标签：android activity coverflow 3d
本例主要介绍CoverFlow3D的实现。首先介绍一下Cover Flow。Cover Flow是苹果首创的将多首歌曲的封面以3D界面的形式显示出来的方式。
本案例摘自网络http://www.cnblogs.com/yyyyy5101/archive/2011/12/14/2287871.html，该案例在真机测试中，出现显示效果的差异，由此可见该演示工程存在一定的兼容性的问题，往浏览本文的有志之士，可以给以指正与修改。最后补充一下，虽然不同机器显示的效果有差异，但是显示效果的确也算优秀。
【转载使用，请注明出处：http://blog.csdn.net/mahoking】
本案例的演示工程设计三个类文件分别为：Activity(CoverFlowActivity)、Gallery(GalleryFlow)、BaseAdapter(ImageAdapter)和布局文件activity_02_gallery.xml。
CoverFlowActivity
import android.app.Activity;
import android.os.Bundle;
public class CoverFlowActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_02_gallery);
Integer[] images = { R.drawable.image01, R.drawable.image02,R.drawable.image03};
ImageAdapter adapter = new ImageAdapter(this, images);
adapter.createReflectedImages();
GalleryFlow galleryFlow = (GalleryFlow) findViewById(R.id.activity_01_galleryFlow);
galleryFlow.setAdapter(adapter);
}
}
Gallery是android的一个浏览图片的组件（不只是图片，可以用适配器），Gallery的中文意思也是画廊的意思，就是说把图片排成一行，然后手动滑动阅览。本文只是入门介绍，如果要深入了解Gallery还需读者自行不断深入了解。
GalleryFlow gallery在拖动图片过程中，会不断调用getChildStaticTransformation 方法,在该方法中,用Camera实现Z轴旋转。
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 GalleryFlow extends Gallery {
private Camera mCamera = new Camera();
private int mMaxRotationAngle = 60;
private int mMaxZoom = -120;
private int mCoveflowCenter;
public GalleryFlow(Context context) {
super(context);
this.setStaticTransformationsEnabled(true);
}
public GalleryFlow(Context context, AttributeSet attrs) {
super(context, attrs);
this.setStaticTransformationsEnabled(true);
}
public GalleryFlow(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
this.setStaticTransformationsEnabled(true);
}
public int getMaxRotationAngle() {
return mMaxRotationAngle;
}
public void setMaxRotationAngle(int maxRotationAngle) {
mMaxRotationAngle = maxRotationAngle;
}
public int getMaxZoom() {
return mMaxZoom;
}
public void setMaxZoom(int maxZoom) {
mMaxZoom = maxZoom;
}
private int getCenterOfCoverflow() {
return (getWidth() - getPaddingLeft() - getPaddingRight()) / 2
+ getPaddingLeft();
}
private static int getCenterOfView(View view) {
return view.getLeft() + view.getWidth() / 2;
}
@Override
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;
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
mCoveflowCenter = getCenterOfCoverflow();
super.onSizeChanged(w, h, oldw, oldh);
}
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);
// 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) {
float zoomAmount = (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();
}
}
ImageAdapter
import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.LinearGradient;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.PorterDuff.Mode;
import android.graphics.PorterDuffXfermode;
import android.graphics.Shader.TileMode;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
public class ImageAdapter extends BaseAdapter {
int mGalleryItemBackground;
private Context mContext;
private Integer[] mImageIds;
private ImageView[] mImages;
public ImageAdapter(Context c, Integer[] ImageIds) {
mContext = c;
mImageIds = ImageIds;
mImages = new ImageView[mImageIds.length];
}
public boolean createReflectedImages() {
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();
Matrix matrix = new Matrix();
matrix.preScale(1, -1);
Bitmap reflectionImage = Bitmap.createBitmap(originalImage, 0,
height / 2, width, height / 2, matrix, false);
Bitmap bitmapWithReflection = Bitmap.createBitmap(width,
(height + height / 2), Config.ARGB_8888);
Canvas canvas = new Canvas(bitmapWithReflection);
canvas.drawBitmap(originalImage, 0, 0, null);
Paint deafaultPaint = new Paint();
canvas.drawRect(0, height, width, height + reflectionGap,
deafaultPaint);
canvas.drawBitmap(reflectionImage, 0, height + reflectionGap, null);
Paint paint = new Paint();
LinearGradient shader = new LinearGradient(0, originalImage
.getHeight(), 0, bitmapWithReflection.getHeight()
+ reflectionGap, 0x70ffffff, 0x00ffffff, TileMode.CLAMP);
paint.setShader(shader);
paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));
canvas.drawRect(0, height, width, bitmapWithReflection.getHeight()
+ reflectionGap, paint);
ImageView imageView = new ImageView(mContext);
imageView.setImageBitmap(bitmapWithReflection);
imageView.setLayoutParams(new GalleryFlow.LayoutParams(180*2, 240*2));
// imageView.setLayoutParams(new GalleryFlow.LayoutParams(180*4, 240*4));
// imageView.setScaleType(ScaleType.MATRIX);
mImages[index++] = imageView;
}
return true;
}
private Resources getResources() {
// TODO Auto-generated method stub
return null;
}
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) {
return mImages[position];
}
public float getScale(boolean focused, int offset) {
return Math.max(0, 1.0f / (float) Math.pow(2, Math.abs(offset)));
}
}
activity_02_gallery.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<com.mahaochen.app.uisharing.example02.GalleryFlow
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/activity_01_galleryFlow"/>
</LinearLayout>
演示效果截图：
【Android UI】案例01Cover Flow3D效果的实现
标签：android activity coverflow 3d
原文地址：http://blog.csdn.net/mahoking/article/details/38876221
