Android: Prevent different spinner heights (empty and filled)

Question

I have some spinners on the layout and use loader to load their data from db in background. The problems is that empty spinners have smaller height until the data are loaded. So the layout jump.

How can I prevent this jumping?

Edit (added spinner row layouts)

Spinner row:

<?xml version="1.0" encoding="utf-8"?>
    <TextView xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/Text1"
        style="@style/StyleSpinner"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

Spinner drop down row:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:padding="@dimen/style_spinner_row_padding" >

    <TextView
        android:id="@+id/Text1"
        style="@style/StyleSpinnerDropDownRow1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true" />

    <TextView
        android:id="@+id/Text2"
        style="@style/StyleSpinnerDropDownRow2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_below="@+id/Text1" />

</RelativeLayout>

Assigned styles:

<!-- // Spinner // -->
<style name="StyleSpinner" parent="AppTheme">
    <item name="android:textStyle">bold</item>
    <item name="android:gravity">start</item>
    <item name="android:textSize">@dimen/default_text_size_normal</item>
    <item name="android:padding">@dimen/style_spinner_row_padding</item>
</style>

<style name="StyleSpinnerDropDownRow1" parent="AppTheme">
    <item name="android:textStyle">bold</item>
    <item name="android:textSize">@dimen/default_text_size_normal</item>
</style>

<style name="StyleSpinnerDropDownRow2" parent="AppTheme">
    <item name="android:textStyle">normal</item>
    <item name="android:textSize">@dimen/default_text_size_small</item>
</style>

Screen shots:

Answer 1

I've just had this same issue and managed to fix it for myself so here's what I did.

I am inflating android.R.layout.simple_spinner_dropdown_item in my spinner adapter for each item layout. When I looked at this layout I noticed it had no margins but just a set height which was coming from android:attr/dropdownListPreferredItemHeight.

So I thought I'd get this list preferred item height value programatically and set it as my spinners minimum height. Using the answer to this stackoverflow question I was able to get the correct value and set it to my spinner.

    android.util.TypedValue value = new android.util.TypedValue();
    getActivity().getTheme().resolveAttribute(android.R.attr.listPreferredItemHeight, value, true);
    android.util.DisplayMetrics metrics = new android.util.DisplayMetrics();
    getActivity().getWindowManager().getDefaultDisplay().getMetrics(metrics);
    float ret = value.getDimension(metrics);

    mSpinner.setMinimumHeight((int) (ret - 1 * metrics.density));

I've removed 1dip because it seems that the returned value has been rounded up which makes it 1 pixel too high.

Now all my spinner are the same height, whether they have items or are empty.

Answer 2

To prevent the heights changing from when I load it in the background I just created a none array and in the xml set the entries to it:

In array.xml

 <string-array name="none">
        <item></item>
 </string-array>

In the spinners

android:entries:@array/none

The heights do not change because once the loader finishes it replaces the contents of the spinner anyway.

Answer 3

I used an arrayAdapter<String> with an empty array.

After you have got what you need just get a new adapter or use the same adapter and call notifyDataSetChanged().