Android 在显示 ProgressDialog 时出现错误

Question

I have an Activity where I want to show a ProgressDialog. I override onCreateDialog in my Activity. Everytime the dialog returns in onCreateDialog I get an force-close, saying:

07-13 13:10:11.449: ERROR/AndroidRuntime(8720): android.util.AndroidRuntimeException:     requestFeature() must be called before adding content
07-13 13:10:11.449: ERROR/AndroidRuntime(8720):     at com.android.internal.policy.impl.PhoneWindow.requestFeature(PhoneWindow.java:181)
07-13 13:10:11.449: ERROR/AndroidRuntime(8720):     at com.android.internal.app.AlertController.installContent(AlertController.java:199)
07-13 13:10:11.449: ERROR/AndroidRuntime(8720):     at android.app.AlertDialog.onCreate(AlertDialog.java:251)
07-13 13:10:11.449: ERROR/AndroidRuntime(8720):     at android.app.ProgressDialog.onCreate(ProgressDialog.java:176)
07-13 13:10:11.449: ERROR/AndroidRuntime(8720):     at android.app.Dialog.dispatchOnCreate(Dialog.java:307)
07-13 13:10:11.449: ERROR/AndroidRuntime(8720):     at android.app.Activity.createDialog(Activity.java:886)
07-13 13:10:11.449: ERROR/AndroidRuntime(8720):     at android.app.Activity.showDialog(Activity.java:2557)
07-13 13:10:11.449: ERROR/AndroidRuntime(8720):     at     android.app.Activity.showDialog(Activity.java:2524)

the onCreateDialog(int id) looks like this:

    protected Dialog onCreateDialog(int id){
    switch (id) {
    case DOWNLOAD_DIALOG:
        ProgressDialog dialog = new ProgressDialog(ListMapActivity.this);
        dialog.setTitle(getResources().getString(R.string.dialog_download_title));
        dialog.setCancelable(true);
        dialog.setOnCancelListener(new OnCancelListener() {

            @Override
            public void onCancel(DialogInterface dialog) {
                if ((mTask.getStatus().equals(AsyncTask.Status.RUNNING) 
                    || mTask.getStatus().equals(AsyncTask.Status.PENDING)) 
                    && !mTask.isCancelled()){
                    mTask.cancel(true);
                }
                Toast.makeText(getApplicationContext(), R.string.dialog_download_cancel, Toast.LENGTH_LONG).show();
            }
        });         
        TextView tw = new TextView(ListMapActivity.this);
        dialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
        LayoutParams params = new ViewGroup.LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT);
        tw.setLayoutParams(params);
        tw.setText(getResources().getString(R.string.dialog_download_text));
        dialog.setContentView(tw);


        return dialog;

    default:
        return null;
    }
}

Note: I tried ProgressDialog.Show(context, title, message) to execute directly instead of showDialog(), with this result:

07-13 13:03:42.910: ERROR/AndroidRuntime(8444): android.view.WindowManager$BadTokenException: Unable to add window -- token null is not for an application
07-13 13:03:42.910: ERROR/AndroidRuntime(8444):     at android.view.ViewRoot.setView(ViewRoot.java:531)
07-13 13:03:42.910: ERROR/AndroidRuntime(8444):     at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:177)
07-13 13:03:42.910: ERROR/AndroidRuntime(8444):     at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91)
07-13 13:03:42.910: ERROR/AndroidRuntime(8444):     at android.app.Dialog.show(Dialog.java:241)
07-13 13:03:42.910: ERROR/AndroidRuntime(8444):     at android.app.ProgressDialog.show(ProgressDialog.java:107)
07-13 13:03:42.910: ERROR/AndroidRuntime(8444):     at android.app.ProgressDialog.show(ProgressDialog.java:90)
07-13 13:03:42.910: ERROR/AndroidRuntime(8444):     at android.app.ProgressDialog.show(ProgressDialog.java:85)

I assume I forget something to initialize. I don't even know where this requestFeature() is been called. Any Idea is welcome

UPDATE: I played around a little bit and found out, that everything works again, if I delete these lines:

        LayoutParams params = new ViewGroup.LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT);
        tw.setLayoutParams(params);
        tw.setText(getResources().getString(R.string.dialog_download_text));
        dialog.setContentView(tw);

So I'm lost on how to set the Content of this View. It doesn't help, when I create the Main-design in onCreate of my Activity as a member and put this into ProgressDialog. I simply don't get the problem. What is wrong putting a TextView on-the-fly to put it as Content from my Dialog?

Answer 1

simply try this.

ProgressDialog dialog = ProgressDialog.show(yourActivity.this, "", 
                        "Loading. Please wait...", true);  

Thanks.

Answer 2

This error message requestFeature() must be called before adding content means that you are invoking a method on the dialog, that you aren't allowed to invoke after you had added content.

I would move these lines:

dialog.setCancelable(true);
dialog.setTitle(getResources().getString(R.string.dialog_download_title));

So that they are before this line:

dialog.setContentView(tw);

setTitle is your most likely candidate for the error.