Android DIY之路 （三） 手绘 仅在限定区域留下痕迹 并再现这一过程

今天介绍一个比较简单的功能手绘。但想做一个再现过程的。但不知道如何去保存当事人画的实际变速度和 不连贯的地方。欢迎大家讨论

原谅我 就是不喜欢提供DEMO 哈

package com.rexviewforchildcandrag;import android.content.Context;import android.graphics.Bitmap;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.graphics.Path;import android.os.Handler;import android.os.Message;import android.os.SystemClock;import android.util.AttributeSet;import android.util.Log;import android.view.MotionEvent;import android.view.View;import android.widget.Button;import android.widget.ImageView;import android.widget.RelativeLayout;import java.util.ArrayList;import java.util.List;/** * Created by  Rex on 2016/9/30. */public class DrawView extends View {    private Paint p;    private float downX;    private float downY;    private float moveX;    private float moveY;    private Paint paint;    private Canvas cacheCanvas;    private Bitmap cachebBitmap;    private Path path;    private int clr_bg, clr_fg;    private boolean isMoving;    private int width;    private int height;    private boolean isTrans = false;    private Path lastPath = null;    private List<Path> lastPaths = new ArrayList<>();    private List<float[]> lasts = new ArrayList<>();    private int i;    private boolean isShowing;    public DrawView(Context context) {        this(context, null, 0);    }    public DrawView(Context context, AttributeSet attrs) {        this(context, attrs, 0);    }    public DrawView(Context context, AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);        init();    }    private void init() {        p = new Paint();        p.setStyle(Paint.Style.STROKE);        p.setStrokeWidth(10);        p.setColor(Color.parseColor("#EB7A77"));        path = new Path();        // 创建一张屏幕大小的位图，作为缓冲        reset();    }    @Override    protected void onSizeChanged(int w, int h, int oldw, int oldh) {        super.onSizeChanged(w, h, oldw, oldh);        width = w;        height = h;    }    @Override    protected void onDraw(Canvas canvas) {        Log.i("rex", "moveX " + moveX + "moveY " + moveY);        canvas.drawColor(Color.GREEN);        if (!isTrans) {            isTrans = true;            cacheCanvas.translate(-(width - cachebBitmap.getWidth()) * 1f / 2, -(height - cachebBitmap.getHeight()) * 1f / 2);        }        // 绘制上一次的，否则不连贯        if (null != cachebBitmap)            canvas.drawBitmap(cachebBitmap, (width - cachebBitmap.getWidth()) * 1f / 2, (height - cachebBitmap.getHeight()) * 1f / 2, null);        canvas.drawPath(path, p);    }    public void clear() {        reset();        invalidate();    }    public void reset() {        cachebBitmap = Bitmap.createBitmap(480, 800, Bitmap.Config.ARGB_8888);        cacheCanvas = new Canvas(cachebBitmap);        cacheCanvas.drawColor(Color.GRAY);        lastPath = new Path();        lastPath.addPath(path);        path.reset();        isTrans = false;    }    Handler mHandler = new Handler() {        @Override        public void handleMessage(Message msg) {            Log.i("rex", "Message" + Thread.currentThread());            cacheCanvas.drawPath(path, p);            path.reset();            invalidate();            super.handleMessage(msg);            switch (msg.what) {                case 0:                    break;                default:                    break;            }        }    };    public void showLastPath() {        path.moveTo(lasts.get(0)[0], lasts.get(0)[1]);        new Thread(new Runnable() {            @Override            public void run() {                for (int i = 1; i < lasts.size(); i++) {                    if (i == lasts.size() - 1) {                        cacheCanvas.drawPath(path, p);                        path.reset();                        postInvalidate();                        return;                    }                    isShowing = true;                    path.quadTo(lasts.get(i - 1)[0], lasts.get(i - 1)[1], lasts.get(i)[0], lasts.get(i)[1]);                    SystemClock.sleep(50);//                    mHandler.sendMessage(mHandler.obtainMessage(0));                    postInvalidate();                }            }        }).start();    }    @Override    public boolean onTouchEvent(MotionEvent event) {        switch (event.getAction()) {            case MotionEvent.ACTION_DOWN:                downX = event.getX();                downY = event.getY();                path.moveTo(downX, downY);                isMoving = true;                lasts.add(new float[]{downX, downY});                break;            case MotionEvent.ACTION_MOVE:                moveX = event.getX();                moveY = event.getY();                if (!isMoving)                    break;                // 二次曲线方式绘制                path.quadTo(downX, downY, moveX, moveY);                downX = moveX;                downY = moveY;                lasts.add(new float[]{downX, downY});                break;            case MotionEvent.ACTION_UP:                cacheCanvas.drawPath(path, p);                path.reset();                isMoving = false;                break;        }        invalidate();        return true;    }}