| /* |
| * Copyright (C) 2010 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 com.example.android.touchexample; |
| |
| import android.content.Context; |
| import android.os.Build; |
| import android.util.Log; |
| import android.view.MotionEvent; |
| import android.view.ScaleGestureDetector; |
| |
| public abstract class VersionedGestureDetector { |
| private static final String TAG = "VersionedGestureDetector"; |
| |
| OnGestureListener mListener; |
| |
| public static VersionedGestureDetector newInstance(Context context, |
| OnGestureListener listener) { |
| final int sdkVersion = Integer.parseInt(Build.VERSION.SDK); |
| VersionedGestureDetector detector = null; |
| if (sdkVersion < Build.VERSION_CODES.ECLAIR) { |
| detector = new CupcakeDetector(); |
| } else if (sdkVersion < Build.VERSION_CODES.FROYO) { |
| detector = new EclairDetector(); |
| } else { |
| detector = new FroyoDetector(context); |
| } |
| |
| Log.d(TAG, "Created new " + detector.getClass()); |
| detector.mListener = listener; |
| |
| return detector; |
| } |
| |
| public abstract boolean onTouchEvent(MotionEvent ev); |
| |
| public interface OnGestureListener { |
| public void onDrag(float dx, float dy); |
| public void onScale(float scaleFactor); |
| } |
| |
| private static class CupcakeDetector extends VersionedGestureDetector { |
| float mLastTouchX; |
| float mLastTouchY; |
| |
| float getActiveX(MotionEvent ev) { |
| return ev.getX(); |
| } |
| |
| float getActiveY(MotionEvent ev) { |
| return ev.getY(); |
| } |
| |
| boolean shouldDrag() { |
| return true; |
| } |
| |
| @Override |
| public boolean onTouchEvent(MotionEvent ev) { |
| switch (ev.getAction()) { |
| case MotionEvent.ACTION_DOWN: { |
| mLastTouchX = getActiveX(ev); |
| mLastTouchY = getActiveY(ev); |
| break; |
| } |
| case MotionEvent.ACTION_MOVE: { |
| final float x = getActiveX(ev); |
| final float y = getActiveY(ev); |
| |
| if (shouldDrag()) { |
| mListener.onDrag(x - mLastTouchX, y - mLastTouchY); |
| } |
| |
| mLastTouchX = x; |
| mLastTouchY = y; |
| break; |
| } |
| } |
| return true; |
| } |
| } |
| |
| private static class EclairDetector extends CupcakeDetector { |
| private static final int INVALID_POINTER_ID = -1; |
| private int mActivePointerId = INVALID_POINTER_ID; |
| private int mActivePointerIndex = 0; |
| |
| @Override |
| float getActiveX(MotionEvent ev) { |
| return ev.getX(mActivePointerIndex); |
| } |
| |
| @Override |
| float getActiveY(MotionEvent ev) { |
| return ev.getY(mActivePointerIndex); |
| } |
| |
| @Override |
| public boolean onTouchEvent(MotionEvent ev) { |
| final int action = ev.getAction(); |
| switch (action & MotionEvent.ACTION_MASK) { |
| case MotionEvent.ACTION_DOWN: |
| mActivePointerId = ev.getPointerId(0); |
| break; |
| case MotionEvent.ACTION_CANCEL: |
| case MotionEvent.ACTION_UP: |
| mActivePointerId = INVALID_POINTER_ID; |
| break; |
| case MotionEvent.ACTION_POINTER_UP: |
| final int pointerIndex = (ev.getAction() & MotionEvent.ACTION_POINTER_INDEX_MASK) |
| >> MotionEvent.ACTION_POINTER_INDEX_SHIFT; |
| final int pointerId = ev.getPointerId(pointerIndex); |
| if (pointerId == mActivePointerId) { |
| // This was our active pointer going up. Choose a new |
| // active pointer and adjust accordingly. |
| final int newPointerIndex = pointerIndex == 0 ? 1 : 0; |
| mActivePointerId = ev.getPointerId(newPointerIndex); |
| mLastTouchX = ev.getX(newPointerIndex); |
| mLastTouchY = ev.getY(newPointerIndex); |
| } |
| break; |
| } |
| |
| mActivePointerIndex = ev.findPointerIndex(mActivePointerId); |
| return super.onTouchEvent(ev); |
| } |
| } |
| |
| private static class FroyoDetector extends EclairDetector { |
| private ScaleGestureDetector mDetector; |
| |
| public FroyoDetector(Context context) { |
| mDetector = new ScaleGestureDetector(context, |
| new ScaleGestureDetector.SimpleOnScaleGestureListener() { |
| @Override public boolean onScale(ScaleGestureDetector detector) { |
| mListener.onScale(detector.getScaleFactor()); |
| return true; |
| } |
| }); |
| } |
| |
| @Override |
| boolean shouldDrag() { |
| return !mDetector.isInProgress(); |
| } |
| |
| @Override |
| public boolean onTouchEvent(MotionEvent ev) { |
| mDetector.onTouchEvent(ev); |
| return super.onTouchEvent(ev); |
| } |
| } |
| } |