如何保存和恢复标记数组

Posted 2023-05-06

【中文标题】如何保存和恢复标记数组

【英文标题】：How to save and restore marker array

【发布时间】：2020-12-05 23:11:52

【问题描述】：

我需要保存触发的位置，以便在我再次打开应用程序时显示它们。

我使用 int array 来保存 onMarkerClick 方法中触发位置的数量。并使用此数组在 createMarkers 方法中创建所需的标记。 我试图保存和恢复这个数组，但它不起作用。

Activity.class 的部分内容

public class MapsActivity extends FragmentActivity
        implements
        OnRequestPermissionsResultCallback,
        OnMapReadyCallback,
        OnMarkerClickListener 

    
    private LatLng[] latLngArray;
    private String[] titleArray;
    private Marker[] markerArray;
    private int[] resIdArray;
    private int ARRAY_SIZE = 7;
    private int COUNTER = 0;
    private static final float DISTANCE = 50;
    private boolean START_POINT_CHECKED = false;

    public final String inArrayName= "inArray";

    //public int outArray[] = new int[ARRAY_SIZE];
    public int inArray[];

    private Location mCurrentLocation;
    private GoogleMap mMap;


    private MediaPlayer mediaPlayer;

    @Override
    protected void onSaveInstanceState(@NonNull Bundle outState) 
            outState.putIntArray(outArrayName,inArray);
        super.onSaveInstanceState(outState);
    

    @Override
    protected void onRestoreInstanceState(@NonNull Bundle inState) 
        inArray = inState.getIntArray(outArrayName);
        super.onRestoreInstanceState(inState);
    

    @Override
    protected void onCreate(Bundle inState) 
        inArray = new int[ARRAY_SIZE];
        super.onCreate(inState);
        setContentView(R.layout.activity_maps);
        if(inState == null)
            for (int i=0; i<ARRAY_SIZE;i++)
                inArray[i]=0;
            
        

   private void createMarkersList()
        markerArray = new Marker[ARRAY_SIZE];
        if(inArray[0] == 777) 

            markerArray[0] = mMap.addMarker(new MarkerOptions()
                    .position(latLngArray[0])
                    .anchor(0.5f, 0.5f)
                    .icon(BitmapDescriptorFactory.fromResource(R.drawable.marker1))
                    .title(titleArray[0])
                    .snippet("0")
                    .visible(true)
            );
            markerArray[0].setTag(666);
            inArray[0] = 777;
            START_POINT_CHECKED = true;
         else 
            markerArray[0] = mMap.addMarker(new MarkerOptions()
                    .position(latLngArray[0])
                    .anchor(0.5f, 0.5f)
                    .icon(BitmapDescriptorFactory.fromResource(R.drawable.marker2))
                    .title(titleArray[0])
                    .snippet("0")
                    .visible(true)
            );
            markerArray[0].setTag(0);
        


        if (START_POINT_CHECKED) 
            for (int i = 1; i < ARRAY_SIZE; i++) 
                if (inArray[i] == 777) 
                    markerArray[i] = mMap.addMarker(new MarkerOptions()
                            .position(latLngArray[i])
                            .anchor(0.5f, 0.5f)
                            .icon(BitmapDescriptorFactory.fromResource(R.drawable.marker1))
                            .title(titleArray[i])
                            .snippet(Integer.toString(i))
                            .visible(true)
                    );
                    markerArray[i].setTag(666);
                    inArray[i]=777;
                 else 
                    markerArray[i] = mMap.addMarker(new MarkerOptions()
                            .position(latLngArray[i])
                            .anchor(0.5f, 0.5f)
                            .icon(BitmapDescriptorFactory.fromResource(R.drawable.marker2))
                            .title(titleArray[i])
                            .snippet(Integer.toString(i))
                            .visible(true)
                    );
                    markerArray[i].setTag(i);
                
            
         else 
            for (int i = 1; i < ARRAY_SIZE; i++) 
                markerArray[i] = mMap.addMarker(new MarkerOptions()
                        .position(latLngArray[i])
                        .anchor(0.5f, 0.5f)
                        .icon(BitmapDescriptorFactory.fromResource(R.drawable.marker2))
                        .title(titleArray[i])
                        .snippet(Integer.toString(i))
                        .visible(false)
                );
                markerArray[i].setTag(i);
            
        

    

    @Override
    public void onMapReady(GoogleMap googleMap) 
        mMap = googleMap;
        mMap.setOnMarkerClickListener(this);


        EnableUserLocation();

        MapStyling();

        createLatLngsList();
        createTitlesList();
        createMarkersList();
        createResIdArray();

    

    @Override
    public boolean onMarkerClick(Marker marker) 
        int id = (int) marker.getTag();
        Log.d(TAG, "Marker" + id + "Clicked");
        if (getDistance(marker.getPosition(), new LatLng(mCurrentLocation.getLatitude(),mCurrentLocation.getLongitude())) <= DISTANCE)
            if (  id == 666)
                if (mediaPlayer.isPlaying())
                    mediaPlayer.pause();
                    return true;
                 else
                    mediaPlayer.start();
                
             else 
                if(START_POINT_CHECKED) 
                    marker.setIcon(BitmapDescriptorFactory.fromResource(R.drawable.marker1));

                    if (mediaPlayer!= null)
                        mediaPlayer.reset();
                    
                    mediaPlayer = MediaPlayer.create(this, resIdArray[id]);
                    mediaPlayer.start();
                    inArray[id] = 777;
                    marker.setTag(666);
                    COUNTER++;
                    if (COUNTER == 7)
                        mediaPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener() 
                            @Override
                            public void onCompletion(MediaPlayer mediaPlayer) 
                                showPicture();
                            
                        );

                    
                    return true;
                 else
                    if(id == 0) 
                        marker.setIcon(BitmapDescriptorFactory.fromResource(R.drawable.marker1));
                        if (mediaPlayer!= null)
                            mediaPlayer.reset();
                        
                        mediaPlayer = MediaPlayer.create(this, resIdArray[id]);
                        mediaPlayer.start();
                        inArray[id] = 777;
                        marker.setTag(666);
                        COUNTER++;
                        START_POINT_CHECKED = true;
                        showMarkers();
                        return true;
                    else 
                        return true;
                    
                
            

        
        return false;
    

【问题讨论】：

latLngArray 在哪里设置过任何东西？

【参考方案1】：

如果你的标签对于相同的标记总是相同的，你可以将一个数组放入共享首选项中并在 onMapReady 中恢复这些位置

您可以在 onMarkerClick 方法中添加标签值

【讨论】：

或者您可以使用 Room 例如创建数据库。