Android UI开发第二十三篇——分享书架UI实现

android中有很多的电子书阅读应用，应用中都仿真了书架的实现，这里也分享一篇读书应用的书架实现：

java：

public class ShelvesView extends GridView {
    private Bitmap mShelfBackground;
    private int mShelfWidth;
    private int mShelfHeight;

    private Bitmap mWebLeft;
    private Bitmap mWebRight;
    private int mWebRightWidth;

    public ShelvesView(Context context) {
        super(context);
        init(context);
    }

    public ShelvesView(Context context, AttributeSet attrs) {
        super(context, attrs);
        load(context, attrs, 0);
		init(context);
    }

    public ShelvesView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        load(context, attrs, defStyle);
        init(context);
    }

    private void load(Context context, AttributeSet attrs, int defStyle) {
        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.ShelvesView, defStyle, 0);

        final Resources resources = getResources();
        final int background = a.getResourceId(R.styleable.ShelvesView_shelfBackground, 0);
        final Bitmap shelfBackground = BitmapFactory.decodeResource(resources, background);
        if (shelfBackground != null) {
            mShelfWidth = shelfBackground.getWidth();
            mShelfHeight = shelfBackground.getHeight();
            mShelfBackground = shelfBackground;
        }

        mWebLeft = BitmapFactory.decodeResource(resources, R.drawable.web_left);

        final Bitmap webRight = BitmapFactory.decodeResource(resources, R.drawable.web_right);
        mWebRightWidth = webRight.getWidth();
        mWebRight = webRight;

        a.recycle();
    }

    private void init(Context context) {
        StateListDrawable drawable = new StateListDrawable();

        SpotlightDrawable start = new SpotlightDrawable(context, this);
        start.disableOffset();
        SpotlightDrawable end = new SpotlightDrawable(context, this, R.drawable.spotlight_blue);
        end.disableOffset();
        TransitionDrawable transition = new TransitionDrawable(start, end);
        drawable.addState(new int[] { android.R.attr.state_pressed },
                transition);

        final SpotlightDrawable normal = new SpotlightDrawable(context, this);
        drawable.addState(new int[] { }, normal);

        normal.setParent(drawable);
        transition.setParent(drawable);

        setSelector(drawable);
        setDrawSelectorOnTop(false);
    }

    @Override
    protected void dispatchDraw(Canvas canvas) {
        final int count = getChildCount();
        final int top = count > 0 ? getChildAt(0).getTop() : 0;
        final int shelfWidth = mShelfWidth;
        final int shelfHeight = mShelfHeight;
        final int width = getWidth();
        final int height = getHeight();
        final Bitmap background = mShelfBackground;

        for (int x = 0; x < width; x += shelfWidth) {
            for (int y = top; y < height; y += shelfHeight) {
                canvas.drawBitmap(background, x, y, null);
            }
        }

        if (count == 0) {
            canvas.drawBitmap(mWebLeft, 0.0f, top + 1, null);
            canvas.drawBitmap(mWebRight, width - mWebRightWidth, top + shelfHeight + 1, null);
        }

        super.dispatchDraw(canvas);
    }

    

    @Override
    public void setPressed(boolean pressed) {
        super.setPressed(pressed);

        final Drawable current = getSelector().getCurrent();
        if (current instanceof TransitionDrawable) {
            if (pressed) {
                ((TransitionDrawable) current).startTransition(
                        ViewConfiguration.getLongPressTimeout());
            } else {
                ((TransitionDrawable) current).resetTransition();
            }
        }
    }
}

代码：http://download.csdn.net/detail/xyz_lmn/4698124

/**

* @author 张兴业

* http://blog.csdn.net/xyz_lmn

* iOS入门群：83702688

* android开发进阶群：241395671

* 我的新浪微博：@张兴业TBOW

*/