Android SurfaceView 繪圖闆

一，如果View 在16ms 之内沒有完成更新就會造成卡頓現象.這是就需要surfaceView來在子線程進行更新.

二：此文章主要是SurfaceView 的手繪闆功能.不多說了，代碼如下：

import android.view.SurfaceHolder;
import android.view.SurfaceView;

/**
 * author: pluto
 * date: 2018/1/10 15:42
 * desc: TODO
 */

public class SurfaceViewTemplate extends SurfaceView implements SurfaceHolder.Callback, Runnable {
    private final static String TAG = SurfaceViewTemplate.class.getSimpleName();
    private SurfaceHolder mSurfaceHolder;
    private Canvas mCanvas;
    //子線程标志位
    private boolean mIsDrawing;
    private Path mPath;
    private Paint mPaint;
    private int x;
    private int y;

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

    public SurfaceViewTemplate(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    public SurfaceViewTemplate(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init();
    }

    public SurfaceViewTemplate(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
        init();
    }

    private void init() {
        mSurfaceHolder = getHolder();
        mSurfaceHolder.addCallback(this);
        mPath = new Path();
        mPaint = new Paint();
        setFocusable(true);
        setFocusableInTouchMode(true);
        this.setKeepScreenOn(true);
    }

    @Override
    public void surfaceCreated(SurfaceHolder surfaceHolder) {
        mIsDrawing = true;
        new Thread(this).start();
    }

    @Override
    public void surfaceChanged(SurfaceHolder surfaceHolder, int i, int i1, int i2) {

    }

    @Override
    public void surfaceDestroyed(SurfaceHolder surfaceHolder) {
        mIsDrawing = false;
    }

    @Override
    public void run() {
        long start = System.currentTimeMillis();
        while (mIsDrawing) {
            draw();
        }
        long end = System.currentTimeMillis();
        if (end - start < 100) {
            try {
                Thread.sleep(100 - (end - start));
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

    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) {
        int x = (int) event.getX();
        int y = (int) event.getY();
        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:
                mPath.moveTo(x, y);
                break;
            case MotionEvent.ACTION_MOVE:
                mPath.lineTo(x, y);
                break;
        }
        return true;
    }
}