Android编程实现的超炫图片浏览器

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 
* 
* [url]http://www.apache.org/licenses/LICENSE-2.0[/url] 
* 
* 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 
*/ 
public class ImageAdapter extends BaseAdapter { 
int mGalleryItemBackground; 
private Context mContext; 
private Integer[] mImageIds ; 
private ImageView[] mImages; 
public ImageAdapter(Context c, int[] ImageIds) { 
mContext = c; 
mImageIds = ImageIds; 
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( 
mContext.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 GalleryFlow.LayoutParams(160, 240)); 
// 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(350,350)); 
* 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) */ 
returnMath.max(0,1.0f / (float) Math.pow(2, Math.abs(offset))); 
} 
} 
}

public class GalleryFlow extendsGallery { 
  /** 
   * Graphics Camera used for transforming the matrix of ImageViews 
   */ 
  privateCamera mCamera = newCamera(); 
  /** 
   * The maximum angle the Child ImageView will be rotated by 
   */ 
  privateint mMaxRotationAngle =60; 
  /** 
   * The maximum zoom on the centre Child 
   */ 
  privateint mMaxZoom = -120; 
  /** 
   * The Centre of the Coverflow 
   */ 
  privateint mCoveflowCenter; 
  publicGalleryFlow(Context context) { 
    super(context); 
    this.setStaticTransformationsEnabled(true); 
  } 
  publicGalleryFlow(Context context, AttributeSet attrs) { 
    super(context, attrs); 
    this.setStaticTransformationsEnabled(true); 
  } 
  publicGalleryFlow(Context context, AttributeSet attrs, int defStyle) { 
    super(context, attrs, defStyle); 
    this.setStaticTransformationsEnabled(true); 
  } 
  /** 
   * Get the max rotational angle of the image 
   * 
   * @return the mMaxRotationAngle 
   */ 
  publicint getMaxRotationAngle() { 
    returnmMaxRotationAngle; 
  } 
  /** 
   * Set the max rotational angle of each image 
   * 
   * @param maxRotationAngle 
   *   the mMaxRotationAngle to set 
   */ 
  publicvoid setMaxRotationAngle(intmaxRotationAngle) { 
    mMaxRotationAngle = maxRotationAngle; 
  } 
  /** 
   * Get the Max zoom of the centre image 
   * 
   * @return the mMaxZoom 
   */ 
  publicint getMaxZoom() { 
    returnmMaxZoom; 
  } 
  /** 
   * Set the max zoom of the centre image 
   * 
   * @param maxZoom 
   *   the mMaxZoom to set 
   */ 
  publicvoid setMaxZoom(intmaxZoom) { 
    mMaxZoom = maxZoom; 
  } 
  /** 
   * Get the Centre of the Coverflow 
   * 
   * @return The centre of this Coverflow. 
   */ 
  privateint getCenterOfCoverflow() { 
    return(getWidth() - getPaddingLeft() - getPaddingRight()) / 2 
        + getPaddingLeft(); 
  } 
  /** 
   * Get the Centre of the View 
   * 
   * @return The centre of the given view. 
   */ 
  privatestatic int getCenterOfView(View view) { 
    returnview.getLeft() + view.getWidth() / 2; 
  } 
  /** 
   * {@inheritDoc} 
   * 
   * @see #setStaticTransformationsEnabled(boolean) 
   */ 
  protectedboolean getChildStaticTransformation(View child, Transformation t) { 
    finalint childCenter = getCenterOfView(child); 
    finalint childWidth = child.getWidth(); 
    introtationAngle = 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); 
    } 
    returntrue; 
  } 
  /** 
   * 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. 
   */ 
  protectedvoid onSizeChanged(intw, 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 
   */ 
  privatevoid transformImageBitmap(ImageView child, Transformation t, 
      introtationAngle) { 
    mCamera.save(); 
    finalMatrix imageMatrix = t.getMatrix(); 
    finalint imageHeight = child.getLayoutParams().height; 
    finalint imageWidth = child.getLayoutParams().width; 
    finalint rotation = Math.abs(rotationAngle); 
    // 在Z轴上正向移动camera的视角，实际效果为放大图片。 
    // 如果在Y轴上移动，则图片上下移动；X轴上对应图片左右移动。 
    mCamera.translate(0.0f,0.0f, 100.0f); 
    // As the angle of the view gets less, zoom in 
    if(rotation < mMaxRotationAngle) { 
      floatzoomAmount = (float) (mMaxZoom + (rotation *1.5)); 
      mCamera.translate(0.0f,0.0f, zoomAmount); 
    } 
    // 在Y轴上旋转，对应图片竖向向里翻转。 
    // 如果在X轴上旋转，则对应图片横向向里翻转。 
    mCamera.rotateY(rotationAngle); 
    mCamera.getMatrix(imageMatrix); 
    imageMatrix.preTranslate(-(imageWidth /2), -(imageHeight /2)); 
    imageMatrix.postTranslate((imageWidth /2), (imageHeight /2)); 
    mCamera.restore(); 
  } 
}

public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.layout_gallery); 
    Integer[] images = { R.drawable.img0001, R.drawable.img0030, 
      R.drawable.img0100, R.drawable.img0130, R.drawable.img0200, 
      R.drawable.img0230, R.drawable.img0300, R.drawable.img0330, 
      R.drawable.img0354 }; 
    ImageAdapter adapter =new ImageAdapter(this, images); 
    adapter.createReflectedImages(); 
    GalleryFlow galleryFlow = (GalleryFlow) findViewById(R.id.gallery_flow); 
    galleryFlow.setAdapter(adapter); 
}

BitmapDrawable bd = new BitmapDrawable(bitmapWithReflection);
bd.setAntiAlias(true);

imageMatrix.preTranslate(-(imageWidth / 2), -(imageHeight / 2));
imageMatrix.postTranslate((imageWidth / 2), (imageHeight / 2));