Set margin in style and apply that style to TextView programmatically

Question

In my application, I want to set top and bottom margin of 8 dip to a textview. So if I do it like -

<TextView
android:id="@+id/tv_text1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
style="@style/settings_plain_text"/>

it works fine where the style contents are -

<style name="settings_plain_text">
    <item name="android:layout_marginTop"> 8dip </item>
    <item name="android:layout_marginBottom"> 8dip </item>
    <item name="android:textSize"> 18sp </item>
</style>

But when I apply the same style to that textview programmatically like -

textview.setTextAppearance(context, R.style.settings_plain_text);

it does not show the top and bottom margin that I've set in style. Please help.

Answer 1

More simplified version of answered by Gianluca P.

public void applyTextStyle(TextView v, int styleResId)
{
    int[] attrs= new int[] {
            android.R.attr.layout_marginTop,     // 0
            android.R.attr.layout_marginLeft,    // 1
            android.R.attr.layout_marginBottom,   // 2 
            android.R.attr.layout_marginRight}; // 3 (used in example)
    final TypedArray arr =  this.obtainStyledAttributes(styleResId,attrs);
    try {
        ViewGroup.MarginLayoutParams lp = (ViewGroup.MarginLayoutParams) v.getLayoutParams();
        lp.topMargin = arr.getDimensionPixelSize(0,lp.topMargin);
        lp.leftMargin = arr.getDimensionPixelSize(1,lp.leftMargin);
        lp.bottomMargin = arr.getDimensionPixelSize(2,lp.bottomMargin);
        lp.rightMargin = arr.getDimensionPixelSize(3,lp.rightMargin);

        v.requestLayout();
    } finally {
        arr.recycle();
    }
}

Answer 2

setTextAppearence(..) only setups xml attributes with the prefix android:text_* but you can still write you own method that reads other attributes and sets them programmatically knowing the underlying LayoutParams implementation.

Please mind that you can use a ContextThemeWrapper for obtaining specific theme values or pass a syle resource id in .obtainStyledAttributes(..)

As an example:

int[] attrs= new int[] {
  android.R.attr.layout_marginTop,     // 0
  android.R.attr.layout_marginLeft,    // 1
  android.R.attr.layout_marginRight,   // 2 (used in example)
  android.R.attr.layout_marginBottom}; // 3
final TypedArray arr = context.obtainStyledAttributes(attrs);
try {
  // ...
  layoutParams.rightMargin = arr.getDimensionPixelSize(2);
  // ...
} finally {
  arr.recycle();
}