Android : How to set same drawable selector xml for more than 2 views

Question

Suppose there are 2 ImageButtons.Now, to display the image based on its state, I should write a selector xml for each of the ImageButton. Can we write a same selector for both the views.Because my app have a lot of buttons and have to write a selector xml for each of the view. Can we optimize it?

Answer 1

if you you try it with xml file then you must create each selector for each button.

So try to do dynamically either by subclassing the StateListDrawable or try the below code which creates selector dynamically:::

StateListDrawable states = new StateListDrawable();
states.addState(new int[] {android.R.attr.state_pressed},
    getResources().getDrawable(R.drawable.pressed));
states.addState(new int[] {android.R.attr.state_focused},
    getResources().getDrawable(R.drawable.focused));
states.addState(new int[] { },
    getResources().getDrawable(R.drawable.normal));
imageView.setImageDrawable(states);

Answer 2

You don't have to create a xml selector for each of your buttons, just re-use the one that fits. I use the following code in my project for many buttons with the selector and other attributes that are the same.

<LinearLayout android:id="@+id/group_news" style="@style/main_button_group" >
    <ImageView android:id="@+id/image_news" style="@style/main_button_image" android:src="@drawable/news" />
    <TextView android:id="@+id/text_news" style="@style/main_button_text" android:text="@string/button_news" />
</LinearLayout>

(Note: I use a LinearLayout with an ImageView and a TextView and not a TextView with the drawableLeft attribute, because I'm replacing the Images in code. Changing the drawableLeft was not working properly)

And then create an styles.xml in the res\values folder with all attribures that are the same for those buttons like:

<resources>
    <style name="main_button_group">
        <item name="android:layout_width">fill_parent</item>
        <item name="android:layout_height">wrap_content</item>
        <item name="android:orientation">horizontal</item>
        <item name="android:layout_marginTop">2dp</item>
        <item name="android:paddingTop">10dp</item>
        <item name="android:paddingBottom">10dp</item>
        <item name="android:paddingRight">10dp</item>
        <item name="android:paddingLeft">25dp</item>
        <item name="android:background">@drawable/main_button_states</item>
        <item name="android:focusable">true</item>
        <item name="android:clickable">true</item>
    </style>
    <style name="main_button_image">
        <item name="android:layout_width">wrap_content</item>
        <item name="android:layout_height">wrap_content</item>
        <item name="android:layout_gravity">center_vertical</item>
        <item name="android:contentDescription">@string/empty</item>
    </style>
    <style name="main_button_text">
        <item name="android:layout_width">fill_parent</item>
        <item name="android:layout_height">wrap_content</item>
        <item name="android:layout_margin">10dp</item>
        <item name="android:layout_gravity">center_vertical</item>
        <item name="android:gravity">center_horizontal</item>
        <item name="android:textSize">20dp</item>
        <item name="android:textColor">@color/general_value</item>
    </style>
</resources>

The selector @drawable/main_button_states looks like this:

<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_pressed="true" android:drawable="@drawable/main_button_pressed" />
    <item android:state_focused="true" android:drawable="@drawable/main_button_focused" />
    <item android:state_hovered="true" android:drawable="@drawable/main_button_focused" />
    <item android:drawable="@drawable/main_button_normal" />
</selector>

This works perfectly.