入门surfaceView实现画图板

出处

http://www.jianshu.com/p/15060fc9ef18

效果图

代码

package com.qunar.yuzhiyun.surfaceviewdrawsomething;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.graphics.Path;import android.util.AttributeSet;import android.util.Log;import android.view.MotionEvent;import android.view.SurfaceHolder;import android.view.SurfaceView;/** * Created by yuzhiyun on 17/11/7. */public class SurfaceViewL extends SurfaceView implements SurfaceHolder.Callback, Runnable {    // SurfaceHolder    private SurfaceHolder mSurfaceHolder;    // 画布    private Canvas mCanvas;    // 子线程标志位    private boolean isDrawing;    // 画笔    Paint mPaint;    // 路径    Path mPath;    private float mLastX, mLastY;//上次的坐标    public SurfaceViewL(Context context, AttributeSet attrs) {        super(context, attrs);        init();    }    /**     * 初始化     */    private void init() {        //初始化 SurfaceHolder mSurfaceHolder        mSurfaceHolder = getHolder();        mSurfaceHolder.addCallback(this);        setFocusable(true);        setFocusableInTouchMode(true);        this.setKeepScreenOn(true);        //画笔        mPaint = new Paint(Paint.ANTI_ALIAS_FLAG | Paint.DITHER_FLAG);        mPaint.setStrokeWidth(10f);        mPaint.setColor(Color.parseColor("#FF4081"));        mPaint.setStyle(Paint.Style.STROKE);        mPaint.setStrokeJoin(Paint.Join.ROUND);        mPaint.setStrokeCap(Paint.Cap.ROUND);        //路径        mPath = new Path();    }    @Override    public void surfaceCreated(SurfaceHolder holder) {//创建        Log.i("surfaceCreated","--"+isDrawing);    }    @Override    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {//改变    }    @Override    public void surfaceDestroyed(SurfaceHolder holder) {//销毁        isDrawing = false;        Log.i("surfaceDestroyed","--"+isDrawing);    }    @Override    public void run() {        while (isDrawing){            drawing();        }    }    /**     * 绘制     */    private void drawing() {        try {            mCanvas = mSurfaceHolder.lockCanvas();            mCanvas.drawColor(Color.WHITE);            mCanvas.drawPath(mPath,mPaint);        } finally {            if (mCanvas != null) {                mSurfaceHolder.unlockCanvasAndPost(mCanvas);            }        }    }    @Override    public boolean onTouchEvent(MotionEvent event) {        float x = event.getX();        float y = event.getY();        switch (event.getAction()) {            case MotionEvent.ACTION_DOWN:                isDrawing = true ;//每次开始将标记设置为ture                new Thread(this).start();//开启线程                mLastX = x;                mLastY = y;                mPath.moveTo(mLastX, mLastY);                break;            case MotionEvent.ACTION_MOVE:                float dx = Math.abs(x - mLastX);                float dy = Math.abs(y - mLastY);                if (dx >= 3 || dy >= 3) {                    mPath.quadTo(mLastX, mLastY, (mLastX + x) / 2, (mLastY + y) / 2);                }                mLastX = x;                mLastY = y;                break;            case MotionEvent.ACTION_UP:                isDrawing = false;                break;        }        return true;    }}