title: android calculator buttons doesnt work
body: <p>I'm trying to make a basic android calculator. when i press button numbers show at edittext but nothing's happining. Thanks for any help.</p>
  
  <p>here is my MainActivity.java`
  public class MainActivity extends AppCompatActivity {</p>
  
  <pre><code>private EditText Scr;
  private float NumerBf;
  private String Operation;
  private ButtonClickListener btnClick;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
  
  
      Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
      setSupportActionBar(toolbar);
  
      FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
      fab.setOnClickListener(new View.OnClickListener() {
          @Override
          public void onClick(View view) {
              Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                      .setAction("Action", null).show();
          }
      });
  
      Scr=(EditText)findViewById(R.id.editText3);
      Scr.setEnabled(false);
      int idList[]={R.id.button0,R.id.button1,R.id.button1,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.buttonAdd,R.id.buttonC,R.id.buttonDivide,
              R.id.buttonEqu,R.id.buttonMinus,R.id.buttonMultiply};
  
  
  
      for(int id:idList){
          View v=(View)findViewById(id);
          v.setOnClickListener(btnClick);
      }
  }
  
  @Override
  public boolean onCreateOptionsMenu(Menu menu) {
      // Inflate the menu; this adds items to the action bar if it is present.
      getMenuInflater().inflate(R.menu.menu_main, menu);
      return true;
  }
  public void mMath(String str){
      NumerBf=Float.parseFloat(Scr.getText().toString());
      Operation =str;
      Scr.setText("0");
  }
  
  
  public void getKeyboard(String str){
      String SrcCurrent = Scr.getText().toString();
      if(SrcCurrent.equals("0"))
          SrcCurrent="";
      SrcCurrent +=str;
      Scr.setText(SrcCurrent);
  }
  
  public void mResult(){
      float NumAf=Float.parseFloat(Scr.getText().toString());
      float result=0;
      if(Operation.equals("+")){
          result=NumAf+NumerBf;
      }
      else if(Operation.equals("-")){
          result=NumerBf-NumAf;
      }
  
      else if(Operation.equals("*")){
          result=NumAf*NumerBf;
      }
      else if(Operation.equals("/")){
          result=NumerBf/NumAf;
      }
      Scr.setText(String.valueOf(result));
  }
  
  
  private  class ButtonClickListener implements View.OnClickListener {
      public void onClick(View v){
          switch(v.getId()){
              case R.id.buttonC: //ekranı temizle
                  Scr.setText("0");
                  NumerBf=0;
                  Operation="";
                  break;
              case R.id.buttonAdd:
                  mMath("+");
                  break;
              case R.id.buttonMinus:
                  mMath("-");
                  break;
              case R.id.buttonMultiply:
                  mMath("*");
                  break;
              case R.id.buttonDivide:
                  mMath("/");
                  break;
              case R.id.buttonEqu:
                  mResult();
                  break;
              default:
                  String numb= ((Button) v).getText().toString();
                  getKeyboard(numb);
                  break;
          }
      }
  }
  </code></pre>
  
  <p>` </p>
  
  <p>and here is my content_main.xml`
  </p>
  
  <pre><code>&lt;Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="3"
      android:id="@+id/button3"
      android:textStyle="bold"
      android:layout_above="@+id/button5"
      android:layout_toRightOf="@+id/button5"
      android:layout_toEndOf="@+id/button5" /&gt;
  
  &lt;Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="C"
      android:id="@+id/buttonC"
      android:textStyle="bold"
      android:longClickable="true"
      android:layout_alignTop="@+id/button3"
      android:layout_alignRight="@+id/buttonDivide"
      android:layout_alignEnd="@+id/buttonDivide"
      android:layout_alignLeft="@+id/buttonDivide"
      android:layout_alignStart="@+id/buttonDivide" /&gt;
  
  &lt;Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="1"
      android:id="@+id/button1"
      android:textStyle="bold"
      android:layout_above="@+id/button4"
      android:layout_alignParentLeft="true"
      android:layout_alignParentStart="true" /&gt;
  
  &lt;Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="4"
      android:id="@+id/button4"
      android:textStyle="bold"
      android:layout_above="@+id/button7"
      android:layout_alignParentLeft="true"
      android:layout_alignParentStart="true" /&gt;
  
  &lt;Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="6"
      android:id="@+id/button6"
      android:textStyle="bold"
      android:layout_below="@+id/button3"
      android:layout_toRightOf="@+id/button5"
      android:layout_toEndOf="@+id/button5" /&gt;
  
  &lt;Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="5"
      android:id="@+id/button5"
      android:textStyle="bold"
      android:layout_above="@+id/button8"
      android:layout_toRightOf="@+id/button4"
      android:layout_toEndOf="@+id/button4" /&gt;
  
  &lt;Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="8"
      android:id="@+id/button8"
      android:textStyle="bold"
      android:layout_above="@+id/button0"
      android:layout_toRightOf="@+id/button7"
      android:layout_toEndOf="@+id/button7" /&gt;
  
  &lt;Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="7"
      android:id="@+id/button7"
      android:textStyle="bold"
      android:layout_below="@+id/button5"
      android:layout_alignParentLeft="true"
      android:layout_alignParentStart="true" /&gt;
  
  &lt;Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="9"
      android:id="@+id/button9"
      android:textStyle="bold"
      android:layout_alignTop="@+id/button8"
      android:layout_toRightOf="@+id/button8"
      android:layout_toEndOf="@+id/button8" /&gt;
  
  &lt;Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="0"
      android:id="@+id/button0"
      android:textStyle="bold"
      android:layout_above="@+id/buttonMinus"
      android:layout_alignLeft="@+id/button8"
      android:layout_alignStart="@+id/button8" /&gt;
  
  &lt;Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="+"
      android:id="@+id/buttonAdd"
      android:textStyle="bold"
      android:layout_centerVertical="true"
      android:layout_alignParentLeft="true"
      android:layout_alignParentStart="true" /&gt;
  
  &lt;Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="-"
      android:id="@+id/buttonMinus"
      android:textStyle="bold"
      android:layout_alignTop="@+id/buttonAdd"
      android:layout_alignLeft="@+id/button0"
      android:layout_alignStart="@+id/button0" /&gt;
  
  &lt;Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="*"
      android:id="@+id/buttonMultiply"
      android:textStyle="bold"
      android:layout_alignBottom="@+id/buttonMinus"
      android:layout_toRightOf="@+id/buttonMinus"
      android:layout_toEndOf="@+id/buttonMinus" /&gt;
  
  &lt;Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="/"
      android:id="@+id/buttonDivide"
      android:textStyle="bold"
      android:layout_alignTop="@+id/buttonMultiply"
      android:layout_toRightOf="@+id/buttonMultiply"
      android:layout_toEndOf="@+id/buttonMultiply" /&gt;
  
  &lt;Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="="
      android:id="@+id/buttonEqu"
      android:textStyle="bold"
      android:layout_below="@+id/buttonMinus"
      android:layout_alignLeft="@+id/buttonMinus"
      android:layout_alignStart="@+id/buttonMinus" /&gt;
  
  &lt;EditText
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:id="@+id/editText3"
      android:layout_alignParentTop="true"
      android:layout_alignParentRight="true"
      android:layout_alignParentEnd="true"
      android:layout_toLeftOf="@+id/button3"
      android:gravity="right"
      android:text="0" /&gt;
  
  &lt;Button
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="2"
      android:id="@+id/button2"
      android:textStyle="bold"
      android:layout_alignBottom="@+id/button3"
      android:layout_toLeftOf="@+id/button3"
      android:layout_toStartOf="@+id/button3" /&gt;
  </code></pre>
  
  <p>
  `</p>