What does the XML for your res/layout/main.xml look like?
Thanks,
Justin
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On Mon, Oct 12, 2009 at 9:28 AM, Sven <koff...@gmail.com> wrote:
>
> Hi,
>
>
> I want to add an ImageView to my layout when a button has been
> pressed. Sadly, I cannot get a handle to the main application's
> linearlayout, I always get a null pointer error when trying to
> retrieve the layout using findViewByID.
>
> Here's the code that ought to display the image when button b has been
> pressed, but I think I have missed something obious:
>
> package com.foo.bar;
>
> import android.app.*;
> import android.os.Bundle;
> import android.view.*;
> import android.view.ViewGroup.LayoutParams;
> import android.widget.*;
> import android.content.*;
> import android.util.Log;
>
>
> public class AndroidTest extends Activity {
> /** Called when the activity is first created. */
> @Override
> public void onCreate(Bundle savedInstanceState) {
> super.onCreate(savedInstanceState);
> setContentView(R.layout.main);
>
> // assign flag.png to the button, loading correct flag image for
> current locale
> Button b;
> b = (Button)findViewById
> (R.id.flag_button) ;//.setBackgroundDrawable(this.getResources
> ().getDrawable(R.drawable.developers));
>
> // build dialog box to display when user clicks the flag
> AlertDialog.Builder builder = new AlertDialog.Builder(this);
> builder.setMessage(R.string.dialog_text)
> .setCancelable(false)
> .setTitle(R.string.dialog_title)
> .setPositiveButton("Done", new
> DialogInterface.OnClickListener() {
> public void onClick(DialogInterface dialog, int id) {
> dialog.dismiss();
> }
> });
> final AlertDialog alert = builder.create();
>
> // set click listener on the flag to show the dialog box
> b.setOnClickListener(new View.OnClickListener() {
> public void onClick(View v) {
> // alert.show();
> ImageView image;
> image = new ImageView(v.getContext());
> image.setImageDrawable(v.getResources().getDrawable
> (R.drawable.developers));
>
>
> LinearLayout main = (LinearLayout)
> AndroidTest.this.findViewById(R.layout.main);
> // some debug code
> if (main == null)
> {
> Log.v("abc", "Main is null");
> }
> else
> {
> main.addView(image, 200, 200);
> }
> }
> });
>
> }
> }
>
> >
>
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