android.widget.ProgressBar cannot be cast to android.widget.RelativeLayout

Question

I'm new to android studio. Currently I'm working on a medlabtut app on android for over 3 months now. I'm having an issue on the login button on the MedLabStartUpScreen that actually supposed to launch the login screen when clicked on. Rather it crashes the app completely and shows a runtimeException at my //Connection Hooks "progressbar = findViewById(R.id.login_progress_bar);" of my login.java class file, that android.widget.ProgressBar cannot be cast to android.widget.RelativeLayout. I need your help please

My Login layout activity

<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".Common.LoginSignup.Login"
    android:orientation="vertical"
    android:background="#fff"
    android:padding="25dp"
    android:transitionName="transition_login">

<LinearLayout
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:orientation="vertical">
    
         

<TextView
            android:id="@+id/logo_name"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:text="Welcome Back! Login Here"
            android:textSize="40sp"
            android:transitionName="logo_text"
            android:fontFamily="@font/bungee"
            android:textColor="#000"
            android:layout_marginTop="20dp"/>

   



<TextView
            android:id="@+id/slogan_name"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Sign In to continue"
            android:textSize="18sp"
            android:layout_marginTop="10dp"
            android:fontFamily="@font/muli_black"
            android:transitionName="logo_desc"/>

        

<RelativeLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="30dp"
                android:layout_marginBottom="20dp">

            

<com.hbb20.CountryCodePicker
                    android:id="@+id/login_country_code_picker"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    app:ccp_autoDetectCountry="true"
                    app:ccp_showFlag="true"
                    app:ccp_showNameCode="true"
                    app:ccp_showFullName="true"
                    android:padding="5dp"
                    android:background="@drawable/black_border"/>

           



<com.google.android.material.textfield.TextInputLayout
                    android:layout_width="match_parent"
                    android:layout_below="@+id/login_country_code_picker"
                    android:id="@+id/login_phone_number"
                    android:layout_height="wrap_content"
                    style="@style/Widget.MaterialComponents.TextInputLayout.OutlinedBox"
                    android:hint="@string/phone_number"
                    android:textColorHint="@color/Black"
                    app:boxStrokeColor="@color/Black"
                    app:boxStrokeWidthFocused="2dp"
                    app:endIconMode="clear_text"
                    app:endIconTint="@color/Black"
                    app:hintTextColor="@color/Black"
                    app:startIconDrawable="@drawable/field_phone_number_icon"
                    app:startIconTint="@color/Black">

                

<com.google.android.material.textfield.TextInputEditText
                        android:id="@+id/login_phone_number_editText"
                        android:layout_width="match_parent"
                        android:layout_height="match_parent"
                        android:inputType="phone" />
  
</com.google.android.material.textfield.TextInputLayout>



<com.google.android.material.textfield.TextInputLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/login_password"
        android:layout_below="@+id/login_phone_number"
        android:hint="@string/password"
        app:startIconDrawable="@drawable/field_password_icon"
        app:startIconTint="@color/Black"
        android:transitionName="password_tran"
        app:passwordToggleEnabled="true"
        app:passwordToggleTint="@color/Black"
        style="@style/Widget.MaterialComponents.TextInputLayout.OutlinedBox">

        <com.google.android.material.textfield.TextInputEditText
            android:id="@+id/login_password_editText"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:fontFamily="@font/muli_bold"
            android:inputType="textPassword" />

    </com.google.android.material.textfield.TextInputLayout>


<RelativeLayout
        android:id="@+id/forget_password_block"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/login_password"
        android:layout_marginTop="10dp">

        <CheckBox
            android:id="@+id/remember_me"
            style="@style/Widget.AppCompat.CompoundButton.CheckBox"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerVertical="true"
            android:text="@string/remember_me" />
        
        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/forget_password"
            android:background="#00000000"
            android:layout_alignParentEnd="true"
            android:onClick="callForgetPassword"
            android:layout_alignParentRight="true"/>

    </RelativeLayout>



 <Button
        android:id="@+id/letTheUserLogin"
        android:layout_below="@+id/forget_password_block"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginBottom="10dp"
        android:layout_marginTop="5dp"
        android:background="#000"
        android:text="@string/login"
        android:onClick="letTheUserLoggedIn"
        android:textColor="#fff"
        android:transitionName="button_tran" />

<RelativeLayout
    android:id="@+id/login_sign_google_box"
    android:layout_width="match_parent"
    android:layout_height="50dp"
    android:padding="10dp"
    android:layout_margin="5dp"
    android:background="@drawable/rounded_rectangle"
    android:layout_below="@+id/letTheUserLogin">

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/signin_with_google_icon"
        android:layout_centerVertical="true"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="SIGN IN WITH GOOGLE"
        android:layout_centerHorizontal="true"
        android:layout_centerInParent="true"
        android:fontFamily="@font/muli_bold"
        android:layout_margin="5dp"
        android:textColor="#000"/>

    <Button
        android:id="@+id/google_signIn"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@color/transparent" />

</RelativeLayout>

            

<Button
                android:id="@+id/signup_screen"
                android:layout_below="@+id/login_sign_google_box"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:background="#00000000"
                android:text="Create Account"
                android:layout_centerHorizontal="true"
                android:elevation="0dp"
                android:layout_margin="5dp"
                android:textColor="#000"
                android:transitionName="login_signup_tran"/>

            

<RelativeLayout
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:padding="20dp"
                    android:layout_centerInParent="true"
                    android:background="@drawable/white_circle"
                    android:elevation="10dp">

                    <ProgressBar
                        android:id="@+id/login_progress_bar"
                        android:layout_width="30dp"
                        android:layout_height="30dp"
                        android:layout_centerInParent="true"/>

                </RelativeLayout>

                

<ImageView
                        android:id="@+id/social_fb"
                        android:layout_below="@+id/signup_screen"
                        android:layout_width="50dp"
                        android:layout_height="45dp"
                        android:src="@drawable/social_facebook_icon"
                        android:layout_marginLeft="130dp" />

                

<ImageView
                        android:id="@+id/social_tw"
                        android:layout_below="@id/signup_screen"
                        android:layout_width="45dp"
                        android:layout_height="45dp"
                        android:layout_centerHorizontal="true"
                        android:layout_marginLeft="150dp"
                        android:src="@drawable/social_twitter_icon" />
                

<ImageView
                        android:id="@+id/social_wh"
                        android:layout_width="45dp"
                        android:layout_height="45dp"
                        android:layout_below="@id/signup_screen"
                        android:layout_marginLeft="250dp"
                        android:src="@drawable/social_whatsapp_icon" />

        

</RelativeLayout>

 </LinearLayout>

And the code for login.java class file

public class Login extends AppCompatActivity {

    CountryCodePicker countryCodePicker;
    Button callSignUp, login_btn;
    TextView logoText, sloganText;
    TextInputLayout username, phoneNumber, password;
    RelativeLayout progressbar;
    CheckBox rememberMe;
    EditText phoneNumberEditText, passwordEditText;
    private GoogleSignInClient mGoogleSignInClient;
    private  final  static int RC_SIGN_IN = 123; // request code

    Button verify;
    private FirebaseAuth mAuth;
@Override
protected void onStart() {
    super.onStart();

    FirebaseUser user = mAuth.getCurrentUser();
    if (user!=null){
        Intent intent = new Intent(getApplicationContext(), MedLabDashboard.class);
        startActivity(intent);
    }
}




 @SuppressLint("WrongViewCast")
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,    WindowManager.LayoutParams.FLAG_FULLSCREEN);
        setContentView(R.layout.activity_login);

        mAuth = FirebaseAuth.getInstance();

        createRequest();

        //when the user clicks the google button,call the signIn method
        findViewById(R.id.google_signIn).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                signIn();
            }
        });



//Connection Hooks
    countryCodePicker = findViewById(R.id.country_code_picker);
    phoneNumber = findViewById(R.id.login_phone_number);
    progressbar = findViewById(R.id.login_progress_bar);
    callSignUp = findViewById(R.id.signup_screen);
    image = findViewById(R.id.logo_image);
    logoText = findViewById(R.id.logo_name);
    sloganText = findViewById(R.id.slogan_name);
    password = findViewById(R.id.login_password);
    login_btn = findViewById(R.id.Login_btn);
    rememberMe =  findViewById(R.id.remember_me);
    phoneNumberEditText = findViewById(R.id.login_phone_number_editText);
    passwordEditText = findViewById(R.id.login_password_editText);




//Check whether phone number and password is already saved in Shared Preference or not
    SessionManager sessionManager = new SessionManager(Login.this, SessionManager.SESSION_REMEMBERME);
    if (sessionManager.checkRemeberMe()){
        HashMap<String,String> rememberMeDetails = sessionManager.getRememberMeDetailFromSession();
        phoneNumberEditText.setText(rememberMeDetails.get(SessionManager.KEY_SESSIONPHONENUMBER));
        passwordEditText.setText(rememberMeDetails.get(SessionManager.KEY_SESSIONPASSWORD));
    }



 callSignUp.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Intent intent = new Intent(Login.this, SignUp.class);

            Pair[] pairs = new Pair[7];
            pairs[0] = new Pair<View, String>(image, "logo_image");
            pairs[1] = new Pair<View, String>(logoText, "logo_name");
            pairs[2] = new Pair<View, String>(sloganText, "logo_desc");
            pairs[3] = new Pair<View, String>(username, "username_tran");
            pairs[4] = new Pair<View, String>(password, "password_tran");
            pairs[5] = new Pair<View, String>(login_btn, "button_tran");
            pairs[6] = new Pair<View, String>(callSignUp, "login_signup_tran");

            if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.LOLLIPOP) {
                try {

                    startActivity(intent);

                } catch (Exception e) {

                    e.printStackTrace();
                }
            }
        }
    });
}




//Setting Auto Google Sign In request
private void createRequest() {
    // Configure Google Sign In
    GoogleSignInOptions gso = new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
            .requestIdToken(getString(R.string.default_web_client_id))
            .requestEmail()
            .build();

    // Build a GoogleSignInClient with the options specified by gso.
    mGoogleSignInClient = GoogleSignIn.getClient(this, gso);
}

//SignIn with google method that'll pop-up user google accounts (Intent)
private void signIn() {
    Intent signInIntent = mGoogleSignInClient.getSignInIntent();
    startActivityForResult(signInIntent, RC_SIGN_IN);
}




@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    // Result returned from launching the Intent from GoogleSignInClient.getSignInIntent(...);
    if (requestCode == RC_SIGN_IN) {
        Task<GoogleSignInAccount> task = GoogleSignIn.getSignedInAccountFromIntent(data);
        try {
            //Google Sign in was successful, authenticate with firebase
            GoogleSignInAccount account = task.getResult(ApiException.class);
            firebaseAuthWithGoogle(account);
        } catch (ApiException e){
            //Sign in failed, update UI appropriately
            Toast.makeText(this, e.getMessage(), Toast.LENGTH_SHORT).show();
        }
    }
}



 private void firebaseAuthWithGoogle(GoogleSignInAccount acct) {
        AuthCredential credential = GoogleAuthProvider.getCredential(acct.getIdToken(), null);
        mAuth.signInWithCredential(credential)
                .addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
                    @Override
                    public void onComplete(@NonNull Task<AuthResult> task) {
                        if (task.isSuccessful()) {
                            // Sign in success, update UI with the signed-in user's information
                            FirebaseUser user = mAuth.getCurrentUser();
                            Intent intent = new Intent(getApplicationContext(), MedLabDashboard.class);
                            startActivity(intent);
                        } else {
                            Toast.makeText(Login.this, "Sorry authentication failed", Toast.LENGTH_SHORT).show();
                        }
                    }
                });
             }

//login the user in app
public void letTheUserLoggedIn(View view) {

    //Check the internet connection
    CheckInternet checkInternet = new CheckInternet();
    if (!isConnected(Login.this)) {
        showCustomDialog();
    }

    //validate user and password
    if (!validateFields()) {
        return;
    }
    progressbar.setVisibility(View.VISIBLE);

    //get value from fields
    String _phoneNumber = phoneNumber.getEditText().getText().toString().trim();
    final String _password = password.getEditText().getText().toString().trim();
    if (_phoneNumber.charAt(0) == '0') { //if the user uses proceeding zero (0)
        _phoneNumber = _phoneNumber.substring(1);
    }


    final String _completePhoneNumber = "+" + countryCodePicker.getFullNumber() + _phoneNumber;




//Remember me checkbox
    if (rememberMe.isChecked()){
        SessionManager sessionManager = new SessionManager(Login.this,SessionManager.SESSION_REMEMBERME);
        sessionManager.createRememberMeSession(_phoneNumber, _password);
    }

    //database query if user exist or not
    Query checkUser = FirebaseDatabase.getInstance().getReference("Users").orderByChild("phoneNo").equalTo(_completePhoneNumber);
    checkUser.addListenerForSingleValueEvent(new ValueEventListener() {
        @Override
        public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
            if (dataSnapshot.exists()) { //if the data has arrived or exists
                phoneNumber.setError(null); //if there's any error on the phoneNumber, remove
                phoneNumber.setErrorEnabled(false); //if there is error space, set to false

                String systemPassword = dataSnapshot.child(_completePhoneNumber).child("password").getValue(String.class);

                //if password exist and matches with users password, then get other fields from firebase database
                if (systemPassword.equals(_password)) {
                    password.setError(null); //if there's any error on the password, remove
                    password.setErrorEnabled(false); //if there is error space, set to false

                    String _fullname = dataSnapshot.child(_completePhoneNumber).child("fullName").getValue(String.class);
                    String _username = dataSnapshot.child(_completePhoneNumber).child("username").getValue(String.class);
                    String _email = dataSnapshot.child(_completePhoneNumber).child("email").getValue(String.class);
                    String _phoneNo = dataSnapshot.child(_completePhoneNumber).child("phoneNo").getValue(String.class);
                    String _password = dataSnapshot.child(_completePhoneNumber).child("password").getValue(String.class);
                    String _dateOfBirth = dataSnapshot.child(_completePhoneNumber).child("date").getValue(String.class);
                    String _gender = dataSnapshot.child(_completePhoneNumber).child("gender").getValue(String.class);

                    //Create a session
                    SessionManager sessionManager = new SessionManager(Login.this, SessionManager.SESSION_USERSESSION);
                    sessionManager.createLoginSession(_fullname, _username, _email, _phoneNo, _password, _dateOfBirth, _gender);

                    startActivity(new Intent(getApplicationContext(), MedLabDashboard.class));

                    Toast.makeText(Login.this, _fullname + "\n" + _email + "\n" + _phoneNo + "\n" + _dateOfBirth, Toast.LENGTH_SHORT).show();
                    progressbar.setVisibility(View.GONE);

                } else {
                    progressbar.setVisibility(View.GONE);
                    Toast.makeText(Login.this, "Password does not match!",  Toast.LENGTH_SHORT).show();
                }
            } else {
                progressbar.setVisibility(View.GONE);
                Toast.makeText(Login.this, "No such user exist", Toast.LENGTH_SHORT).show();
            }
        }

        @Override
        public void onCancelled(@NonNull DatabaseError databaseError) {
            progressbar.setVisibility(View.GONE);
            Toast.makeText(Login.this, databaseError.getMessage(), Toast.LENGTH_SHORT).show();
        }
    });
}


//check internet connection
private boolean isConnected(Login login) {
    ConnectivityManager connectivityManager = (ConnectivityManager)   login.getSystemService(Context.CONNECTIVITY_SERVICE);

    NetworkInfo wifiConn = connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI);
    NetworkInfo mobileConn = connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);

    if ((wifiConn != null && wifiConn.isConnected()) || (mobileConn != null && mobileConn.isConnected())) {
        return true;
    } else {
        return false;
    }
}

private void showCustomDialog() {

    AlertDialog.Builder builder = new AlertDialog.Builder(Login.this);
    builder.setMessage("Please connect to the internet to continue");
    builder.setCancelable(false)
            .setPositiveButton("Connect", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialogInterface, int i) {
                    startActivity(new Intent(Settings.ACTION_WIFI_SETTINGS));
                }
            })
            .setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialogInterface, int i) {
                    startActivity(new Intent(getApplicationContext(), MedLabStartUpScreen.class));
                    finish();
                }
            });
         }



private boolean validateFields() {

    String _phoneNumber = phoneNumber.getEditText().getText().toString().trim();
    String _password = password.getEditText().getText().toString().trim();

    if (_phoneNumber.isEmpty()) {
        phoneNumber.setError("Phone number cannot be empty");
        phoneNumber.requestFocus();
        return false;
    } else if (_password.isEmpty()) {
        password.setError("Password cannot be empty");
        password.requestFocus();
        return false;
    } else {
        password.setError(null);
        password.setErrorEnabled(false);
        return true;
    }
}



public void callForgetPassword(View view){
    startActivity(new Intent(getApplicationContext(), ForgetPassword.class));
}

@Override
public void onBackPressed() {
    Intent a = new Intent(Intent.ACTION_MAIN);
    a.addCategory(Intent.CATEGORY_HOME);
    a.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    startActivity(a);
    finish();
}}

MedLabStartUpScreen Activity screen

<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/White"
    android:padding="30dp"
    tools:context=".Common.LoginSignup.MedLabStartUpScreen">

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical">

    <ImageView
        android:layout_width="match_parent"
        android:layout_height="300dp"
        android:src="@drawable/splash_screen" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_marginTop="120dp"
        android:fontFamily="@font/muli_black"
        android:text="@string/medlab_heading"
        android:textAlignment="center"
        android:textAllCaps="true"
        android:textColor="@color/Black"
        android:textSize="36sp" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:fontFamily="@font/muli_light"
        android:text="@string/medlab_tab_line"
        android:textAlignment="center"
        android:textColor="@color/Black" />




<LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="40dp">

        <Button
            android:id="@+id/login_btn"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_marginRight="10dp"
            android:layout_marginEnd="10dp"
            android:onClick="callLoginScreen"
            android:layout_weight="1"
            android:background="@color/colorPrimaryDark"
            android:text="@string/login"
            android:textColor="@color/Black"
            tools:ignore="ButtonStyle"
            android:transitionName="transition_login"/>

        <Button
            android:id="@+id/signup_btn"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_marginLeft="10dp"
            android:layout_weight="1"
            android:background="@color/colorPrimaryDark"
            android:text="@string/sign_up"
            android:textColor="@color/Black" />

    </LinearLayout>

<Button
        android:layout_width="match_parent"
        android:layout_weight="1"
        android:layout_height="wrap_content"
        android:text="@string/how_we_work"
        android:textColor="@color/Black"
        android:layout_marginTop="20dp"
        android:background="#00000000"/>

</LinearLayout>

</ScrollView>

MedLabStartUPScreen.java class that has the login button

public class MedLabStartUpScreen extends AppCompatActivity {

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
            setContentView(R.layout.activity_med_lab_start_up_screen);
        }



public void callLoginScreen(View view){
        Intent intent = new Intent(getApplicationContext(), Login.class);

        Pair[] pairs = new Pair[1];
        pairs[0] = new Pair<View,String>(findViewById(R.id.login_btn), "transition_login");

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            ActivityOptions options = ActivityOptions.makeSceneTransitionAnimation(MedLabStartUpScreen.this, pairs);
            startActivity(intent, options.toBundle());
        }
        else {
            startActivity(intent);
        }
    }
 }

Answer 1

On around line 7 you declare this variable:

RelativeLayout progressbar;

You then correctly go on to initialise this variable with:

progressbar = findViewById(R.id.login_progress_bar);

The issue is that in the xml, the view (widget) with this ID is a ProgressBar, but the type declaration for progressbar in the Java code is RelativeLayout . Your code is therefore trying to cast the ProgressBar in the layout file into a RelativeLayout, which can't be done.

You can fix this by changing the declaration on line 7 to:

ProgressBar progressbar;

(And then adding the necessary import at the top of your Java file: import android.widget.ProgressBar; ).

Hope this helped.