private long firstTime; @Override public void onBackPressed() { long secondTime = System.currentTimeMillis(); if (secondTime - firstTime > 2000) { SnackbarManager.show(com.nispok.snackbar.Snackbar.with(getApplicationContext()).text("再按一次退出"), this); firstTime = secondTime; } else { finish(); } } SnackbarManager报错可以在buld.gradle里面dependencies添加一行compile "com.nispok:snackbar:2.11.0"