SurfaceView系列——绘制绘图板

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工作一下子就闲下来了，有点不习惯，就没事回顾下以前用的东西，总结下，

上次写了一篇关于surfaceVieW的博客，这次在写基本上差不多，没什么好写的。自己写着玩吧。（这次不算完，持续更新。。。(一个完整的绘图板）

上代码，注释的都比价细致，

package reeman.com.surfaceviewpaint;import android.content.Context;import android.graphics.Canvas;import android.graphics.Paint;import android.graphics.Path;import android.graphics.PixelFormat;import android.graphics.PorterDuff;import android.graphics.PorterDuffXfermode;import android.util.AttributeSet;import android.view.MotionEvent;import android.view.SurfaceHolder;import android.view.SurfaceView;public class PaintView extends SurfaceView implements SurfaceHolder.Callback, Runnable {    private Paint mPaint = null;    private Path mPath = null;    // 线程结束标志位    boolean mLoop = true;    SurfaceHolder mSurfaceHolder = null;    Canvas mCanvas;    public PaintView(Context context, AttributeSet arr) {        super(context, arr);        mSurfaceHolder = this.getHolder();//获取holder        mSurfaceHolder.addCallback(this);        mSurfaceHolder.setFormat(PixelFormat.OPAQUE);//不透明        this.setFocusable(true);        init();    }    private void init() {        mPaint = new Paint();        mPath = new Path();        mPaint.setAntiAlias(true);        mPaint.setStyle(Paint.Style.STROKE);        mPaint.setStrokeWidth(5);        mPaint.setColor(COLOR_BLUE);        mPaint.setStrokeCap(Paint.Cap.ROUND);  //圆头        mPaint.setDither(true);//消除拉动，使画面圓滑        mPaint.setStrokeJoin(Paint.Join.ROUND); //结合方式，平滑    }    @Override    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {    }    @Override    public void surfaceCreated(SurfaceHolder holder) {        new Thread(this).start();//启动线程    }    @Override    public void surfaceDestroyed(SurfaceHolder holder) {        mLoop = false; //结束线程    }    @Override    public void run() {        while (mLoop == true) {            Draw();            try {                Thread.sleep(100);            } catch (InterruptedException e) {                e.printStackTrace();            }        }    }    int COLOR_WHITE = 0xffffffff;    int COLOR_BLUE = 0xff3F51B5;    // 绘图    private void Draw() {        try {            mCanvas = mSurfaceHolder.lockCanvas();            mCanvas.drawColor(COLOR_WHITE);            mCanvas.drawPath(mPath, mPaint);        } catch (Exception e) {        } finally {            if (mCanvas != null) {                mSurfaceHolder.unlockCanvasAndPost(mCanvas);            }        }    }    @Override    public boolean onTouchEvent(MotionEvent event) {        switch (event.getAction()) {            case MotionEvent.ACTION_DOWN:                touchDown(event);                break;            case MotionEvent.ACTION_MOVE:                touchMove(event);        }        //更新绘制        return true;    }    private float defaultX;    private float defaultY;    //手指点下屏幕时调用    private void touchDown(MotionEvent event) {        float xDown = event.getX();        float yDown = event.getY();        defaultX = xDown;        defaultY = yDown;        //mPath绘制的绘制起点        mPath.moveTo(xDown, yDown);    }    //手指在屏幕上滑动时调用    private void touchMove(MotionEvent event) {        float xUp = event.getX();        float yUp = event.getY();        float middleX = (xUp + defaultX) / 2;        float middleY = (yUp + defaultY) / 2;        mPath.quadTo(defaultX, defaultY, middleX, middleY);        defaultX = xUp;        defaultY = yUp;        invalidate();    }    private void setEraser() {        mPaint = new Paint();        mPath = new Path();        mPaint.setAntiAlias(true);        mPaint.setStyle(Paint.Style.STROKE);        mPaint.setStrokeWidth(50);        mPaint.setStrokeCap(Paint.Cap.ROUND);  //圆头        mPaint.setDither(true);//消除拉动，使画面圓滑        mPaint.setStrokeJoin(Paint.Join.ROUND); //结合方式，平滑        mPaint.setAlpha(0); ////        mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));    }}

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