Back to project page HydraListAndroid.
The source code is released under:
Apache License
If you think the Android project HydraListAndroid listed in this page is inappropriate, such as containing malicious code/tools or violating the copyright, please email info at java2s dot com, thanks.
/* * Copyright (C) 2013 The Android Open Source Project * /*from w w w.j a va2s. c o m*/ * 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.fada21.android.hydralist.expandable; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import android.animation.Animator; import android.animation.AnimatorListenerAdapter; import android.animation.AnimatorSet; import android.animation.ObjectAnimator; import android.animation.PropertyValuesHolder; import android.graphics.Canvas; import android.support.v4.view.ViewCompat; import android.view.View; import android.view.ViewTreeObserver; import android.widget.AbsListView; import android.widget.AdapterView; import com.fada21.android.hydralist.HydraListAdapter; import com.fada21.android.hydralist.expandable.interfaces.ExpandableListItem; import com.fada21.android.hydralist.util.PublicListView; /** * A custom listview which supports the preview of extra content corresponding to each cell by clicking on the cell to hide and show the extra content. */ public class ExpandingListViewDelegate { private boolean mShouldRemoveObserver = false; private List<View> mViewsToDraw = new ArrayList<View>(); private int[] mTranslate; private final PublicListView nlv; public ExpandingListViewDelegate(PublicListView nlv) { this.nlv = nlv; init(); } @SuppressWarnings("unchecked") public HydraListAdapter<ExpandableListItem> getExpandingAdapter() { return (HydraListAdapter<ExpandableListItem>) nlv.getAdapter(); } /** * Listens for item clicks and expands or collapses the selected view depending on its current state. */ private AdapterView.OnItemClickListener mItemClickListener; protected void init() { mItemClickListener = new AdapterView.OnItemClickListener() { @Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) { @SuppressWarnings("unchecked") ExpandableListItem item = (ExpandableListItem) nlv.getItemAtPosition(nlv.getPositionForView(view)); if (item.isExpandable()) { if (!item.isExpanded()) { expandView(view, position, id); } else { collapseView(view, position, id); } } } }; nlv.setOnItemClickListener(mItemClickListener); } /** * <p> * Calculates the top and bottom bound changes of the selected item. These values are also used to move the bounds of the items around the one that is * actually being expanded or collapsed. * </p> * * <p> * This method can be modified to achieve different user experiences depending on how you want the cells to expand or collapse. In this specific demo, the * cells always try to expand downwards (leaving top bound untouched), and similarly, collapse upwards (leaving top bound untouched). If the change in * bounds results in the complete disappearance of a cell, its lower bound is moved is moved to the top of the screen so as not to hide any additional * content that the user has not interacted with yet. Furthermore, if the collapsed cell is partially off screen when it is first clicked, it is translated * such that its full contents are visible. Lastly, this behavior varies slightly near the bottom of the listview in order to account for the fact that the * bottom bounds of the actual listview cannot be modified. * </p> */ private int[] getTopAndBottomTranslations(int top, int bottom, int yDelta, boolean isExpanding) { int yTranslateTop = 0; int yTranslateBottom = yDelta; int height = bottom - top; if (isExpanding) { boolean isOverTop = top < 0; boolean isBelowBottom = (top + height + yDelta) > nlv.getHeight(); if (isOverTop) { yTranslateTop = top; yTranslateBottom = yDelta - yTranslateTop; } else if (isBelowBottom) { int deltaBelow = top + height + yDelta - nlv.getHeight(); yTranslateTop = top - deltaBelow < 0 ? top : deltaBelow; yTranslateBottom = yDelta - yTranslateTop; } } else { int offset = nlv.computeVerticalScrollOffset(); int range = nlv.computeVerticalScrollRange(); int extent = nlv.computeVerticalScrollExtent(); boolean isListFilled = range >= extent; float pixelsConvertion = (float) nlv.getHeight() / (float) extent; int allowedToShinkTop = (int) (offset * pixelsConvertion); int allowedToShinkBottom = (int) ((range - offset - extent) * pixelsConvertion); boolean isCollapsingBelowBottom = isListFilled && yTranslateBottom > allowedToShinkBottom; boolean isCellCompletelyDisappearing = bottom - yTranslateBottom < 0; if (isCollapsingBelowBottom) { yTranslateTop = Math.min(allowedToShinkTop, yTranslateBottom); yTranslateBottom = yDelta - yTranslateTop; } else if (isCellCompletelyDisappearing) { yTranslateBottom = bottom; yTranslateTop = yDelta - yTranslateBottom; } } return new int[] { yTranslateTop, yTranslateBottom }; } /** * <p> * This method expands the view that was clicked and animates all the views around it to make room for the expanding view. There are several steps required * to do this which are outlined below. * </p> * * <li>Store the current top and bottom bounds of each visible item in the listview.</li> <li>Update the layout parameters of the selected view. In the * context of this method, the view should be originally collapsed and set to some custom height. The layout parameters are updated so as to wrap the * content of the additional text that is to be displayed.</li> * * <br/> * <br/> * <p> * After invoking a layout to take place, the listview will order all the items such that there is space for each view. This layout will be independent of * what the bounds of the items were prior to the layout so two pre-draw passes will be made. This is necessary because after the layout takes place, some * views that were visible before the layout may now be off bounds but a reference to these views is required so the animation completes as intended. * </p> * <br/> * * <li>The first predraw pass will set the bounds of all the visible items to their original location before the layout took place and then force another * layout. Since the bounds of the cells cannot be set directly, the method setSelectionFromTop can be used to achieve a very similar effect.</li> <li>The * expanding view's bounds are animated to what the final values should be from the original bounds.</li> <li>The bounds above the expanding view are * animated upwards while the bounds below the expanding view are animated downwards.</li> <li>The extra text is faded in as its contents become visible * throughout the animation process.</li> * * <br/> * <br/> * <p> * It is important to note that the listview is disabled during the animation because the scrolling behavior is unpredictable if the bounds of the items * within the listview are not constant during the scroll. * </p> * <br/> * * @param view * expanding view * @param position * item position in list * @param id * item id */ private void expandView(final View view, int position, long id) { // final ExpandableListItem item = (ExpandableListItem) nlv.getItemAtPosition(nlv.getPositionForView(view)); HydraListAdapter<ExpandableListItem> expandingAdapter = getExpandingAdapter(); final ExpandableListItem item = expandingAdapter.getDataProvider().get(position); ExpandingLayout expandingLayout = expandingAdapter.getExpandingHelper().getExpandedView(view, item); /* Store the original top and bottom bounds of all the cells. */ final int oldTop = view.getTop(); final int oldBottom = view.getBottom(); final HashMap<View, int[]> oldCoordinates = new HashMap<View, int[]>(); int childCount = nlv.getChildCount(); for (int i = 0; i < childCount; i++) { View v = nlv.getChildAt(i); ViewCompat.setHasTransientState(v, true); oldCoordinates.put(v, new int[] { v.getTop(), v.getBottom() }); } /* Update the layout so the extra content becomes visible. */ expandingLayout.setVisibility(View.VISIBLE); /* * Add an onPreDraw Listener to the listview. onPreDraw will get invoked after onLayout * and onMeasure have run but before anything has been drawn. This * means that the final post layout properties for all the items have already been * determined, but still have not been rendered onto the screen. */ final ViewTreeObserver observer = nlv.getViewTreeObserver(); observer.addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() { @Override public boolean onPreDraw() { /* Determine if this is the first or second pass. */ if (!mShouldRemoveObserver) { mShouldRemoveObserver = true; /* * Calculate what the parameters should be for setSelectionFromTop. * The ListView must be offset in a way, such that after the animation * takes place, all the cells that remain visible are rendered completely * by the ListView. */ int newTop = view.getTop(); int newBottom = view.getBottom(); int newHeight = newBottom - newTop; int oldHeight = oldBottom - oldTop; int delta = newHeight - oldHeight; mTranslate = getTopAndBottomTranslations(oldTop, oldBottom, delta, true); int currentTop = view.getTop(); int futureTop = oldTop - mTranslate[0]; int firstChildStartTop = nlv.getChildAt(0).getTop(); int firstVisiblePosition = nlv.getFirstVisiblePosition(); int deltaTop = currentTop - futureTop; int i; int childCount = nlv.getChildCount(); for (i = 0; i < childCount; i++) { View v = nlv.getChildAt(i); int height = v.getBottom() - Math.max(0, v.getTop()); if (deltaTop - height > 0) { firstVisiblePosition++; deltaTop -= height; } else { break; } } if (i > 0) { firstChildStartTop = 0; } nlv.setSelectionFromTop(firstVisiblePosition, firstChildStartTop - deltaTop); /* Request another layout to update the layout parameters of the cells. */ nlv.requestLayout(); /* * Return false such that the ListView does not redraw its contents on * this layout but only updates all the parameters associated with its * children. */ return false; } /* Remove the predraw listener so this method does not keep getting called. */ mShouldRemoveObserver = false; observer.removeOnPreDrawListener(this); int yTranslateTop = mTranslate[0]; int yTranslateBottom = mTranslate[1]; ArrayList<Animator> animations = new ArrayList<Animator>(); int index = nlv.indexOfChild(view); /* * Loop through all the views that were on the screen before the cell was * expanded. Some cells will still be children of the ListView while * others will not. The cells that remain children of the ListView * simply have their bounds animated appropriately. The cells that are no * longer children of the ListView also have their bounds animated, but * must also be added to a list of views which will be drawn in dispatchDraw. */ for (View v : oldCoordinates.keySet()) { int[] old = oldCoordinates.get(v); v.setTop(old[0]); v.setBottom(old[1]); if (v.getParent() == null) { mViewsToDraw.add(v); int delta = old[0] < oldTop ? -yTranslateTop : yTranslateBottom; animations.add(getAnimation(v, delta, delta)); } else { int i = nlv.indexOfChild(v); if (v != view) { int delta = i > index ? yTranslateBottom : -yTranslateTop; animations.add(getAnimation(v, delta, delta)); } ViewCompat.setHasTransientState(v, false); } } /* Adds animation for expanding the cell that was clicked. */ animations.add(getAnimation(view, -yTranslateTop, yTranslateBottom)); /* Adds an animation for fading in the extra content. */ animations.add(ObjectAnimator.ofFloat(view.findViewById(getExpandingAdapter().getExpandingHelper().getExpandingLayout()), View.ALPHA, 0, 1)); /* Disabled the ListView for the duration of the animation. */ nlv.setEnabled(false); nlv.setClickable(false); /* Play all the animations created above together at the same time. */ AnimatorSet s = new AnimatorSet(); s.playTogether(animations); s.addListener(new AnimatorListenerAdapter() { @Override public void onAnimationEnd(Animator animation) { item.setExpanded(true); nlv.setEnabled(true); nlv.setClickable(true); if (mViewsToDraw.size() > 0) { for (View v : mViewsToDraw) { ViewCompat.setHasTransientState(v, false); } } mViewsToDraw.clear(); } }); s.start(); return true; } }); } /** * By overriding dispatchDraw, we can draw the cells that disappear during the expansion process. When the cell expands, some items below or above the * expanding cell may be moved off screen and are thus no longer children of the ListView's layout. By storing a reference to these views prior to the * layout, and guaranteeing that these cells do not get recycled, the cells can be drawn directly onto the canvas during the animation process. After the * animation completes, the references to the extra views can then be discarded. */ public void dispatchDraw(Canvas canvas) { if (mViewsToDraw.size() == 0) { return; } for (View v : mViewsToDraw) { canvas.translate(0, v.getTop()); v.draw(canvas); canvas.translate(0, -v.getTop()); } } /** * This method collapses the view that was clicked and animates all the views around it to close around the collapsing view. There are several steps * required to do this which are outlined below. * * <li>Update the layout parameters of the view clicked so as to minimize its height to the original collapsed (default) state.</li> <li>After invoking a * layout, the listview will shift all the cells so as to display them most efficiently. Therefore, during the first predraw pass, the listview must be * offset by some amount such that given the custom bound change upon collapse, all the cells that need to be on the screen after the layout are rendered by * the listview.</li> <li>On the second predraw pass, all the items are first returned to their original location (before the first layout).</li> <li>The * collapsing view's bounds are animated to what the final values should be.</li> <li>The bounds above the collapsing view are animated downwards while the * bounds below the collapsing view are animated upwards.</li> <li>The extra text is faded out as its contents become visible throughout the animation * process.</li> * * @param view * collapsing view * @param position * item position in list * @param id * item id */ private void collapseView(final View view, int position, long id) { final ExpandableListItem item = (ExpandableListItem) nlv.getItemAtPosition(nlv.getPositionForView(view)); /* Store the original top and bottom bounds of all the cells. */ final int oldTop = view.getTop(); final int oldBottom = view.getBottom(); final HashMap<View, int[]> oldCoordinates = new HashMap<View, int[]>(); int childCount = nlv.getChildCount(); for (int i = 0; i < childCount; i++) { View v = nlv.getChildAt(i); ViewCompat.setHasTransientState(v, true); oldCoordinates.put(v, new int[] { v.getTop(), v.getBottom() }); } /* Update the layout so the extra content becomes invisible. */ view.setLayoutParams(new AbsListView.LayoutParams(AbsListView.LayoutParams.MATCH_PARENT, item.getCollapsedHeight())); /* Add an onPreDraw listener. */ final ViewTreeObserver observer = nlv.getViewTreeObserver(); observer.addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() { @Override public boolean onPreDraw() { if (!mShouldRemoveObserver) { /* * Same as for expandingView, the parameters for setSelectionFromTop must * be determined such that the necessary cells of the ListView are rendered * and added to it. */ mShouldRemoveObserver = true; int newTop = view.getTop(); int newBottom = view.getBottom(); int newHeight = newBottom - newTop; int oldHeight = oldBottom - oldTop; int deltaHeight = oldHeight - newHeight; mTranslate = getTopAndBottomTranslations(oldTop, oldBottom, deltaHeight, false); int currentTop = view.getTop(); int futureTop = oldTop + mTranslate[0]; int firstChildStartTop = nlv.getChildAt(0).getTop(); int firstVisiblePosition = nlv.getFirstVisiblePosition(); int deltaTop = currentTop - futureTop; int i; int childCount = nlv.getChildCount(); for (i = 0; i < childCount; i++) { View v = nlv.getChildAt(i); int height = v.getBottom() - Math.max(0, v.getTop()); if (deltaTop - height > 0) { firstVisiblePosition++; deltaTop -= height; } else { break; } } if (i > 0) { firstChildStartTop = 0; } nlv.setSelectionFromTop(firstVisiblePosition, firstChildStartTop - deltaTop); nlv.requestLayout(); return false; } mShouldRemoveObserver = false; observer.removeOnPreDrawListener(this); int yTranslateTop = mTranslate[0]; int yTranslateBottom = mTranslate[1]; int index = nlv.indexOfChild(view); int childCount = nlv.getChildCount(); for (int i = 0; i < childCount; i++) { View v = nlv.getChildAt(i); int[] old = oldCoordinates.get(v); if (old != null) { /* * If the cell was present in the ListView before the collapse and * after the collapse then the bounds are reset to their old values. */ v.setTop(old[0]); v.setBottom(old[1]); ViewCompat.setHasTransientState(v, false); } else { /* * If the cell is present in the ListView after the collapse but * not before the collapse then the bounds are calculated using * the bottom and top translation of the collapsing cell. */ int delta = i > index ? yTranslateBottom : -yTranslateTop; v.setTop(v.getTop() + delta); v.setBottom(v.getBottom() + delta); } } final View expandingLayout = view.findViewById(getExpandingAdapter().getExpandingHelper().getExpandingLayout()); /* Animates all the cells present on the screen after the collapse. */ ArrayList<Animator> animations = new ArrayList<Animator>(); for (int i = 0; i < childCount; i++) { View v = nlv.getChildAt(i); if (v != view) { float diff = i > index ? -yTranslateBottom : yTranslateTop; if (diff != 0f) animations.add(getAnimation(v, diff, diff)); } } /* Adds animation for collapsing the cell that was clicked. */ animations.add(getAnimation(view, yTranslateTop, -yTranslateBottom)); /* Adds an animation for fading out the extra content. */ animations.add(ObjectAnimator.ofFloat(expandingLayout, View.ALPHA, 1, 0)); /* Disabled the ListView for the duration of the animation. */ nlv.setEnabled(false); nlv.setClickable(false); /* Play all the animations created above together at the same time. */ AnimatorSet s = new AnimatorSet(); s.playTogether(animations); s.addListener(new AnimatorListenerAdapter() { @Override public void onAnimationEnd(Animator animation) { expandingLayout.setVisibility(View.GONE); view.setLayoutParams(new AbsListView.LayoutParams(AbsListView.LayoutParams.MATCH_PARENT, AbsListView.LayoutParams.WRAP_CONTENT)); item.setExpanded(false); nlv.setEnabled(true); nlv.setClickable(true); /* * Note that alpha must be set back to 1 in case this view is reused * by a cell that was expanded, but not yet collapsed, so its state * should persist in an expanded state with the extra content visible. */ expandingLayout.setAlpha(1); } }); s.start(); return true; } }); } /** * This method takes some view and the values by which its top and bottom bounds should be changed by. Given these params, an animation which will animate * these bound changes is created and returned. */ private Animator getAnimation(final View view, float translateTop, float translateBottom) { int top = view.getTop(); int bottom = view.getBottom(); int endTop = (int) (top + translateTop); int endBottom = (int) (bottom + translateBottom); PropertyValuesHolder translationTop = PropertyValuesHolder.ofInt("top", top, endTop); PropertyValuesHolder translationBottom = PropertyValuesHolder.ofInt("bottom", bottom, endBottom); return ObjectAnimator.ofPropertyValuesHolder(view, translationTop, translationBottom); } }