Introduction to the method of using Path to draw basic graphics such as circles, rectangles, ellipses, triangles, etc. in Android development Canvas

This article mainly introduces the method of using Path to draw basic graphics in Canvas in Android programming development, involving basic graphics drawing skills of Android, and analyzes the implementation of drawing basic graphics such as circles, rectangles, ellipses, triangles, etc. with examples. For the method, friends who need it can refer to

Drawing basic collection graphics in Android. This program is to customize a View component. The program rewrites the onDraw(Canvase) method of the View component, and then draws it on the Canvas. Draw a large number of basic set shapes.

Go directly to the code:

1. Customized View component code:

package com.infy.configuration;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.LinearGradient;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.RectF;
import android.graphics.Shader;
import android.util.AttributeSet;
import android.view.View;
public class MyView extends View{
    public MyView(Context context, AttributeSet attrs) {
      super(context, attrs);
    }
    @Override
    protected void onDraw(Canvas canvas) {
      // TODO Auto-generated method stub
      super.onDraw(canvas);
      //把整张画布绘制成白色
      canvas.drawColor(Color.WHITE);
      Paint paint = new Paint();
      //去锯齿
      paint.setAntiAlias(true);
      paint.setColor(Color.BLUE);
      paint.setStyle(Paint.Style.STROKE);
      paint.setStrokeWidth(3);
      //绘制圆形
      canvas.drawCircle(40, 40, 30, paint);
      //绘制正方形
      canvas.drawRect(10, 80, 70, 140, paint);
      //绘制矩形
      canvas.drawRect(10, 150, 70, 190, paint);
      RectF rel = new RectF(10,240,70,270);
      //绘制椭圆
      canvas.drawOval(rel, paint);
      //定义一个Path对象，封闭一个三角形
      Path path1 = new Path();
      path1.moveTo(10, 340);
      path1.lineTo(70, 340);
      path1.lineTo(40, 290);
      path1.close();
      //根据Path进行绘制，绘制三角形
      canvas.drawPath(path1, paint);
      //定义一个Path对象，封闭一个五角星
      Path path2 = new Path();
      path2.moveTo(27, 360);
      path2.lineTo(54, 360);
      path2.lineTo(70, 392);
      path2.lineTo(40, 420);
      path2.lineTo(10, 392);
      path2.close();
      //根据Path进行绘制，绘制五角星
      canvas.drawPath(path2, paint);
      //设置填丛风格后进行绘制
      paint.setStyle(Paint.Style.FILL);
      paint.setColor(Color.RED);
      canvas.drawCircle(120, 40, 30, paint);
      //绘制正方形
      canvas.drawRect(90, 80, 150, 140, paint);
      //绘制矩形
      canvas.drawRect(90, 150, 150, 190, paint);
      //绘制圆角矩形
      RectF re2 = new RectF(90,200,150,230);
      canvas.drawRoundRect(re2, 15, 15, paint);
      //绘制椭圆
      RectF re21 = new RectF(90, 240, 150, 270);
      canvas.drawOval(re21, paint);
      Path path3 = new Path();
      path3.moveTo(90, 340);
      path3.lineTo(150, 340);
      path3.lineTo(120, 290);
      path3.close();
      //绘制三角形
      canvas.drawPath(path3,paint);
      //绘制五角形
      Path path4 = new Path();
      path4.moveTo(106, 360);
      path4.lineTo(134, 360);
      path4.lineTo(150, 392);
      path4.lineTo(120, 420);
      path4.lineTo(90, 392);
      path4.close();
      canvas.drawPath(path4, paint);
      //设置渐变器后绘制
      //为Paint设置渐变器
      Shader mShasder = new LinearGradient(0, 0, 40, 60, new int[]{Color.RED,Color.GREEN,Color.BLUE,Color.YELLOW}, null, Shader.TileMode.REPEAT);
      paint.setShader(mShasder);
      //设置阴影
      paint.setShadowLayer(45, 10, 10, Color.GRAY);
      //绘制圆形
      canvas.drawCircle(200, 40, 30, paint);
      //绘制正方形
      canvas.drawRect(170, 80, 230, 140, paint);
      //绘制矩形
      canvas.drawRect(170, 150, 230, 190, paint);
      //绘制圆角的矩形
      RectF re31 = new RectF();
      canvas.drawRoundRect(re31, 15, 15, paint);
      //绘制椭圆
      RectF re32 =new RectF();
      canvas.drawOval(re32, paint);
      //根据Path,绘制三角形
      Path path5 = new Path();
      path5.moveTo(170, 340);
      path5.lineTo(230, 340);
      path5.lineTo(200, 290);
      path5.close();
      canvas.drawPath(path5, paint);
      //根据PAth,进行绘制五角形
      Path path6 = new Path();
      path6.moveTo(186, 360);
      path6.lineTo(214, 360);
      path6.lineTo(230, 392);
      path6.lineTo(200, 420);
      path6.lineTo(170, 392);
      path6.close();
      canvas.drawPath(path6, paint);
    }
}

2. Use a basic Activity to implement the customized MyView component,

Define an Activity of ZiDingYiViewTes:

package com.infy.configuration;
import android.app.Activity;
import android.os.Bundle;
public class ZiDingYiViewTes extends Activity{
    private MyView myView =null;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
      // TODO Auto-generated method stub
      super.onCreate(savedInstanceState);
      myView = new MyView(this, null);
      setContentView(myView);
    }
}

Android's Canvas can draw simple collection graphics or draw a Bitmap directly to the canvas.
Finally attached is the rendering (with an extra ellipse):

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