eText.setError() Fatal error

Question

Nach dem Einschalten Absenden-Button bekomme ich Fehler

04-30 11:08:19.990 14339-14339/hr.tosapinaetfos.quizmaker E/AndroidRuntime:  FATAL EXCEPTION: main 
                     java.lang.IllegalStateException: Could not execute method for android:onClick 
                      at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:293) 
                      at android.view.View.performClick(View.java:4084) 
                      at android.view.View$PerformClick.run(View.java:16966) 
                      at android.os.Handler.handleCallback(Handler.java:615) 
                      at android.os.Handler.dispatchMessage(Handler.java:92) 
                      at android.os.Looper.loop(Looper.java:137) 
                      at android.app.ActivityThread.main(ActivityThread.java:4745) 
                      at java.lang.reflect.Method.invokeNative(Native Method) 
                      at java.lang.reflect.Method.invoke(Method.java:511) 
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786) 
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 
                      at dalvik.system.NativeStart.main(Native Method) 
                     Caused by: java.lang.reflect.InvocationTargetException 
                      at java.lang.reflect.Method.invokeNative(Native Method) 
                      at java.lang.reflect.Method.invoke(Method.java:511) 
                      at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288) 
                      at android.view.View.performClick(View.java:4084)  
                      at android.view.View$PerformClick.run(View.java:16966)  
                      at android.os.Handler.handleCallback(Handler.java:615)  
                      at android.os.Handler.dispatchMessage(Handler.java:92)  
                      at android.os.Looper.loop(Looper.java:137)  
                      at android.app.ActivityThread.main(ActivityThread.java:4745)  
                      at java.lang.reflect.Method.invokeNative(Native Method)  
                      at java.lang.reflect.Method.invoke(Method.java:511)  
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)  
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)  
                      at dalvik.system.NativeStart.main(Native Method)  
                     Caused by: java.lang.NullPointerException 
                      at hr.tosapinaetfos.quizmaker.RegisterActivity.isEmpty(RegisterActivity.java:72) 
                      at hr.tosapinaetfos.quizmaker.RegisterActivity.registerOnclick(RegisterActivity.java:58) 
                      at java.lang.reflect.Method.invokeNative(Native Method)  
                      at java.lang.reflect.Method.invoke(Method.java:511)  
                      at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)  
                      at android.view.View.performClick(View.java:4084)  
                      at android.view.View$PerformClick.run(View.java:16966)  
                      at android.os.Handler.handleCallback(Handler.java:615)  
                      at android.os.Handler.dispatchMessage(Handler.java:92)  
                      at android.os.Looper.loop(Looper.java:137)  
                      at android.app.ActivityThread.main(ActivityThread.java:4745)  
                      at java.lang.reflect.Method.invokeNative(Native Method)  
                      at java.lang.reflect.Method.invoke(Method.java:511)  
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)  
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)  
                      at dalvik.system.NativeStart.main(Native Method) 

Hier Code ist

public class RegisterActivity extends AppCompatActivity{ 

EditText username; 
EditText password; 
EditText passwordAgain; 
Spinner accountTypeSpinner; 
Button registerButton; 


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

    //Fetch registerbutton by id 
    Button registerButton = (Button) findViewById(R.id.registerButton); 

    //Fetch username, password,passwordAgain , accountTypeSpinner by id 
    EditText username = (EditText) findViewById(R.id.registerUsername); 
    EditText password = (EditText) findViewById(R.id.registerPassword); 
    EditText passwordAgain = (EditText) findViewById(R.id.registerPasswordAgain); 
    Spinner accountTypeSpinner = (Spinner) findViewById(R.id.registerSpinner); 
} 

public void registerOnclick(View v){ 



    //Get text from objects 
    String strUsername = username.getText().toString(); 
    String strPassword = password.getText().toString(); 
    String strPassowrdAgain = passwordAgain.getText().toString(); 
    String accounttype = accountTypeSpinner.getSelectedItem().toString(); 

    if(isEmpty(strUsername,strPassword,strPassowrdAgain) == false){ 
     Toast.makeText(this, "this is text", Toast.LENGTH_LONG).show(); 
    } 



}//End of registerOnclick 

public Boolean isEmpty(String strUsername, String strPassword, String strPassowrdAgain){ 
    Boolean isThereEmptyFields = false; 


    if (strUsername.length() == 0) { 
     Log.d("test", "before set error"); 
     username.setError("First name is required!"); 
     Log.d("test", "after set error"); 
     isThereEmptyFields =true; 
    } 
    if (strPassword.length() == 0) { 
     password.setError("First name is required!"); 
     isThereEmptyFields =true; 
    } 
    if (strPassowrdAgain.length() == 0) { 
     passwordAgain.setError("First name is required!"); 
     isThereEmptyFields =true; 
    } 

    return isThereEmptyFields; 
} 

}

Methode setError() verursacht schwere Ausnahme ..wenn i benutze setError() in der Funktion registerOnclick (View v) es funktioniert gut, aber ich muss neue Funktion erstellen isEmpty()

Answer 1

@Override 
protected void onCreate(Bundle savedInstanceState) { 
super.onCreate(savedInstanceState); 
setContentView(R.layout.activity_register); 
Button registerButton = (Button) findViewById(R.id.registerButton); 
//Fetch username, password,passwordAgain , accountTypeSpinner by id 
username = (EditText) findViewById(R.id.registerUsername); 
password = (EditText) findViewById(R.id.registerPassword); 
passwordAgain = (EditText) findViewById(R.id.registerPasswordAgain); 
accountTypeSpinner = (Spinner) findViewById(R.id.registerSpinner); 
} 

public void registerOnclick(View v){ 

String strUsername = username.getText().toString(); 
String strPassword = password.getText().toString(); 
String strPassowrdAgain = passwordAgain.getText().toString(); 
String accounttype = accountTypeSpinner.getSelectedItem().toString(); 
if(!isEmpty(strUsername,strPassword,strPassowrdAgain)){ 
    Toast.makeText(this, "this is text", Toast.LENGTH_LONG).show(); 

} } 

Sie verwendet, wenn die Bedingung boolean in falsche Format

Verwendung

if(!isEmpty(strUsername,strPassword,strPassowrdAgain)) 

statt

if(isEmpty(strUsername,strPassword,strPassowrdAgain) == false) 

Answer 2

public class RegisterActivity extends AppCompatActivity{ 

EditText username; 
EditText password; 
EditText passwordAgain; 
Spinner accountTypeSpinner; 
Button registerButton; 


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

    //Fetch registerbutton by id 
    Button registerButton = (Button) findViewById(R.id.registerButton); 

    //Fetch username, password,passwordAgain , accountTypeSpinner by id 
    EditText username = (EditText) findViewById(R.id.registerUsername); 
    EditText password = (EditText) findViewById(R.id.registerPassword); 
    EditText passwordAgain = (EditText) findViewById(R.id.registerPasswordAgain); 
    Spinner accountTypeSpinner = (Spinner) findViewById(R.id.registerSpinner); 
} 

public void registerOnclick(View v){ 



    //Get text from objects 
    String strUsername = username.getText().toString(); 
    String strPassword = password.getText().toString(); 
    String strPassowrdAgain = passwordAgain.getText().toString(); 
    String accounttype = accountTypeSpinner.getSelectedItem().toString(); 

    if(isEmpty(strUsername,strPassword,strPassowrdAgain) == false){ 
     Toast.makeText(this, "this is text", Toast.LENGTH_LONG).show(); 
    } 



}//End of registerOnclick 

public Boolean isEmpty(String strUsername, String strPassword, String strPassowrdAgain){ 
    Boolean isThereEmptyFields = false; 


    if (strUsername.length() == 0) { 
     Log.d("test", "before set error"); 
     username.setError("First name is required!"); 
     Log.d("test", "after set error"); 
     isThereEmptyFields =true; 
    } 
    if (strPassword.length() == 0) { 
     password.setError("First name is required!"); 
     isThereEmptyFields =true; 
    } 
    if (strPassowrdAgain.length() == 0) { 
     passwordAgain.setError("First name is required!"); 
     isThereEmptyFields =true; 
    } 

    return isThereEmptyFields; 
} 

}