U.java

/**
 * Part of my utils class that I use in my apps.
 * Contains only functions related to showing snackbars and toasts.
 * Some string/resources are missing in this gist. Names of resources are self explanatory. Hence, it shouldn't be hard to define it in your resources.
 */
public class U {

    public static float density = 1;

    public static final int SNACK_DEFAULT = 0;
    public static final int SNACK_SUCCESS = 1;
    public static final int SNACK_ERROR = 2;

    static {
        density = (App.getContext() != null) ? App.getContext().getResources().getDisplayMetrics().density : 1;
    }

    public static int dp(double value) {
        if (value == 0) {
            return 0;
        }
        return (int) Math.ceil(density * value);
    }

    public static double px(int value) {
        if (value == 0) {
            return 0;
        }
        return Math.ceil(density / value);
    }

    /**
     * @param context context
     * @param string  string
     * @param gravity gravity. set -100 to not set
     */
    public static void showToast(Context context, String string, int gravity) {
        if (context == null) {
            return;
        }
        if (string == null || string.equals("")) {
            string = "null";
        }
        Toast toast = Toast.makeText(context, string, Toast.LENGTH_LONG);
        if (gravity != - 100) {
            toast.setGravity(gravity, 0, 0);
        }
        toast.show();
    }

    public static void showCenteredToast(Context context, String string) {
        showToast(context, string, Gravity.CENTER);
    }

    public static void showCenteredToast(Context context, @StringRes int stringRes) {
        showCenteredToast(context, context.getString(stringRes));
    }

    /**
     * Show {@link Snackbar}
     *
     * @param view           The view to find a parent from.
     * @param stringResource The resource id of the string resource to use. Can be formatted text. Lower than 0 if not specified
     * @param stringMessage  The text to show. Can be formatted text. null if not specified
     * @param style          color of snack text DEFAULT, SUCCESS, ERROR
     * @return showed instance of snackbar. Set actions or hide.
     */
    public static Snackbar addSnack(View view, @StringRes
        int stringResource, String stringMessage, int style) {
        try {
            Snackbar snackbar = null;
            if (view != null && (stringMessage != null || stringResource > 0)) {
                if (stringResource > 0) {
                    snackbar = Snackbar.make(view, stringResource, Snackbar.LENGTH_LONG);
                } else if (stringMessage != null) {
                    snackbar = Snackbar.make(view, stringMessage, Snackbar.LENGTH_LONG);
                }

                if (snackbar != null) {
                    // https://github.com/roughike/BottomBar/issues/442
                    displaySnackBarWithBottomMargin(snackbar, 0, dp(51));

                    if (style > SNACK_DEFAULT) {
                        TextView snackText = (TextView) snackbar.getView().findViewById(android.support.design.R.id.snackbar_text);
                        if (style == SNACK_SUCCESS) {
                            snackText.setTextColor(view.getContext().getResources().getColor(R.color.green));
                        }
                        if (style == SNACK_ERROR) {
                            snackText.setTextColor(view.getContext().getResources().getColor(R.color.red_light));
                        }
                    }
                    snackbar.show();
                }
            }
            return snackbar;
        } catch (Exception e) {
            if (stringMessage != null || stringResource > 0) {
                if (stringResource > 0) {
                    showCenteredToast(stringResource);
                } else if (stringMessage != null) {
                    showCenteredToast(stringMessage);
                }
            }
            return null;
        }
    }

    public static Snackbar addSnack(View view, @StringRes int stringResource, int style) {
        return addSnack(view, stringResource, null, style);
    }

    public static Snackbar addSnack(View view, String stringMessage, int style) {
        return addSnack(view, - 1, stringMessage, style);
    }

    public static Snackbar addError(View view, @StringRes int stringResource) {
        return addSnack(view, stringResource, null, SNACK_ERROR);
    }

    public static Snackbar addError(View view, String stringMessage) {
        return addSnack(view, - 1, stringMessage, SNACK_ERROR);
    }

    public static Snackbar addNetworkError(View view) {
        return addSnack(view, R.string.error_network, SNACK_ERROR);
    }

    public static Snackbar addUnknownError(View view) {
        return addSnack(view, R.string.error, SNACK_ERROR);
    }

    public static void displaySnackBarWithBottomMargin(Snackbar snackbar, int sideMargin, int marginBottom) {
        final View snackBarView = snackbar.getView();
        final CoordinatorLayout.LayoutParams params = (CoordinatorLayout.LayoutParams) snackBarView.getLayoutParams();

        params.setMargins(params.leftMargin + sideMargin,
            params.topMargin,
            params.rightMargin + sideMargin,
            params.bottomMargin + marginBottom);

        snackBarView.setLayoutParams(params);
    }
}