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POHandling RadioGroup and Button Events in Android
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  1. POHandling RadioGroup and Button Events in Android
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    copied!<p>I am a beginner in Android and I am trying to create a simple Android app which has two Text boxes (EditText) to take two Numbers as Input. Then I am Creating Radio Group having four Radio Buttons (Add,Sub,Multiply,Divide). Then I am having a Button to get the results. I am getting an AlertBox saying "Unfortunately, SimpleApp has stopped working" the moment I click the Button. Kindly assist me. </p> <p>*<em>Here is my Java code *</em> </p> <pre><code>package com.example.simpleapp; import android.os.Bundle; import android.app.Activity; import android.view.Menu; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.EditText; import android.widget.RadioButton; import android.widget.TextView; public class MainActivity extends Activity implements OnClickListener { private EditText txt1; private EditText txt2; private String input1; private String input2; private Double Num1; private Double Num2; private String flag; private EditText TextResult; Double Result=0.0; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); initControls(); } private void initControls() { ((Button)findViewById(R.id.button1)).setOnClickListener(this); } public void onradioButtonClicked(View view) { boolean checked = ((RadioButton) view).isChecked(); switch(view.getId()) { case R.id.radio0: if(checked) flag = "add"; //Result = Num1+Num2; break; case R.id.radio1: if(checked) flag = "sub"; //Result = Num1-Num2; break; case R.id.radio2: if(checked) flag = "prod"; //Result = Num1*Num2; break; case R.id.radio3: if(checked) flag = "div"; //Result = Num1/Num2; break; } } @Override public void onClick(View v) { // TODO Auto-generated method stub TextResult = (EditText)findViewById(R.id.textView2); TextResult.setText("0"); txt1 = (EditText)findViewById(R.id.editText1); txt2 = (EditText)findViewById(R.id.editText2); input1 = txt1.getText().toString(); input2 = txt2.getText().toString(); Num1 = Double.parseDouble(input1); Num2 = Double.parseDouble(input2); if(flag == "add") Result = Num1+Num2; else if(flag == "sub") Result = Num1-Num2; else if(flag == "prod") Result = Num1*Num2; else Result = Num1/Num2; TextResult.setText(String.valueOf(Result)); } } </code></pre> <p><strong>Here is my Activity_Main.xml</strong></p> <pre><code> &lt;RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" tools:context=".MainActivity" &gt; &lt;LinearLayout android:id="@+id/linearLayout1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentLeft="true" android:layout_alignParentTop="true" android:layout_marginLeft="102dp" android:layout_marginTop="66dp" android:orientation="vertical" &gt; &lt;/LinearLayout&gt; &lt;TableRow android:id="@+id/tableRow1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignLeft="@+id/textView1" android:layout_below="@+id/linearLayout1" android:layout_marginTop="34dp" &gt; &lt;/TableRow&gt; &lt;TableRow android:id="@+id/tableRow2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignLeft="@+id/tableRow1" android:layout_below="@+id/tableRow1" android:layout_marginLeft="14dp" &gt; &lt;/TableRow&gt; &lt;EditText android:id="@+id/editText2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignLeft="@+id/tableRow1" android:layout_alignTop="@+id/tableRow2" android:ems="10" android:hint="Enter Second Number" android:inputType="number" /&gt; &lt;EditText android:id="@+id/editText1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@+id/linearLayout1" android:layout_centerHorizontal="true" android:ems="10" android:hint="Enter First Number" android:inputType="number" /&gt; &lt;TextView android:id="@+id/textView1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignLeft="@+id/editText1" android:layout_alignParentTop="true" android:layout_marginTop="14dp" android:text="Simple Calculator App" android:textAppearance="?android:attr/textAppearanceLarge" /&gt; &lt;TableRow android:id="@+id/tableRow3" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignLeft="@+id/editText2" android:layout_below="@+id/editText2" android:layout_marginTop="36dp" &gt; &lt;/TableRow&gt; &lt;RadioGroup android:id="@+id/radioGroup1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignLeft="@+id/textView2" android:layout_below="@+id/editText2" &gt; &lt;RadioButton android:id="@+id/radio0" android:layout_width="wrap_content" android:layout_height="wrap_content" android:checked="true" android:text="Add" android:onClick="onradioButtonClicked"/&gt; &lt;RadioButton android:id="@+id/radio1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Sub" android:onClick="onradioButtonClicked"/&gt; &lt;RadioButton android:id="@+id/radio2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Multiply" android:onClick="onradioButtonClicked"/&gt; &lt;RadioButton android:id="@+id/radio3" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Divide" android:onClick="onradioButtonClicked"/&gt; &lt;/RadioGroup&gt; &lt;Button android:id="@+id/button1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignLeft="@+id/linearLayout1" android:layout_below="@+id/radioGroup1" android:text="Check" /&gt; &lt;TextView android:id="@+id/textView2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@+id/button1" android:layout_centerHorizontal="true" android:layout_marginTop="18dp" android:text="" android:textAppearance="?android:attr/textAppearanceLarge" /&gt; &lt;/RelativeLayout&gt; </code></pre>
 

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