Android: findViewById in a not main.xml file

Question

I have two layouts: main.xml and journal.xml When I click on a button in the main.xml layout, the journal.xml layout will be opened.

The problem is that i would like to create a back button which will re-open the main.xml layout. When I try to do:

ImageButton buttonHome = (ImageButton)findViewById(R.id.image);

The image is not found because she is not in my main.xml

Could you please help me.

Thanks

Here is the code:

public class MDPI_1Activity extends Activity 
{
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.journal);
        ImageButton buttonJournal = (ImageButton)findViewById(R.id.imageButton1); //Journal
        ImageButton buttonHome = (ImageButton)findViewById(R.id.image); //Journal


        buttonJournal.setOnClickListener(new Button.OnClickListener() 
        {

            public void onClick(View v) 
            {

                setContentView(R.layout.journal);
            }
        });


        buttonHome.setOnClickListener(new Button.OnClickListener() 
        {

            public void onClick(View v) 
            {

                setContentView(R.layout.main);
            }
        });

    }

}

The "imageButton1" is in my main.xml file and works good but the "image" is in my second xml file named "journal" and does not exist in the R file.

Answer 1

EDIT: I don't know if this will work.. but you can set the onClick parameter on your layout (XML) like this:

//Activity
public class MDPI_1Activity extends Activity 
{
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.journal);

    }


    public void goJournal(View v)
    {

        setContentView(R.layout.journal);
    }


    public void goHome(View v)
    {

        setContentView(R.layout.main);
    }

}

//BUTTON IN HOME LAYOUT
<Button
    android:id="@+id/button1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Journal"
    android:onClick="goJournal" />

//BUTTON IN JOURNAL LAYOUT
<Button
    android:id="@+id/button1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Home"
    android:onClick="goHome" />

Answer 2

I have compiled a code for you. This code is working on my side. You can switch between two layouts using Button in the following way.

public class TestActivity extends Activity implements OnClickListener {
    Button btnGoToJournal = null;
    Button btnGoToMain = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        btnGoToJournal = (Button) findViewById(R.id.btn_go_to_journal);
        btnGoToJournal.setOnClickListener(this);
    }
    @Override
    public void onClick(View v) {
        switch(v.getId()){
        case R.id.btn_go_to_journal:
            setContentView(R.layout.journal);
            btnGoToMain = (Button) findViewById(R.id.btn_go_to_main);
            btnGoToMain.setOnClickListener(this);
            break;
        case R.id.btn_go_to_main:
            setContentView(R.layout.main);
            btnGoToJournal = (Button) findViewById(R.id.btn_go_to_journal);
            btnGoToJournal.setOnClickListener(this);
            break;
        }       
    }
}

Main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <Button
        android:id="@+id/btn_go_to_journal"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Go to journal" />

</LinearLayout>

Journal.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <Button
        android:id="@+id/btn_go_to_main"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Go to Main" />

</LinearLayout>

Answer 3

You need to use separate activities for your two layouts. You can call and display them like so:

Intent yourIntent = new Intent(currentActivity.this, nextActivity.class);
startActivity(yourIntent);

You can do this on your button click. Don't forget to declare the activities in your AndroidManifest.xml. Let me know if you need any help.