如何在设置片段中添加共享首选项并使用导航组件在 android kotlin 中的片段之间移动

分类：编程问答

如何解决如何在设置片段中添加共享首选项并使用导航组件在 android kotlin 中的片段之间移动

我不知道如何在设置片段中添加共享首选项，也不知道如何使用 android 导航组件在片段之间移动，用户可以在其中更改 API 键的“值”。这是我使用的 https://earthquake.usgs.gov/fdsnws/event/1/query?format=geojson&orderby=time&minmag=5&limit=10 API。从 API 中，我想更改 minmag 值，用户可以在设置片段中放置 minmag 的任何值，结果应保存在共享首选项中，并且结果应显示在主活动中{ {3}}

this is just a prototype of the setting fragment that i want to get

我正在使用 kotlin，改造并遵循 android 架构组件

EarthquakeApiService.kt

    private const val BASE_URL = "https://earthquake.usgs.gov/fdsnws/"

// https://earthquake.usgs.gov/fdsnws/event/1/query?format=geojson&orderby=time&minmag=5&limit=10
private val moshi = Moshi.Builder()
    .add(KotlinJsonAdapterFactory())
    .build()

private val retrofit = Retrofit.Builder()
    .addConverterFactory(MoshiConverterFactory.create(moshi))
    .baseUrl(BASE_URL)
    .build()

interface EarthquakeApiService {
    @GET("event/1/query?")
    suspend fun getJson (@Query("minmag") minMagnitude : String,@Query("format") formatted : String,@Query("limit") limited: String,@Query("orderby") orderBy : String) : EarthquakeResponse
}

object BookApi {
    val retrofitService : EarthquakeApiService by lazy { retrofit.create(EarthquakeApiService::class.java) }
}

地震响应.kt

    data class EarthquakeResponse( val features : Array<Feature> ?)

data class Feature( val properties : Properties)

data class Properties(val mag : Double,val place : String,val time : Long)

概览片段

   class OverviewFragment : Fragment() {

     private val viewModel: OverviewViewModel by lazy {
        ViewModelProvider(this).get(OverviewViewModel::class.java)
    }

    override fun onCreateView(
        inflater: LayoutInflater,container: ViewGroup?,savedInstanceState: Bundle?): View? {

        val binding: FragmentOverviewBinding = DataBindingUtil.inflate(
            inflater,R.layout.fragment_overview,container,false)
        binding.viewModel = viewModel
        binding.recycleList.adapter = RecyclerviewAdapter()

        binding.lifecycleOwner = this

        setHasOptionsMenu(true)
        return binding.root
    }

     override fun onCreateOptionsMenu(menu: Menu,inflater: MenuInflater) {
         super.onCreateOptionsMenu(menu,inflater)
         inflater?.inflate(R.menu.overflow_menu,menu)
     }

     override fun onOptionsItemSelected(item: MenuItem): Boolean {
         return NavigationUI.onNavDestinationSelected(item,requireView().findNavController())
                 || super.onOptionsItemSelected(item)
     }
}

概览视图模型

 class OverviewViewModel : ViewModel() {
      lateinit var  minMagnitude : String
     lateinit var orderBy: String
     // Internally,we use a MutableLiveData,because we will be updating the List of MarsProperty
    // with new values
    private val _properties = MutableLiveData<EarthquakeResponse> ()

    // The external LiveData interface to the property is immutable,so only this class can modify
    val properties: LiveData<EarthquakeResponse>
        get() = _properties
    init {
        getBookProperties()
    }

    private fun getBookProperties() {
        viewModelScope.launch {
            try {
                _properties.value = BookApi.retrofitService.getJson("2","geojson","10","time")
            } catch (e : Exception) {
            }
        }
    }
}

RecyclerviewAdapter.kt

 class RecyclerviewAdapter() : ListAdapter<Feature,RecyclerviewAdapter.EarthquakePropertyViewHolder>(DiffCallback()) {

    override fun onCreateViewHolder(parent: ViewGroup,viewType: Int): EarthquakePropertyViewHolder {
        return EarthquakePropertyViewHolder.from(parent)
    }

    override fun onBindViewHolder(holder: EarthquakePropertyViewHolder,position: Int) {
        val item = getItem(position)
        holder.bind(item)
    }
    class EarthquakePropertyViewHolder private constructor(val binding: EarthquakeRawBinding) : RecyclerView.ViewHolder(binding.root) {
        fun bind(books: Feature) {
            binding.property = books
            binding.executePendingBindings()
        }
        companion object {
            fun from(parent: ViewGroup): EarthquakePropertyViewHolder {
                val layoutInflater = LayoutInflater.from(parent.context)
                val view = EarthquakeRawBinding.inflate(layoutInflater,parent,false)
                return EarthquakePropertyViewHolder(view)
            }
        }
    }
}

class  DiffCallback : DiffUtil.ItemCallback<Feature>() {
    override fun areItemsTheSame(oldItem: Feature,newItem: Feature): Boolean {
        return oldItem === newItem
    }
    override fun areContentsTheSame(oldItem: Feature,newItem: Feature): Boolean {
        return oldItem == newItem

    }
}

BindingAdapter.kt

    @BindingAdapter("listData")
fun bindRecyclerView(recyclerView: RecyclerView,data: EarthquakeResponse?) {
    val adapter = recyclerView.adapter as RecyclerviewAdapter
    if (data != null) {
        adapter.submitList(data.features?.toList())
    }
}

@BindingAdapter("magnitude")
fun bindAuthor(textView: TextView,magName : Double) {
   val decimalFormat = DecimalFormat("0.0")
    val formattedMagnitude = decimalFormat.format(magName)
    textView.setText(formattedMagnitude.toString())
}

@BindingAdapter("place")
fun bindTitle(textView: TextView,titlePlace : String) {
    textView.setText(titlePlace)       
}

@BindingAdapter("time")
fun bindTime(textView: TextView,titleTime :Long) {
    val timeFormat = SimpleDateFormat("h:mm a")
    val formattedTime = timeFormat.format(titleTime)
    textView.setText(formattedTime.toString())
}

@BindingAdapter("date")
fun bindDate(textView: TextView,titleTime :Long) {
    val timeFormat = SimpleDateFormat("LLL dd,yyyy")
    val formattedDate = timeFormat.format(titleTime)
    textView.setText(formattedDate.toString())
}

主活动

 class MainActivity : AppCompatActivity() {

    private lateinit var navController: NavController
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
    }
}

activity_main.xml

 <RelativeLayout android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.kotlinearthquake.MainActivity"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:android="http://schemas.android.com/apk/res/android">

<fragment
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/myNavHostFragment"
    android:name="androidx.navigation.fragment.NavHostFragment"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:defaultNavHost="true"
    app:navGraph="@navigation/nav_graph"
    tools:ignore="MissingClass" />
</RelativeLayout>

earthquake_raw.xml

    <layout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto" >

    <data>
        <variable
            name="property"
            type="com.example.kotlinearthquake.network.Feature" />
    </data>

<LinearLayout
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="150dp"
    android:orientation="horizontal"
    android:paddingStart="16dp"
    android:paddingLeft="16dp"
    android:paddingEnd="16dp"
    android:paddingRight="16dp">

    <TextView
        android:id="@+id/magnitude"
        android:layout_width="36dp"
        android:layout_height="36dp"
        android:layout_gravity="center_vertical"
        android:background="@drawable/magnitude_circle"
        android:fontFamily="sans-serif-medium"
        android:gravity="center"
        android:textColor="@android:color/black"
        android:textSize="16sp"
        app:magnitude="@{property.properties.mag}"
        tools:text="8.9" />

    <LinearLayout
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_gravity="center_vertical"
        android:layout_marginStart="16dp"
        android:layout_marginLeft="16dp"
        android:layout_weight="1"
        android:orientation="vertical">

        <TextView
            android:id="@+id/location_offset"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:ellipsize="end"
            android:fontFamily="sans-serif-medium"
            android:maxLines="1"
            android:textAllCaps="true"
            android:textColor="@android:color/black"
            android:textSize="12sp"
            tools:text="30km S of\n" />

        <TextView

            android:id="@+id/primary_location"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:ellipsize="end"
            android:maxLines="2"
            android:textColor="@android:color/black"
            android:textSize="12sp"
            app:place="@{property.properties.place}"
            tools:text="Long placeholder that should wrap to more than 2 line of text" />

    </LinearLayout>

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_vertical"
        android:layout_marginStart="16dp"
        android:layout_marginLeft="16dp"
        android:orientation="vertical">

        <TextView
            android:id="@+id/date"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="end"
            android:textColor="@color/textColorEarthquakeDetails"
            android:textSize="12sp"
            app:date="@{property.properties.time}"
            tools:text="Mar 6,2010" />

        <TextView
            android:id="@+id/time"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="end"
            android:textColor="@color/textColorEarthquakeDetails"
            android:textSize="12sp"
            app:time="@{property.properties.time}"
            tools:text="3:00 PM" />
    </LinearLayout>
</LinearLayout>
</layout>

fragment_overview.xml

    <layout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto">

    <data>
        <variable
            name="viewModel"
            type="com.example.kotlinearthquake.overview.OverviewViewModel" />
    </data>


<RelativeLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context = "com.example.kotlinearthquake.MainActivity"
    >

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recycle_list"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
        app:listData="@{viewModel.properties}"
        tools:listitem="@layout/earthquake_raw"
        app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"/>


    <TextView
        android:id="@+id/empty_view"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:textAppearance="?android:textAppearanceMedium"/>

    <ProgressBar
        android:id="@+id/loading_indicator"
        style="@style/Widget.AppCompat.ProgressBar"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"/>

</RelativeLayout>
</layout>

我尝试过，但没有找到解决我的问题的任何好的答案..我从过去 1 个月开始就陷入困境，请帮助我，我还是 android 和 Kotlin 编程的新手。

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