Android編程開發之在Canvas中利用Path繪制基本圖形(圓形,矩形,橢圓,三角形等)

本文實例講述了Android編程開發之在Canvas中利用Path繪制基本圖形的方法。分享給大家供大家參考，具體如下：

在Android中繪制基本的集合圖形，本程序就是自定義一個View組件，程序重寫該View組件的onDraw(Canvase)方法，然後在該Canvas上繪制大量的基本的集合圖形。

直接上代碼：

1.自定義的View組件代碼：

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);
      //把整張畫布繪制成白色
      canvas.drawColor(Color.WHITE);
      Paint paint = new Paint();
      //去鋸齒
      paint.setAntiAlias(true);
      paint.setColor(Color.BLUE);
      paint.setStyle(Paint.Style.STROKE);
      paint.setStrokeWidth(3);
      //繪制圓形
      canvas.drawCircle(40, 40, 30, paint);
      //繪制正方形
      canvas.drawRect(10, 80, 70, 140, paint);
      //繪制矩形
      canvas.drawRect(10, 150, 70, 190, paint);
      RectF rel = new RectF(10,240,70,270);
      //繪制橢圓
      canvas.drawOval(rel, paint);
      //定義一個Path對象，封閉一個三角形
      Path path1 = new Path();
      path1.moveTo(10, 340);
      path1.lineTo(70, 340);
      path1.lineTo(40, 290);
      path1.close();
      //根據Path進行繪制，繪制三角形
      canvas.drawPath(path1, paint);
      //定義一個Path對象，封閉一個五角星
      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();
      //根據Path進行繪制，繪制五角星
      canvas.drawPath(path2, paint);
      //設置填叢風格後進行繪制
      paint.setStyle(Paint.Style.FILL);
      paint.setColor(Color.RED);
      canvas.drawCircle(120, 40, 30, paint);
      //繪制正方形
      canvas.drawRect(90, 80, 150, 140, paint);
      //繪制矩形
      canvas.drawRect(90, 150, 150, 190, paint);
      //繪制圓角矩形
      RectF re2 = new RectF(90,200,150,230);
      canvas.drawRoundRect(re2, 15, 15, paint);
      //繪制橢圓
      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();
      //繪制三角形
      canvas.drawPath(path3,paint);
      //繪制五角形
      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);
      //設置漸變器後繪制
      //為Paint設置漸變器
      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);
      //設置陰影
      paint.setShadowLayer(45, 10, 10, Color.GRAY);
      //繪制圓形
      canvas.drawCircle(200, 40, 30, paint);
      //繪制正方形
      canvas.drawRect(170, 80, 230, 140, paint);
      //繪制矩形
      canvas.drawRect(170, 150, 230, 190, paint);
      //繪制圓角的矩形
      RectF re31 = new RectF();
      canvas.drawRoundRect(re31, 15, 15, paint);
      //繪制橢圓
      RectF re32 =new RectF();
      canvas.drawOval(re32, paint);
      //根據Path,繪制三角形
      Path path5 = new Path();
      path5.moveTo(170, 340);
      path5.lineTo(230, 340);
      path5.lineTo(200, 290);
      path5.close();
      canvas.drawPath(path5, paint);
      //根據PAth,進行繪制五角形
      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來實現自定義的MyView組件，

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

希望本文所述對大家Android程序設計有所幫助。