android GradLayout实现计算器

<GridLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/root"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:columnCount="4"
    android:rowCount="6"
    tools:context="com.ssln.gridlayoutcalc.MainActivity" >

    <TextView
        android:id="@+id/tvResult"
        android:layout_column="0"
        android:layout_columnSpan="4"
        android:layout_row="0"
        android:background="#eee"
        android:lines="1"
        android:minLines="1"
        android:textColor="#000"
        android:padding="5dp"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="50sp" />

    <Button
        android:id="@+id/btnClear"
        android:layout_columnSpan="4"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="清除" />

</GridLayout>

package com.ssln.gridlayoutcalc;
 
import android.app.Activity;
import android.os.Bundle;
import android.view.Gravity;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.GridLayout;
import android.widget.TextView;

public class MainActivity extends Activity implements OnClickListener{

    private GridLayout gridLayout;
    private Button btnClear;
    private TextView tvResult;
    private String[] btns=new String[]{
        "7","8","9","/",
        "4","5","6","x",
        "1","2","3","-",
        ".","0","=","+"
    };
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        
        gridLayout=(GridLayout)findViewById(R.id.root);
        btnClear=(Button)findViewById(R.id.btnClear);
        tvResult=(TextView)findViewById(R.id.tvResult);
        
        btnClear.setOnClickListener(this);
        
        for (int i = 0; i < btns.length; i++) {
             Button btn=new Button(this);
             btn.setText(btns[i]);
             btn.setTextSize(40);
             //设置所在行，+2是因为上面有两行了，一行显示一行按钮
             GridLayout.Spec rowSpec=GridLayout.spec(i/4+2);
             //设置第几列
             GridLayout.Spec colSpec=GridLayout.spec(i%4);
             GridLayout.LayoutParams params=new GridLayout.LayoutParams(rowSpec,colSpec);
             //占满父容器
             params.setGravity(Gravity.FILL);
             
             btn.setOnClickListener(this);
             
             gridLayout.addView(btn,params);
            
        }
    }
    @Override
    public void onClick(View v) {
         if(v==btnClear)
         {
             tvResult.setText("");
         }
         else
         {
             String btnText=((Button)v).getText().toString();
             tvResult.setText(tvResult.getText().toString()+btnText);
             if(btnText.equals("="))
             {
                 Calc calc=new Calc(tvResult.getText().toString());
                 String[] Rpn=calc.expToRpn().split(",");
                 double dbResult=calc.CalcRpn(Rpn);
                 tvResult.setText(String.valueOf(dbResult));
                 
             }
         }
    }

}

package com.ssln.gridlayoutcalc;

import java.util.HashMap;
import java.util.Map;
import java.util.Stack;

/**
 *  逆波兰式 Reverse Polish Notation 
 * @author xcj
 *
 */
public class Calc {

    //操作数
    private Stack<Double> calcStack=new Stack<Double>();
    //操作符
    private Stack<String> operatorStack=new Stack<String>();
    
    //操作符优先级
    private Map<String,Integer> priorityMap=new HashMap<String,Integer>();
    
    private String Expression;//计算表达式
    
    private Double calcResult=0.0d; //计算结果
    
    public Calc(String exp) {
         Expression=exp;
         priorityMap.put("+", 0);
         priorityMap.put("-", 0);
         priorityMap.put("x", 1);
         priorityMap.put("/", 1);
    }
    
    /**
     * 获取操作符优先级
     * @param operator
     * @return
     */
    public int getPriority(String operator)
    {
        return priorityMap.get(operator);
    }
    
    /**
     * 判断是否最高优先级
     * @param operator
     * @return
     */
    public boolean isHighpriority(String operator)
    {
        int operPrio=getPriority(operator); //获取优先级
        if(!operatorStack.empty())
        {
            for (String str : operatorStack) {
                int currPrio=getPriority(str);
                if(operPrio<currPrio)
                    return false;
            }
        }
        return true;
    }
    
    /**
     * 表达式转换为逆波兰
     * @return
     */
    public String expToRpn(){
        int index=0,end=0;
        String Rpn="";
        for (int i = 0; i < Expression.length(); i++) {
         String tmp=String.valueOf(Expression.charAt(i));
        //如果是数字，就把结束符加1
         if(tmp.matches("[0-9.]"))
         {
             end++;
         }
         else
         {
             //获取得到的操作数
             String calcStr=Expression.substring(index,end);
             Rpn+=calcStr+","; //加入操作数
             //取得操作符
             int endx=end+1;
             String calcOper=Expression.substring(end,endx);
             end++;
             if(calcOper.equals("="))//如果要计算结果了
             {
                 while(!operatorStack.empty())
                 {
                     //将所有的操作符放入RpN
                     Rpn+=operatorStack.pop()+",";
                 }
             }
             else
             {
                 if(isHighpriority(calcOper))
                 {
                     //如果优先级较高,压入堆栈
                     operatorStack.push(calcOper);
                 }
                 else
                 {
                     //如果不是最高的,将最高的放到前面
                     while(!operatorStack.empty())
                     {
                         Rpn+=operatorStack.pop()+",";
                     }
                     operatorStack.push(calcOper);
                 }
                 index=end;
             }
         }
        }
         return Rpn;
    }
    
    /**
     * 根据逆波兰计算
     * @param Rpn
     * @return
     */
    public double CalcRpn(String[] Rpn)
    {
        for (int i = 0; i < Rpn.length; i++) {
            String str = Rpn[i];
            if(str.matches("^[0-9]+.?[0-9]*$"))
            {
                //如果是数字,压入操作数堆栈
                calcStack.push(Double.parseDouble(str));
            }
            else
            {
                //计算数值
                CalcOperator(str);
            }
        }
        return calcResult;
    }
    
    /**
     * 计算数值 
     * @param operator
     */
    private void CalcOperator(String operator)
    {
        double d1=calcStack.pop();
        double d2=calcStack.pop();
        if(operator.equals("+"))
            calcResult=d2+d1;  
        if(operator.equals("-"))  
            calcResult=d2-d1;  
        if(operator.equals("x"))  
            calcResult=d2*d1;  
        if(operator.equals("/"))  
            calcResult=d2/d1;  
        
        //结果再次放入栈
         calcStack.push(calcResult);  
    }

    public String getExpression() {
        return Expression;
    }

    public void setExpression(String expression) {
        Expression = expression;
    }

 

}