Question

I downloaded latest ADT from the main website and it came with Eclipse. So, I set everything up fine > Start new Android project. Set my settings, and the Activity to “Blank Activity”, click finish.

Now, I go to the visual editor and add a button and some text. The problem is, is that “findViewById” is not detecting the button for some reason. Yes, I “Cleaned” the project and all that..

Here’s the xml portion:

<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"
    tools:context=".MainActivity" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentRight="true"
        android:layout_below="@+id/button1"
        android:layout_marginTop="37dp"
        android:textAppearance="?android:attr/textAppearanceMedium" />

    <EditText
        android:id="@+id/editText1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentRight="true"
        android:layout_alignParentTop="true"
        android:ems="10" >

        <requestFocus />
    </EditText>

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentRight="true"
        android:layout_below="@+id/editText1"
        android:layout_marginTop="52dp"
        android:text="@string/button" />

</RelativeLayout>

Here’s my source code:

package com.example.tcp;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.widget.Button;

public class MainActivity extends Activity {

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

        Button ibtn = (Button) findViewById(R.id.button1); // Error
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }
}

Answer 1

Did you actually save the activity_main.xml? View ID’s are not accessible to the rest of the project until you save the layout you’re working on.

I copied and pasted your code straight into a blank project and it worked fine after saving.