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)

2020-04-11 10:59:38

字體：大中小

來源：轉載

供稿：網友

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，然后在該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);      //設置填叢風格后進行繪制      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);      //設置漸變器后繪制      //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。
最后附上效果圖(多了一個橢圓)：