自定义View控件 购物车加减号

//MainActivity全代码

package com.example.jiajianbuju;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Myview test = findViewById(R.id.test);
        test.setNumberlistener(new Myview.NumberLisner() {
            @Override
            public void callBack(int couint) {
                Toast.makeText(MainActivity.this, "购物车商品数量变化" + couint,Toast.LENGTH_SHORT).show();
            }
        });
    }
}

//Myview

package com.example.jiajianbuju;

import android.content.Context;
import android.support.annotation.Nullable;
import android.util.AttributeSet;
import android.view.View;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.Toast;

/**
 * Created by Administrator on 2018/3/2.
 */

public class Myview extends LinearLayout implements View.OnClickListener {

    private Button tvDecrease;
    private Button tvIncrease;
    private Button etNumber;
    private Context context;

    //定一个商品默认数量
    private int count = 1;
    //定义一个变量规范这个商品数量的最大值
    private int max = 1000;
    //定义默认颜色
   // private int defaultColor = Color.parseColor("#ff3660");

    public Myview(Context context) {
        this(context, null);
    }

    public Myview(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public Myview(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        this.context = context;
        //将自定义属性与当前的这个自定组合控件进行关联
        //TypedArray ta = context.getTheme().obtainStyledAttributes(attrs, R.styleable.Myview, defStyleAttr, 0);

        //得到集合中的背景颜色属性，如果没有，用默认的颜色

        //int color = ta.getColor(R.styleable.Myview_bgcolor, defaultColor);

        View view = View.inflate(context, R.layout.jiajian, this);
        tvDecrease = view.findViewById(R.id.tvDecrease);
        tvIncrease = view.findViewById(R.id.tvIncrease);
        etNumber = view.findViewById(R.id.etNumber);

        //设置点击事件
        tvDecrease.setOnClickListener(this);
        tvIncrease.setOnClickListener(this);

        //初始两个按钮的颜色
//        tvDecrease.setBackgroundColor(color);
//        tvIncrease.setBackgroundColor(color);
    }


    //对数字进行实时监听
    public interface NumberLisner {
        void callBack(int couint);
    }

    private NumberLisner numberLisner;


    public void setNumberlistener(NumberLisner numberLisner) {
        this.numberLisner = numberLisner;
    }

    //定义一个方法，给调用者设置最大商品数量
    public void setGoodsMax(int max) {
        this.max = max;
    }

    @Override
    public void onClick(View v) {

        switch (v.getId()) {
            case R.id.tvDecrease://减商品的数量
            {
                if (count > 1) {
                    count--;
                    etNumber.setText("" + count);

                    numberLisner.callBack(Integer.parseInt(etNumber.getText().toString()));
                } else {
                    Toast.makeText(context, "已经为1了不能再减了", Toast.LENGTH_SHORT).show();
                }
            }
            break;

            case R.id.tvIncrease: {
                if (count < max) {
                    count++;

                    etNumber.setText("" + count);

                    numberLisner.callBack(Integer.parseInt(etNumber.getText().toString()));
                }
            }
            break;
        }
    }
}

//activity_main.xml

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.jiajianbuju.MainActivity">
    <com.example.jiajianbuju.Myview
        android:layout_marginTop="300px"
        android:layout_marginLeft="50px"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/test">com.example.jiajianbuju.Myview>
LinearLayout>

//jiajian.xml

xml version="1.0" encoding="utf-8"?>
<LinearLayout
    android:orientation="horizontal"
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <Button
        android:gravity="center_horizontal"
        android:id="@+id/tvDecrease"
        android:layout_width="45px"
        android:layout_height="45px"
        android:layout_weight="1"
        android:background="#ff3660"
        android:text="-"
        />

    <Button
        android:gravity="center_horizontal"
        android:id="@+id/etNumber"
        android:layout_width="45px"
        android:layout_height="45px"
        android:layout_weight="1"
        android:background="#ffffff"
        android:text="1"
        />
    <Button
        android:gravity="center_horizontal"
        android:id="@+id/tvIncrease"
        android:layout_width="45px"
        android:layout_height="45px"
        android:layout_weight="1"
        android:background="#ff3660"
        android:text="+"
        />

LinearLayout>

//attrs.xml

xml version="1.0" encoding="utf-8"?>
<resources>
    
    <declare-styleable name="Myview">
        <attr name="bgcolor" format="color"/>
    declare-styleable>
resources>