购物车详解之自定义加减器

package zjj.bwie.com.shopcar.view;

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

import zjj.bwie.com.shopcar.R;

public class MyJiaJianView extends LinearLayout {


    private TextView jia;
    private TextView jian;
    private EditText et_num;
    private int num=1;

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

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

    public MyJiaJianView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);

        View view = LayoutInflater.from(context).inflate(R.layout.jiajian_layout, this, true);
        jia = view.findViewById(R.id.jia);
        jian = view.findViewById(R.id.jian);
        et_num = view.findViewById(R.id.num);

        et_num.setText(num+"");

        jia.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                num++;
                et_num.setText(num+"");
                if (jiaJianListenter!=null){
                    jiaJianListenter.getNum(num);
                }
            }
        });
        jian.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                num--;
                if(num<=0){
                    Toast.makeText(getContext(), "数量不能小于1", Toast.LENGTH_SHORT).show();
                    num=1;
                }
                et_num.setText(num+"");
                if(jiaJianListenter!=null){
                    jiaJianListenter.getNum(num);
                }
            }
        });
    }

    public void setNum(int n){
        et_num.setText(n+"");
        num= Integer.parseInt(et_num.getText().toString());
    }

    private JiaJianListenter jiaJianListenter;

    public void setJiaJianListenter(JiaJianListenter jiaJianListenter) {
        this.jiaJianListenter = jiaJianListenter;
    }

    public interface JiaJianListenter{
        void getNum(int num);
    }
}
/////////////////////////////////////////////////////////////////////////////layout
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_margin="5dp"
    android:orientation="horizontal"
    android:background="@drawable/jiajian_shape"
    >

    <TextView
        android:id="@+id/jian"
        android:layout_width="25dp"
        android:layout_height="wrap_content"
        android:text="-"
        android:textSize="25sp"
        android:gravity="center"
        android:padding="5dp"/>

    <View
        android:layout_width="1px"
        android:layout_height="match_parent"
        android:background="#999999"/>

    <EditText
        android:id="@+id/num"
        android:layout_weight="1"
        android:text="10"
        android:gravity="center"
        android:background="#00000000"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>
    <View
        android:layout_width="1px"
        android:layout_height="match_parent"
        android:background="#999999"/>
    <TextView
        android:id="@+id/jia"
        android:textSize="25sp"
        android:padding="5dp"
        android:text="+"
        android:layout_width="25dp"
        android:layout_height="wrap_content"/>

</LinearLayout>

、、、、、、、、、、、、、、、、、、、、、、、、、、、、、shape
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle"
    >

    <solid android:color="#ffffff"/>
    <size android:width="100dp" android:height="30dp"/>
    <stroke android:width="1px" android:color="#999999"/>
</shape>