自定义控件 加减器

package com.sn.shopcat;

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

/**
 * date:2018/11/20
 * author:易宸锋(dell)
 * function:组合式自定义控件简易版
 */
public class MyAddSubView extends LinearLayout implements View.OnClickListener {
    private int number = 1;
    private TextView sub_tv;
    private TextView product_number_tv;
    private TextView add_tv;

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

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

    public MyAddSubView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        View view = inflate(context, R.layout.add_remove_view_layout, this);

        sub_tv=view.findViewById(R.id.sub_tv);
        product_number_tv=view.findViewById(R.id.product_number_tv);
        add_tv=view.findViewById(R.id.add_tv);


        sub_tv.setOnClickListener(this);
        add_tv.setOnClickListener(this);
    }


    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.sub_tv:
                if (number > 1) {
                    --number;
                    product_number_tv.setText(number + "");
                    if (onNumberChangeListener != null) {
                        onNumberChangeListener.onNumberChange(number);
                    }
                } else {
                    Toast.makeText(getContext(), "不能再少了", Toast.LENGTH_SHORT).show();
                }
                break;


            case R.id.add_tv:
                ++number;
                product_number_tv.setText(number + "");
                if (onNumberChangeListener != null) {
                    onNumberChangeListener.onNumberChange(number);
                }
                break;
        }
    }


    public int getNumber() {
        return number;
    }

    public void setNumber(int number) {
        this.number = number;
        product_number_tv.setText(number + "");
    }

    OnNumberChangeListener onNumberChangeListener;

    public void setOnNumberChangeListener(OnNumberChangeListener onNumberChangeListener) {
        this.onNumberChangeListener = onNumberChangeListener;
    }

    interface OnNumberChangeListener {
        void onNumberChange(int num);
    }

}

布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:padding="2dp"
    android:layout_width="60dp"
    android:layout_height="30dp"
    android:background="#99000000">

    <TextView
        android:background="#ffffff"
        android:layout_weight="1"
        android:id="@+id/sub_tv"
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:gravity="center"
        android:text="-"
        android:textSize="16sp" />

    <TextView
        android:text="1"
        android:layout_marginLeft="2dp"
        android:background="#ffffff"
        android:layout_weight="1"
        android:id="@+id/product_number_tv"
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:gravity="center"
        />

    <TextView
        android:id="@+id/add_tv"
        android:layout_width="wrap_content"
        android:layout_height="30dp"
        android:layout_marginLeft="2dp"
        android:layout_weight="1"
        android:background="#ffffff"
        android:gravity="center"
        android:text="+"
        android:textSize="16sp" />

</LinearLayout>