Android Studio长方体表面积计算器(双Activity)

写了两个方法（在我理解之中有三个方法，其中循环字符串匹配太low了，pass掉），目前先上传一个，后续补上。。
针对这个问题 总共有四个文件

方法一：正则表达式

（1）MainActivity.java

package com.example.flyyu.four;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

import java.util.regex.Pattern;

public class MainActivity extends AppCompatActivity implements View.OnClickListener{

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
    @Override
    public void onClick(View v) {
        EditText a=(EditText)findViewById(R.id.editText);

        EditText b=(EditText)findViewById(R.id.editText2);

        EditText c=(EditText)findViewById(R.id.editText3);
        Intent it=new Intent(this,biapmianji.class);
        if (!isNumber(a.getText().toString())&&!isNumber(b.getText().toString())&&!isNumber(c.getText().toString())){
            it.putExtra("a",a.getText().toString());
            it.putExtra("b",b.getText().toString());
            it.putExtra("c",c.getText().toString());
            MainActivity.this.startActivity(it);
        }
    }
    public boolean isNumber(String s){

        String pattern = ".*\\D.*";

        boolean isMatch = Pattern.matches(pattern,s);
        if (isMatch||s.length()==0){
            Toast.makeText(this,"输入异常",Toast.LENGTH_SHORT).show();
            return true;
        }
        return isMatch;
    }
}

2.biapmianji.java

package com.example.flyyu.four;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;

public class biapmianji extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_biapmianji);
        TextView textView=(TextView)findViewById(R.id.textView4);
        Intent it=this.getIntent();
        float a=Float.valueOf(it.getStringExtra("a")) ;
        float b=Float.valueOf(it.getStringExtra("b")) ;
        float c=Float.valueOf(it.getStringExtra("c")) ;
        String s=(2*(a*b+a*c+b*c))+"";
        textView.setText("该长方体的表面积为:"+s);

//        textView.setText("该长方体的表面积为:"+a);
    }


}

3.activity_biapmianji.XML

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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.flyyu.four.biapmianji">

    <TextView
        android:id="@+id/textView4"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginRight="8dp"
        android:layout_marginTop="8dp"
        android:text="TextView"
        android:textSize="18sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintHorizontal_bias="0.174"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.083" />
</android.support.constraint.ConstraintLayout>

4.activity_main.XML

<?xml version="1.0" encoding="utf-8"?>
<!--<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"-->

<android.widget.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"
    android:orientation="vertical"
    tools:context="com.example.flyyu.four.MainActivity">

    <TextView
        android:id="@+id/textView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:text="长：" />

    <EditText
        android:id="@+id/editText"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:ems="10"
        android:inputType="text" />

    <TextView
        android:id="@+id/textView2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:text="宽：" />

    <EditText
        android:id="@+id/editText2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:ems="10"
        android:inputType="text" />

    <TextView
        android:id="@+id/textView3"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:text="高：" />

    <EditText
        android:id="@+id/editText3"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:ems="10"
        android:inputType="text" />

    <Button
        android:id="@+id/button"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:onClick="onClick"
        android:text="计算" />
</android.widget.LinearLayout>