为什么我的switch语句会报错啊？

switch(item.getItemId()){

    case 1:

    Toast.makeText(MainActivity.this, "点击复制", Toast.LENGTH_LONG).show();

    break;

    case 2:

    Toast.makeText(MainActivity.this, "点击粘贴", Toast.LENGTH_LONG).show();

    break;

    case 3:

    Toast.makeText(MainActivity.this, "点击剪切", Toast.LENGTH_LONG).show();

    break;

    case 4:

    Toast.makeText(MainActivity.this, "点击呵呵", Toast.LENGTH_LONG).show();

    break;

    }

电脑让我直接删掉这段代码