控件变运算符的方法？？---加法运算+

package com.example.sum;//sum

import com.example.sum.R;//sum


//import com.example.hello.R;

import android.app.Activity;
import android.view.View.OnClickListener;
import android.os.Bundle;
//import android.view.Menu;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

//import android.view.Menu;
import android.view.View;
//import android.widget.Button;
//import android.widget.EditText;
//import android.widget.TextView;//导入各种包



public class MainActivity extends Activity {
    

        
        
        
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main); 
     
        final Button button1 = (Button) findViewById(R.id.button1);//final获得句柄 获得句柄
        final  Button button2 = (Button) findViewById(R.id.button2);
        final  EditText editText1 = (EditText) findViewById(R.id.editText1);
        final    EditText editText2 = (EditText) findViewById(R.id.editText2);
        final  EditText editText3 = (EditText) findViewById(R.id.editText3);
        final   TextView textView =  (TextView) findViewById(R.id.textView1);    
        
        
        button1.setOnClickListener(new OnClickListener()
        { 
           public void onClick(View v)
           {        
  
               String a=editText3.getText().toString().trim();//判断编辑框3是否为字符串加号 赋值
               String b="+";
               
               
               if (a.equals(b)){//如果编辑框3为字符串加号，那么执行加法运算 字符串比较
                   
                   
                   
                   textView.setText(String.valueOf(
                           Integer.parseInt(editText1.getText().toString().trim())   //控件转字符串，字符串转整形，整形转字符串
                          +Integer.parseInt(editText2.getText().toString().trim())   //去除空格
                   
                           ));
                            
               }else{ System.out.println("A");        }
               
               
           }
        });
        
      
        //+Integer.parseFloa(editText3.getText().toString().trim())        
        
        button2.setOnClickListener(new OnClickListener()
        { 
           public void onClick(View v)
           {
               
              
                  editText3.setText(button2.getText());
                    
           }
        });
        
        
        }
    

    

 
    
    
    
    
}