我正在制作一个应用程序，显示用户附近的道路施工，我已经实现了一张地图和一个带有三个选项的微调框，我希望我的微调框索引来确定地图的缩放程度。当我编译代码时，它将放大到默认缩放设置，但是当我从下拉列表中选择另一个选项时，什么也没有发生。
这是我的地图回调
` private val callback = OnMapReadyCallback { googleMap ->
/**
* Manipulates the map once available.
* This callback is triggered when the map is ready to be used.
* This is where we can add markers or lines, add listeners or move the camera.
* In this case, we just add a marker near Sydney, Australia.
* If Google Play services is not installed on the device, the user will be prompted to
* install it inside the SupportMapFragment. This method will only be triggered once the
* user has installed Google Play services and returned to the app.
*/
val (latitude, longitude) = getLocation()
currentLocation = LatLng(latitude, longitude)
googleMap.addMarker(MarkerOptions().position(currentLocation).title("Current location"))
//Moves the camera to users position with the zoom level
googleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(currentLocation, selectedZoomLevel))
}`
这是我在项目选定侦听器上的微调器
binding.searchSpinner.onItemSelectedListener = object : AdapterView.OnItemSelectedListener {
override fun onItemSelected(
parent: AdapterView<*>?,
view: View?,
position: Int,
id: Long
) {
//gets the array of items for the spinner
val spinnerItems = resources.getStringArray(R.array.spinner_items)
// Zoom levels based off of my spinner items
val zoomLevels = mapOf(
"10 km" to 12.0f,
"25 km" to 8.0f,
"50 km" to 2.0f
)
// Retrieve selected item and make it a string
val selectedItem = binding.searchSpinner.selectedItem.toString()
// Sets the zoom level based on selected item, otherwise default to 12.0f
selectedZoomLevel = zoomLevels[selectedItem] ?: 12.0f
// Call showToastWithIndex with the selected position
showToastWithIndex(requireContext(), spinnerItems, position)
}
moveCamera()animateCamera()onItemSelectedListener首先，您需要确保使用
lateinitprivate lateinit var gMap: GoogleMap
然后在地图中插入
GoogleMapoverride fun onMapReady(googleMap: GoogleMap) {
gMap = googleMap
//..other code..//
}
还有其他方法可以做到这一点，例如将
googleMaponItemSelectedListener因此，完成此操作后，您可以在
moveCamera()animateCamera()onItemSelectedListener您提供的
onItemSelectedListenerbinding.searchSpinner.onItemSelectedListener = object : AdapterView.OnItemSelectedListener {
override fun onItemSelected(
parent: AdapterView<*>?,
view: View?,
position: Int,
id: Long
) {
//gets the array of items for the spinner
val spinnerItems = resources.getStringArray(R.array.spinner_items)
// Zoom levels based off of my spinner items
val zoomLevels = mapOf(
"10 km" to 12.0f,
"25 km" to 8.0f,
"50 km" to 2.0f
)
// Retrieve selected item and make it a string
val selectedItem = binding.searchSpinner.selectedItem.toString()
// Sets the zoom level based on selected item, otherwise default to 12.0f
selectedZoomLevel = zoomLevels[selectedItem] ?: 12.0f
// Call showToastWithIndex with the selected position
showToastWithIndex(requireContext(), spinnerItems, position)
// Since you can access googleMaps here, you can call the animateCamera / moveCamera method here:
googleMap.animateCamera(CameraUpdateFactory.newLatLngZoom(currentLocation, selectedZoomLevel))
// or...
googleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(currentLocation, selectedZoomLevel))
}
MapsActivity.kt：
package com.example.kotlindemos
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.view.View
import android.widget.AdapterView
import android.widget.ArrayAdapter
import android.widget.Spinner
import android.widget.Toast
import com.google.android.gms.maps.CameraUpdateFactory
import com.google.android.gms.maps.GoogleMap
import com.google.android.gms.maps.OnMapReadyCallback
import com.google.android.gms.maps.SupportMapFragment
import com.google.android.gms.maps.model.LatLng
import com.google.android.gms.maps.model.MarkerOptions
import com.example.kotlindemos.databinding.ActivityMapsBinding
class MapsActivity : AppCompatActivity(), OnMapReadyCallback {
val SYDNEY = LatLng(-33.862, 151.21)
val ZOOM_LEVEL = 13f
private lateinit var gMap: GoogleMap
private lateinit var spinner: Spinner
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_basic_map_demo)
val mapFragment : SupportMapFragment? =
supportFragmentManager.findFragmentById(R.id.map) as? SupportMapFragment
mapFragment?.getMapAsync(this)
spinner = findViewById(R.id.spinner)
val listItems = listOf("10 km", "25 km", "50 km")
val arrayAdapter = ArrayAdapter(this, android.R.layout.simple_spinner_item, listItems)
arrayAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item)
spinner.adapter = arrayAdapter
spinner.onItemSelectedListener = object : AdapterView.OnItemSelectedListener {
override fun onItemSelected(parent: AdapterView<*>, view: View, position: Int, id: Long) {
val selectedItem = parent.getItemAtPosition(position).toString()
// Zoom levels based off of my spinner items
val zoomLevels = mapOf(
"10 km" to 12.0f,
"25 km" to 8.0f,
"50 km" to 2.0f
)
// Sets the zoom level based on selected item, otherwise default to 12.0f
val selectedZoomLevel = zoomLevels[selectedItem] ?: 12.0f
Toast.makeText(applicationContext, "Selected: $selectedZoomLevel", Toast.LENGTH_SHORT).show()
// Since we have confirmed that the zoom level values are correct, we can now use them to set the zoom level
gMap.animateCamera(CameraUpdateFactory.newLatLngZoom(SYDNEY, selectedZoomLevel))
}
override fun onNothingSelected(parent: AdapterView<*>) {
// write code to perform some action
}
}
}
/**
* This is where we can add markers or lines, add listeners or move the camera. In this case,
* we just move the camera to Sydney and add a marker in Sydney.
*/
override fun onMapReady(googleMap: GoogleMap) {
gMap = googleMap
with(gMap) {
moveCamera(CameraUpdateFactory.newLatLngZoom(SYDNEY, ZOOM_LEVEL))
addMarker(MarkerOptions().position(SYDNEY))
}
}
}
layout.xml：
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.kotlindemos.BasicMapDemoActivity"
android:orientation="vertical">
<!-- insert spinner-->
<Spinner
android:id="@+id/spinner"
android:layout_width="match_parent"
android:layout_height="45dp"
/>
<androidx.fragment.app.FragmentContainerView
android:id="@+id/map"
android:name="com.google.android.gms.maps.SupportMapFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.kotlindemos.BasicMapDemoActivity">
</androidx.fragment.app.FragmentContainerView>
</LinearLayout>