自定义view视图之Canvas+Paint图形绘制

paint = new Paint(); 
canvas.drawColor(Color.WHITE);

  //我们给画笔设置一些属性，

        paint.setAntiAlias(true);//取消锯齿
        paint.setColor(Color.BLUE);//画笔的颜色
        paint.setStyle(Paint.Style.STROKE);//画笔的粗细
        paint.setStrokeWidth(4);//画笔的宽度
        int viewWidth = this.getWidth();//获取系统屏幕


//-------------------------------------------------------------------------
        
//        paint.setStyle(Paint.Style.FILL);//充满填充
//        paint.setColor(Color.RED);//填充颜色

//-------------------------------------------------------------------------
        
//        Shader mShader = new LinearGradient(0, 0, 40, 60
//                ,new int[] {Color.RED, Color.GREEN, Color.BLUE, Color.YELLOW }
//                , null , Shader.TileMode.REPEAT);
//        paint.setShader(mShader);
//        //设置阴影
//        paint.setShadowLayer(25 , 20 , 20 , Color.GRAY);

  
        canvas.drawCircle(viewWidth / 10 + 10, viewWidth / 10 + 10, viewWidth / 10, paint);

package tester.ermu.com.canvasdemo;

import Android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.RectF;
import android.util.AttributeSet;
import android.view.View;



public class CanvasText extends View {
    //声明一个画笔的对象
    private Paint paint;

    public CanvasText(Context context) {
        super(context);
    }

    //如果这个不引用，会报错哦！自定义View，必须在构造函数有AttributeSet attrs这个参数，便于自定义属性的引用。
    public CanvasText(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    //我们重写onDraw()方法
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        //声明一个画笔，设置一个白色的画布，这样笔和画布都有了
        paint = new Paint();
        canvas.drawColor(Color.WHITE);

        //我们给画笔设置一些属性，

        paint.setAntiAlias(true);//取消锯齿
        paint.setColor(Color.BLUE);//画笔的颜色
        paint.setStyle(Paint.Style.STROKE);//画笔的粗细
        paint.setStrokeWidth(4);//画笔的宽度
        int viewWidth = this.getWidth();//获取控件屏幕


//-------------------------------------------------------------------------
        
//        paint.setStyle(Paint.Style.FILL);//充满填充
//        paint.setColor(Color.RED);//填充颜色

//-------------------------------------------------------------------------
        
//        Shader mShader = new LinearGradient(0, 0, 40, 60
//                ,new int[] {Color.RED, Color.GREEN, Color.BLUE, Color.YELLOW }
//                , null , Shader.TileMode.REPEAT);
//        paint.setShader(mShader);
//        //设置阴影
//        paint.setShadowLayer(25 , 20 , 20 , Color.GRAY);

//-------------------------------------------------------------------------
        
        canvas.drawCircle(viewWidth / 10 + 10, viewWidth / 10 + 10, viewWidth / 10, paint);
//-------------------------------------------------------------------------
        
        canvas.drawRect(10 , viewWidth / 5 + 20 , viewWidth / 5 + 10,viewWidth * 2 / 5 + 20 , paint);

//-------------------------------------------------------------------------
        
        canvas.drawRect(10, viewWidth * 2 / 5 + 30, viewWidth / 5 + 10, viewWidth / 2 + 30, paint);

//-------------------------------------------------------------------------

        
        RectF re1 = new RectF(10, viewWidth / 2 + 40, 10 + viewWidth / 5 ,viewWidth * 3 / 5 + 40);
        // 绘制圆角矩形
        canvas.drawRoundRect(re1, 15, 15, paint);

//-------------------------------------------------------------------------
        

        Path path1 = new Path();
        path1.moveTo(10, viewWidth * 9 / 10 + 60);
        path1.lineTo(viewWidth / 5 + 10, viewWidth * 9 / 10 + 60);
        path1.lineTo(viewWidth / 10 + 10, viewWidth * 7 / 10 + 60);
        path1.close();
        canvas.drawPath(path1, paint);
//-------------------------------------------------------------------------
        

        Path path2 = new Path();
        path2.moveTo(10 + viewWidth / 15, viewWidth * 9 / 10 + 70);
        path2.lineTo(10 + viewWidth * 2 / 15, viewWidth * 9 / 10 + 70);
        path2.lineTo(10 + viewWidth / 5, viewWidth + 70);
        path2.lineTo(10 + viewWidth / 10, viewWidth * 11/10 + 70);
        path2.lineTo(10 , viewWidth + 70);
        path2.close();
        canvas.drawPath(path2, paint);

//-------------------------------------------------------------------------
        
        paint = new Paint();
        paint.setAntiAlias(true);
        paint.setColor(Color.RED);
        paint.setStrokeWidth(2);
        paint.setTextSize(36);
        canvas.drawText("圆形", 60 + viewWidth * 3 / 5, viewWidth / 10 + 10, paint);
        canvas.drawText("正方形", 60 + viewWidth * 3 / 5, viewWidth * 3 / 10 + 20, paint);
        canvas.drawText("长方形", 60 + viewWidth * 3 / 5, viewWidth * 1 / 2 + 20, paint);
        canvas.drawText("圆角矩形" , 60 + viewWidth * 3 / 5, viewWidth * 3 / 5 + 30, paint);
        canvas.drawText("椭圆", 60 + viewWidth * 3 / 5, viewWidth * 7 / 10 + 30, paint);
        canvas.drawText("三角", 60 + viewWidth * 3 / 5, viewWidth * 9 / 10 + 30, paint);
        canvas.drawText("五角星", 60 + viewWidth * 3 / 5, viewWidth * 11 / 10 + 30, paint);
    }
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="Http://schemas.android.com/apk/res/android"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    >

    <tester.ermu.com.canvasdemo.CanvasText
        android:layout_width="match_parent"
        android:layout_height="match_parent"
       />
</LinearLayout>