title: How to solve the error "Fatal Error : Main Unable to start the activity"
body: <p>I've been trying to run this app but it throws the same error every time, I've tried everything I could. I would really like an expert's help over this.
  This is a simple app to calculate and play with numbers in some manner idk if I should provide the .xml files too but I definitely will if they are needed.</p>
  
  <pre><code>   public class MainActivity extends AppCompatActivity {
  
          @Override
          protected void onCreate(Bundle savedInstanceState) {
              super.onCreate(savedInstanceState);
              setContentView(R.layout.activity_main);
  
              final EditText e1=(EditText) findViewById(R.id.name);
              final EditText e2=(EditText)findViewById(R.id.date);
              final EditText e3=(EditText)findViewById(R.id.month);
              final EditText e4=(EditText)findViewById(R.id.year);
              Button b=(Button) findViewById(R.id.button);
  
              char[] n = e1.getText().toString().toCharArray();
              int date = Integer.parseInt(e2.toString());
              int month = Integer.parseInt(e3.toString());
              int year = Integer.parseInt(e4.toString());
              int nn = 0;
              int driver=date, conductor=date+month+year;
              int temp,k=0;
  
  
      //EditText Jumping Module-------------------------------
  
  
          e2.addTextChangedListener(new TextWatcher() {
  
              @Override
              public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {
  
              }
  
              public void onTextChanged(CharSequence s, int start, int before,
                                        int count) {
                  int tl = e2.getText().length();
  
                  if (tl &gt;= 2) {
                      e3.requestFocus();
                  }
              }
  
              @Override
              public void afterTextChanged(Editable editable) {
  
              }
          });
          e3.addTextChangedListener(new TextWatcher() {
  
              @Override
              public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {
  
              }
  
              public void onTextChanged(CharSequence s, int start, int before,
                                        int count) {
                  int lt = e3.getText().length();
  
                  if (lt &gt;= 2) {
                      e4.requestFocus();
                  }
              }
  
              @Override
              public void afterTextChanged(Editable editable) {
  
              }
          });
  </code></pre>
  
  <p>I don't think the rest of the code has any problem is the starting section so I've provided that above. Thank you</p>