如何在画布上绘制多个圆圈？

时间：2018-11-20 13:25:33

标签： java android canvas paint

我可以画一个圆，但是我的问题是每次单击都知道如何绘制多个圆。 圆的中心必须是被单击的X和Y坐标，我需要将该点存储在我的Vector上，并且每次单击View都不能破坏该Vector。 如果我在 if（图== 1）的末尾没有无效项，则根本不会画出该圆。 我的中心是一个Point2D，其中存储了int x，int y。

package com.example.soalr.myapplication;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;

import java.util.Vector;


public class MyView extends View {
    Paint paint = null;
    int figure;
    int lados_poly;
    int cor;
    int deletar;
    Circulo cir;
    Circulo raio;
    int CursorX, CursorY;
    int nrCliques;
    Vector<Ponto2D> ptsCirc = new Vector<Ponto2D>();

    public MyView(Context context) {
        super(context);
        paint = new Paint();
        figure = 0;
        cor = 0;
    }

    public MyView(Context context, AttributeSet attrs) {
        super(context, attrs);
        paint = new Paint();
        paint.setStrokeWidth(10);
        figure = 0;
        cor = 0;

        Ponto2D centroCirc = new Ponto2D();
        centroCirc.x = CursorX;
        centroCirc.y = CursorY;
        cir = new Circulo(centroCirc);
    }

    public MyView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        paint = new Paint();
        figure = 0;
        cor = 0;

    }


    public void clickEcra() {
        setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {

                switch (event.getActionMasked()) {
                    case MotionEvent.ACTION_DOWN:
                        nrCliques++;

                    case MotionEvent.ACTION_UP:

                        CursorX = (int)event.getX();
                        CursorY = (int)event.getY();

                        if (figure == 1) {
                            Ponto2D centroCirc = new Ponto2D();
                            centroCirc.x = CursorX;
                            centroCirc.y = CursorY;
                            ptsCirc.add(centroCirc);
                            invalidate();
                        }

                    default:
                        return false;
                }
            }
        });
    }


    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        clickEcra();

        Ponto2D p3 = new Ponto2D();
        p3.x = 600;
        p3.y = 150;

        paint.setStyle(Paint.Style.FILL);
        paint.setColor(Color.parseColor("#F5F1E0"));
        canvas.drawPaint(paint);
        paint.setColor(Color.parseColor("#3F5866"));

        //cores
        if (cor == 1) {
            paint.setColor(Color.parseColor("#393E46"));
        } else if (cor == 2){
            paint.setColor(Color.parseColor("#00ADB5"));
        } else if (cor == 3) {
            paint.setColor(Color.parseColor("#F8B500"));
        } else if (cor == 4) {
            paint.setColor(Color.parseColor("#FC3C3C"));
        }


        //figuras

        if (figure == 1) {

            if (ptsCirc.size() > 0) {
                for (int a = 0; a <= ptsCirc.size(); a++) {
                    Circulo raio = new Circulo(ptsCirc.get(a));
                    raio.radius = 100;
                    canvas.drawCircle(ptsCirc.get(a).x, ptsCirc.get(a).y, raio.radius, paint);
                }
            }
        }

       else if (figure == 2) {
            clickEcra();
            Ponto2D p1 = new Ponto2D();
            Ponto2D p2 = new Ponto2D();

            Reta retinha = new Reta(p1, p2);

            if (nrCliques == 1) {
                p1.x = CursorX;
                p1.y = CursorY;
                System.out.println("x1: " + p1.x + " y1: " + p1.y);
            } else if (nrCliques == 2) {
                p2.x = CursorX;
                p2.y = CursorY;
                System.out.println("x2: " + p2.x + " y2: " + p2.y);
            }

            System.out.println("x2_: " + retinha.pfinal.x + " y2_: " + retinha.pfinal.y);
            System.out.println("x1_: " + retinha.pinicial.x + " y1_: " + retinha.pinicial.y);
            canvas.drawLine(retinha.pinicial.x, retinha.pinicial.y, retinha.pfinal.x, retinha.pfinal.y, paint);
        } else if (figure == 3) {
            Poligono poly = new Poligono(lados_poly);

            if (lados_poly >= 3) {
                for (int i = 0; i <= lados_poly - 1; i++) {
                    Ponto2D ponto4 = new Ponto2D(poly.pontosPolig.get(i).x, poly.pontosPolig.get(i).y);
                    Ponto2D ponto5 = new Ponto2D();

                    if (i < lados_poly) {
                        ponto5.x = poly.pontosPolig.get(i + 1).x;
                        ponto5.y = poly.pontosPolig.get(i + 1).y;

                        Reta retaPoli = new Reta(ponto4, ponto5);
                        int var_lados = lados_poly - 1;

                        if (i != var_lados) {
                            canvas.drawLine(retaPoli.pinicial.x, retaPoli.pinicial.y, retaPoli.pfinal.x, retaPoli.pfinal.y, paint);
                        } else {
                            canvas.drawLine(poly.pontosPolig.firstElement().x, poly.pontosPolig.firstElement().y, retaPoli.pinicial.x, retaPoli.pinicial.y, paint);
                        }

                    }
                }
            }
        }

        if (deletar == 2){
            paint.setStyle(Paint.Style.FILL);
            paint.setColor(Color.parseColor("#F5F1E0"));
            canvas.drawPaint(paint);
            nrCliques = 0;
        }
    }




    public void setfigure(int a) {
        this.figure = a;
    }

    public void Cor1_mudar(int text_cor) {
        this.cor = text_cor;
    }

    public void verLados (int lados){
        this.lados_poly = lados;
    }

    public void Resetar(int delete){
        this.deletar = delete;
    }
}

这是Circle.java： 打包com.example.soalr.myapplication; 

public class Circulo {
    int radius;
    Ponto2D centro;


    public Circulo(Ponto2D c) {
        radius = 0;
        centro = c;
    }
}

2 个答案:

答案 0 :(得分：0)

您在这里有两个问题：

  1. 您只会看到1个圆圈。这可能是因为nrCliques不是您期望的值。与其从0迭代到nrCliques，不如从0迭代到ptsCirc.size()，或者使用for..each循环。对于此类问题，请the debugger is your friend。

  2. 除非您在invalidate()中进行了onDraw()通话，否则您不会看到任何圈子。从invalidate()调用onDraw()导致框架以最快的速度重复调用onDraw()。这并没有什么坏处，但是它没有充分的理由却消耗了大量的处理器功能。最好在其伴随数据发生更改时“提示”您的View重绘。在这种情况下，这意味着将invalidate()调用放在对ptsCirc.add()的调用之后。然后，每次点击屏幕，您只会收到大约onDraw()的一个电话。

答案 1 :(得分：0)

这是有效的代码，问题是我没有核实Vector内是否有东西。

public class MyView extends View {
    Paint paint = null;
    int figure;
    int lados_poly;
    int cor;
    int deletar;
    int CursorX, CursorY;
    int nrCliques;
    Vector<Ponto2D> ptsCirc = new Vector<Ponto2D>();

    public MyView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        paint = new Paint();
        figure = 0;
        cor = 0;
    }

    public void clickEcra() {
        setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {

                switch (event.getActionMasked()) {
                    case MotionEvent.ACTION_DOWN:

                    case MotionEvent.ACTION_UP:

                        CursorX = (int)event.getX();
                        CursorY = (int)event.getY();

                        if (figure == 1) {
                            Ponto2D centroCirc = new Ponto2D();
                            centroCirc.x = CursorX;
                            centroCirc.y = CursorY;
                            ptsCirc.add(centroCirc);
                            invalidate();
                        }

                    default:
                        return false;
                }
            }
        });
    }


    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        clickEcra();

        paint.setStyle(Paint.Style.FILL);
        paint.setColor(Color.parseColor("#F5F1E0"));
        canvas.drawPaint(paint);
        paint.setColor(Color.parseColor("#3F5866"));

        //cores
        if (cor == 1) {
            paint.setColor(Color.parseColor("#393E46"));
        } else if (cor == 2){
            paint.setColor(Color.parseColor("#00ADB5"));
        } else if (cor == 3) {
            paint.setColor(Color.parseColor("#F8B500"));
        } else if (cor == 4) {
            paint.setColor(Color.parseColor("#FC3C3C"));
        }


        //figuras
        if (figure == 1) {
            if (ptsCirc.size() > 0) {
                for (int a = 0; a < ptsCirc.size(); a++) {
                    Circulo raio = new Circulo(ptsCirc.get(a));
                    raio.radius = 100;
                    canvas.drawCircle(ptsCirc.get(a).x, ptsCirc.get(a).y, raio.radius, paint);
                }
            }
        }

        if (deletar == 2){
            paint.setStyle(Paint.Style.FILL);
            paint.setColor(Color.parseColor("#F5F1E0"));
            canvas.drawPaint(paint);
            nrCliques = 0;
            ptsCirc.removeAllElements();
            ptsReta.removeAllElements();
        }
    }




    public void setfigure(int a) {
        this.figure = a;
    }

    public void Cor1_mudar(int text_cor) {
        this.cor = text_cor;
    }

    public void Resetar(int delete){
        this.deletar = delete;
    }
}
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