Question

我想知道如何在用户关闭应用时，将标记保存到文件中，然后在再次打开应用时将其重新加载这是我的代码：

package com.example.mapapp;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.provider.Settings;
import android.util.Log;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.content.Intent;
import android.view.View;
import android.widget.Button;

import org.osmdroid.config.Configuration;
import org.osmdroid.tileprovider.tilesource.TileSourceFactory;
import org.osmdroid.util.GeoPoint;
import org.osmdroid.views.MapView;
import org.osmdroid.views.overlay.ItemizedIconOverlay;
import org.osmdroid.views.overlay.OverlayItem;

import java.io.File;
import java.util.ArrayList;


public class MainActivity extends Activity
{

    MapView mv;
    StringBuffer filePath;
    File file;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState)
    {

        super.onCreate(savedInstanceState);

        // This line sets the user agent, a requirement to download OSM maps
        Configuration.getInstance().load(this, PreferenceManager.getDefaultSharedPreferences(this));
        setContentView(R.layout.activity_main);

        mv = (MapView)findViewById(R.id.map1);
        ItemizedIconOverlay<OverlayItem> items;


        mv.setBuiltInZoomControls(true);
        mv.getController().setZoom(11);
        mv.getController().setCenter(new GeoPoint(53.3710,-1.4502));

    }
    public boolean onOptionsItemSelected(MenuItem item)
    {
        if(item.getItemId() == R.id.addpoi)
        {
            // react to the menu item being selected...
            Intent intent = new Intent(this,AddPoi.class);
            startActivityForResult(intent,0);

            return true;
        }
        Intent intent = new Intent(this,AddPoi.class);
        startActivityForResult(intent,0);

        return false;

    }

    public boolean onCreateOptionsMenu(Menu menu)
    {
        MenuInflater inflater=getMenuInflater();
        inflater.inflate(R.menu.menu_mad_assignment, menu);
        return true;
    }
    protected void onActivityResult(int requestCode,int resultCode,Intent intent)
    {

        if(requestCode==0)
        {
            if (resultCode==RESULT_OK)
            {
                Bundle extras=intent.getExtras();
                String poiName= extras.getString("poiName");
                String poiType= extras.getString("poiType");
                String poiDesc= extras.getString("poiDesc");
                ItemizedIconOverlay<OverlayItem> items = new ItemizedIconOverlay<>(this, new ArrayList<OverlayItem>(), null);
                OverlayItem marker = new OverlayItem(poiName, poiType,poiDesc, new GeoPoint(53.3710,-1.4502));
                items.addItem(marker);
                mv.getOverlays().add(items);


                Log.d("NAME",poiName);
                Log.d("NAME",poiType);
                Log.d("NAME",poiDesc);
            }
        }
    }


}

添加标记代码：

package com.example.mapapp;
import android.app.Activity;
import android.os.Bundle;
import android.content.Intent;
import android.widget.Button;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.EditText;

import com.example.luke.madassignment.R;

public class AddPoi extends Activity implements OnClickListener {

    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.add_poi);
        Button addPoiButton = (Button)findViewById(R.id.addPoi);
        Button cancelButton = (Button)findViewById(R.id.cancel);
        addPoiButton.setOnClickListener(this);
        cancelButton.setOnClickListener(this);

    }

    @Override
    public void onClick(View v) {
        Intent intent = new Intent();
        Bundle bundle=new Bundle();
        EditText poiName = (EditText)findViewById(R.id.editTextPoiName);
        EditText poiType = (EditText)findViewById(R.id.editTextPoiType);
        EditText poiDesc = (EditText)findViewById(R.id.editTextPoiDesc);
        String poiNameString = poiName.toString();
        String poiTypeString = poiName.toString();
        String poiDescString = poiName.toString();
        bundle.putString("poiName",poiNameString);
        bundle.putString("poiType",poiTypeString);
        bundle.putString("poiDesc",poiDescString);
        intent.putExtras(bundle);
        setResult(RESULT_OK,intent);
        finish();

    }
}

问题是我无法找到一种方法将用户标记保存到文件中，如果应用程序关闭，然后在应用程序再次打开时加载回标记

Answer 1

使用内置的sharedPref，简单的键值存储，以持久模式保存数据。查看doc here

SharedPreferences类提供了允许的通用框架您可以保存和检索原始数据的持久键值对类型。您可以使用SharedPreferences保存任何原始数据：布尔，浮子，整数，长整数和字符串。这些数据将持续存在跨用户会话（即使你的应用程序被杀死）。

https://developer.android.com/guide/topics/data/data-storage.html#pref

Answer 2

使用OSMBonusPack，您可以grab your markers in a KML structure，然后在本地保存KML文件（在onStop中）。并在打开应用程序时（在onCreate中）加载此KML文件。

将标记保存到csv文件

2 个答案: