How to change progress bar's progress color in Android

For a horizontal ProgressBar, you can use a ColorFilter, too, like this:

progressBar.getProgressDrawable().setColorFilter(
    Color.RED, android.graphics.PorterDuff.Mode.SRC_IN);

Note: This modifies the appearance of all progress bars in your app. To only modify one specific progress bar, do this:

Drawable progressDrawable = progressBar.getProgressDrawable().mutate();
progressDrawable.setColorFilter(Color.RED, android.graphics.PorterDuff.Mode.SRC_IN);
progressBar.setProgressDrawable(progressDrawable);

If progressBar is indeterminate then use getIndeterminateDrawable() instead of getProgressDrawable().

Since Lollipop (API 21) you can set a progress tint:

progressBar.setProgressTintList(ColorStateList.valueOf(Color.RED));

This is not programmatically but I think it could help a lot of people anyway.
I tried a lot and the most efficient way was to add this lines to my ProgressBar in the .xml File:

            android:indeterminate="true"
            android:indeterminateTintMode="src_atop"
            android:indeterminateTint="@color/secondary"

So in the end this code did it for me:

<ProgressBar
            android:id="@+id/progressBar"
            style="?android:attr/progressBarStyleLarge"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerHorizontal="true"
            android:layout_centerVertical="true"
            android:layout_marginTop="50dp"
            android:layout_marginBottom="50dp"
            android:visibility="visible"
            android:indeterminate="true"
            android:indeterminateTintMode="src_atop"
            android:indeterminateTint="@color/secondary">

This solution works for API 21+

I'm sorry that it's not the answer, but what's driving the requirement setting it from code ? And .setProgressDrawable should work if it's defined correctly

<layer-list xmlns:android="http://schemas.android.com/apk/res/android">

<item android:id="@android:id/background">
    <shape>
        <corners android:radius="5dip" />
        <gradient
                android:startColor="#ff9d9e9d"
                android:centerColor="#ff5a5d5a"
                android:centerY="0.75"
                android:endColor="#ff747674"
                android:angle="270"
        />
    </shape>
</item>

<item android:id="@android:id/secondaryProgress">
    <clip>
        <shape>
            <corners android:radius="5dip" />
            <gradient
                    android:startColor="#80ffd300"
                    android:centerColor="#80ffb600"
                    android:centerY="0.75"
                    android:endColor="#a0ffcb00"
                    android:angle="270"
            />
        </shape>
    </clip>
</item>

<item android:id="@android:id/progress">
    <clip>
        <shape>
            <corners
                android:radius="5dip" />
            <gradient
                android:startColor="@color/progress_start"
                android:endColor="@color/progress_end"
                android:angle="270" 
            />
        </shape>
    </clip>
</item>

</layer-list>