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Android自定义view之线条等待动画（灵感来源：金铲铲之战）

文章最后有源码

前言

又快要毕业了，最近在学人脸识别方面的东西，想写Android方面的博客又没有灵感，昨天同学给博主发课表的时候，邀博主一起玩这款游戏，博主对游戏中的等待动画线条的效果比较感兴趣，于是写一篇类似的效果。

游戏中的效果：

模仿的效果

一、实现

1. 测量，定义测量最小长度

 @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        mWidth = w;
        mHeight = h;
        useWidth = mWidth;
        if (mWidth > mHeight) {
            useWidth = mHeight;
        }
    }

将布局分为10份。以minwidth的1，3，5，7，9的倍数为标准点。

 minwidth = useWidth / 10;

2.绘制线条

初始化画笔：

    private void initPaint() {
        mPaint = new Paint();        //创建画笔对象
        mPaint.setColor(Color.BLACK);    //设置画笔颜色
        mPaint.setStyle(Paint.Style.STROKE);
        mPaint.setStrokeWidth(4f);     //设置画笔宽度为10px
        mPaint.setAntiAlias(true);     //设置抗锯齿
        mPaint.setAlpha(255);        //设置画笔透明度
    }

第一部分线条：

        canvas.drawLine(minwidth*5,minwidth*5,minwidth*5+mSweep,minwidth*5+mSweep,mPaint);
        canvas.drawLine(minwidth*5,minwidth*5,minwidth*5-mSweep,minwidth*5-mSweep,mPaint);
        canvas.drawLine(minwidth*5,minwidth*5,minwidth*5+mSweep,minwidth*5-mSweep,mPaint);
        canvas.drawLine(minwidth*5,minwidth*5,minwidth*5-mSweep,minwidth*5+mSweep,mPaint);

效果：

第二部分线条

        canvas.drawLine(minwidth*5+mSweep,minwidth*5+mSweep,minwidth*5+mSweep,minwidth*5+mSweep-mSweep1,mPaint);
        canvas.drawLine(minwidth*5-mSweep,minwidth*5-mSweep,minwidth*5-mSweep,minwidth*5-mSweep+mSweep1,mPaint);
        canvas.drawLine(minwidth*5+mSweep,minwidth*5-mSweep,minwidth*5+mSweep-mSweep1,minwidth*5-mSweep,mPaint);
        canvas.drawLine(minwidth*5-mSweep,minwidth*5+mSweep,minwidth*5-mSweep+mSweep1,minwidth*5+mSweep,mPaint);

效果：

3.动画实现

借助四个变量

    private boolean viewContinue=true,viewContinue1=true;
    private float mSweep,mSweep1;

第一部分动画逻辑

   if (viewContinue&&viewContinue1){
            mSweep += 2;
            if (mSweep > minwidth*2) {
               viewContinue=false;
            }
        }

效果图：

第二部分动画逻辑

        if (!viewContinue&&viewContinue1){
            mSweep1 += 4;
            if (mSweep1 > 4*minwidth) {
                viewContinue1=false;
                viewContinue=true;
            }
        }

效果图：

第三部分动画逻辑（回退）

   if (viewContinue&&!viewContinue1){
            if (mSweep1 <=0) {
               mSweep-=4;
               if (mSweep<0){
                   viewContinue=true;
                   viewContinue1=true;
               }
            }else{
                mSweep1 -= 2;
            }
        }

效果图：

记得刷新view

  invalidate();

源码

public class JCCLoadingView extends View {
    private Paint mPaint;
    private int mWidth;
    private int mHeight;
    private int useWidth, minwidth;
    private boolean viewContinue=true,viewContinue1=true;
    private float mSweep,mSweep1;


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

    public JCCLoadingView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    public JCCLoadingView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }
    private void init() {
        initPaint();
    }


    /**
     * 初始化画笔
     */
    private void initPaint() {
        mPaint = new Paint();        //创建画笔对象
        mPaint.setColor(Color.BLACK);    //设置画笔颜色
        mPaint.setStyle(Paint.Style.STROKE);
        mPaint.setStrokeWidth(4f);     //设置画笔宽度为10px
        mPaint.setAntiAlias(true);     //设置抗锯齿
        mPaint.setAlpha(255);        //设置画笔透明度
    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        mWidth = w;
        mHeight = h;
        useWidth = mWidth;
        if (mWidth > mHeight) {
            useWidth = mHeight;
        }

    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        minwidth = useWidth / 10;

        canvas.drawLine(minwidth*5,minwidth*5,minwidth*5+mSweep,minwidth*5+mSweep,mPaint);
        canvas.drawLine(minwidth*5,minwidth*5,minwidth*5-mSweep,minwidth*5-mSweep,mPaint);
        canvas.drawLine(minwidth*5,minwidth*5,minwidth*5+mSweep,minwidth*5-mSweep,mPaint);
        canvas.drawLine(minwidth*5,minwidth*5,minwidth*5-mSweep,minwidth*5+mSweep,mPaint);

        canvas.drawLine(minwidth*5+mSweep,minwidth*5+mSweep,minwidth*5+mSweep,minwidth*5+mSweep-mSweep1,mPaint);
        canvas.drawLine(minwidth*5-mSweep,minwidth*5-mSweep,minwidth*5-mSweep,minwidth*5-mSweep+mSweep1,mPaint);
        canvas.drawLine(minwidth*5+mSweep,minwidth*5-mSweep,minwidth*5+mSweep-mSweep1,minwidth*5-mSweep,mPaint);
        canvas.drawLine(minwidth*5-mSweep,minwidth*5+mSweep,minwidth*5-mSweep+mSweep1,minwidth*5+mSweep,mPaint);


        if (viewContinue&&viewContinue1){
            mSweep += 2;
            if (mSweep > minwidth*2) {
               viewContinue=false;

            }

        }
        if (!viewContinue&&viewContinue1){
            mSweep1 += 4;
            if (mSweep1 > 4*minwidth) {
                viewContinue1=false;
                viewContinue=true;

            }
        }
        if (viewContinue&&!viewContinue1){
            if (mSweep1 <=0) {
               mSweep-=4;
               if (mSweep<0){
                   viewContinue=true;
                   viewContinue1=true;
               }

            }else{
                mSweep1 -= 2;
            }
        }

        //刷新View
        invalidate();
    }
}