Android開發之Canvas中利用Path繪製圓形、矩形、橢圓、三角形等基本圖形的方法介紹

這篇文章主要介紹了Android程式開發之在Canvas中利用Path繪製基本圖形的方法,涉及Android基本的圖形繪製技巧,結合實例分析了繪製圓形,矩形,橢圓,三角形等基本圖形的實現方法,需要的朋友可以參考下

在Android中繪製基本的集合圖形，本程式就是自訂一個View元件，程式重寫該View元件的onDraw(Canvase)方法，然後在該Canvas上繪製大量的基本的集合圖形。

直接上程式碼：

1.自訂的View元件程式碼：

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. 使用一個基本的Activity來實作自訂的MyView元件，

定義一個ZiDingYiViewTes的Activity：

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的Canvas既可以繪製簡單的集合圖形，也可以直接將一個Bitmap繪製到畫布上。
最後附上效果圖(多了一個橢圓)：

 

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