Android--surfaceView简易画板

最新推荐文章于 2023-03-29 14:39:17 发布

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最新推荐文章于 2023-03-29 14:39:17 发布

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CC 4.0 BY-SA版权

本文链接：https://blog.youkuaiyun.com/ykx_1448488568/article/details/81514377

本文介绍了一个基于Android平台的手绘应用开发实例，通过SurfaceView和MotionEvent实现画笔效果，包括颜色和宽度的设置，以及触屏操作的响应。

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先来一个效果图:

activity代码(都有注释):

public class MainActivity extends AppCompatActivity {

    private SurfaceView faceview;
    private SurfaceHolder holder;
    private Paint paint;
    private Path path;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initView();
        paint = new Paint();
        //设置画笔的宽高
        paint.setStrokeWidth(5);
        //设置画笔的颜色
        path = new Path();
        paint.setStyle(Paint.Style.STROKE);
        paint.setColor(Color.WHITE);
        holder = faceview.getHolder();
        holder.addCallback(new SurfaceHolder.Callback() {
            @Override
            public void surfaceCreated(SurfaceHolder holder) {

            }

            @Override
            public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {

            }

            @Override
            public void surfaceDestroyed(SurfaceHolder holder) {

            }
        });
        faceview.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                float x = event.getX();
                float y = event.getY();
                int action = event.getAction();
                switch (action) {
                    //点击下去的时候执行这个
                    case MotionEvent.ACTION_DOWN:
                        path.moveTo(x,y);
                        break;
                        //移动画笔的时候执行这个
                    case MotionEvent.ACTION_MOVE:
                        Canvas canvas = holder.lockCanvas();
                        path.lineTo(x,y);
                        canvas.drawPath(path,paint);
                        holder.unlockCanvasAndPost(canvas);
                        break;
                        //松开画笔的时候执行这个
                    case MotionEvent.ACTION_UP:

                        break;

                }

                return true;
            }
        });
    }

    private void initView() {
        faceview = (SurfaceView) findViewById(R.id.faceview);
    }
}

当然,可以根据自己的喜好更改画笔的颜色和画板的颜色!