Having more than one button crashes my app

Question

I am currently creating an app on Android Studio.

I use different buttons (in the same activity) that go to different activities. The problem is that, with one button, it all works, but when I add another one the emulator crashes.

Here is my code:

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

    defineButtons();
}

public void defineButtons() {
    findViewById(R.id.next1).setOnClickListener(buttonClickListener);
    findViewById(R.id.next2).setOnClickListener(buttonClickListener);
    findViewById(R.id.next3).setOnClickListener(buttonClickListener);
}

private View.OnClickListener buttonClickListener = new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        switch (v.getId()){
            case R.id.next1:
                Intent Next1 = new Intent (Start.this, Next1.class);
                startActivity(Next1);
                break;
            case R.id.next2:
                Intent Next2 = new Intent (Start.this, Next2.class);
                startActivity(Next2);
                break;
            case R.id.next3:
                Intent Next3 = new Intent (Start.this, Next3.class);
                startActivity(Next3);
                break;
        }
    }
};

And here the XML:

<RelativeLayout 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=".Start"
android:background="@drawable/background">
    <TextView
        android:layout_width="match_parent"
        android:layout_height="700px"
        android:id="@+id/statement"
        android:text="TEXT1"
        android:background="@drawable/button_border"
        android:textColor="#000000"
        android:alpha="0.95"
        android:layout_marginHorizontal="70px"
        android:layout_marginTop="180px"
        android:gravity="center"
        android:paddingHorizontal="50px"
        android:textSize="16sp"
        />

    <Button
        android:id="@+id/next1"
        style="@style/Widget.AppCompat.Button.Borderless"
        android:layout_width="match_parent"
        android:layout_height="150px"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:layout_marginBottom="160dp"
        android:layout_marginHorizontal="70px"
        android:alpha="0.9"
        android:background="@drawable/button_border"
        android:text="TEXT2"
        android:textColor="@android:color/black"
        android:textSize="16sp"
        android:textAllCaps="false"/>

    <Button
        android:id="@+id/next2"
        style="@style/Widget.AppCompat.Button.Borderless"
        android:layout_width="match_parent"
        android:layout_height="150px"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:layout_marginBottom="90dp"
        android:layout_marginHorizontal="70px"
        android:alpha="0.9"
        android:background="@drawable/button_border"
        android:text="TEXT3"
        android:textColor="@android:color/black"
        android:textSize="16sp"
        android:textAllCaps="false"/>

    <Button
        android:id="@+id/next3"
        style="@style/Widget.AppCompat.Button.Borderless"
        android:layout_width="match_parent"
        android:layout_height="150px"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:layout_marginBottom="20dp"
        android:layout_marginHorizontal="70px"
        android:alpha="0.9"
        android:background="@drawable/button_border"
        android:text="TEXT4"
        android:textColor="@android:color/black"
        android:textSize="16sp"
        android:textAllCaps="false"/>
</RelativeLayout>

I know this is messy, I'm new at programming.

Answer 1

Your code is perfectly fine you just need to declare your Next2, and Next3 activities in manifest file like this

<activity android:name=".Next2"
        android:screenOrientation="portrait"/>
    <activity android:name=".Next3"
        android:screenOrientation="portrait"/>

Android reads your app components from manifest file, refer this link for more details https://developer.android.com/guide/topics/manifest/manifest-intro