在startActivityForResult之后隐藏警报对话框

Question

我有一个启动警报对话框的主要活动，在警告对话框中我有一个按钮，启动另一个活动来选择文件，在选择文件并隐藏文件选择器活动后，原始警报对话框也会隐藏用户实际上无法单击警报对话框的“确定”按钮。知道为什么会这样吗？

public class PlaceholderFragment extends Fragment {

    @Override
    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
        MenuInflater inflater = getActivity().getMenuInflater();
        if(v.getId() == R.id.zoneImageContainer)
            inflater.inflate(R.menu.zone_menu, menu);
        else if(v instanceof RadioButton)
        {
            menuRadio = (RadioButton)v;
            inflater.inflate(R.menu.key_menu, menu);
        }
    }

    @Override
    public boolean onContextItemSelected(MenuItem item) {
        switch(item.getItemId())
        {
            case R.id.editZoneMenuItem:
                showEditZoneDialog();
                break;
            case R.id.newZoneMenuItem:
                break;
            case R.id.deleteZoneMenuItem:
                break;

            case R.id.editKeyMenuItem:
                showEditKeyDialog(menuRadio);
                break;
            case R.id.newKeyMenuItem:
                showNewKeyDialog();
                break;
            case R.id.deleteKeyMenuItem:
                break;
        }
        return true;
    }

    public void showEditZoneDialog(){
        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
        builder.setTitle("Zone Details:");
        builder.setCancelable(false);

        LayoutInflater inflater = LayoutInflater.from(getActivity());
        View view = inflater.inflate(R.layout.fragment_zone_dialog, null);
        builder.setView(view);

        final ImageButton imageButton = (ImageButton)view.findViewById(R.id.imageButton);
        final Button houseAddressButton = (Button)view.findViewById(R.id.housePickerButton);
        final EditText nameText = (EditText)view.findViewById(R.id.nameEditText);
        final TextView addressText = (TextView)view.findViewById(R.id.addressTextView);

    .
    .
    .

        houseAddressButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
        .
        .
        .
            }
        });

        imageButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(getActivity(), FileDialog.class);
                intent.putExtra(FileDialog.START_PATH, Environment.DIRECTORY_DCIM);
                intent.putExtra(FileDialog.CAN_SELECT_DIR, false);
                intent.putExtra(FileDialog.SELECTION_MODE, SelectionMode.MODE_OPEN);
                intent.putExtra(FileDialog.FORMAT_FILTER,
                        new String[] { "png", "jpg", "jpeg", "bmp", "gif" });
                getActivity().startActivityForResult(intent, 1);
            }
        });

        // Set up the buttons
        builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
        .
        .
        .
                dialog.dismiss();
            }
        });
        builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                dialog.cancel();
            }
        });

        builder.show();
    }
}