title: Calculator Android Studio
body: <p>I am a beginner in android studio.I am trying to build a calculator here is my code but the buttons on my calculator are not working Here is the java code.The problem seems to be with clicklistener when i click the button on my android virtual machine the text doesnot changes and the operators are also not working what is the problem in my code if there is any.</p>
  
  <pre><code>package com.example.app;
  
  import android.support.v7.app.ActionBarActivity;
  import android.support.v7.app.ActionBar;
  import android.support.v4.app.Fragment;
  import android.os.Bundle;
  import android.view.LayoutInflater;
  import android.view.Menu;
  import android.view.MenuItem;
  import android.view.View;
  import android.view.ViewGroup;
  import android.os.Build;
  import android.widget.Button;
  import android.widget.EditText;
  
  import static android.view.View.OnClickListener;
  
  public class MainActivity extends ActionBarActivity {
  private EditText Scr;
  private float NumberBf;
  private String Operation;
  private ButtonClickListener btnClick;
  
  
  @Override
  protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  Scr = (EditText)findViewById(R.id.textView);
  int idList[]=                        {
  
  R.id.button,R.id.button2,R.id.button3,R.id.button4,R.id.button5,
  R.id.button6,R.id.button7,R.id.button8,
  R.id.button9,R.id.button10,R.id.buttonC,
  R.id.buttonEq,R.id.buttonAdd,R.id.buttonSub,R.id.buttonDiv,
  R.id.buttonDot,R.id.buttonMul};
  for(int id:idList)
  {
  View v = (View) findViewById(id);
  v.setOnClickListener(btnClick);
  
  }
  
  
  }
  
  
  public void mMath(String str){
  NumberBf=Float.parseFloat(Scr.getText().toString());
  Operation=str;
  Scr.setText("0");
  
  }
  public void getKeyboard(String str)
  {
  String ScrCurrent = Scr.getText().toString();
  ScrCurrent += str;
  Scr.setText(ScrCurrent);
  
  }
  public void mResult()
  {
  float NumAf=Float.parseFloat(Scr.getText().toString());
  float result=0;
  if(Operation.equals("+"))
  {
  result =NumAf + NumberBf;
  }
  
  if(Operation.equals("-"))
  {
  result =NumAf - NumberBf;
  }
  
  if(Operation.equals("*"))
  {
  result =NumAf * NumberBf;
  }
  
  if(Operation.equals("/"))
  {
  result =NumAf / NumberBf;
  }
  Scr.setText(String.valueOf(result));
  }
  private class ButtonClickListener implements OnClickListener {
  public void onClick(View v){
  switch (v.getId()){
  case R.id.buttonC:
  Scr.setText("0");
  NumberBf=0;
  Operation="";
  break;
  case R.id.buttonAdd:
  mMath("+");
  break;
  case R.id.buttonSub:
  mMath("-");
  break;
  case R.id.buttonDiv:
  mMath("/");
  break;
  case R.id.buttonMul:
  mMath("*");
  break;
  case R.id.buttonEq:
  mResult();
  break;
  default :
  String numb;
  numb = ((Button)v).getText().toString();
  getKeyboard(numb);
  break;
  
  
  }
  
  }
  }
  
  }
  </code></pre>
  
  <p>And Here is the XML Code.
      </p>
  
  <pre><code>&lt;EditText
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:textAppearance="?android:attr/textAppearanceLarge"
  android:text="0"
  android:id="@+id/textView"
  android:layout_alignParentTop="true"
  android:layout_alignParentLeft="true"
      android:layout_alignParentStart="true"
      android:layout_marginLeft="54dp"
      android:layout_marginTop="73dp"
      android:layout_alignParentRight="true"
      android:layout_alignParentEnd="true"
      android:gravity="right"
      android:onClick="setContentView" /&gt;
  
  &lt;Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="7"
      android:id="@+id/button"
      android:textStyle="bold"
      android:layout_below="@+id/textView"
      android:layout_alignLeft="@+id/textView"
      android:layout_alignStart="@+id/textView"
      android:onClick="onClick" /&gt;
  
  &lt;Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="8"
      android:id="@+id/button2"
      android:layout_alignTop="@+id/button"
      android:layout_toRightOf="@+id/button"
      android:textStyle="bold" /&gt;
  
  &lt;Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="9"
      android:id="@+id/button3"
      android:layout_alignTop="@+id/button2"
      android:layout_toRightOf="@+id/button2"
      android:textStyle="bold" /&gt;
  
  &lt;Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="4"
      android:id="@+id/button4"
      android:layout_below="@+id/button"
      android:layout_alignLeft="@+id/button"
      android:layout_alignStart="@+id/button"
      android:textStyle="bold" /&gt;
  
  &lt;Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="5"
      android:id="@+id/button5"
      android:layout_below="@+id/button2"
      android:layout_toRightOf="@+id/button4"
      android:textStyle="bold" /&gt;
  
  &lt;Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="6"
      android:id="@+id/button6"
      android:layout_below="@+id/button3"
      android:layout_toRightOf="@+id/button5"
      android:textStyle="bold" /&gt;
  
  &lt;Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="1"
      android:id="@+id/button7"
      android:layout_below="@+id/button4"
      android:layout_alignLeft="@+id/button4"
      android:layout_alignStart="@+id/button4"
      android:textStyle="bold" /&gt;
  
  &lt;Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="2"
      android:id="@+id/button8"
      android:layout_alignTop="@+id/button7"
      android:layout_toRightOf="@+id/button7"
      android:textStyle="bold" /&gt;
  
  &lt;Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="3"
      android:id="@+id/button9"
      android:layout_below="@+id/button6"
      android:layout_toRightOf="@+id/button8"
      android:textStyle="bold" /&gt;
  
  &lt;Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="0"
      android:id="@+id/button10"
      android:layout_below="@+id/button7"
      android:layout_alignLeft="@+id/button7"
      android:layout_alignStart="@+id/button7"
      android:textStyle="bold" /&gt;
  
  &lt;Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="."
      android:id="@+id/buttonDot"
      android:layout_alignTop="@+id/button10"
      android:layout_toRightOf="@+id/button10"
      android:textStyle="bold" /&gt;
  
  &lt;Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="C"
      android:id="@+id/buttonC"
      android:layout_alignTop="@+id/button3"
      android:layout_alignParentRight="true"
      android:layout_alignParentEnd="true"
      android:textStyle="bold" /&gt;
  
  &lt;Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="+"
      android:id="@+id/buttonAdd"
      android:layout_alignTop="@+id/button3"
      android:layout_toRightOf="@+id/button3"
      android:textStyle="bold" /&gt;
  
  &lt;Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="-"
      android:id="@+id/buttonSub"
      android:layout_above="@+id/button9"
      android:layout_toRightOf="@+id/button6"
      android:textStyle="bold" /&gt;
  
  &lt;Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="*"
      android:id="@+id/buttonMul"
      android:layout_above="@+id/buttonDot"
      android:layout_toRightOf="@+id/button9"
      android:textStyle="bold" /&gt;
  
  &lt;Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="/"
      android:id="@+id/buttonDiv"
      android:layout_alignTop="@+id/buttonDot"
      android:layout_alignLeft="@+id/buttonMul"
      android:layout_alignStart="@+id/buttonMul"
      android:textStyle="bold" /&gt;
  
  &lt;Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="="
      android:id="@+id/buttonEq"
      android:layout_alignTop="@+id/buttonDiv"
      android:layout_toLeftOf="@+id/buttonDiv"
      android:textStyle="bold" /&gt;
  </code></pre>
  
  <p></p>