package com.example.test;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.os.Build;
import android.util.AttributeSet;
import androidx.appcompat.widget.AppCompatButton;
public class MyButton extends AppCompatButton {
Paint paint1 ,paint2;
public MyButton(Context context) {
super(context);
initView();
}
public MyButton(Context context, AttributeSet attrs) {
super(context, attrs);
initView();
}
public MyButton(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
initView();
}
private void initView() {
paint1 = new Paint();
paint1.setColor(getResources().getColor(android.R.color.holo_orange_light));
paint1.setStyle(Paint.Style.FILL); //实心
paint2 = new Paint();
paint2.setColor(getResources().getColor(android.R.color.holo_blue_bright));
paint2.setStyle(Paint.Style.STROKE); //空心
}
/*
* 程序调用super.onDraw(canvas);实现原生控件的功能，我们可以在其前后设计自己的控件*/
@Override
protected void onDraw(Canvas canvas) {
//调用父类方法前，实现自己的逻辑，
//四个实心圆
canvas.drawCircle(0,0,30,paint1);
canvas.drawCircle(0,getHeight(),30,paint1);
canvas.drawCircle(getWidth(),0,30,paint1);
canvas.drawCircle(getWidth(),getHeight(),30,paint1);
//三个空心圆
canvas.drawCircle(getWidth()/2,getHeight()/2,getWidth()/8,paint2);
canvas.drawCircle(getWidth()/2,getHeight()/2,getWidth()/6,paint2);
canvas.drawCircle(getWidth()/2,getHeight()/2,getWidth()/4,paint2);
//设置背景
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
setBackground(getResources().getDrawable(R.color.colorAccent));
}
canvas.save(); //保存画布
super.onDraw(canvas); //父类方法
//调用父类方法后，实现自己的逻辑
canvas.restore(); //合并图像
}
}
xml中引用
<com.example.test.MyButton
android:id="@+id/main_my_btn_expendView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="ExpendView1"
android:textAllCaps="false"
android:layout_margin="10dp" />
运行效果如下：
参考链接
https://blog.csdn.net/jinmie0193/article/details/80777331?utm_medium=distribute.pc_relevant.none-task-blog-BlogCommendFromMachineLearnPai2-4.channel_param&depth_1-utm_source=distribute.pc_relevant.none-task-blog-BlogCommendFromMachineLearnPai2-4.channel_param
