如何使用导航类型 safeargs 插件将 Parcelable 类型的对象传递给 Fragment

Question

I am rewriting my simple UI app to use Navigation architecture component, I need to pass a Pojo that implements Parcelable, have not seen any doc on how to do that.

Any help would be appreciated.

Answer 1

Since safe-args-gradle-plugin:1.0.0-alpha03 you can use Parcelable objects by using their fully qualified class name:

<argument
    android:name="item"
    app:argType="com.example.app.model.Item"/>

Parcelable arguments are now supported, using a fully qualified class name for app:type. The only default value supported is "@null" ( https://issuetracker.google.com/issues/79563966 )

Source: https://developer.android.com/jetpack/docs/release-notes

---

To support nullability one has to use android:defaultValue="@null" with app:nullable="true" .

Answer 2

I know the answer is already there but this may help someone. Code snippet

In build.gradle add this dependancy

ext{
     ...
     navigation_version = '1.0.0-alpha11'
}
dependencies {
     ...
     classpath "android.arch.navigation:navigation-safe-args-gradle-plugin:$navigation_version"
}

In app/build.gradle

apply plugin: 'androidx.navigation.safeargs'
...

In Navigation graph

 <fragment
            android:id="@+id/source_fragment_id"
            android:name="app.test.SourceFragment"
            android:label="@string/source_fragment_label"
            tools:layout="@layout/source_fragment_layout">

         <action
                android:id="@+id/action_source_fragment_to_destination_fragment"
                app:destination="@id/destination_fragment_id"
                ...
                />


</fragment>

<fragment
            android:id="@+id/destination_fragment_id"
            android:name="app.test.DestinationFragment"
            android:label="@string/destination_fragment_label"
            tools:layout="@layout/destination_fragment_layout">

        <argument
                android:name="variableName"
                app:argType="app.test.data.model.CustomModel" />

        ...

</fragment>

Note: CustomModel should be Parcelable or Serializable.

When navigating to this DestinationFragment from SourceFragment

val direction = SourceFragmentDirections.ActionSourceFragmentToDestinationFragment(customModel)
findNavController().navigate(direction)

Now retrieving the value from bundle in DestinationFragment

...
import app.test.DestinationFragmentArgs.fromBundle

class DestinationFragment : Fragment() {
   val variableName by lazy {
       fromBundle(arguments!!).variableName
   }

   ...
   override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
        Log.e(DESTINATION_FRAGMENT_TAG,"onCreateView")

        //Can use CustomModel variable here i.e. variableName


   }

}

Answer 3

Right now you can't use safe args with types apart from integer , string , inferred and reference , there's an issue opened asking for other types.

What you can do now is to normally pass a bundle when using the navigate() method to navigate to a destination:

var bundle = bundleOf("amount" to amount)
view.findNavController().navigate(R.id.confirmationAction, bundle)

And you can use the usual getArguments (or just arguments in kotlin) to retrieve that:

val tv = view.findViewById(R.id.textViewAmount)
tv.text = arguments.getString("amount")

Answer 4

You can use boolean , reference , integer , long , string , enum , parcelable and even serializable . But forget about the last one ;-)

Better use the latest plugin version safe-args-gradle-plugin:1.0.0-alpha08 and specify the fully qualified classname:

<fragment
    ...>
    <argument
        android:name="data"
        app:argType="com.example.ParcelableData" />
</fragment>

from your

package com.example

data class ParcelableData(val content: String) : Parcelable { ... }

And you can send arrays of all the argType s:

<argument
        android:name="data"
        app:argType="string[]" />