android - 如何处理 NavController 目标更改？

Question

我想实现 addOnDestinationChangedListener 但是，没有运气。我试过自己实现它，但是 id 不匹配

NavController mController = Navigation.findNavController(this, R.id.nav_auth_fragment);
mController.addOnDestinationChangedListener((controller, destination, arguments) -> {
    switch (destination.getId()){
        case R.id.action_loginFragment_to_numberEntryFragment:
            Toast.makeText(this, "Welcome to number Entry", Toast.LENGTH_SHORT).show();
            break;
        case R.id.action_numberEntryFragment_to_otpFragment:
            Toast.makeText(this, "Enter your OTP", Toast.LENGTH_SHORT).show();
            break;
        case R.id.action_otpFragment_to_userRegistrationFragment:
            Toast.makeText(this, "Your number is verified!", Toast.LENGTH_SHORT).show();
            break;
        default:
            break;
    }
});

我尝试记录它，这是结果

2019-11-04 11:39:17.179 26830-26830/com.example.myapp D/AuthActivity: 2131230930 == 2131230775 = false
2019-11-04 11:39:17.179 26830-26830/com.example.myapp D/AuthActivity: 2131230930 == 2131230781 = false
2019-11-04 11:39:17.180 26830-26830/com.example.myapp D/AuthActivity: 2131230930 == 2131230782 = false
where 2131230930 is the destination.getId() and (2131230775, 2131230781, 2131230782) is the resource ids
even when I'm at the destination, the id still doesn't match with the resource id

Answer 1

您正在使用R.id.action_numberEntryFragment_to_otpFragment- 即您正在使用的操作的 ID 。但是，OnDestinationChangedListener接收到您最终实际要去的目的地app:destination的 ID -即<action>.

因此，您应该使用目标 ID（只是猜测您的目标 ID 是什么）：

mController.addOnDestinationChangedListener((controller, destination, arguments) -> {
    switch (destination.getId()){
        case R.id.numberEntryFragment:
            Toast.makeText(this, "Welcome to number Entry", Toast.LENGTH_SHORT).show();
            break;
        case R.id.otpFragment:
            Toast.makeText(this, "Enter your OTP", Toast.LENGTH_SHORT).show();
            break;
        case R.id.userRegistrationFragment:
            Toast.makeText(this, "Your number is verified!", Toast.LENGTH_SHORT).show();
            break;
        default:
            break;
    }
});