Java 无法解析符号'；项目'；

我试图使我的菜单项转到不同的活动，所以我试图覆盖每个活动上选择的OnOptions项，但我得到了这个错误

还可以在每一个“R.id.ItemX”案例中获得“需要常量表达式”

用这个

menu.getItemId()

而不是这个

item.getItemId()

示例代码

@Override
    public boolean onOptionsItemSelected(MenuItem menu){

        switch (menu.getItemId()){ // ERROR IS HERE ON THE WORD 'item', THE REST WORKS FINE.

            Intent goToNextActivity = new Intent(getApplicationContext(), MainActivity.class);

            case R.id.Item1:

                goToNextActivity = new Intent(getApplicationContext(), MainActivity.class);
                startActivity(goToNextActivity);
                break;

            case R.id.Item2:

                goToNextActivity = new Intent(getApplicationContext(), VidPage.class);
                startActivity(goToNextActivity);
                break;

            case R.id.Item3:

                goToNextActivity = new Intent(getApplicationContext(), DatePage.class);
                startActivity(goToNextActivity);
                break;


        }

        return true;
    }

用这个

menu.getItemId（）

---

这将返回您的项目id，

也会建议这样做<代码>项不在问题中定义的方法范围内<代码>菜单类型

菜单项

是如何声明

项

的？它没有在您的方法中声明。

@Override
    public boolean onOptionsItemSelected(MenuItem menu){

        switch (menu.getItemId()){ // ERROR IS HERE ON THE WORD 'item', THE REST WORKS FINE.

            Intent goToNextActivity = new Intent(getApplicationContext(), MainActivity.class);

            case R.id.Item1:

                goToNextActivity = new Intent(getApplicationContext(), MainActivity.class);
                startActivity(goToNextActivity);
                break;

            case R.id.Item2:

                goToNextActivity = new Intent(getApplicationContext(), VidPage.class);
                startActivity(goToNextActivity);
                break;

            case R.id.Item3:

                goToNextActivity = new Intent(getApplicationContext(), DatePage.class);
                startActivity(goToNextActivity);
                break;


        }

        return true;
    }