Question

我遇到了问题，我无法理解为什么会这样......我是新手！

我希望每当我打开MainActivity2时，我的最后一个OnItemLongClick choisse（我的意思是marker和moveCamera，就是我最后一次选择）

然而

1）每次启动我的应用程序时，我必须再次从listview中选择一项，然后按下模拟器上的后退按钮，然后再次打开MainActivity2以实现它。

2）我的第二个错误是，当我选择OnItemLongClick marker项时，我的地图不会更改moveCamera和Toast。

为了使这项工作正常，我必须做些什么改变？

P.S。关于我上一次选择OnItemLongClick的{{1}}可以正确显示，因此favoritekafe正确存储在Preferences

中

（对不起我的英语，这不是我的母语）

我的MainActivity2是：

import android.support.v4.app.FragmentActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;
import android.content.SharedPreferences;

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.google.android.gms.maps.model.StreetViewPanoramaCamera;

public class MainActivity2 extends FragmentActivity implements OnMapReadyCallback {


ListView kafeteries;
String favoritekafe;
GoogleMap mMap;
String i;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.coffee);

    // Obtain the SupportMapFragment and get notified when the map is ready to be used.
    SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);
    mapFragment.getMapAsync(this);

    i = getSharedPreferences("pref1", MODE_PRIVATE).getString("data1", null);

    //emfanisi  toast gia to poio einai  to agapimeno */

    favoritekafe = getSharedPreferences("pref", MODE_PRIVATE).getString("data", null);
    if (favoritekafe==null) {
        Toast.makeText(getApplicationContext(), "you don't have a favorite caffe yet", Toast.LENGTH_SHORT).show();
    }
    else{
        Toast.makeText(getApplicationContext(), favoritekafe,
                Toast.LENGTH_SHORT).show();
    }



    /* oi kafeteries se lista */
    kafeteries = (ListView) findViewById(R.id.kafeteries);

    ArrayAdapter<String> mAdapter = new ArrayAdapter<String>(MainActivity2.this,
            android.R.layout.simple_list_item_1,
            getResources().getStringArray(R.array.kafeteries_syros));

    kafeteries.setAdapter(mAdapter);

    // mnmta TOAST otan kanw click kapoio stixeio tis listas */
    kafeteries.setOnItemClickListener(new AdapterView.OnItemClickListener() {

        @Override
        public void onItemClick(AdapterView<?> parent, View view, int   position, long id) {

            String sMessage = "";
            switch(position) {
                case 0: sMessage = "Coffee and drinks with hospitable locals\nArea:Ermoupoli\nPhone:2281083354";  break;
                case 1: sMessage = "Coffee in the narrow streets of the city\nArea:Ermoupoli\nPhone:2281079225";  break;
                case 2: sMessage = "The smallest and most adorable coffee in town\nArea:Ermoupoli\nPhone:2281300880";  break;
                case 3: sMessage = "Coffee and snacks at the city's harbor\nArea:Ermoupoli\nPhone:2281076144";  break;
                case 4: sMessage = "The city's most famous café\nArea:Ermoupoli\nPhone:2281085337";  break;
            }
            Toast.makeText(getApplicationContext(), sMessage, Toast.LENGTH_LONG).show();


        }
    });


    // long clik add sta favorite kai save*/
    kafeteries.setLongClickable(true);
    kafeteries.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
        @Override
        public boolean onItemLongClick(AdapterView<?> arg0, View arg1,int position, long id) {



            String fMessage = "";
            switch(position) {
                case 0: fMessage = "Boheme del mar is your favorite caffe"; i="1"; break;
                case 1: fMessage = "Jar is favorite caffe"; i="2"; break;
                case 2: fMessage = "Kouchico is your favorite caffe"; i="3"; break;
                case 3: fMessage = "Okio is your favorite caffe"; i="4"; break;
                case 4: fMessage = "Plaza is your favorite caffe"; i="5"; break;
            }

            //save i */
            SharedPreferences.Editor editor2 = getSharedPreferences("pref1", MODE_PRIVATE).edit();
            editor2.putString("data1", i);
            editor2.commit();

            gotStringFromLongClick(fMessage);

            // save fmessage */
            SharedPreferences.Editor editor = getSharedPreferences("pref", MODE_PRIVATE).edit();
            editor.putString("data", fMessage);
            editor.commit();

            Toast.makeText(getApplicationContext(), fMessage, Toast.LENGTH_SHORT).show();


            return true;
        }


        void gotStringFromLongClick(String fMessage){
            favoritekafe=fMessage;

        }


    });



    }

// markers...
@Override
public void onMapReady(GoogleMap googleMap) {
    mMap = googleMap;

    mMap.setTrafficEnabled(true);
    mMap.setIndoorEnabled(true);
    mMap.setBuildingsEnabled(true);
    mMap.getUiSettings().setZoomControlsEnabled(true);

    // Add a markers
    LatLng Boheme = new LatLng(37.442801, 24.944866);
    LatLng Jar = new LatLng(37.444241, 24.943962);
    LatLng Kouchico = new LatLng(37.444705, 24.944009);
    LatLng Okio = new LatLng(37.443111, 24.944542);
    LatLng Plaza = new LatLng(37.443517, 24.943775);
    LatLng ermoupoli = new LatLng(37.443245, 24.943385);

    // add marker estiasi

    if (i=="1") {
        mMap.addMarker(new MarkerOptions().position(Boheme).title("Boheme del Mar"));
    }
    else if (i=="2") {
        mMap.addMarker(new MarkerOptions().position(Jar).title("Jar"));
    }
    else if (i=="3") {
        mMap.addMarker(new MarkerOptions().position(Kouchico).title("Kouchiko"));
    }
    else if (i=="4") {
        mMap.addMarker(new MarkerOptions().position(Okio).title("Okio"));
    }
    else if (i=="5") {
        mMap.addMarker(new MarkerOptions().position(Plaza).title("Plaza"));

    }

    //estiasi marker

    if (favoritekafe== "Boheme del mar is your favorite caffe"){
        mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(Boheme,19));
    }
    else if (favoritekafe== "Jar is favorite caffe") {
        mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(Jar, 19));
    }
    else if (favoritekafe== "Kouchico is your favorite caffe") {
        mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(Kouchico, 19));
    }
    else if (favoritekafe== "Okio is your favorite caffe") {
        mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(Okio, 19));
    }
    else if (favoritekafe== "Plaza is your favorite caffe") {
        mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(Plaza, 19));
    }
    else {
        mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(ermoupoli,16));
    }

}

}

Answer 1

您需要将适配器数组保存到String []变量。然后使用favoritekafe从String []中查找先前所选选项的位置。然后在点击侦听器后添加以下行：

kafeteries.getChildAt(previousSelectedPosition).performClick();

或者您可以直接保存位置而不是名称并添加以上行：）

活动生命周期不起作用

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