[Android] - 改變ToolBar左側的返回建顏色

除了一開始建立Project的顏色之外，在Code裡面改變顏色的方法：

final Drawable upArrow = getResources().getDrawable(R.drawable.abc_ic_ab_back_mtrl_am_alpha);
upArrow.setColorFilter(getResources().getColor(R.color.color_name), PorterDuff.Mode.SRC_ATOP);
getSupportActionBar().setHomeAsUpIndicator(upArrow);

不過這邊用的getDrawable跟getColor都快被棄用了，
也許以後要改成這樣：

final Drawable upArrow = getResources().getDrawable(R.drawable.abc_ic_ab_back_mtrl_am_alpha, getApplicationContext().getTheme());
upArrow.setColorFilter(getResources().getColor(R.color.color_name, getApplicationContext().getTheme()), PorterDuff.Mode.SRC_ATOP);
getSupportActionBar().setHomeAsUpIndicator(upArrow);

參考資料
http://stackoverflow.com/questions/26788464/how-to-change-color-of-the-back-arrow-in-the-new-material-theme