效果展示

good_view.gif

知識(shí)儲(chǔ)備:

1,清楚了解Androidview的坐標(biāo)系
2,清楚了解View.MeasureSpec類
3,清楚了解集合動(dòng)畫
沒了解過的親,建議先找相關(guān)文章閱讀了解清楚

解析流程:

1,實(shí)現(xiàn)思路:
繼承PopupWindow,設(shè)置寬高,彈出位置,動(dòng)畫效果.

實(shí)現(xiàn)思路看起來挺簡單的,難點(diǎn)在于
a,popwindow的彈出定位,需要對(duì)view的坐標(biāo)系比較熟悉
b,popwindow的大小計(jì)算,需要對(duì)View.MeasureSpec熟悉
c,popwindow的動(dòng)畫效果,組合動(dòng)畫,透明度以及位移動(dòng)畫.位移動(dòng)畫初始位置需要搞清楚.

2,難點(diǎn)解析

a,彈出定位
overwrite popwindow show(View v)

核心代碼:

int offsetX = v.getWidth() / 2 - getWidth() / 2;//X方向上的偏移量
int offsetY = -v.getHeight() - getHeight();//Y方向上的偏移量
showAsDropDown(v,offsetX , offsetY);

定位圖

popwindow定位圖.jpg

關(guān)鍵點(diǎn)

1,知道Popwindow.showAsDropDown()方法的坐標(biāo)原點(diǎn)在view的左下方!!!
2,在該坐標(biāo)下,已知view和popwindow各自的寬高,計(jì)算偏移坐標(biāo)
(貌似初中知識(shí),囧)

計(jì)算寬高
在構(gòu)造方法中計(jì)算寬高

 //根據(jù)提供的大小值和模式，創(chuàng)建一個(gè)測量值(格式)
int w = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);//未指定模式,子元素大小任意.
int h = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
mGoodTv.measure(w, h);
setWidth(mGoodTv.getMeasuredWidth());
setHeight(mDistance + mGoodTv.getMeasuredHeight());

在設(shè)置文字后計(jì)算寬高

 int w = (int) mGoodTv.getPaint().measureText(text);
setWidth(w);
setHeight(mDistance + getTextViewHeight(mGoodTv, w));

 private static int getTextViewHeight(TextView textView, int width) {
        int widthMeasureSpec = View.MeasureSpec.makeMeasureSpec(width, View.MeasureSpec.AT_MOST);//最多不超過width
        int heightMeasureSpec = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
        textView.measure(widthMeasureSpec, heightMeasureSpec);
        return textView.getMeasuredHeight();
    }

在設(shè)置圖片后計(jì)算寬高

 /**
 * 設(shè)置圖片
 *
 * @param drawable
 */
public void setImage(Drawable drawable) {
    if (drawable == null) {
        throw new IllegalArgumentException("drawable cannot be null.");
    }
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
        mGoodTv.setBackground(drawable);
    } else {
        mGoodTv.setBackgroundDrawable(drawable);
    }
    /*******************************************************************/
    //drawable獲取實(shí)際寬高的方式
    mGoodTv.setText("");
    setWidth(drawable.getIntrinsicWidth());//獲取drawable實(shí)際寬高
    //加上mDistance 移動(dòng)動(dòng)畫不會(huì)被遮蓋
    setHeight(mDistance + drawable.getIntrinsicHeight());
    /*******************************************************************/

}

c,動(dòng)畫

/**
 * 動(dòng)畫
 *
 * @return
 */
private AnimationSet createAnimation() {
    mAnimationSet = new AnimationSet(true);
    /**
     * 核心代碼
     * *****************************************************************/
    TranslateAnimation translateAnim = new TranslateAnimation(0, 0, mFromY, -mToY);
    /*******************************************************************/
    AlphaAnimation alphaAnim = new AlphaAnimation(mFromAlpha, mToAlpha);
    mAnimationSet.addAnimation(translateAnim);
    mAnimationSet.addAnimation(alphaAnim);
    mAnimationSet.setDuration(mDuration);
    mAnimationSet.setAnimationListener(new Animation.AnimationListener() {
        @Override
        public void onAnimationStart(Animation animation) {
        }

        @Override
        public void onAnimationEnd(Animation animation) {
            if (isShowing()) {
                new Handler().post(new Runnable() {
                    @Override
                    public void run() {
                        dismiss();
                    }
                });
            }
        }

        @Override
        public void onAnimationRepeat(Animation animation) {
        }
    });
    return mAnimationSet;
}