<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;    } }