Android 相册 支持图片缩放滑动 边界回弹 双击放大

/******************************************************************************* * Copyright 2011, 2012 Chris Banes. * * 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 uk.co.senab.photoview; import android.content.Context; import android.graphics.Matrix; import android.graphics.Matrix.ScaleToFit; import android.graphics.RectF; import android.graphics.drawable.Drawable; import android.util.Log; import android.view.GestureDetector; import android.view.MotionEvent; import android.view.View; import android.view.View.OnLongClickListener; import android.view.ViewTreeObserver; import android.widget.ImageView; import android.widget.ImageView.ScaleType; import java.lang.ref.WeakReference; public class PhotoViewAttacher implements IPhotoView, View.OnTouchListener, VersionedGestureDetector.OnGestureListener, GestureDetector.OnDoubleTapListener, ViewTreeObserver.OnGlobalLayoutListener { static final String LOG_TAG = "PhotoViewAttacher"; // let debug flag be dynamic, but still Proguard can be used to remove from release builds static final boolean DEBUG = Log.isLoggable(LOG_TAG, Log.DEBUG); static final int EDGE_NONE = -1; static final int EDGE_LEFT = 0; static final int EDGE_RIGHT = 1; static final int EDGE_BOTH = 2; public static final float DEFAULT_MAX_SCALE = 3.0f; public static final float DEFAULT_MID_SCALE = 1.75f; public static final float DEFAULT_MIN_SCALE = 1.0f; private float mMinScale = DEFAULT_MIN_SCALE; private float mMidScale = DEFAULT_MID_SCALE; private float mMaxScale = DEFAULT_MAX_SCALE; private boolean mAllowParentInterceptOnEdge = true; private static void checkZoomLevels(float minZoom, float midZoom, float maxZoom) { if (minZoom >= midZoom) { throw new IllegalArgumentException("MinZoom should be less than MidZoom"); } else if (midZoom >= maxZoom) { throw new IllegalArgumentException("MidZoom should be less than MaxZoom"); } } /** * @return true if the ImageView exists, and it's Drawable existss */ private static boolean hasDrawable(ImageView imageView) { return null != imageView && null != imageView.getDrawable(); } /** * @return true if the ScaleType is supported. */ private static boolean isSupportedScaleType(final ScaleType scaleType) { if (null == scaleType) { return false; } switch (scaleType) { case MATRIX: throw new IllegalArgumentException(scaleType.name() + " is not supported in PhotoView"); default: return true; } } /** * Set's the ImageView's ScaleType to Matrix. */ private static void setImageViewScaleTypeMatrix(ImageView imageView) { if (null != imageView) { if (imageView instanceof PhotoView) { /** * PhotoView sets it's own ScaleType to Matrix, then diverts all * calls setScaleType to this.setScaleType. Basically we don't * need to do anything here */ } else { imageView.setScaleType(ScaleType.MATRIX); } } } private WeakReference<ImageView> mImageView; private ViewTreeObserver mViewTreeObserver; // Gesture Detectors private GestureDetector mGestureDetector; private VersionedGestureDetector mScaleDragDetector; // These are set so we don't keep allocating them on the heap private final Matrix mBaseMatrix = new Matrix(); private final Matrix mDrawMatrix = new Matrix(); private final Matrix mSuppMatrix = new Matrix(); private final RectF mDisplayRect = new RectF(); private final float[] mMatrixValues = new float[9]; // Listeners private OnMatrixChangedListener mMatrixChangeListener; private OnPhotoTapListener mPhotoTapListener; private OnViewTapListener mViewTapListener; private OnLongClickListener mLongClickListener; private int mIvTop, mIvRight, mIvBottom, mIvLeft; private FlingRunnable mCurrentFlingRunnable; private int mScrollEdge = EDGE_BOTH; private boolean mZoomEnabled; private ScaleType mScaleType = ScaleType.FIT_CENTER; public PhotoViewAttacher(ImageView imageView) { mImageView = new WeakReference<ImageView>(imageView); imageView.setOnTouchListener(this); mViewTreeObserver = imageView.getViewTreeObserver(); mViewTreeObserver.addOnGlobalLayoutListener(this); // Make sure we using MATRIX Scale Type setImageViewScaleTypeMatrix(imageView); if (!imageView.isInEditMode()) { // Create Gesture Detectors... mScaleDragDetector = VersionedGestureDetector.newInstance(imageView.getContext(), this); mGestureDetector = new GestureDetector(imageView.getContext(), new GestureDetector.SimpleOnGestureListener() { // forward long click listener @Override public void onLongPress(MotionEvent e) { if(null != mLongClickListener) { mLongClickListener.onLongClick(mImageView.get()); } }}); mGestureDetector.setOnDoubleTapListener(this); // Finally, update the UI so that we're zoomable setZoomable(true); } } @Override public final boolean canZoom() { return mZoomEnabled; } /** * Clean-up the resources attached to this object. This needs to be called * when the ImageView is no longer used. A good example is from * {@link android.view.View#onDetachedFromWindow()} or from {@link android.app.Activity#onDestroy()}. * This is automatically called if you are using {@link uk.co.senab.photoview.PhotoView}. */ @SuppressWarnings("deprecation") public final void cleanup() { if (null != mImageView) { mImageView.get().getViewTreeObserver().removeGlobalOnLayoutListener(this); } mViewTreeObserver = null; // Clear listeners too mMatrixChangeListener = null; mPhotoTapListener = null; mViewTapListener = null; // Finally, clear ImageView mImageView = null; } @Override public final RectF getDisplayRect() { checkMatrixBounds(); return getDisplayRect(getDisplayMatrix()); } public final ImageView getImageView() { ImageView imageView = null; if (null != mImageView) { imageView = mImageView.get(); } // If we don't have an ImageView, call cleanup() if (null == imageView) { cleanup(); throw new IllegalStateException( "ImageView no longer exists. You should not use this PhotoViewAttacher any more."); } return imageView; } @Override public float getMinScale() { return mMinScale; } @Override public float getMidScale() { return mMidScale; } @Override public float getMaxScale() { return mMaxScale; } @Override public final float getScale() { return getValue(mSuppMatrix, Matrix.MSCALE_X); } @Override public final ScaleType getScaleType() { return mScaleType; } public final boolean onDoubleTap(MotionEvent ev) { try { float scale = getScale(); float x = ev.getX(); float y = ev.getY(); if (scale < mMidScale) { zoomTo(mMidScale, x, y); } else if (scale >= mMidScale && scale < mMaxScale) { zoomTo(mMaxScale, x, y); } else { zoomTo(mMinScale, x, y); } } catch (ArrayIndexOutOfBoundsException e) { // Can sometimes happen when getX() and getY() is called } return true; } public final boolean onDoubleTapEvent(MotionEvent e) { // Wait for the confirmed onDoubleTap() instead return false; } public final void onDrag(float dx, float dy) { if (DEBUG) { Log.d(LOG_TAG, String.format("onDrag: dx: %.2f. dy: %.2f", dx, dy)); } ImageView imageView = getImageView(); if (null != imageView && hasDrawable(imageView)) { mSuppMatrix.postTranslate(dx, dy); checkAndDisplayMatrix(); /**