java.lang.ClassCastException: androidx.appcompat.widget.AppCompatImageButton cannot be cast to android.widget.Button

Question

Problem: I have a java/xml file in android studio. I need to play two buttons; One for "Map page" and second for "Create new account" (Signup activity). The first button work, but the second close my app. What is the problem?

What I know: if it is empty xml file the button for to go to the xml file work.

The errors:

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.sampleapp, PID: 8062
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.sampleapp/com.example.sampleapp.SignUpActivity}: java.lang.ClassCastException: androidx.appcompat.widget.AppCompatImageButton cannot be cast to android.widget.Button
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3270)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3409)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016)
        at android.os.Handler.dispatchMessage(Handler.java:107)
        at android.os.Looper.loop(Looper.java:214)
        at android.app.ActivityThread.main(ActivityThread.java:7356)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)
     Caused by: java.lang.ClassCastException: androidx.appcompat.widget.AppCompatImageButton cannot be cast to android.widget.Button
        at com.example.sampleapp.SignUpActivity.onCreate(SignUpActivity.java:33)
        at android.app.Activity.performCreate(Activity.java:7802)
        at android.app.Activity.performCreate(Activity.java:7791)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1299)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3245)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3409) 
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83) 
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) 
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016) 
        at android.os.Handler.dispatchMessage(Handler.java:107) 
        at android.os.Looper.loop(Looper.java:214) 
        at android.app.ActivityThread.main(ActivityThread.java:7356) 
        at java.lang.reflect.Method.invoke(Native Method)

Scripts:

LoginActivity.java:

package com.example.sampleapp;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class LoginActivity extends AppCompatActivity {
    public EditText username;
    public EditText password;
    public TextView errorView;
    public Button login;
    public Button createNewAccount;

    public void initMapPage(){
        Intent mapPage = new Intent(LoginActivity.this, MainActivity.class);
        startActivity(mapPage);
        finish();
    }

    public void initSignUpPage(){
        Intent signUpPage = new Intent(LoginActivity.this, SignUpActivity.class);
        startActivity(signUpPage);
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);
        username = (EditText) findViewById(R.id.UsernameBox);
        password = (EditText) findViewById(R.id.PasswordBox);
        errorView = (TextView) findViewById(R.id.errorView);
        login = (Button) findViewById(R.id.LoginButton);
        createNewAccount = (Button) findViewById(R.id.SignupButton);

        login.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String errorMsg = "";
                if (username.getText().toString().equals("") || password.getText().toString().equals("")) {
                    if (username.getText().toString().equals("")) {
                        errorMsg += "Username block is empty\n";
                    }
                    if (password.getText().toString().equals("")) {
                        errorMsg += "Password block is empty\n";
                    }

                    errorView.setText(errorMsg);
                }
                else {
                    initMapPage();
                }
            }
        });

        createNewAccount.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                initSignUpPage();
            }
        });
    }
}

activity_login.xml:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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=".LoginActivity">

    <TextView
        android:id="@+id/WelcomeBox"
        android:layout_width="210dp"
        android:layout_height="101dp"
        android:layout_marginTop="64dp"
        android:text="Welcome \nTo Our App!"
        android:textAlignment="center"
        android:textColor="#000000"
        android:textSize="30sp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <EditText
        android:id="@+id/UsernameBox"
        android:layout_width="300dp"
        android:layout_height="55dp"
        android:layout_marginTop="40dp"
        android:ems="10"
        android:hint="Username"
        android:inputType="textPersonName"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/WelcomeBox" />

    <EditText
        android:id="@+id/PasswordBox"
        android:layout_width="300dp"
        android:layout_height="55dp"
        android:layout_marginTop="24dp"
        android:ems="10"
        android:hint="Password"
        android:inputType="textPassword"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/UsernameBox" />

    <Button
        android:id="@+id/SignupButton"
        android:layout_width="237dp"
        android:layout_height="55dp"
        android:layout_marginTop="24dp"
        android:text="Create New Acount"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView4" />

    <Button
        android:id="@+id/LoginButton"
        android:layout_width="115dp"
        android:layout_height="63dp"
        android:layout_marginTop="12dp"
        android:text="LOGIN"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/errorView" />

    <TextView
        android:id="@+id/textView4"
        android:layout_width="60dp"
        android:layout_height="29dp"
        android:layout_marginTop="24dp"
        android:text="OR"
        android:textAlignment="center"
        android:textColor="#D3000000"
        android:textSize="24sp"
        android:textStyle="bold"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/LoginButton" />

    <TextView
        android:id="@+id/errorView"
        android:layout_width="209dp"
        android:layout_height="62dp"
        android:layout_marginTop="16dp"
        app:layout_constraintEnd_toEndOf="parent"
        android:textAlignment="center"
        android:textColor="#FF0000"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/PasswordBox" />

</androidx.constraintlayout.widget.ConstraintLayout>

SignUpActivity.java:

package com.example.sampleapp;

import androidx.appcompat.app.AppCompatActivity;

import android.annotation.SuppressLint;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class SignUpActivity extends AppCompatActivity {

    public Button backToLogin;
    public Button SignUp;
    public EditText username;
    public EditText password;
    public EditText email;


    public void initLoginPage(){
        Intent loginPage = new Intent(SignUpActivity.this, LoginActivity.class);
        startActivity(loginPage);
        finish();
    }

    @SuppressLint("WrongViewCast")
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_sign_up);
        SignUp = (Button) findViewById(R.id.suButton);
        backToLogin = (Button) findViewById(R.id.back_to_login);
        username = (EditText) findViewById(R.id.UsernameBoxSignUp);
        password = (EditText) findViewById(R.id.PasswordBoxSignUp);
        email = (EditText) findViewById(R.id.EmailBox);

        backToLogin.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                initLoginPage();
            }
        });
    }
}

activity_sign_up.xml:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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=".SignUpActivity">

    <EditText
        android:id="@+id/UsernameBoxSignUp"
        android:layout_width="300dp"
        android:layout_height="40dp"
        android:layout_marginStart="54dp"
        android:layout_marginTop="160dp"
        android:ems="10"
        android:hint="Username"
        android:inputType="textPersonName"
        android:textSize="18sp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/back_to_login" />

    <EditText
        android:id="@+id/PasswordBoxSignUp"
        android:layout_width="300dp"
        android:layout_height="40dp"
        android:layout_marginStart="55dp"
        android:layout_marginTop="20dp"
        android:ems="10"
        android:hint="Password"
        android:inputType="textPassword"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/EmailBox" />

    <Button
        android:id="@+id/suButton"
        android:layout_width="170dp"
        android:layout_height="53dp"
        android:layout_marginStart="120dp"
        android:layout_marginTop="36dp"
        android:text="SignUp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/PasswordBoxSignUp" />

    <EditText
        android:id="@+id/EmailBox"
        android:layout_width="300dp"
        android:layout_height="40dp"
        android:layout_marginStart="44dp"
        android:layout_marginTop="16dp"
        android:ems="10"
        android:hint="Email"
        android:inputType="textEmailAddress"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/UsernameBoxSignUp" />

    <ImageButton
        android:id="@+id/back_to_login"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="54dp"
        android:layout_marginTop="28dp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:srcCompat="?attr/actionModeCloseDrawable" />

</androidx.constraintlayout.widget.ConstraintLayout>

If your app is forced closed there's most likely some helpful information in Logcat. See if you can find a stacktrace and post it here. — TofferJ
– TofferJ, Commented Apr 6, 2020 at 22:23
Please add which button (which XML ID and which Java ID) causing close my app. Have you got any exception , error, something in Logcat? — Boken
– Boken, Commented Apr 6, 2020 at 22:24
the problem is that ImageButton (and thus the appcompat version) is a subclass of ImageView, not of Button. You should either change the cast to that, or just remove it entirely if you're only using View methods. — Ryan M
– Ryan M ♦, Commented Apr 8, 2020 at 8:57
Does this answer your question? class cast exception in android? — cutiko
– cutiko, Commented Apr 26, 2020 at 23:33
@cutiko that question is about mistyped class names in XML. The class name here is correct, but there's a common misconception about the inheritance involved. See my answer and my comment above for more details. — Ryan M
– Ryan M ♦, Commented Apr 26, 2020 at 23:36

Ryan M · Accepted Answer · 2020-04-26 23:30:36Z

3

The problem is that ImageButton (and thus also the appcompat version) is a subclass of ImageView, not of Button. You should either change the cast to that, or just remove it entirely if you're only using View methods like setOnClickListener.

answered Apr 26, 2020 at 23:30

Ryan M♦

20.6k35 gold badges75 silver badges85 bronze badges

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Comments

Arath · Accepted Answer · 2020-04-07 00:17:31Z

0

Is the username or password text set up?

Android:text="" A hint is just a hint, not the actual response. So it gets an error when it looking for something that's not even set up yet.

answered Apr 7, 2020 at 0:17

Arath

12 bronze badges

Comments

xLogger · Accepted Answer · 2020-04-07 00:34:12Z

0

Your calling SignUpActivity twice

Place the intent

Intent signUpPage = new Intent(LoginActivity.this, SignUpActivity.class);
        startActivity(signUpPage);

on onClick method

and don't forget to add android:onClick="OnCreateAccount" on your button

answered Apr 7, 2020 at 0:34

xLogger

631 silver badge9 bronze badges

1 Comment

Mordechai Shalev Over a year ago

Where I calling twicw?

Anishk Kumar Yadav · Accepted Answer · 2023-08-01 06:10:48Z

0

You are casting button on imagebutton

Just follow this simple step

go to 'SignUpActivity.java' then

public ImageButton backToLogin;
backToLogin = (ImageButton) findViewById(R.id.back_to_login);

edited Aug 1, 2023 at 6:10

answered Jul 23, 2023 at 9:10

Anishk Kumar Yadav

11 bronze badge

1 Comment

Community Over a year ago

Your answer could be improved with additional supporting information. Please edit to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers in the help center.

Mirwise Khan · Accepted Answer · 2024-03-26 17:29:34Z

0

Your issue is in SignUpActivity and activity_sign_up.xml. In the xml your back_to_login is of type ImageButton but in the SignUpActivity you have declared it as a Button. The IDE is also showing you by giving you that warning you are suppressing with @SuppressLint("WrongViewCast").

Changes you need to do: Update

public Button backToLogin;

to

public ImageButton backToLogin;

and

backToLogin = (Button) findViewById(R.id.back_to_login);

to

backToLogin = (ImageButton) findViewById(R.id.back_to_login);

edited Mar 26, 2024 at 17:29

Mirwise Khan

1,42819 silver badges29 bronze badges

answered Mar 25, 2024 at 12:02

George Tsiga

11 bronze badge

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