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); init(); } private void init() { // Disable clipping of children so non-selected pages are visible setClipChildren(false); // Child clipping doesn't work with hardware acceleration in Android // 3.x/4.x // You need to set this value here if using hardware acceleration in an // application targeted at these releases. setLayerType(View.LAYER_TYPE_SOFTWARE, null); } @Override protected void onFinishInflate() { try { mPager = (ViewPager) getChildAt(0); mPager.setOnPageChangeListener(this); mPager.setClipChildren(false); mPager.setOnTouchListener(new View.OnTouchListener() { @Override public boolean onTouch(View v, MotionEvent event) { v.getParent().requestDisallowInterceptTouchEvent(true); return false; } }); } catch (Exception e) { throw new IllegalStateException("The root child of PagerContainer must be a ViewPager"); } } public ViewPager getViewPager() { return mPager; } @Override protected void onSizeChanged(int w, int h, int oldw, int oldh) { mCenter.x = w / 2; mCenter.y = h / 2; } @Override public boolean onTouchEvent(MotionEvent ev) { int marginClick = 10; // We capture any touches not already handled by the ViewPager // to implement scrolling from a touch outside the pager bounds. switch (ev.getAction()) { case MotionEvent.ACTION_DOWN: mInitialTouch.x = (int) ev.getX(); mInitialTouch.y = (int) ev.getY(); break; case MotionEvent.ACTION_UP: // capturing the click on the PagerGalleryContainer to perform // selection of an item in the PagerGallery if ((int) ev.getX() >= (mInitialTouch.x - marginClick) && (int) ev.getX() <= (mInitialTouch.x + marginClick) && (int) ev.getY() >= mInitialTouch.y - marginClick && (int) ev.getY() <= mInitialTouch.y + marginClick) { float pageWidth = mPager.getChildAt(0).getWidth(); float pageMargin = mPager.getPageMargin(); int jump = Math.round((ev.getX() - mCenter.x) / (pageWidth + pageMargin)); jump = mPager.getCurrentItem() + jump; if (jump < 0) { jump = 0; } else if (jump > mPager.getChildCount()) { jump = mPager.getChildCount() - 1; } mPager.setCurrentItem(jump, true); return true; } break; default: break; } ev.offsetLocation(mCenter.x - mInitialTouch.x, mCenter.y - mInitialTouch.y); return mPager.dispatchTouchEvent(ev); } @Override public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { // Force the container to redraw on scrolling. // Without this the outer pages render initially and then stay static if (mNeedsRedraw) invalidate(); } @Override public void onPageSelected(int position) { if (position == mPreviousSelectedPosition) { return; } View v = mPager.getChildAt(position); if (v != null) { if (v.getBackground() instanceof TransitionDrawable) { TransitionDrawable transition = (TransitionDrawable) v.getBackground(); if (transition != null) { transition.startTransition(700); } } } View mprev = mPager.getChildAt(mPreviousSelectedPosition); if (mprev != null) { if (mprev.getBackground() instanceof TransitionDrawable) { TransitionDrawable transition = (TransitionDrawable) mprev.getBackground(); if (transition != null) { transition.reverseTransition(700); transition.resetTransition(); } } } if (mOnItemChangedListener != null) { mOnItemChangedListener.onItemSelected(v, position); mOnItemChangedListener.onItemUnSelected(mprev, mPreviousSelectedPosition); } mPreviousSelectedPosition = position; } @Override public void onPageScrollStateChanged(int state) { mNeedsRedraw = (state != ViewPager.SCROLL_STATE_IDLE); } public void setCurrentItem(final int item) { if (mPager.getChildCount() > 0) { mPager.setCurrentItem(item, false); } else { mPager.post(new Runnable() { @Override public void run() { mPager.setCurrentItem(item, false); } }); } } public void setOnItemChangedListener(OnItemChangedListener listener) { mOnItemChangedListener = listener; } public final OnItemChangedListener getOnItemSelectedListener() { return mOnItemChangedListener; } /** * * @author medhdj interface to listen to items position changing * */ public interface OnItemChangedListener { /** * * @param item * The item beeing selected * @param position * The position of the item whithin the Pager */ void onItemSelected(View item, int position); /** * * @param item * The previous selected item * @param position * The previous selcted item position */ void onItemUnSelected(View item, int position); } }