day16

自定义控件的学习，设计一个购物车内的数量的加减控制

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"

    android:gravity="center_horizontal"
    android:background="@drawable/selector_number_add_sub">



    <Button
        android:id="@+id/btn_sub"
        android:layout_width="50dp"
        android:layout_height="wrap_content"
        android:background="@drawable/car_btn"
        android:textColor="@color/black"
        android:text="-"/>

    <TextView
        android:id="@+id/etxt_num"
        android:layout_width="70dp"
        android:layout_height="wrap_content"
        android:textColor="@color/black"
        android:minWidth="100dp"

        android:gravity="center"/>

    <Button
        android:id="@+id/btn_add"
        android:layout_width="50dp"
        android:layout_height="wrap_content"
        android:background="@drawable/car_btn"
        android:textColor="@color/black"
        android:text="+"/>



</LinearLayout>

第一是布局是两个button实现加减功能，第二是中间设计一个Textview用来显示数字

代码实现功能，设计理念——对两个button设置监听事件，然后对textview的text设置数字

package Home.widget;

import android.annotation.SuppressLint;
import android.annotation.TargetApi;
import android.content.Context;
import android.graphics.drawable.Drawable;
import android.os.Build;
import androidx.appcompat.widget.TintTypedArray;
import android.text.InputType;
import android.util.AttributeSet;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.TextView;

import com.example.expressdelivery.R;



public class NumberAddSubView extends LinearLayout implements View.OnClickListener {


    public static final String TAG="NumberAddSubView";
    public static final int DEFUALT_MAX=100;

    private TextView mEtxtNum;
    private Button mBtnAdd;
    private Button mBtnSub;

    private OnButtonClickListener onButtonClickListener;




    private LayoutInflater mInflater;


    private  int value;
    private int minValue;
    private int maxValue=DEFUALT_MAX;



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

    public NumberAddSubView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    @SuppressLint("RestrictedApi")
    public NumberAddSubView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);

        mInflater = LayoutInflater.from(context);
        initView();
        if(attrs!=null)
        {
            @SuppressLint("RestrictedApi") TintTypedArray a=TintTypedArray.obtainStyledAttributes(context,attrs,R.styleable.NumberAddSubView,defStyleAttr,0);
            @SuppressLint("RestrictedApi") int val =  a.getInt(R.styleable.NumberAddSubView_value,0);
            setValue(val);

            @SuppressLint("RestrictedApi") int maxVal = a.getInt(R.styleable.NumberAddSubView_maxValue,0);
            if(maxVal!=0)
                setMaxValue(maxVal);

            @SuppressLint("RestrictedApi") int minVal = a.getInt(R.styleable.NumberAddSubView_minValue,0);
            setMinValue(minVal);

            @SuppressLint("RestrictedApi") Drawable etBackground = a.getDrawable(R.styleable.NumberAddSubView_editBackground);
            if(etBackground!=null)
                setEditTextBackground(etBackground);


            @SuppressLint("RestrictedApi") Drawable buttonAddBackground = a.getDrawable(R.styleable.NumberAddSubView_buttonAddBackgroud);
            if(buttonAddBackground!=null)
                setButtonAddBackgroud(buttonAddBackground);

            @SuppressLint("RestrictedApi") Drawable buttonSubBackground = a.getDrawable(R.styleable.NumberAddSubView_buttonSubBackgroud);
            if(buttonSubBackground!=null)
                setButtonSubBackgroud(buttonSubBackground);




            a.recycle();
        }


    }


    private void initView(){



        View view = mInflater.inflate(R.layout.widet_num_add_sub,this,true);

        mEtxtNum = (TextView) view.findViewById(R.id.etxt_num);
        mEtxtNum.setInputType(InputType.TYPE_NULL);
        mEtxtNum.setKeyListener(null);



        mBtnAdd = (Button) view.findViewById(R.id.btn_add);
        mBtnSub = (Button) view.findViewById(R.id.btn_sub);

        mBtnAdd.setOnClickListener(this);
        mBtnSub.setOnClickListener(this);



    }


    @Override
    public void onClick(View v) {
        if(v.getId() == R.id.btn_add){

            numAdd();

            if(onButtonClickListener !=null){
                onButtonClickListener.onButtonAddClick(v,this.value);
            }
        }
        else if(v.getId()==R.id.btn_sub){
                numSub();
            if(onButtonClickListener !=null){
                onButtonClickListener.onButtonSubClick(v,this.value);
            }

        }
    }


    private void numAdd(){


        getValue();

        if(this.value<=maxValue)
            this.value=+this.value+1;

        mEtxtNum.setText(value+"");
    }


    private void numSub(){


        getValue();

        if(this.value>minValue)
            this.value=this.value-1;

        mEtxtNum.setText(value+"");
    }


    public int getValue(){

        String value = mEtxtNum.getText().toString();

        if(value !=null && !"".equals(value))
            this.value = Integer.parseInt(value);

        return this.value;
    }

    public void setValue(int value) {
        mEtxtNum.setText(value+"");
        this.value = value;
    }




    public void setMaxValue(int maxValue) {
        this.maxValue = maxValue;
    }

    public void setMinValue(int minValue) {
        this.minValue = minValue;
    }


    public void setEditTextBackground(Drawable drawable){

        mEtxtNum.setBackgroundDrawable(drawable);

    }


    public void setEditTextBackground(int drawableId){

      setEditTextBackground(getResources().getDrawable(drawableId));

    }


    @TargetApi(Build.VERSION_CODES.JELLY_BEAN)
    public void setButtonAddBackgroud(Drawable backgroud){
        this.mBtnAdd.setBackground(backgroud);
    }


    @TargetApi(Build.VERSION_CODES.JELLY_BEAN)
    public void setButtonSubBackgroud(Drawable backgroud){
        this.mBtnSub.setBackground(backgroud);
    }


    public void setOnButtonClickListener(OnButtonClickListener onButtonClickListener) {
        this.onButtonClickListener = onButtonClickListener;
    }

    public interface  OnButtonClickListener{

        public void onButtonAddClick(View view, int value);
        public void onButtonSubClick(View view, int value);

    }


}