组合式自定义控件

MainActivity

package com.sub.subview;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
    private SubView sub_view;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initView();
        sub_view.setMaxValue(20);
        sub_view.setOnNumChangeListener(new SubView.OnNumChangeListener() {
            @Override
            public void OnNumChangeListener(int value) {
                Toast.makeText(MainActivity.this, value+"",Toast.LENGTH_SHORT).show();
            }
        });
    }
    private void initView() {
        sub_view = (SubView) findViewById(R.id.sub_view);
    }
}

自定义控件 内部数据的增减 使用接口回调

package com.sub.subview;

import android.content.Context;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.text.TextUtils;
import android.util.AttributeSet;
import android.view.View;
import android.widget.Button;
import android.widget.FrameLayout;
import android.widget.TextView;

public class SubView extends FrameLayout implements View.OnClickListener {

    private Button sub;
    private Button add;
    private TextView text;

    public int max = 20;

    public SubView(@NonNull Context context) {
        this(context,null);
    }

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

    public SubView(@NonNull Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        initView(context);
    }

    //初始化资源控件
    private void initView(Context context) {

        View view = View.inflate(context, R.layout.activity_sub, this);
        sub = view.findViewById(R.id.sub);
        add = view.findViewById(R.id.add);
        text = view.findViewById(R.id.text);

        sub.setOnClickListener(this);
        add.setOnClickListener(this);
        int textValue = getValue();
        setValue(textValue);

    }


    private void setValue(int textValue) {
        text.setText(textValue+"");
    }

    private int value = 1 ;
    private int getValue() {

        String trim = text.getText().toString().trim();
        if (!TextUtils.isEmpty(trim)){
            value = Integer.valueOf(trim);
        }
        return value;

    }

    @Override
    public void onClick(View view) {
        switch (view.getId()){
            case R.id.add:
                addNumValue();
                break;
            case R.id.sub:
                subNumValue();
                break;
        }

    }

    private void subNumValue() {
        if (value > 1){
            value--;
        }
        setValue(value);
        mOnNumChangeListener.OnNumChangeListener(value);
    }

    public void setMaxValue(int maxx){
        max=  maxx;
    }
    private void addNumValue() {
        if (value < max){
            value++;
        }
        setValue(value);
        mOnNumChangeListener.OnNumChangeListener(value);
    }
    //接口回调
    public interface OnNumChangeListener{
        void OnNumChangeListener(int value);
    }
    private OnNumChangeListener mOnNumChangeListener;

    public void setOnNumChangeListener(OnNumChangeListener onNumChangeListener){
      mOnNumChangeListener = onNumChangeListener;
       // onNumChangeListener = mOnNumChangeListener;
    }


}

接下来 看一下布局文件

<?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=".MainActivity">

    <com.sub.subview.SubView
        android:id="@+id/sub_view"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"></com.sub.subview.SubView>

</LinearLayout>

组合式控件的布局文件

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

    <Button
        android:id="@+id/sub"
        android:text="-"
        android:layout_width="100dp"
        android:background="@drawable/shape"
        android:layout_height="wrap_content" />
    <TextView
        android:id="@+id/text"
        android:text="1"
        android:textSize="25sp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
    <Button
        android:id="@+id/add"
        android:text="+"
        android:background="@drawable/shape"
        android:layout_width="100dp"
        android:layout_height="wrap_content" />

</LinearLayout>

稍微加一个shape 美化一下按钮

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
   <solid android:color="@color/colorAccent"/>

    <stroke android:width="1dp"
        android:color="@color/colorAccent"/>

    <corners android:radius="30dp"/>

</shape>