绘制曲线符合android的帆布箭头

本文介绍了绘制曲线符合android的帆布箭头的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

绘制的曲线与从点1的箭头（X1，Y1）至点2（X2，Y2）所示

draw a curved line with arrow from point1(x1,y1) to point2(x2,y2) like this

IM开发android的画布的应用程序。
自动像遇到问题在年底画带箭头曲线的应用和IM
指向下一个循环。

im developing an application in android canvas.automata like application and im having trouble drawing a curved line with arrow at the endpointing the next circle.

U可以给我一个code或建议这个问题。

can u give me a code or suggestion about this.

推荐答案

我想你需要的是一个组合出来的路径和线描平局。声明你的onDraw里面这个方法：

I think what You need is a mix out of draw on path and line drawing. Declare this method inside Your onDraw:

    private void drawOvalAndArrow(Canvas canvas){


    Paint circlePaint = new Paint();
    circlePaint.setStyle(Paint.Style.FILL_AND_STROKE);
    circlePaint.setAntiAlias(true);
    circlePaint.setStrokeWidth(2);
    circlePaint.setColor(Color.CYAN);

    float centerWidth = canvas.getWidth()/2; //get center x of display
    float centerHeight = canvas.getHeight()/2; //get center y of display
    float circleRadius = 20; //set radius
    float circleDistance = 200; //set distance between both circles

    //draw circles
    canvas.drawCircle(centerWidth, centerHeight, circleRadius, circlePaint);
    canvas.drawCircle(centerWidth+circleDistance, centerHeight, circleRadius, circlePaint);


    //to draw an arrow, just lines needed, so style is only STROKE
    circlePaint.setStyle(Paint.Style.STROKE);
    circlePaint.setColor(Color.RED);

    //create a path to draw on
    Path arrowPath = new Path();

    //create an invisible oval. the oval is for "behind the scenes" ,to set the path´
    //area. Imagine this is an egg behind your circles. the circles are in the middle of this egg
    final RectF arrowOval = new RectF();
    arrowOval.set(centerWidth,
            centerHeight-80,
            centerWidth + circleDistance,
            centerHeight+80);

    //add the oval to path
    arrowPath.addArc(arrowOval,-180,180);

    //draw path on canvas
    canvas.drawPath(arrowPath, circlePaint);


    //draw arrowhead on path start
     arrowPath.moveTo(centerWidth,centerHeight ); //move to the center of first circle
     arrowPath.lineTo(centerWidth-circleRadius, centerHeight-circleRadius);//draw the first arrowhead line to the left
     arrowPath.moveTo(centerWidth,centerHeight );//move back to the center
     arrowPath.lineTo(centerWidth+circleRadius, centerHeight-circleRadius);//draw the next arrowhead line to the right

     //same as above on path end
     arrowPath.moveTo(centerWidth+circleDistance,centerHeight );
     arrowPath.lineTo((centerWidth+circleDistance)-circleRadius, centerHeight-circleRadius);
     arrowPath.moveTo(centerWidth+circleDistance,centerHeight );
     arrowPath.lineTo((centerWidth+circleDistance)+circleRadius, centerHeight-circleRadius);

     //draw the path
     canvas.drawPath(arrowPath,circlePaint);

}

这仅仅是一个坏榜样，但itshould显示从哪里开始的。

This is just a poor example, but itshould show where to start with.

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OnDraw