Check current toolbar's subTitle and set valid subTitle

[ted-prnd]

Problem

• If I try set toolbar's subtitle in onCreate()(not xml), subtitle is not shown.
• sample code work, but I don't want use postDelay(), post() https://github.com/InflationX/Calligraphy/blob/881f11fe37491aee56ae155eb1ae4ff0599373ae/CalligraphySample/src/main/java/io/github/inflationx/calligraphy3/sample/MainActivity.java#L34

final Handler handler = new Handler(Looper.getMainLooper());
handler.postDelayed(new Runnable() {
    @Override
    public void run() {
        toolbar.setSubtitle("Added subtitle");
    }
}, 1000);

Reason

1. When activity start ToolbarLayoutListener get toolbar's original subTitle and set blank string https://github.com/InflationX/Calligraphy/blob/881f11fe37491aee56ae155eb1ae4ff0599373ae/calligraphy/src/main/java/io/github/inflationx/calligraphy3/Calligraphy.java#L231
2. After view shown, ToolbarLayoutListener set original subTitle to toolbar https://github.com/InflationX/Calligraphy/blob/881f11fe37491aee56ae155eb1ae4ff0599373ae/calligraphy/src/main/java/io/github/inflationx/calligraphy3/Calligraphy.java#L253

• But that is problem. set toolbar's subtitle in onCreate() is ignore.

Solution

• After view shown, ToolbarLayoutListener check toolbar's current subTitle.
• If toolbar's current subTitle is BLANK, use original subtitle.
• If toolbar's current subTitle is not BLANK, user set toolbar's subtitle. so toolbar use current subtitle.