android UI效果一: coverFlow

先看效果图:

自定义Gallery控件实现.

主要有4个文件，1个Layout,1个Activity,1个Adapter,1个Gallery

Activity:

public class ActivityMain extends Activity {
    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.Gallery01);
        galleryFlow.setAdapter(adapter);

    }
}

Gallery:

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();
    }
}

Adapter:

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 , 240 ));
//          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)));
    }

}

　　

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。

 

http://www.cnblogs.com/yyyyy5101/archive/2011/12/14/2287871.html