Question

我想创建一个由（1）Main FragmentActivity +（2）Google Map V2 FragmentActivity组成的应用程序。

然而，以下代码在我单击Button * btn1时成功显示了初始（1）Main FragmentActivity和（2）Google Map V2 FragmentActivity。

然而，问题是..当我点击Android上的“后退”按钮时，它成功杀死了2）Google Map V2 FragmentActivity并显示（1）主FragmentActivity但丢失了TextView字段上的所有数据..

所以我想做的就是

当首先点击“后退”按钮时，（2）Google Map V2 FragmentActivity应该被终止，TextView字段上的所有数据（在（1）Main FragmentActivity中）应该是活着的。
当第二次单击“后退”按钮时，应用程序shuold被杀死（退出），没有错误。

感谢

---------- -------------- MainActivity.java

public class MainActivity extends FragmentActivity {

    TextView site1_lat, site1_lon, site2_lat, site2_lon, distance_kilo, distance_miles, azimuth1_content, azimuth2_content;
    TextView current_lat, current_lon, current_mgrs_result;
    TextView distance_kilo1, distance_kilo2,    azimuth1_content1, azimuth1_content2;
    Variables vari;

    //for geoCoord
    //Context mContext;
    LocationManager mLocMan;
    String mProvider;
    Location location;
    Context context;
    //double latitude, longitude;
    @Override
    public void onBackPressed() {
        //setContentView(R.layout.activity_main);
        this.recreate();
        //this.getSupportFragmentManager().beginTransaction().remove(getSupportFragmentManager().findFragmentById(R.id.mapview)).commit();
        //this.getSupportFragmentManager().popBackStack();
        //this.getFragmentManager().beginTransaction().remove(getFragmentManager().findFragmentById(R.id.mapview)).commit();
        //this.getSupportFragmentManager().beginTransaction().hide(getSupportFragmentManager().findFragmentById(R.id.mapview)).commit();

    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        //for geoCoord
        /*
        mLocMan = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
        mProvider = mLocMan.getBestProvider(new Criteria(), true);
        LocationListener mListener = new Geocoord();        
        mLocMan.requestLocationUpdates(mProvider, 6000, 10, mListener);
        */
        //
        mLocMan = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
        mProvider = mLocMan.getBestProvider(new Criteria(), true);
        LocationListener mListener = new Geocoord();
        //mLocMan.requestLocationUpdates(mProvider, 0, 0, mListener);
        mLocMan.requestLocationUpdates(mLocMan.GPS_PROVIDER, 6000, 10, mListener);

        /*
        mlocManager.requestLocationUpdates( LocationManager.GPS_PROVIDER, 0, 0, mlocListener);
         */

        //for google Map
        GoogleMap mGoogleMap;


    //Button 0
    final Button btn = (Button)findViewById(R.id.btn);
    btn.setOnClickListener(new Button.OnClickListener() {
    public void onClick(View v) {

        //1st site
        try{
        EditText mgrs_site1 = (EditText)findViewById(R.id.editText1);
        String site1 = mgrs_site1.getText().toString().toUpperCase();
        .........

        }catch(Exception e){
            Toast.makeText(MainActivity.this, "Please input valid Coordination!", Toast.LENGTH_SHORT).show();}//ends try-catch      
    }
    }); //ends button0

    //Button 1
    Button btn1 = (Button)findViewById(R.id.btn1);
    btn1.setOnClickListener(new Button.OnClickListener() {
        public void onClick(View v) {
            btn.performClick();
            //setting up google Map!
            GoogleMap mGoogleMap;
            Converter converter = new Converter();

            //initial values for marker
            //current position
            ...

              setContentView(R.layout.mapview);           
              mGoogleMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.mapview)).getMap();
              mGoogleMap.setMapType(GoogleMap.MAP_TYPE_HYBRID);
              //add marker
              mGoogleMap.addMarker(new MarkerOptions().position(position).title("current")).showInfoWindow();
              mGoogleMap.addMarker(new MarkerOptions().icon(BitmapDescriptorFactory.fromResource(R.drawable.site1)).position(position1).title("Site#1")).showInfoWindow();
              mGoogleMap.addMarker(new MarkerOptions().icon(BitmapDescriptorFactory.fromResource(R.drawable.site2)).position(position2).title("Site#2")).showInfoWindow();

              //
              mGoogleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(position1, 7));


            //Intent intent = new Intent(MainActivity.this, MapView.class);
            //startActivity(intent);
        }//ends onClick 



        });

    }//ends onCreate

}//ends Activity

//Things to do

Android关闭片段活动并返回初始显示

0 个答案: