按back键后台运行

//region 按back键后台运行

    @Override

    public boolean onKeyDown(int keyCode, KeyEvent event) {

        if (keyCode == KeyEvent.KEYCODE_BACK) {

            Intent home = new Intent(Intent.ACTION_MAIN);

            home.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);

            home.addCategory(Intent.CATEGORY_HOME);

            startActivity(home);

            return true;

        }

        return super.onKeyDown(keyCode, event);

    }

    //endregion