易采站长站为您分析Android编程实现的超炫图片浏览器,涉及Android针对图片的查看与显示方法,包含对图片的各种常见操作技巧,需要的朋友可以参考下
本文实例讲述了Android编程实现的超炫图片浏览器。，具体如下：
使用过Android自带的gallery组件的人都知道，gallery实现的效果就是拖动浏览一组图片，相比iphone里也是用于拖动浏览图片的coverflow，显然逊色不少。实际上，可以通过扩展gallery，通过伪3D变换可以基本实现coverflow的效果。本文通过源代码解析这一功能的实现。具体代码作用可参照注释。
最终实现效果如下：
要使用gallery，我们必须首先给其指定一个adapter。在这里，我们实现了一个自定义的ImageAdapter，为图片制作倒影效果。
传入参数为context和程序内drawable中的图片ID数组。之后调用其中的createReflectedImages()方法分别创造每一个图像的倒影效果，生成对应的ImageView数组，最后在getView()中返回。
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.easck.com/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)));
}
}
}
