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

标签： androidandroid-jetpackandroid-jetpack-navigation

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;
    }
});