Java tutorial
/* * Copyright 2013 Roman Nurik, Tim Roes * * 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 de.timroes.swipetodismiss; import android.annotation.TargetApi; import android.content.Context; import android.graphics.Rect; import android.os.Build; import android.os.Handler; import android.os.Message; import android.support.v4.view.MotionEventCompat; import android.view.Gravity; import android.view.LayoutInflater; import android.view.MotionEvent; import android.view.VelocityTracker; import android.view.View; import android.view.ViewConfiguration; import android.view.ViewGroup; import android.widget.AbsListView; import android.widget.Button; import android.widget.ListView; import android.widget.PopupWindow; import android.widget.TextView; import com.nineoldandroids.animation.Animator; import com.nineoldandroids.animation.AnimatorListenerAdapter; import com.nineoldandroids.animation.ValueAnimator; import java.lang.ref.WeakReference; import java.util.ArrayList; import java.util.Collections; import java.util.List; import java.util.SortedSet; import java.util.TreeSet; import static com.nineoldandroids.view.ViewHelper.setAlpha; import static com.nineoldandroids.view.ViewHelper.setTranslationX; import static com.nineoldandroids.view.ViewPropertyAnimator.animate; /** * A {@link android.view.View.OnTouchListener} that makes the list items in a * {@link ListView} dismissable. {@link ListView} is given special treatment * because by default it handles touches for its list items... i.e. it's in * charge of drawing the pressed state (the list selector), handling list item * clicks, etc. * * Read the README file for a detailed explanation on how to use this class. */ public final class SwipeDismissList implements View.OnTouchListener { // Cached ViewConfiguration and system-wide constant values private int mSlop; private int mMinFlingVelocity; private int mMaxFlingVelocity; private long mAnimationTime; // Fixed properties private AbsListView mListView; private OnDismissCallback mCallback; private int mViewWidth = 1; // 1 and not 0 to prevent dividing by zero // Transient properties private SortedSet<PendingDismissData> mPendingDismisses = new TreeSet<PendingDismissData>(); private int mDismissAnimationRefCount = 0; private float mDownX; private float mDownY; private boolean mSwiping; private VelocityTracker mVelocityTracker; private int mDownPosition; private View mDownView; private int mSwipeLayout; private boolean mPaused; private boolean mEnabled; private float mDensity; private UndoMode mMode; private List<Undoable> mUndoActions; private Handler mHandler; private PopupWindow mUndoPopup; private int mPopupXOffset = 0; private int mPopupYOffset = 15; private int mPopupGravity = Gravity.CENTER_HORIZONTAL | Gravity.BOTTOM; private TextView mUndoText; private Button mUndoButton; private SwipeDirection mSwipeDirection = SwipeDirection.BOTH; private int mAutoHideDelay = 5000; private String mDeleteString = "Item deleted"; private String mDeleteMultipleString = "%d items deleted"; private int mDelayedMsgId; /** * Defines the mode a {@link SwipeDismissList} handles multiple undos. */ public enum UndoMode { /** * Only give the user the possibility to undo the last action. * As soon as another item is deleted, there is no chance to undo * the previous deletion. */ SINGLE_UNDO, /** * Give the user the possibility to undo multiple deletions one by one. * Every click on Undo will undo the previous deleted item. Undos will be * collected as long as the undo popup stays open. As soon as the popup * vanished (because {@link #setAutoHideDelay(int) autoHideDelay} is over) * all saved undos will be discarded. */ MULTI_UNDO, /** * Give the user the possibility to undo multiple deletions all together. * As long as the popup stays open all further deletions will be collected. * A click on the undo button will undo ALL deletions saved. As soon as * the popup vanished (because {@link #setAutoHideDelay(int) autoHideDelay} * is over) all saved undos will be discarded. */ COLLAPSED_UNDO }; /** * Defines the direction in which the swipe to delete can be done. The default * is {@link SwipeDirection#BOTH}. Use {@link #setSwipeDirection(de.timroes.swipetodismiss.SwipeDismissList.SwipeDirection)} * to set the direction. */ public enum SwipeDirection { /** * The user can swipe each item into both directions (left and right) * to delete it. */ BOTH, /** * The user can only swipe the items to the beginning of the item to * delete it. The start of an item is in Left-To-Right languages the left * side and in Right-To-Left languages the right side. Before API level * 17 this is always the left side. */ START, /** * The user can only swipe the items to the end of the item to delete it. * This is in Left-To-Right languages the right side in Right-To-Left * languages the left side. Before API level 17 this will always be the * right side. */ END } /** * The callback interface used by {@link SwipeDismissListViewTouchListener} * to inform its client about a successful dismissal of one or more list * item positions. */ public interface OnDismissCallback { /** * Called when the user has indicated they she would like to dismiss one * or more list item positions. * * @param listView The originating {@link ListView}. * @param position The position of the item to dismiss. */ Undoable onDismiss(AbsListView listView, int position); } /** * An implementation of this abstract class must be returned by the * {@link OnDismissCallback#onDismiss(android.widget.ListView, int)} method, * if the user should be able to undo that dismiss. If the action will be undone * by the user {@link #undo()} will be called. That method should undo the previous * deletion of the item and add it back to the adapter. Read the README file for * more details. If you implement the {@link #getTitle()} method, the undo popup * will show an individual title for that item. Otherwise the default title * (set via {@link #setUndoString(java.lang.String)}) will be shown. */ public abstract static class Undoable { /** * Returns the individual undo message for this item shown in the * popup dialog. * * @return The individual undo message. */ public String getTitle() { return null; } /** * Undoes the deletion. */ public abstract void undo(); /** * Will be called when this Undoable won't be able to undo anymore, * meaning the undo popup has disappeared from the screen. */ public void discard() { } } /** * Constructs a new swipe-to-dismiss touch listener for the given list view. * * @param listView The list view whose items should be dismissable. * @param callback The callback to trigger when the user has indicated that * she would like to dismiss one or more list items. */ public SwipeDismissList(AbsListView listView, OnDismissCallback callback) { this(listView, callback, UndoMode.SINGLE_UNDO); } /** * Constructs a new swipe-to-dismiss touch listener for the given list view. * * @param listView The list view whose items should be dismissable. * @param callback The callback to trigger when the user has indicated that * she would like to dismiss one or more list items. * @param mode The mode this list handles multiple undos. */ public SwipeDismissList(AbsListView listView, OnDismissCallback callback, UndoMode mode) { if (listView == null) { throw new IllegalArgumentException("listview must not be null."); } mHandler = new HideUndoPopupHandler(this); mListView = listView; mCallback = callback; mMode = mode; ViewConfiguration vc = ViewConfiguration.get(listView.getContext()); mSlop = vc.getScaledTouchSlop(); mMinFlingVelocity = vc.getScaledMinimumFlingVelocity(); mMaxFlingVelocity = vc.getScaledMaximumFlingVelocity(); mAnimationTime = listView.getContext().getResources().getInteger(android.R.integer.config_shortAnimTime); mDensity = mListView.getResources().getDisplayMetrics().density; // -- Load undo popup -- LayoutInflater inflater = (LayoutInflater) mListView.getContext() .getSystemService(Context.LAYOUT_INFLATER_SERVICE); View v = inflater.inflate(R.layout.undo_popup, null); mUndoButton = (Button) v.findViewById(R.id.undo); mUndoButton.setOnClickListener(new UndoHandler()); mUndoButton.setOnTouchListener(new View.OnTouchListener() { public boolean onTouch(View v, MotionEvent event) { // If user tabs "undo" button, reset delay time to remove popup mDelayedMsgId++; return false; } }); mUndoText = (TextView) v.findViewById(R.id.text); mUndoPopup = new PopupWindow(v); mUndoPopup.setAnimationStyle(R.style.fade_animation); // Get scren width in dp and set width respectively int xdensity = (int) (mListView.getContext().getResources().getDisplayMetrics().widthPixels / mDensity); if (xdensity < 300) { mUndoPopup.setWidth((int) (mDensity * 280)); } else if (xdensity < 350) { mUndoPopup.setWidth((int) (mDensity * 300)); } else if (xdensity < 500) { mUndoPopup.setWidth((int) (mDensity * 330)); } else { mUndoPopup.setWidth((int) (mDensity * 450)); } mUndoPopup.setHeight((int) (mDensity * 56)); // -- END Load undo popu -- listView.setOnTouchListener(this); listView.setOnScrollListener(this.makeScrollListener()); mEnabled = true; switch (mode) { case SINGLE_UNDO: mUndoActions = new ArrayList<Undoable>(1); break; default: mUndoActions = new ArrayList<Undoable>(10); break; } } /** * Enables or disables (pauses or resumes) watching for swipe-to-dismiss * gestures. * * @param enabled Whether or not to watch for gestures. */ public void setEnabled(boolean enabled) { mEnabled = enabled; } /** * Sets the time in milliseconds after which the undo popup automatically * disappears. * * @param delay Delay in milliseconds. */ public void setAutoHideDelay(int delay) { mAutoHideDelay = delay; } public void setSwipeLayout(int swipeLayout) { mSwipeLayout = swipeLayout; } /** * Sets the offset, in dips, of the x position of * the undo popup. * * @param popupXOffset x position in dips. */ public void setPopupXOffset(int popupXOffset) { mPopupXOffset = popupXOffset; } /** * Sets the offset, in dips, of the y position of * the undo popup. * * @param popupYOffset y position in dips. */ public void setPopupYOffset(int popupYOffset) { mPopupYOffset = popupYOffset; } /** * Sets the Gravity controlling the placement of * the undo popup. * * @param popupGravity the gravity which controls the placement of the popup window */ public void setPopupGravity(int popupGravity) { mPopupGravity = popupGravity; } /** * Sets the directions in which a list item can be swiped to delete. * By default this is set to {@link SwipeDirection#BOTH} so that an item * can be swiped into both directions. * * @param direction The direction to limit the swipe to. */ public void setSwipeDirection(SwipeDirection direction) { mSwipeDirection = direction; } /** * Sets the string shown in the undo popup. This will only show if * the {@link Undoable} returned by the {@link OnDismissCallback} returns * {@code null} from its {@link Undoable#getTitle()} method. * * @param msg The string shown in the undo popup. */ public void setUndoString(String msg) { mDeleteString = msg; } /** * Sets the string shown in the undo popup, when {@link UndoMode} is set to * {@link UndoMode#MULTI_UNDO} or {@link UndoMode#COLLAPSED_UNDO} and * multiple deletions has been stored for undo. If this string contains * one {@code %d} inside, this will be filled by the numbers of stored undos. * * @param msg The string shown in the undo popup for multiple undos. */ public void setUndoMultipleString(String msg) { mDeleteMultipleString = msg; } /** * Discard all stored undos and hide the undo popup dialog. */ public void discardUndo() { for (Undoable undoable : mUndoActions) { undoable.discard(); } mUndoActions.clear(); mUndoPopup.dismiss(); } /** * Returns an {@link android.widget.AbsListView.OnScrollListener} to be * added to the {@link ListView} using * {@link ListView#setOnScrollListener(android.widget.AbsListView.OnScrollListener)}. * If a scroll listener is already assigned, the caller should still pass * scroll changes through to this listener. This will ensure that this * {@link SwipeDismissListViewTouchListener} is paused during list view * scrolling.</p> * * @see {@link SwipeDismissListViewTouchListener} */ private AbsListView.OnScrollListener makeScrollListener() { return new AbsListView.OnScrollListener() { @Override public void onScrollStateChanged(AbsListView absListView, int scrollState) { mPaused = !(scrollState != AbsListView.OnScrollListener.SCROLL_STATE_TOUCH_SCROLL); } @Override public void onScroll(AbsListView absListView, int i, int i1, int i2) { } }; } @Override public boolean onTouch(View view, MotionEvent motionEvent) { if (mViewWidth < 2) { mViewWidth = mListView.getWidth(); } switch (MotionEventCompat.getActionMasked(motionEvent)) { case MotionEvent.ACTION_DOWN: { if (mPaused || !mEnabled) { return false; } resetSwipeState(); // TODO: ensure this is a finger, and set a flag // Find the child view that was touched (perform a hit test) Rect rect = new Rect(); int childCount = mListView.getChildCount(); int[] listViewCoords = new int[2]; mListView.getLocationOnScreen(listViewCoords); int x = (int) motionEvent.getRawX() - listViewCoords[0]; int y = (int) motionEvent.getRawY() - listViewCoords[1]; View child; for (int i = 0; i < childCount; i++) { child = mListView.getChildAt(i); child.getHitRect(rect); if (rect.contains(x, y)) { if (mSwipeLayout != 0) { View swipeView = child.findViewById(mSwipeLayout); if (swipeView != null) { mDownView = swipeView; break; } } mDownView = child; break; } } if (mDownView != null) { mDownX = motionEvent.getRawX(); mDownY = motionEvent.getRawY(); mDownPosition = mListView.getPositionForView(mDownView); mVelocityTracker = VelocityTracker.obtain(); mVelocityTracker.addMovement(motionEvent); } view.onTouchEvent(motionEvent); return true; } case MotionEvent.ACTION_UP: { if (mVelocityTracker == null) { break; } float deltaX = motionEvent.getRawX() - mDownX; mVelocityTracker.addMovement(motionEvent); mVelocityTracker.computeCurrentVelocity(1000); float velocityX = Math.abs(mVelocityTracker.getXVelocity()); float velocityY = Math.abs(mVelocityTracker.getYVelocity()); boolean dismiss = false; boolean dismissRight = false; if (Math.abs(deltaX) > mViewWidth / 2 && mSwiping) { dismiss = true; dismissRight = deltaX > 0; } else if (mMinFlingVelocity <= velocityX && velocityX <= mMaxFlingVelocity && velocityY < velocityX && mSwiping && isDirectionValid(mVelocityTracker.getXVelocity()) && deltaX >= mViewWidth * 0.2f) { dismiss = true; dismissRight = mVelocityTracker.getXVelocity() > 0; } if (dismiss) { // dismiss final View downView = mDownView; // mDownView gets null'd before animation ends final int downPosition = mDownPosition; ++mDismissAnimationRefCount; mPaused = true; animate(mDownView).translationX(dismissRight ? mViewWidth : -mViewWidth).alpha(0) .setDuration(mAnimationTime).setListener(new AnimatorListenerAdapter() { @Override public void onAnimationEnd(Animator animation) { performDismiss(downView, downPosition); } }); } else { // cancel animate(mDownView).translationX(0).alpha(1).setDuration(mAnimationTime).setListener(null); } resetSwipeState(); break; } case MotionEvent.ACTION_MOVE: { if (mUndoPopup.isShowing()) { // Send a delayed message to hide popup mHandler.sendMessageDelayed(mHandler.obtainMessage(mDelayedMsgId), mAutoHideDelay); } if (mVelocityTracker == null || mPaused || !mEnabled) { break; } mVelocityTracker.addMovement(motionEvent); float deltaX = motionEvent.getRawX() - mDownX; float deltaY = motionEvent.getRawY() - mDownY; // Only start swipe in correct direction if (isDirectionValid(deltaX)) { if (Math.abs(deltaX) > mSlop && Math.abs(deltaX) > Math.abs(deltaY)) { mSwiping = true; mListView.requestDisallowInterceptTouchEvent(true); // Cancel ListView's touch (un-highlighting the item) MotionEvent cancelEvent = MotionEvent.obtain(motionEvent); cancelEvent.setAction(MotionEvent.ACTION_CANCEL | (MotionEventCompat .getActionIndex(motionEvent) << MotionEvent.ACTION_POINTER_INDEX_SHIFT)); mListView.onTouchEvent(cancelEvent); cancelEvent.recycle(); } } else { // If we swiped into wrong direction, act like this was the new // touch down point mDownX = motionEvent.getRawX(); deltaX = 0; } if (mSwiping) { setTranslationX(mDownView, deltaX); setAlpha(mDownView, Math.max(0f, Math.min(1f, 1f - 2f * Math.abs(deltaX) / mViewWidth))); return true; } break; } } return false; } private void resetSwipeState() { if (mVelocityTracker != null) { mVelocityTracker.recycle(); } mVelocityTracker = null; mDownX = 0; mDownY = 0; mDownView = null; mDownPosition = ListView.INVALID_POSITION; mSwiping = false; } /** * Checks whether the delta of a swipe indicates, that the swipe is in the * correct direction, regarding the direction set via * {@link #setSwipeDirection(de.timroes.swipetodismiss.SwipeDismissList.SwipeDirection)} * * @param deltaX The delta of x coordinate of the swipe. * @return Whether the delta of a swipe is in the right direction. */ @TargetApi(Build.VERSION_CODES.JELLY_BEAN_MR1) private boolean isDirectionValid(float deltaX) { int rtlSign = 1; // On API level 17 and above, check if we are in a Right-To-Left layout if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) { if (mListView.getLayoutDirection() == View.LAYOUT_DIRECTION_RTL) { rtlSign = -1; } } // Check if swipe has been done in the corret direction switch (mSwipeDirection) { default: case BOTH: return true; case START: return rtlSign * deltaX < 0; case END: return rtlSign * deltaX > 0; } } class PendingDismissData implements Comparable<PendingDismissData> { public int position; public View view; public PendingDismissData(int position, View view) { this.position = position; this.view = view; } @Override public int compareTo(PendingDismissData other) { // Sort by descending position return other.position - position; } } private void performDismiss(final View dismissView, final int dismissPosition) { // Animate the dismissed list item to zero-height and fire the dismiss callback when // all dismissed list item animations have completed. This triggers layout on each animation // frame; in the future we may want to do something smarter and more performant. final ViewGroup.LayoutParams lp = dismissView.getLayoutParams(); final int originalHeight = dismissView.getHeight(); ValueAnimator animator = ValueAnimator.ofInt(originalHeight, 1).setDuration(mAnimationTime); animator.addListener(new AnimatorListenerAdapter() { @Override public void onAnimationEnd(Animator animation) { --mDismissAnimationRefCount; if (mDismissAnimationRefCount == 0) { // No active animations, process all pending dismisses. for (PendingDismissData dismiss : mPendingDismisses) { if (mMode == UndoMode.SINGLE_UNDO) { for (Undoable undoable : mUndoActions) { undoable.discard(); } mUndoActions.clear(); } Undoable undoable = mCallback.onDismiss(mListView, dismiss.position); if (undoable != null) { mUndoActions.add(undoable); } mDelayedMsgId++; } if (!mUndoActions.isEmpty()) { changePopupText(); changeButtonLabel(); // Show undo popup mUndoPopup.showAtLocation(mListView, mPopupGravity, (int) (mDensity * mPopupXOffset), (int) (mDensity * mPopupYOffset)); } ViewGroup.LayoutParams lp; for (PendingDismissData pendingDismiss : mPendingDismisses) { // Reset view presentation setAlpha(pendingDismiss.view, 1f); setTranslationX(pendingDismiss.view, 0); lp = pendingDismiss.view.getLayoutParams(); lp.height = originalHeight; pendingDismiss.view.setLayoutParams(lp); } mPendingDismisses.clear(); } mPaused = false; } }); animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() { @Override public void onAnimationUpdate(ValueAnimator valueAnimator) { lp.height = (Integer) valueAnimator.getAnimatedValue(); dismissView.setLayoutParams(lp); } }); mPendingDismisses.add(new PendingDismissData(dismissPosition, dismissView)); animator.start(); } /** * Changes text in the popup depending on stored undos. */ private void changePopupText() { String msg = ""; if (mUndoActions.size() > 1 && mDeleteMultipleString != null) { msg = String.format(mDeleteMultipleString, mUndoActions.size()); } else if (mUndoActions.size() >= 1) { // Set title from single undoable or when no multiple deletion string // is given if (mUndoActions.get(mUndoActions.size() - 1).getTitle() != null) { msg = mUndoActions.get(mUndoActions.size() - 1).getTitle(); } else { msg = mDeleteString; } } mUndoText.setText(msg); } private void changeButtonLabel() { String msg; if (mUndoActions.size() > 1 && mMode == UndoMode.COLLAPSED_UNDO) { msg = mListView.getResources().getString(R.string.undoall); } else { msg = mListView.getResources().getString(R.string.undo); } mUndoButton.setText(msg); } /** * Takes care of undoing a dismiss. This will be added as a * {@link View.OnClickListener} to the undo button in the undo popup. */ private class UndoHandler implements View.OnClickListener { public void onClick(View v) { if (!mUndoActions.isEmpty()) { switch (mMode) { case SINGLE_UNDO: mUndoActions.get(0).undo(); mUndoActions.clear(); break; case COLLAPSED_UNDO: Collections.reverse(mUndoActions); for (Undoable undo : mUndoActions) { undo.undo(); } mUndoActions.clear(); break; case MULTI_UNDO: mUndoActions.get(mUndoActions.size() - 1).undo(); mUndoActions.remove(mUndoActions.size() - 1); break; } } // Dismiss dialog or change text if (mUndoActions.isEmpty()) { mUndoPopup.dismiss(); } else { changePopupText(); changeButtonLabel(); } mDelayedMsgId++; } } /** * Handler used to hide the undo popup after a special delay. */ private static class HideUndoPopupHandler extends Handler { private final WeakReference<SwipeDismissList> parentRef; public HideUndoPopupHandler(SwipeDismissList parent) { this.parentRef = new WeakReference<SwipeDismissList>(parent); } @Override public void handleMessage(Message msg) { SwipeDismissList parent = parentRef.get(); if (parent != null && msg.what == parent.mDelayedMsgId) { // Call discard on any element for (Undoable undo : parent.mUndoActions) { undo.discard(); } parent.mUndoActions.clear(); parent.mUndoPopup.dismiss(); } } } }