利用TextView中的DrawableTop实现图片在文字上方，点击TextView能实现图片旋转

来源：互联网发布：linux 混合硬盘编辑：程序博客网时间：2024/05/22 04:58

在今日头条里面Home按钮点击时候，能出现旋转的动画。这里模仿今日头条的Home按钮效果，通过自定义View来实现该效果。

先给出工程代码的GitHub地址：TopTextView

其实主要是在onDraw里面先绘制图片，然后再绘制text。旋转的动画通过animation-rotate实现。具体代码如下：

    @Override    protected void onDraw(Canvas canvas) {        if (mDrawableTop == null) {            super.onDraw(canvas);            return;        }        int drawablePadding = getCompoundDrawablePadding();        int drawableWidth = this.mDrawableTop.getIntrinsicWidth();        int drawableHeight = this.mDrawableTop.getIntrinsicHeight();//        startDrawableX = (getWidth() >> 1) - ((drawablePadding + textWidth + drawableWidth) >> 1);//        startDrawableY = (getHeight() >> 1) - (drawableHeight >> 1);        startDrawableX = (getWidth()>>1) - (drawableWidth>>1);        startDrawableY = (getHeight()>>1) - ((drawableHeight+textHeight+drawablePadding)>>1);        //画旋转图片        canvas.save();        canvas.translate(startDrawableX, startDrawableY);        this.mDrawableTop.draw(canvas);        canvas.restore();        //画文字//        int boxht = this.getMeasuredHeight() - this.getExtendedPaddingTop() - this.getExtendedPaddingBottom();//        int textht = getLayout().getHeight();//        int  voffsetText = boxht - textht >> 1;//        int boxht = this        canvas.save();//        canvas.translate((float) (startDrawableX + drawableWidth + drawablePadding), (float) (getExtendedPaddingTop() + voffsetText));        canvas.translate((float)(getExtendedPaddingBottom()),(float)(startDrawableY+drawableHeight+drawablePadding));        getLayout().draw(canvas);        canvas.restore();    }

为了实现重复绘制，需要重写下面函数：

 @Override    public void invalidateDrawable(Drawable drawable) {//        super.invalidateDrawable(drawable);        final Rect dirty = drawable.getBounds();        int scrollX = 0;        int scrollY = 0;        if(drawable == this.mDrawableTop){            scrollX = startDrawableX;            scrollY = startDrawableY;        }        this.invalidate(dirty.left + scrollX-2, dirty.top + scrollY-2, dirty.right + scrollX+2, dirty.bottom + scrollY+2);    }

具体代码可以参考工程里面代码。

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