CODEWITHSUNDEEP
androidfindviewbyid
the13thdev
the13thdev

Reputation: 11

Android findViewById for a parent layout

As you can see in the code, I have a parent layout which has a button. I want to change the bg. color of parent layout randomly every time the button is clicked. But findViewById(R.layout.activity_main) for my parent layout gives null as setContentView(R.layout.activity_main) is set for the same layout. I dont want to create another parent layout and add this layout as its child,then setContentView for parentlayout and then ffindViewById my child layout.

this is the activity class code :

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
 public void button1Click(View view)
    {       
        EditText edittext1;
        Button button1;     
        button1 = (Button) view;
        button1.setBackgroundColor(Color.GRAY);
        edittext1 = (EditText) this.findViewById(R.id.editText1);
        edittext1.setText("Welcome !");
        RelativeLayout rlayout = (RelativeLayout) this.findViewById(R.layout.activity_main);
        rlayout.setBackgroundColor(Color.rgb((int)Math.random()*10,(int)Math.random()*10,(int)Math.random()*10));

    }

this is the xml :

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:onClick="button1Click"
        android:text="@string/button_click" />

    <EditText
        android:id="@+id/editText1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:ems="15"
        android:inputType="text" >

        <requestFocus />
    </EditText>

</RelativeLayout>

Upvotes: 0

Views: 5706

Answers (1)

Neoh
Neoh

Reputation: 16164

Add an id to the parent relative layout:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/activity_main"
    ...

    ...
</RelativeLayout>

Then change 

RelativeLayout rlayout = (RelativeLayout) this.findViewById(R.layout.activity_main);

to

RelativeLayout rlayout = (RelativeLayout) this.findViewById(R.id.activity_main);

Upvotes: 4

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