java.lang.ClassCastException：android.widget.RelativeLayout无法强制转换为android.widget.EditText

Question

Before posting I have already read many similar questions to mine but have had no luck.

02-24 15:12:11.334 22856-22856/k.testproject E/AndroidRuntime: FATAL EXCEPTION: main
                                                           Process: k.testproject, PID: 22856
                                                           java.lang.RuntimeException: Unable to start activity ComponentInfo{k.testproject/k.testproject.MainActivity}: java.lang.ClassCastException: android.widget.RelativeLayout cannot be cast to android.widget.EditText
                                                               at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416)
                                                               at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
                                                               at android.app.ActivityThread.-wrap11(ActivityThread.java)
                                                               at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
                                                               at android.os.Handler.dispatchMessage(Handler.java:102)
                                                               at android.os.Looper.loop(Looper.java:148)
                                                               at android.app.ActivityThread.main(ActivityThread.java:5417)
                                                               at java.lang.reflect.Method.invoke(Native Method)
                                                               at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
                                                               at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
                                                            Caused by: java.lang.ClassCastException: android.widget.RelativeLayout cannot be cast to android.widget.EditText
                                                               at k.testproject.MainActivity.onCreate(MainActivity.java:23)
                                                               at android.app.Activity.performCreate(Activity.java:6237)
                                                               at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)
                                                               at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369)
                                                               at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476) 
                                                               at android.app.ActivityThread.-wrap11(ActivityThread.java) 
                                                               at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344) 
                                                               at android.os.Handler.dispatchMessage(Handler.java:102) 
                                                               at android.os.Looper.loop(Looper.java:148) 
                                                               at android.app.ActivityThread.main(ActivityThread.java:5417) 
                                                               at java.lang.reflect.Method.invoke(Native Method) 
                                                               at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
                                                               at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 

The portion of the code when I'm sure that the error is emerging is:

public class MainActivity extends AppCompatActivity {

EditText etEmail, etPassword;
Button signInButton;
UserLocalStore userLocalStore;

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

    etEmail = (EditText) findViewById(R.id.etEmail);
    etPassword = (EditText) findViewById(R.id.etPassword);
    signInButton = (Button) findViewById(R.id.signInButton);

And the particular XML file related to the portion is:

    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:orientation="vertical"
    android:layout_height="match_parent"
    android:layout_width="match_parent"
    android:padding="20dp"
    android:layout_marginTop="70dp"
    tools:showIn="@layout/activity_main">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="E-Mail" />

    <EditText
        android:id="@+id/etEmail"
        android:layout_marginTop="10dp"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:inputType="textEmailAddress" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Password" />

    <EditText
        android:id="@+id/etPassword"
        android:layout_marginTop="10dp"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:inputType="textPassword" />
    <Button
        android:id="@+id/signInButton"
        android:text="Sign In"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
</LinearLayout>

What is the reason for this exception and how am I able to fix?

I'm not entirely sure why the exception is relating to relative layout when I am using linear.

Please note that I am quite new to Android so this may not be the smartest of questions! Thank you for your help in advance!

activity_main.xml code as requested (As far as I am aware I have not created nor touched this file myself) :

    <?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout 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:fitsSystemWindows="true"
    tools:context="k.testproject.MainActivity">

    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/AppTheme.AppBarOverlay">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="?attr/colorPrimary"
            app:popupTheme="@style/AppTheme.PopupOverlay" />

    </android.support.design.widget.AppBarLayout>

    <include
        android:id="@+id/etEmail"
        layout="@layout/content_main" />

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/fab"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom|end"
        android:layout_margin="@dimen/fab_margin"
        android:src="@android:drawable/ic_dialog_email" />

</android.support.design.widget.CoordinatorLayout>

Answer 1

you can try this

1 clean code and try again

2 close IDE and rebuild the code again

hope it helps

Answer 2

clean/rebuild your project to see if that fixes it. If not:

Your XML looks fine, as does the small snippet of code - so this is hard to answer. It looks like you're including this layout in activity_main - would you mind pasting the XML for that, and any other layouts included?

My suspicion is that you have a conflict between two id's.

Answer 3

Check your IDs. Are you using etEmail and etPassword somewhere else in the project?

Are those ids uniquely associated to an EditText?