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/*
* Copyright (C) 2008-2009 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 android.gesture;
import android.view.MotionEvent;
import android.view.View;
import java.util.ArrayList;
import java.lang.ref.WeakReference;
/**
* TouchThroughGesturing implements the interaction behavior that allows a user
* to gesture over a regular UI widget such as ListView and at the same time,
* still allows a user to perform basic interactions (clicking, scrolling and panning)
* with the underlying widget.
*/
public class TouchThroughGestureListener implements GestureOverlayView.OnGestureListener {
public static final int SINGLE_STROKE = 0;
public static final int MULTIPLE_STROKE = 1;
// TODO: Add properties for all these
private static final float STROKE_LENGTH_THRESHOLD = 30;
private static final float SQUARENESS_THRESHOLD = 0.275f;
private static final float ANGLE_THRESHOLD = 40;
private boolean mIsGesturing = false;
private float mTotalLength;
private float mX;
private float mY;
private WeakReference<View> mModel;
private int mGestureType = SINGLE_STROKE;
// TODO: Use WeakReferences
private final ArrayList<OnGesturePerformedListener> mPerformedListeners =
new ArrayList<OnGesturePerformedListener>();
private boolean mStealEvents = false;
public TouchThroughGestureListener(View model) {
this(model, false);
}
public TouchThroughGestureListener(View model, boolean stealEvents) {
mModel = new WeakReference<View>(model);
mStealEvents = stealEvents;
}
/**
*
* @param type SINGLE_STROKE or MULTIPLE_STROKE
*/
public void setGestureType(int type) {
mGestureType = type;
}
public void onGestureStarted(GestureOverlayView overlay, MotionEvent event) {
if (mGestureType == MULTIPLE_STROKE) {
overlay.cancelFadingOut();
}
mX = event.getX();
mY = event.getY();
mTotalLength = 0;
mIsGesturing = false;
if (mGestureType == SINGLE_STROKE || overlay.getCurrentGesture() == null
|| overlay.getCurrentGesture().getStrokesCount() == 0) {
overlay.setGestureDrawingColor(overlay.getUncertainGestureColor());
}
dispatchEventToModel(event);
}
private void dispatchEventToModel(MotionEvent event) {
View v = mModel.get();
if (v != null) v.dispatchTouchEvent(event);
}
public void onGesture(GestureOverlayView overlay, MotionEvent event) {
//noinspection PointlessBooleanExpression
if (!mStealEvents) {
dispatchEventToModel(event);
}
if (mIsGesturing) {
return;
}
final float x = event.getX();
final float y = event.getY();
final float dx = x - mX;
final float dy = y - mY;
mTotalLength += (float) Math.sqrt(dx * dx + dy * dy);
mX = x;
mY = y;
if (mTotalLength > STROKE_LENGTH_THRESHOLD) {
final OrientedBoundingBox box =
GestureUtilities.computeOrientedBoundingBox(overlay.getCurrentStroke());
float angle = Math.abs(box.orientation);
if (angle > 90) {
angle = 180 - angle;
}
if (box.squareness > SQUARENESS_THRESHOLD || angle < ANGLE_THRESHOLD) {
mIsGesturing = true;
overlay.setGestureDrawingColor(overlay.getGestureColor());
if (mStealEvents) {
event = MotionEvent.obtain(event.getDownTime(), System.currentTimeMillis(),
MotionEvent.ACTION_UP, x, y, event.getPressure(), event.getSize(),
event.getMetaState(), event.getXPrecision(), event.getYPrecision(),
event.getDeviceId(), event.getEdgeFlags());
}
}
}
if (mStealEvents) {
dispatchEventToModel(event);
}
}
public void onGestureEnded(GestureOverlayView overlay, MotionEvent event) {
if (mIsGesturing) {
overlay.clear(true);
final ArrayList<OnGesturePerformedListener> listeners = mPerformedListeners;
final int count = listeners.size();
for (int i = 0; i < count; i++) {
listeners.get(i).onGesturePerformed(overlay, overlay.getCurrentGesture());
}
} else {
dispatchEventToModel(event);
overlay.clear(false);
}
}
public void addOnGestureActionListener(OnGesturePerformedListener listener) {
mPerformedListeners.add(listener);
}
public void removeOnGestureActionListener(OnGesturePerformedListener listener) {
mPerformedListeners.remove(listener);
}
public boolean isGesturing() {
return mIsGesturing;
}
public static interface OnGesturePerformedListener {
public void onGesturePerformed(GestureOverlayView overlay, Gesture gesture);
}
}
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