<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context="com.example.a1129xia.MainActivity"><com.example.a1129xia.Bao.Myclass android:layout_width="wrap_content" android:layout_height="wrap_content" /></LinearLayout>
新建classpackage com.example.a1129xia.Bao;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.support.annotation.Nullable;import android.util.AttributeSet;import android.view.View;/** * author:Created by WangZhiQiang on 2017/11/29. */public class Myclass extends View { //写一个画笔 private Paint aints=new Paint(); //重写三个方法 public Myclass(Context context) { super(context); init(); } public Myclass(Context context, @Nullable AttributeSet attrs) { super(context, attrs); init(); } public Myclass(Context context, @Nullable AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); init(); }//设置属性 private void init(){ //给画笔设定一个颜色 aints.setColor(Color.YELLOW); aints.setStrokeWidth(50); } //写一个布局画图行 @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); canvas.drawCircle(getWidth()/2,getHeight()/2,200,aints); aints.setColor(Color.BLUE); canvas.drawLine(100,50,200,50,aints); }}