转自:http://www.inter-fuser.com/2010/02/android-coverflow-widget-v2.html
/* * Copyright (C) 2010 Neil Davies * * 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. * * This code is base on the Android Gallery widget and was Created * by Neil Davies neild001 'at' gmail dot com to be a Coverflow widget * * @author Neil Davies */ package com.example.coverflow; import android.content.Context; import android.graphics.Camera; import android.graphics.Matrix; import android.util.AttributeSet; import android.view.View; import android.view.animation.Transformation; import android.widget.Gallery; import android.widget.ImageView; public class CoverFlow extends Gallery { /** * Graphics Camera used for transforming the matrix of ImageViews */ private Camera mCamera = new Camera(); /** * The maximum angle the Child ImageView will be rotated by */ private int mMaxRotationAngle = 60; /** * The maximum zoom on the centre Child */ private int mMaxZoom = -120; /** * The Centre of the Coverflow */ private int mCoveflowCenter; public CoverFlow(Context context) { super(context); this.setStaticTransformationsEnabled(true); } public CoverFlow(Context context, AttributeSet attrs) { super(context, attrs); this.setStaticTransformationsEnabled(true); } public CoverFlow(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); this.setStaticTransformationsEnabled(true); } /** * Get the max rotational angle of the image * @return the mMaxRotationAngle */ public int getMaxRotationAngle() { return mMaxRotationAngle; } /** * Set the max rotational angle of each image * @param maxRotationAngle the mMaxRotationAngle to set */ public void setMaxRotationAngle(int maxRotationAngle) { mMaxRotationAngle = maxRotationAngle; } /** * Get the Max zoom of the centre image * @return the mMaxZoom */ public int getMaxZoom() { return mMaxZoom; } /** * Set the max zoom of the centre image * @param maxZoom the mMaxZoom to set */ public void setMaxZoom(int maxZoom) { mMaxZoom = maxZoom; } /** * Get the Centre of the Coverflow * @return The centre of this Coverflow. */ private int getCenterOfCoverflow() { return (getWidth() - getPaddingLeft() - getPaddingRight()) / 2 + getPaddingLeft(); } /** * Get the Centre of the View * @return The centre of the given view. */ private static int getCenterOfView(View view) { return view.getLeft() + view.getWidth() / 2; } /** * {@inheritDoc} * * @see #setStaticTransformationsEnabled(boolean) */ protected boolean getChildStaticTransformation(View child, Transformation t) { final int childCenter = getCenterOfView(child); final int childWidth = child.getWidth() ; int rotationAngle = 0; t.clear(); t.setTransformationType(Transformation.TYPE_MATRIX); if (childCenter == mCoveflowCenter) { transformImageBitmap((ImageView) child, t, 0); } else { rotationAngle = (int) (((float) (mCoveflowCenter - childCenter)/ childWidth) * mMaxRotationAngle); if (Math.abs(rotationAngle) > mMaxRotationAngle) { rotationAngle = (rotationAngle < 0) ? -mMaxRotationAngle : mMaxRotationAngle; } transformImageBitmap((ImageView) child, t, rotationAngle); } return true; } /** * This is called during layout when the size of this view has changed. If * you were just added to the view hierarchy, you're called with the old * values of 0. * * @param w Current width of this view. * @param h Current height of this view. * @param oldw Old width of this view. * @param oldh Old height of this view. */ protected void onSizeChanged(int w, int h, int oldw, int oldh) { mCoveflowCenter = getCenterOfCoverflow(); super.onSizeChanged(w, h, oldw, oldh); } /** * Transform the Image Bitmap by the Angle passed * * @param imageView ImageView the ImageView whose bitmap we want to rotate * @param t transformation * @param rotationAngle the Angle by which to rotate the Bitmap */ private void transformImageBitmap(ImageView child, Transformation t, int rotationAngle) { mCamera.save(); final Matrix imageMatrix = t.getMatrix();; final int imageHeight = child.getLayoutParams().height;; final int imageWidth = child.getLayoutParams().width; final int rotation = Math.abs(rotationAngle); mCamera.translate(0.0f, 0.0f, 100.0f); //As the angle of the view gets less, zoom in if ( rotation < mMaxRotationAngle ) { float zoomAmount = (float) (mMaxZoom + (rotation * 1.5)); mCamera.translate(0.0f, 0.0f, zoomAmount); } mCamera.rotateY(rotationAngle); mCamera.getMatrix(imageMatrix); imageMatrix.preTranslate(-(imageWidth/2), -(imageHeight/2)); imageMatrix.postTranslate((imageWidth/2), (imageHeight/2)); mCamera.restore(); } }
/* * Copyright (C) 2010 Neil Davies * * 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. * * This code is base on the Android Gallery widget and was Created * by Neil Davies neild001 'at' gmail dot com to be a Coverflow widget * * @author Neil Davies */ package com.example.coverflow; import java.io.FileInputStream; import android.app.Activity; import android.content.Context; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Canvas; import android.graphics.LinearGradient; import android.graphics.Matrix; import android.graphics.Paint; import android.graphics.PorterDuffXfermode; import android.graphics.Bitmap.Config; import android.graphics.PorterDuff.Mode; import android.graphics.Shader.TileMode; import android.graphics.drawable.BitmapDrawable; import android.os.Bundle; import android.view.View; import android.view.ViewGroup; import android.widget.BaseAdapter; import android.widget.ImageView; import android.widget.ImageView.ScaleType; public class CoverFlowExample extends Activity { /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); CoverFlow coverFlow; coverFlow = new CoverFlow(this); coverFlow.setAdapter(new ImageAdapter(this)); ImageAdapter coverImageAdapter = new ImageAdapter(this); //coverImageAdapter.createReflectedImages(); coverFlow.setAdapter(coverImageAdapter); coverFlow.setSpacing(-25); coverFlow.setSelection(4, true); coverFlow.setAnimationDuration(1000); setContentView(coverFlow); } public class ImageAdapter extends BaseAdapter { int mGalleryItemBackground; private Context mContext; private FileInputStream fis; private Integer[] mImageIds = { R.drawable.kasabian_kasabian, R.drawable.starssailor_silence_is_easy, R.drawable.killers_day_and_age, R.drawable.garbage_bleed_like_me, R.drawable.death_cub_for_cutie_the_photo_album, R.drawable.kasabian_kasabian, R.drawable.massive_attack_collected, R.drawable.muse_the_resistance, R.drawable.starssailor_silence_is_easy }; private ImageView[] mImages; public ImageAdapter(Context c) { mContext = c; mImages = new ImageView[mImageIds.length]; } public boolean createReflectedImages() { //The gap we want between the reflection and the original image final int reflectionGap = 4; int index = 0; for (int imageId : mImageIds) { Bitmap originalImage = BitmapFactory.decodeResource(getResources(), imageId); int width = originalImage.getWidth(); int height = originalImage.getHeight(); //This will not scale but will flip on the Y axis Matrix matrix = new Matrix(); matrix.preScale(1, -1); //Create a Bitmap with the flip matrix applied to it. //We only want the bottom half of the image Bitmap reflectionImage = Bitmap.createBitmap(originalImage, 0, height/2, width, height/2, matrix, false); //Create a new bitmap with same width but taller to fit reflection Bitmap bitmapWithReflection = Bitmap.createBitmap(width , (height + height/2), Config.ARGB_8888); //Create a new Canvas with the bitmap that's big enough for //the image plus gap plus reflection Canvas canvas = new Canvas(bitmapWithReflection); //Draw in the original image canvas.drawBitmap(originalImage, 0, 0, null); //Draw in the gap Paint deafaultPaint = new Paint(); canvas.drawRect(0, height, width, height + reflectionGap, deafaultPaint); //Draw in the reflection canvas.drawBitmap(reflectionImage,0, height + reflectionGap, null); //Create a shader that is a linear gradient that covers the reflection Paint paint = new Paint(); LinearGradient shader = new LinearGradient(0, originalImage.getHeight(), 0, bitmapWithReflection.getHeight() + reflectionGap, 0x70ffffff, 0x00ffffff, TileMode.CLAMP); //Set the paint to use this shader (linear gradient) paint.setShader(shader); //Set the Transfer mode to be porter duff and destination in paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN)); //Draw a rectangle using the paint with our linear gradient canvas.drawRect(0, height, width, bitmapWithReflection.getHeight() + reflectionGap, paint); ImageView imageView = new ImageView(mContext); imageView.setImageBitmap(bitmapWithReflection); imageView.setLayoutParams(new CoverFlow.LayoutParams(120, 180)); imageView.setScaleType(ScaleType.MATRIX); mImages[index++] = imageView; } return true; } public int getCount() { return mImageIds.length; } public Object getItem(int position) { return position; } public long getItemId(int position) { return position; } public View getView(int position, View convertView, ViewGroup parent) { //Use this code if you want to load from resources ImageView i = new ImageView(mContext); i.setImageResource(mImageIds[position]); i.setLayoutParams(new CoverFlow.LayoutParams(130, 130)); i.setScaleType(ImageView.ScaleType.CENTER_INSIDE); //Make sure we set anti-aliasing otherwise we get jaggies BitmapDrawable drawable = (BitmapDrawable) i.getDrawable(); drawable.setAntiAlias(true); return i; //return mImages[position]; } /** Returns the size (0.0f to 1.0f) of the views * depending on the 'offset' to the center. */ public float getScale(boolean focused, int offset) { /* Formula: 1 / (2 ^ offset) */ return Math.max(0, 1.0f / (float)Math.pow(2, Math.abs(offset))); } } }