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Android Build a Simple Android App with Java Improving Our Code Dynamically Changing the Background Color

Noah Price
Noah Price
365 Points

Can't find relativeLayout id with findViewById

I am having an issue when I try to access the relativeLayout view object by id, it does not show up in auto-complete, and typing in the id manually results in an error.. I have ensured I am referring to it exactly the same as it is labeled inside of the activity_fun_facts.xml file, but it still appears red. I have also gone ahead and downloaded the course file for this particular episode and compared my source code with that provided using a separate program, but aside from the use of a cast which isn't necessary in my version, I can't see any difference in my code.

Related Source code: FunFactsActivity.java

public class FunFactsActivity extends AppCompatActivity {
    private FactBook factBook = new FactBook();
    // Declare our View Variables
    private TextView factTextView;
    private Button showFactButton;
    private RelativeLayout relativeLayout;

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

        // Assign the Views from the layout file to the corresponding variables
        factTextView = findViewById(R.id.factTextView);
        showFactButton = findViewById(R.id.showFactButton);
        relativeLayout = findViewById(R.id.relativeLayout); // this final part is where it turns red, and I am unable to find the id that is being referenced in my .xml file.

activity_fun_facts.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"
    android:background="#51b64d"
    android:clickable="false"
    android:padding="50dp"
    android:id="@+id/relativeLayout" <!-- This is the id I have declared -->
    tools:context="com.rug.funfacts.FunFactsActivity">

3 Answers

Noah Price
Noah Price
365 Points

It seems that Android Studio doesn't like the id of 'relativeLayout'. I changed it to be 'funFactLayout' inside of the activity_fun_facts.xml file:

android:id="@+id/funFactLayout"

and went ahead with the exact same procedure inside of the FunFactsActivity.java

public class FunFactsActivity extends AppCompatActivity {
// ......
    private TextView factTextView;
    private Button showFactButton;
    private RelativeLayout relativeLayout;
// .....
protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_fun_facts);

        // Assign the Views from the layout file to the corresponding variables
        factTextView = findViewById(R.id.factTextView);
        showFactButton = findViewById(R.id.showFactButton);
        relativeLayout = findViewById(R.id.funFactLayout);
Marcus Hallenberg
Marcus Hallenberg
2,772 Points

i had the problem when i wrote the name Android:id="@+id/relativeLayout" i forgot the + and added it afterward it didnt work but when i wrote the exact same code without missing the + it worked same with the color cause of the auto helping i wrote color.RED instead of Color.RED so i just change the c to a C.

Same here.

Moira Lawrie-Martyn
Moira Lawrie-Martyn
7,818 Points

have you tried casting each of the views to their correct view type? Has that resolved the issue? Because I'd say that you're having a problem because Android doesn't know what it's looking for.

Noah Price
Noah Price
365 Points

In the newer version that I am using (I believe it is Ice Cream Sandwhich) just says that casting is redundant. When I wrote the code for the button and TextView, I did not require a cast either. The issue I had, which I resolved in my own answer above, is that android didn't like me naming the id of the RelativeLayout to RelativeLayout.

Thank you for your response anyway! :)