This code working fine for me
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends Activity {
Button btnClick = null;
TextView txtView = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btnClick = (Button) findViewById(R.id.btnClick);
txtView = (TextView) findViewById(R.id.txtView);
btnClick.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
txtView.setText("MP 204");
}
});
}
}
the layout file
<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" >
<Button
android:id="@+id/btnClick"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:text="ClickMe" />
<TextView
android:id="@+id/txtView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/btnClick"
android:layout_alignParentRight="true"
android:layout_below="@+id/btnClick"
android:text="@string/hello_world" />
</RelativeLayout>