當點擊註冊按鈕與空字段應用程序崩潰的錯誤「NumberFormatException」

Question

我的註冊工作正常，但我想驗證當字段（EditText）是空的，如果我點擊註冊應用程序崩潰，如果我留一個空場崩潰太..

public class register extends AppCompatActivity { 

AlertDialog.Builder builder; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_register); 


    builder = new AlertDialog.Builder(register.this); 
    final EditText etAge = (EditText) findViewById(R.id.etAge); 
    final EditText etName = (EditText) findViewById(R.id.etName); 
    final EditText etUsername = (EditText) findViewById(R.id.etUsername); 
    final EditText etPassword = (EditText) findViewById(R.id.etPassword); 
    final Button bRegister = (Button) findViewById(R.id.bRegister); 



    bRegister.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      final String name = etName.getText().toString(); 
      final String username = etUsername.getText().toString(); 
      final int age = Integer.parseInt(etAge.getText().toString()); 
      final String password = etPassword.getText().toString(); 

      //test of error 

      if (name.equals("") || username.equals("") || age == 0 || password.equals("")) { 
       builder.setTitle("Something Went Wrong"); 
       builder.setMessage("Please fill in all the fileds").setPositiveButton("OK", null).create().show(); 

      } else { 


       Response.Listener<String> responseListener = new Response.Listener<String>() { 
        @Override 
        public void onResponse(String response) { 
         try { 
          JSONObject jsonResponse = new JSONObject(response); 
          boolean success = jsonResponse.getBoolean("success"); 
          if (success) { 
           Intent intent = new Intent(register.this, login.class); 
           register.this.startActivity(intent); 
          } else { 
           AlertDialog.Builder builder = new AlertDialog.Builder(register.this); 
           builder.setMessage("Register Failed") 
             .setNegativeButton("Retry", null) 
             .create() 
             .show(); 
          } 
         } catch (JSONException e) { 
          e.printStackTrace(); 
         } 
        } 
       }; 

       RegisterRequest registerRequest = new RegisterRequest(name, username, age, password, responseListener); 
       RequestQueue queue = Volley.newRequestQueue(register.this); 
       queue.add(registerRequest); 
      } 
     } 
    }); 
} 

Answer 1

Integer age =null; 
if(!etAge.getText().toString().trim().equals("")) 
{ 
    age=Integer.parseInt(etAge.getText().toString()); 
    } 

      final String password = etPassword.getText().toString(); 

      //test of error 

      if (name.equals("") || username.equals("") || age == null || password.equals("")) { 
       builder.setTitle("Something Went Wrong"); 
       builder.setMessage("Please fill in all the fileds").setPositiveButton("OK", null).create().show(); 
       return ; 
      }