可动态绘制PATH的VIEW，会动态显示整个绘制过程

    可动态绘制PATH的VIEW，会动态显示整个绘制过程，可实现各种划线，复杂图形的动态绘制动画。

    通过自定义VIEW和Path 路径动画实现。直接上代码：

    PathView.java   自定义VIEW，直接放到XML里调用API就可以绘制

 

package com.ubt.animatortest.viewDrawer;

import android.animation.Animator;
import android.animation.AnimatorListenerAdapter;
import android.animation.ValueAnimator;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.PathMeasure;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.util.AttributeSet;
import android.util.Log;
import android.view.View;

/**
 * @日期: 2017/11/13 16:39
 * @描述: 动态绘制路径动画
 */

public class PathView extends View implements ValueAnimator.AnimatorUpdateListener{
    private static final String TAG = "PathView";

    private Paint mPaint;
    private Path dst;
    private float value;
    private Path mPath;
    private PathMeasure mPathMeasure;
    private ValueAnimator valueAnimator;

    private IPathAniamtion mPathListener;

    private Canvas mCanvas;
    private Bitmap mBitmap;


    public PathView(Context context) {
        this(context, null);
    }

    public PathView(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public PathView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        initView();
    }

    private void initView() {
        dst = new Path();
        mPathMeasure = new PathMeasure();
        valueAnimator = ValueAnimator.ofFloat(0, 1);
        valueAnimator.addUpdateListener(this);
        valueAnimator.addListener(new AnimatorListenerAdapter() {
            @Override
            public void onAnimationEnd(Animator animation) {
                super.onAnimationEnd(animation);
                if(mPathListener != null){
                    mPathListener.onAnimationEnd();
                }
            }
        });
    }


    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        //初始化bitmap和canvas
        mBitmap = Bitmap.createBitmap(getMeasuredWidth(),getMeasuredHeight(), Bitmap.Config.ARGB_8888);
        mCanvas = new Canvas(mBitmap);

    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        if(mPath != null) {
            drawBitmap();
            canvas.drawBitmap(mBitmap, 0, 0, null);
        }
    }

    /**
     * 将路径绘制到bitmap上
     */
    private void drawBitmap(){
        mPathMeasure.setPath(mPath, false);
        mPathMeasure.getSegment(0, value * mPathMeasure.getLength(), dst, true);
        mCanvas.drawPath(dst, mPaint);
    }

    @Override
    public void onAnimationUpdate(ValueAnimator animation) {
        value = (float) animation.getAnimatedValue();
        invalidate();
    }

    /**
     * 开始路径绘制动画
     * @param path 需要绘制的路径
     * @param duration 动画持续时长
     * @param paint 画笔
     */
    public void startPathAnimator(@NonNull Path path, long duration, @NonNull Paint paint){
        if(!valueAnimator.isRunning()) {
            mPath = path;
            mPaint = paint;
            valueAnimator.setDuration(duration);
            valueAnimator.start();
        }else{
            Log.e(TAG,"正在执行动画，此次忽略!!!");
        }
    }

    /**
     * 设置动画回调
     * @param iPathAniamtion
     */
    public void setPathListener(IPathAniamtion iPathAniamtion){
        mPathListener = iPathAniamtion;
    }

}

    

IPathAniamtion.java  绘制完成回调

package com.ubt.animatortest.viewDrawer;

/**
 * @日期: 2017/11/14 14:24
 * @描述: 路径绘制动画接口
 */

public interface IPathAniamtion {
    void onAnimationEnd();
}

TestViewFragmeng.java  调用DEMO

package com.ubt.animatortest.viewDrawer;

import android.graphics.Color;
import android.graphics.DashPathEffect;
import android.graphics.Paint;
import android.graphics.Path;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import com.ubt.animatortest.R;

import butterknife.BindView;
import butterknife.ButterKnife;
import butterknife.Unbinder;

/**
 * @日期: 2017/11/13 16:38
 * @描述:
 */

public class TestViewFragment extends Fragment implements IPathAniamtion{

    @BindView(R.id.myView)
    PathView myView;
    Unbinder unbinder;


    private Paint mPaint;
    private float mLineWidth = 10.0f;
    private Path mPath;


    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.view_test, container, false);
        initPaint();
        initPath();
        unbinder = ButterKnife.bind(this, view);
        myView.setPathListener(this);
        myView.startPathAnimator(mPath,1500, mPaint);
        return view;
    }

    @Override
    public void onDestroyView() {
        super.onDestroyView();
        unbinder.unbind();
    }

    private void initPaint() {
        mPaint = new Paint();
        mPaint.setAntiAlias(true);
        mPaint.setStrokeWidth(mLineWidth);
        mPaint.setStyle(Paint.Style.STROKE);
        mPaint.setColor(Color.YELLOW);
        mPaint.setPathEffect(new DashPathEffect(new float[]{20f,10f}, 0));
    }

    private void initPath(){
        mPath = new Path();
        mPath.moveTo(100, 100);
        mPath.cubicTo(300, 500, 400, 200, 500,500);
    }

    @Override
    public void onAnimationEnd() {
        mPath = new Path();
        mPath.moveTo(500, 500);
        mPath.cubicTo(300, 500, 400, 200, 100,100);
        myView.startPathAnimator(mPath,1500, mPaint);
    }
}