Android曲线绘制demo

一个可交互的Android绘制曲线的demo：

 

 

 

package com.ray.demo;

import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Paint.Style;
import android.graphics.Path;
import android.graphics.Point;
import android.graphics.RectF;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;

public class LineFunActivity extends Activity {
    
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(new SampleView(this));
    }
    
    private class SampleView extends View{
    	public static final int RECT_SIZE = 8;
    	private Point mSelectedPoint = null;

		public static final int POINT_ARRAY_SIZE = 7;
		public static final int C_START = 0;
		public static final int C_END = 1;
		public static final int C_CONTROL_1 = 2;
		public static final int C_CONTROL_2 = 3;
		public static final int Q_START = 4;
		public static final int Q_END = 5;
		public static final int Q_CONTROL = 6;

		private Point[] mPoints = new Point[POINT_ARRAY_SIZE];
		
		public SampleView(Context context) {
			super(context);
			mPoints[C_START] = new Point(100,100);
			mPoints[C_END] = new Point(200,200);
			mPoints[C_CONTROL_1] = new Point (150,100);
			mPoints[C_CONTROL_2] = new Point(150,200);
			
			mPoints[Q_START] = new Point(100,300);
			mPoints[Q_END] = new Point(150,400);
			mPoints[Q_CONTROL] = new Point(200,350);
		}

		@Override
		protected void onDraw(Canvas canvas) {
			super.onDraw(canvas);
			canvas.drawColor(Color.WHITE);

			// set up paint
			Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
			paint.setColor(Color.BLACK);

			// draw the cubic line
			Path path = new Path();
			path.moveTo(mPoints[C_START].x,mPoints[C_START].y);
			path.cubicTo(mPoints[C_CONTROL_1].x, mPoints[C_CONTROL_1].y, 
					mPoints[C_CONTROL_2].x, mPoints[C_CONTROL_2].y, 
					mPoints[C_END].x, mPoints[C_END].y);
			paint.setStrokeWidth(2);
			paint.setStyle(Style.STROKE);
			canvas.drawPath(path, paint);
			canvas.drawLine(mPoints[C_START].x,mPoints[C_START].y, 
					mPoints[C_CONTROL_1].x, mPoints[C_CONTROL_1].y, paint);
			canvas.drawLine(mPoints[C_END].x, mPoints[C_END].y, 
					mPoints[C_CONTROL_2].x, mPoints[C_CONTROL_2].y, paint);
			
			// draw the quad line
			paint.setColor(Color.BLACK);
			paint.setStyle(Style.FILL);
			paint.setStrokeWidth(2);
			path.reset();
			path.moveTo(mPoints[Q_START].x, mPoints[Q_START].y);
			path.quadTo(mPoints[Q_CONTROL].x, mPoints[Q_CONTROL].y, 
					mPoints[Q_END].x, mPoints[Q_END].y);
			canvas.drawPath(path, paint);
			canvas.drawLine(mPoints[Q_START].x, mPoints[Q_START].y, 
					mPoints[Q_CONTROL].x, mPoints[Q_CONTROL].y, paint);
			canvas.drawLine(mPoints[Q_END].x, mPoints[Q_END].y, 
					mPoints[Q_CONTROL].x, mPoints[Q_CONTROL].y, paint);
			
			// draw control points
			paint.setColor(Color.RED);
			paint.setStyle(Style.FILL);
			for (int i=0; i<POINT_ARRAY_SIZE; i++){
				canvas.drawRect(pointToRect(mPoints[i]),paint);
			}
		}

		@Override
		public boolean onTouchEvent(MotionEvent event) {
			switch (event.getAction()) {
			case MotionEvent.ACTION_DOWN:
				for (int i=0; i<POINT_ARRAY_SIZE; i++){
					if (pointToRect(mPoints[i]).contains(event.getX(),event.getY())){
						mSelectedPoint = mPoints[i];
					}
				}
				break;
			case MotionEvent.ACTION_MOVE:
				if ( null != mSelectedPoint){			
					mSelectedPoint.x = (int) event.getX();
					mSelectedPoint.y = (int) event.getY();
					invalidate();
				}
				break;
			case MotionEvent.ACTION_UP:
				mSelectedPoint = null;
				break;
			default:
				break;
			}		
			return true;
			
		}
		
		private RectF pointToRect(Point p){
			return new RectF(p.x -RECT_SIZE/2, p.y - RECT_SIZE/2,
					p.x + RECT_SIZE/2, p.y + RECT_SIZE/2);
		}
    }
}

评论

4 楼 raymondlueng 2012-06-18  

nsd 写道

好久没你消息了

学习去了，积累不够，呵呵

3 楼 nsd 2012-06-14  

好久没你消息了

2 楼 raymondlueng 2012-05-19  

unicorn25 写道

终于回归了。。。还以为楼主就此休博了呢

谢谢朋友支持！

1 楼 unicorn25 2012-05-17  

终于回归了。。。还以为楼主就此休博了呢