RecyclerView零点突破(动画+边线篇）

0、前言:

动画和边线估计有点冷门，很多人都将就凑合,今天我就来深入讲解一下吧
边线的方案是网上流传的一种，个人感觉也是最好的，并稍稍改进了一点
本篇使用的测试布局见上篇：RecyclerView零点突破(基本使用篇）

留图镇楼

镇楼1	镇楼2

本系列分为3篇：

• RecyclerView零点突破(基本使用篇）
• RecyclerView零点突破(动画+边线篇）
• RecyclerView零点突破(详细分析篇）

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1、动画--解析内置DefaultItemAnimator与自定义

一共就不到700行代码，应该能hold住吧
为了方便研究，将DefaultItemAnimator拷贝一份到工程中

整体了解一下：

DefaultItemAnimator-->SimpleItemAnimator-->RecyclerView.ItemAnimator
几个核心的回调函数如下：

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1.1.添加的时候：

默认效果是下面的条目整体下移,之后插入的条目淡入(透明度0~1)

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1.1.1：查看添加时函数的执行情况

animateMove、endAnimationy一对调用了10次  
animateAdd、endAnimation一对调用了1次  
最后调用了runPendingAnimations

animateMove的最大的条目position是：11,也就是当前页面的最大Position   
经多次测试：
插入位置之后的所有当前页的条目都会响应animateMove方法，且执行的先后顺序是随机的  
插入目标的条目响应animateAdd方法
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1.1.2：animateAdd分析

-->[DefaultItemAnimator#animateAdd]
-----------------------------------------------------
@Override
public boolean animateAdd(final ViewHolder holder) {
    resetAnimation(holder);//重置动画
    holder.itemView.setAlpha(0);//将该条目透明度设为0,也就是点击时的空白区域
    mPendingAdditions.add(holder);//将这个透明的条目加入mPendingAdditions列表
    return true;
}

-->[DefaultItemAnimator#animateAdd]
-----------------------------------------------------
private void resetAnimation(ViewHolder holder) {
    if (sDefaultInterpolator == null) {
        sDefaultInterpolator = new ValueAnimator().getInterpolator();
    }
    holder.itemView.animate().setInterpolator(sDefaultInterpolator);
    endAnimation(holder);
}

-->[待添加的ViewHolder列表]
-----------------------------------------------------
private ArrayList<ViewHolder> mPendingAdditions = new ArrayList<>();

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1.1.3：mPendingAdditions的endAnimation分析

 @Override
    public void endAnimation(ViewHolder item) {
        Log.e(TAG, "endAnimation: ");
        final View view = item.itemView;//条目视图
        view.animate().cancel();//先取消条目视图的动画
        //略n行....
        //添加的条目布局列表：mPendingAdditions  
        if (mPendingAdditions.remove(item)) {//移除该条目
            view.setAlpha(1);//将该条目透明度设为1
            dispatchAddFinished(item);
        }
        //略n行....
        dispatchFinishedWhenDone();
    }
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1.1.4：mPendingAdditions在runPendingAnimations中

-->[ArrayList<ViewHolder>列表]
-----------------------------------------------------
ArrayList<ArrayList<ViewHolder>> mAdditionsList = new ArrayList<>();

-->[DefaultItemAnimator#runPendingAnimations]
-----------------------------------------------------
@Override
public void runPendingAnimations() {
    //mPendingAdditions不为空，可以添加
    boolean additionsPending = !mPendingAdditions.isEmpty();
    //additionsPending为false可导致直接返回，不执行动画
    if (!removalsPending && !movesPending && !additionsPending && !changesPending) {
        return;
    }
    //略n行....
    if (additionsPending) {
        final ArrayList<ViewHolder> additions = new ArrayList<>();
        additions.addAll(mPendingAdditions);//将mPendingAdditions的视图装到additions
        mAdditionsList.add(additions);//mAdditionsList的盒子装additions
        mPendingAdditions.clear();//mPendingAdditions光荣下岗
        Runnable adder = new Runnable() {//居然是Runnable...记住这小子的名字[adder]
            @Override
            public void run() {
                for (ViewHolder holder : additions) {//遍历：additions
                    animateAddImpl(holder);//----动画的核心----
                }
                additions.clear();//清空additions
                mAdditionsList.remove(additions);//移除additions
            }
        };
        if (removalsPending || movesPending || changesPending) {//如果有其他的动画待执行
            long removeDuration = removalsPending ? getRemoveDuration() : 0;
            long moveDuration = movesPending ? getMoveDuration() : 0;
            long changeDuration = changesPending ? getChangeDuration() : 0;
            long totalDelay = removeDuration + Math.max(moveDuration, changeDuration);
            View view = additions.get(0).itemView;
            ViewCompat.postOnAnimationDelayed(view, adder, totalDelay);
        } else {
            adder.run();//[adder]走起
        }
    }
}

-->[要进行添加动画的ViewHolder]
-----------------------------------------------------
ArrayList<ViewHolder> mAddAnimations = new ArrayList<>();

-->[DefaultItemAnimator#animateAddImpl]
-----------------------------------------------------
void animateAddImpl(final ViewHolder holder) {
    final View view = holder.itemView;//获取布局视图
    final ViewPropertyAnimator animation = view.animate();//获取视图的animate
    mAddAnimations.add(holder);//mAddAnimations篮子装一下
    animation.alpha(1).setDuration(getAddDuration())//tag1:默认时长120ms---执行透明度动画
            .setListener(new AnimatorListenerAdapter() {
                @Override
                public void onAnimationStart(Animator animator) {
                    dispatchAddStarting(holder);
                }
                @Override//取消动画时将Alpha设为1
                public void onAnimationCancel(Animator animator) {
                    view.setAlpha(1);
                }
                @Override//办完事，清场，该走的走，该清的清
                public void onAnimationEnd(Animator animator) {
                    animation.setListener(null);
                    dispatchAddFinished(holder);
                    mAddAnimations.remove(holder);
                    dispatchFinishedWhenDone();
                }
            }).start();
}

-->[android.support.v7.widget.RecyclerView.ItemAnimator#getAddDuration]
------------------------tag1-----------------------------
private long mAddDuration = 120;
public long getAddDuration() {
    return mAddDuration;
}
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1.2：自定义添加动画

1.2.1：定点旋转

既然分析到它是怎么动起来的，当然可以改一下,比如：
注意：animateAddImpl里的动画是在移动结束后调用的

-->[RItemAnimator#animateAddImpl]
-----------------------------------------------------
animation.rotation(360).setDuration(1000)
        .setListener(new AnimatorListenerAdapter() {
            @Override
            public void onAnimationStart(Animator animator) {
                view.setAlpha(1);

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---

1.2.2抖动

缩放抖动	移动抖动

感觉ViewPropertyAnimator用得不怎么爽，还是用AnimatorSet+ObjectAnimator吧
用AnimatorSet装一下效果，可以实现更复杂的多动画叠加，然后添加监听，和源码保持一致
一直想做条目抖动效果，总是实现了，如果不会用ObjectAnimator的童鞋，可以参见

void animateAddImpl(final ViewHolder holder) {
    final View view = holder.itemView;
    mAddAnimations.add(holder);
    ObjectAnimator translationX = ObjectAnimator//创建实例
            //(View,属性名,初始化值,结束值)
            .ofFloat(view, "translationX", 0, 20, -20, 0, 20, -20, 0, 20, -20, 0)
            .setDuration(300);//设置时长
    ObjectAnimator scaleX = ObjectAnimator//创建实例
            //(View,属性名,初始化值,结束值)
            .ofFloat(view, "scaleX", 1, 0.95f, 1.05f, 1, 0.95f, 1.05f, 1, 0.95f, 1.05f,1)
            .setDuration(300);//设置时长
    AnimatorSet set = new AnimatorSet();
    set.playTogether(scaleX,translationX);//两个效果一起
    //set.playSequentially(translationX);//添加动画
    //set.playSequentially(scaleX);//添加动画
    set.addListener(new AnimatorListenerAdapter() {
        @Override
        public void onAnimationCancel(Animator animation) {
            view.setAlpha(1);
        }
        @Override
        public void onAnimationEnd(Animator animation) {
            dispatchAddFinished(holder);
            mAddAnimations.remove(holder);
            dispatchFinishedWhenDone();
        }
        @Override
        public void onAnimationStart(Animator animation) {
            view.setAlpha(1);
            dispatchAddStarting(holder);
        }
    });
    set.start();
}
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1.2.3：定轴旋转

rotationX	rotationY

//定轴旋转
ObjectAnimator rotationY = ObjectAnimator//创建实例
        //(View,属性名,初始化值,结束值)
        .ofFloat(view, "rotationY", 0,360)
        .setDuration(1000);//设置时长
ObjectAnimator rotationX = ObjectAnimator//创建实例
        //(View,属性名,初始化值,结束值)
        .ofFloat(view, "rotationX", 0,360)
        .setDuration(1000);//设置时长
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---

1.3:插入下item的动画：

效果1	效果2

1.3.1：简析：

分析同添加：运动核心在DefaultItemAnimator#animateMoveImpl方法里,相关集合：  
private ArrayList<MoveInfo> mPendingMoves = new ArrayList<>();   
ArrayList<ArrayList<MoveInfo>> mMovesList = new ArrayList<>();  
ArrayList<ViewHolder> mRemoveAnimations = new ArrayList<>();
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-->[下面的条目执行：animateMove()]
-----------------------------------------------------
@Override
public boolean animateMove(final ViewHolder holder, int fromX, int fromY,
                           int toX, int toY) {
    final View view = holder.itemView;//获取item视图View
    fromX += (int) holder.itemView.getTranslationX();
    fromY += (int) holder.itemView.getTranslationY();
    resetAnimation(holder);
    int deltaX = toX - fromX;
    int deltaY = toY - fromY;
    if (deltaX == 0 && deltaY == 0) {
        dispatchMoveFinished(holder);
        return false;
    }//尺寸计算
    if (deltaX != 0) {//对item视图进行平移
        view.setTranslationX(-deltaX);
    }
    if (deltaY != 0) {
        view.setTranslationY(-deltaY);
    }
    //mPendingMoves添加MoveInfo---移动的相关信息封装在MoveInfo中，相当于封装属性的空壳类
    mPendingMoves.add(new MoveInfo(holder, fromX, fromY, toX, toY));
    return true;
}


-->[mPendingMoves在runPendingAnimations()中的表现]
-----------------------------------------------------
boolean movesPending = !mPendingMoves.isEmpty();
if (!removalsPending && !movesPending && !additionsPending && !changesPending) {
    // nothing to animate
    return;
}
//和添加是一个套路---核心运动方法在：animateMoveImpl
if (movesPending) {
    final ArrayList<MoveInfo> moves = new ArrayList<>();
    moves.addAll(mPendingMoves);
    mMovesList.add(moves);
    mPendingMoves.clear();
    Runnable mover = new Runnable() {
        @Override
        public void run() {
            for (MoveInfo moveInfo : moves) {
                animateMoveImpl(moveInfo.holder, moveInfo.fromX, moveInfo.fromY,
                        moveInfo.toX, moveInfo.toY);
            }
            moves.clear();
            mMovesList.remove(moves);
        }
    };

-->[mPendingMoves在runPendingAnimations()中的表现]
-----------------------------------------------------
void animateMoveImpl(final ViewHolder holder, int fromX, int fromY, int toX, int toY) {
    final View view = holder.itemView;
    final int deltaX = toX - fromX;
    final int deltaY = toY - fromY;
    if (deltaX != 0) {
        view.animate().translationX(0);
    }
    if (deltaY != 0) {
        view.animate().translationY(0);
    }
    final ViewPropertyAnimator animation = view.animate();
    mMoveAnimations.add(holder);
    //运动的逻辑(此处无特效)：
    animation.setDuration(getMoveDuration()).setListener(new AnimatorListenerAdapter() {
        @Override
        public void onAnimationStart(Animator animator) {
            dispatchMoveStarting(holder);
        }
        @Override
        public void onAnimationCancel(Animator animator) {
            if (deltaX != 0) {
                view.setTranslationX(0);
            }
            if (deltaY != 0) {
                view.setTranslationY(0);
            }
        }
        @Override
        public void onAnimationEnd(Animator animator) {
            animation.setListener(null);
            dispatchMoveFinished(holder);
            mMoveAnimations.remove(holder);
            dispatchFinishedWhenDone();
        }
    }).start();
}
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---

1.3.2：效果1：

-->[animateMoveImpl()中]
-----------------------------------------------------
//定轴旋转
ObjectAnimator//创建实例
        .ofFloat(view, "rotationX", 0, 360)
        .setDuration(1000).start();//设置时长
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---

1.3.3：效果2：

-->[animateMoveImpl()中]
-----------------------------------------------------
ObjectAnimator//创建实例
        .ofFloat(view, "ScaleX", 1, 0.5f, 1.2f,0.8f,1)
        .setDuration(1000).start();//设置时长
ObjectAnimator//创建实例
        .ofFloat(view, "ScaleY", 1, 0.5f, 1.2f,0.8f,1)
        .setDuration(1000).start();//设置时长
复制代码

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1.4：小结

移除貌似没有对当前item的特效，对item下面的特效还是在animateMoveImpl
更新数据的item的特效在：animateChangeImpl()都是一个套路，这里就不赘述了 将上篇的视图改改就能实现镇楼图了,这里也不赘述了

其实看懂了DefaultItemAnimator,item的动画也不是很难  
貌似有个动画库,个人感觉没有必要,拿DefaultItemAnimator稍微改几句就行了  
毕竟需求是不断变动的，一个库不可能涵盖所以需求，而且很多用不到的特效还占空间    
微妙的修整还是要懂才行，能应对变化的只有变化本身,记住修改效果的地方：

更新数据：animateChangeImpl()  
添加数据：animateAddImpl()  
移动：animateMoveImpl()
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---

2.边线的绘制：

2.1：效果一览

2.1.1：三个构造函数：

2.1.2：三种样式：

---

2.2:代码实现

2.2.1：使用

//mIdRvGoods.addItemDecoration(new RVItemDivider(this, RVItemDivider.Type.HORIZONTAL,10,Color.BLACK));
//mIdRvGoods.addItemDecoration(new RVItemDivider(this, RVItemDivider.Type.HORIZONTAL));
mIdRvGoods.addItemDecoration(new RVItemDivider(this, RVItemDivider.Type.BOTH,R.drawable.shape_div));
//mIdRvGoods.addItemDecoration(new RVItemDivider(this, RVItemDivider.Type.BOTH,10,Color.BLACK));
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2.2.2：代码实现

/**
 * 作者：张风捷特烈<br/>
 * 时间：2018/12/3 0003:10:36<br/>
 * 邮箱：[email protected]<br/>
 * 说明：RecyclerView的分割线
 */
public class RVItemDivider extends RecyclerView.ItemDecoration {

    public enum Type {
        VERTICAL,//竖直线
        HORIZONTAL,//水平线
        BOTH;//水平+垂直
    }

    private Paint mPaint;//画笔
    private Drawable mDivider;//Drawable分割线
    private int mDividerHeight = 1;//分割线高度，默认为1px
    private Type mOrientation;//线的方向
    private static final int[] ATTRS = new int[]{android.R.attr.listDivider};


    public RVItemDivider(Context context, Type orientation) {
        mOrientation = orientation;
        final TypedArray a = context.obtainStyledAttributes(ATTRS);
        mDivider = a.getDrawable(0);
        a.recycle();
    }

    public RVItemDivider(Context context, Type orientation, int drawableId) {
        this(context, orientation);
        mDivider = ContextCompat.getDrawable(context, drawableId);
        mDividerHeight = mDivider.getIntrinsicHeight();
    }

    /**
     * 自定义分割线
     *
     * @param context       上下文
     * @param orientation   列表方向
     * @param dividerHeight 分割线高度
     * @param dividerColor  分割线颜色
     */
    public RVItemDivider(Context context, Type orientation, int dividerHeight, int dividerColor) {
        this(context, orientation);
        mDividerHeight = dividerHeight;
        mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        mPaint.setColor(dividerColor);
        mPaint.setStyle(Paint.Style.FILL);
    }


    /**
     * 获取分割线尺寸
     *
     * @param outRect 线的矩框
     * @param view    线
     * @param parent  RecyclerView
     * @param state   状态
     */
    @Override
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
        super.getItemOffsets(outRect, view, parent, state);
        if (mOrientation == Type.VERTICAL||mOrientation == Type.BOTH) {
            outRect.set(0, 0, 0, mDividerHeight);//横线矩框
        } else {
            outRect.set(0, 0, mDividerHeight, 0);//竖线矩框
        }
    }

    /**
     * 绘制分割线
     *
     * @param canvas 画布
     * @param parent RecyclerView
     * @param state  状态
     */
    @Override
    public void onDraw(Canvas canvas, RecyclerView parent, RecyclerView.State state) {
        super.onDraw(canvas, parent, state);

        switch (mOrientation) {
            case BOTH:
                drawVertical(canvas, parent);//竖线矩框
                drawHorizontal(canvas, parent);//横线矩框
                break;
            case VERTICAL:
                drawVertical(canvas, parent);//竖线矩框
                break;
            case HORIZONTAL:
                drawHorizontal(canvas, parent);//横线矩框
                break;
        }
    }

    /**
     * 绘制水平线
     *
     * @param canvas 画布
     * @param parent RecyclerView
     */
    private void drawHorizontal(Canvas canvas, RecyclerView parent) {
        final int left = parent.getPaddingLeft();
        final int right = parent.getMeasuredWidth() - parent.getPaddingRight();
        final int childNum = parent.getChildCount();
        for (int i = 0; i < childNum; i++) {//遍历所有的孩子
            final View child = parent.getChildAt(i);
            RecyclerView.LayoutParams layoutParams = (RecyclerView.LayoutParams) child.getLayoutParams();
            //线的左上角坐标(itemView底部+边距,itemView底部+边距+线高)
            final int top = child.getBottom() + layoutParams.bottomMargin;
            final int bottom = top + mDividerHeight;
            if (mDivider != null) {//有mDivider时---绘制mDivider
                mDivider.setBounds(left, top, right, bottom);
                mDivider.draw(canvas);
            }
            if (mPaint != null) {//有mPaint时---绘制矩形
                canvas.drawRect(left, top, right, bottom, mPaint);
            }
        }
    }

    /**
     * 绘制竖直线--------同理
     *
     * @param canvas 画布
     * @param parent RecyclerView
     */
    private void drawVertical(Canvas canvas, RecyclerView parent) {
        final int top = parent.getPaddingTop();
        final int bottom = parent.getMeasuredHeight() - parent.getPaddingBottom();
        final int childSize = parent.getChildCount();
        for (int i = 0; i < childSize; i++) {
            final View child = parent.getChildAt(i);
            RecyclerView.LayoutParams layoutParams = (RecyclerView.LayoutParams) child.getLayoutParams();
            final int left = child.getRight() + layoutParams.rightMargin;
            final int right = left + mDividerHeight;
            if (mDivider != null) {
                mDivider.setBounds(left, top, right, bottom);
                mDivider.draw(canvas);
            }
            if (mPaint != null) {
                canvas.drawRect(left, top, right, bottom, mPaint);
            }
        }
    }
}
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后记：捷文规范

1.本文成长记录及勘误表

项目源码	日期	备注
V0.1--github	2018-12-5	RecyclerView零点突破(动画+边线篇）

2.更多关于我

笔名	QQ	微信	爱好
张风捷特烈	1981462002	zdl1994328	语言
我的github	我的简书	我的掘金	个人网站

3.声明

1----本文由张风捷特烈原创,转载请注明
2----欢迎广大编程爱好者共同交流
3----个人能力有限，如有不正之处欢迎大家批评指证，必定虚心改正
4----看到这里，我在此感谢你的喜欢与支持

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