Android calculator simple edition [Android evolution 1]

 

1. layout file main. xml

<? XML version = "1.0" encoding = "UTF-8"?> <Linearlayout xmlns: Android = "http://schemas.android.com/apk/res/android" Android: Orientation = "vertical" Android: layout_width = "fill_parent" Android: layout_height = "fill_parent"> <textview Android: layout_width = "fill_parent" Android: layout_height = "wrap_content" Android: text = "@ string/Hello"/> <edittext Android: Id = "@ + ID/number1" Android: layout_width = "fill_parent" Android: layout_height = "wrap_content"/> <radiogroup Android: Id = "@ + ID/radiogroup_choice" Android: layout_width = "wrap_content" Android: layout_height = "wrap_content" Android: Orientation = "horizontal" Android: layout_x = "3px" Android: layout_y = "54px"> <radiobutton Android: id = "@ + ID/add_radiobutton" Android: layout_width = "wrap_content" Android: layout_height = "wrap_content" Android: layout_marginright = "10px" Android: TEXT = "+"/> <radiobutton Android: Id = "@ + ID/jian_radiobutton" Android: layout_width = "wrap_content" Android: layout_height = "wrap_content" Android: layout_marginright = "10px" Android: text = "-"/> <radiobutton Android: Id = "@ + ID/cheng_radiobutton" Android: layout_width = "wrap_content" Android: layout_height = "wrap_content" Android: layout_marginright = "10px" Android: text = "*"/> <radiobutton Android: Id = "@ + ID/chu_radiobutton" Android: layout_width = "wrap_content" Android: layout_height = "wrap_content" Android: layout_marginright = "10px" Android: text = "/"/> </radiogroup> <edittext Android: id = "@ + ID/number2" Android: layout_width = "fill_parent" Android: layout_height = "wrap_content"/> <button Android: Id = "@ + ID/resultbutton" Android: layout_width = "fill_parent" Android: layout_height = "wrap_content" Android: text = "result"/> <textview Android: Id = "@ + ID/resulttextview" Android: layout_width = "fill_parent" Android: layout_height = "wrap_content"/> </linearlayout>

Ii. Android code implementation

package com.cn.android;import android.app.Activity;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.EditText;import android.widget.RadioButton;import android.widget.RadioGroup;import android.widget.RadioGroup.OnCheckedChangeListener;import android.widget.TextView;public class MainActivity extends Activity {    /** Called when the activity is first created. */  private EditText number1 = null; private EditText number2 = null; private Button resultButton = null; private TextView resultTextView = null; private RadioGroup mRadioGroup = null; private RadioButton jiaRadioButton,jianRadioButton,chengRadioButton,chuRadioButton; private String yunsuan;     @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);        number1 = (EditText)findViewById(R.id.number1);        number2 = (EditText)findViewById(R.id.number2);        resultButton = (Button)findViewById(R.id.resultButton);        mRadioGroup = (RadioGroup)findViewById(R.id.RadioGroup_choice);        jiaRadioButton = (RadioButton)findViewById(R.id.add_RadioButton);        jianRadioButton = (RadioButton)findViewById(R.id.jian_RadioButton);        chengRadioButton = (RadioButton)findViewById(R.id.cheng_RadioButton);        chuRadioButton = (RadioButton)findViewById(R.id.chu_RadioButton);        resultTextView = (TextView)findViewById(R.id.resultTextView);                mRadioGroup.setOnCheckedChangeListener(new OnCheckedChangeListener(){   public void onCheckedChanged(RadioGroup arg0, int arg1) {    // TODO Auto-generated method stub    if(arg1 == jiaRadioButton.getId()){     yunsuan = "+";    }    else if(arg1 == jianRadioButton.getId()){     yunsuan = "-";    }    else if(arg1 == chengRadioButton.getId()){     yunsuan = "*";    }    else if(arg1 == chuRadioButton.getId()){     yunsuan = "/";    }   }                 });                resultButton.setOnClickListener(new OnClickListener(){   public void onClick(View arg0) {        // TODO Auto-generated method stub    String num1 = number1.getText().toString();    String num2 = number2.getText().toString();    final double dnum1 = Double.parseDouble(num1);    final double dnum2 = Double.parseDouble(num2);        double resultNum = 0.0;        if(yunsuan.equals("+")){     resultNum = dnum1 + dnum2;    }    else if(yunsuan.equals("-")){     resultNum = dnum1 - dnum2;    }    else if(yunsuan.equals("*")){     resultNum = dnum1 * dnum2;    }    else if(yunsuan.equals("/")){     resultNum = dnum1 / dnum2;    }     String resultString = String.valueOf(resultNum);    resultTextView.setText(resultString);   }         });    }}