無法導入SharedPreferences

Question

替換SharedPreferences文件后，我無法加載新的SharedPreferences文件。 重新安裝應用程序后即可正常工作。 重新啟動應用程序后，沒有任何變化。

這是導入/導出類：

public class Prefs {
    private String PrefsDir = "/data/%packagename%/shared_prefs/";
    private String ExportDir = "/";

    private SharedPreferences _sharedPrefs;
    private SharedPreferences.Editor _prefsEditor;
    private Context context;

    Prefs(Context context, String form) {
        this.ExportDir = Environment.getExternalStorageDirectory().getPath() + ExportDir;
        this.PrefsDir = Environment.getDataDirectory().getPath() + PrefsDir;
        _sharedPrefs = context.getSharedPreferences(form, Activity.MODE_PRIVATE);
        _prefsEditor = _sharedPrefs.edit();
    }

    private boolean copyfile(String srFile, String dtFile){
        Popup.log("srFile = "+srFile);
        Popup.log("dtFile = "+dtFile);
        try{
            File f1 = new File(srFile);
            File f2 = new File(dtFile);
            InputStream in = new FileInputStream(f1);
            OutputStream out = new FileOutputStream(f2);

            byte[] buf = new byte[1024];
            int len;
            while ((len = in.read(buf)) > 0){
                out.write(buf, 0, len);
            }
            in.close();
            out.close();
        } catch(FileNotFoundException ex) {
            Popup.popup(context, "File not found");
            Popup.log(ex.getMessage());
            return false;
        } catch(IOException e) {
            Popup.popup(context, "IO Error");
            return false;
        }
        return true;
    }

    boolean Export(String form) {
        return copyfile(PrefsDir+form+".xml", ExportDir+form+".xml");
    }

    boolean Import(String form) {
        return copyfile(ExportDir+form+".xml", PrefsDir+form+".xml");
    }
}

對不起我的英語

Answer 1

我的實現的第一部分包括一些聲明，這些聲明定義了用於檢索“共享首選項”的鍵以及可以將它們存儲在其中的變量。 第一個例程是初始化共享首選項（為了加載共享首選項，您需要在代碼中保存值，因此需要一些代碼在代碼中初始化這些值）。 第二個例程是保存共享首選項。 第三個例程是加載共享首選項。

這是關鍵定義部分

private SharedPreferences sharedPreferences;
public final static String MARV_INIT = "MARV_INIT";
public final static String MARV_LAT = "MARV_LATITUDE";
public final static String MARV_LON = "MARV_LONGITUDE";
public final static String MARV_ZOOM = "MARV_ZOOM";
public final static String MARV_PDFL = "MARV_PDFL";
public final static String MARV_PRON = "MARV_PRON";
public final static String MARV_LTRD = "MARV_LTRD";

這是3個例程。

// Shared Preferences and other data loading routines for this activity
private void initSharedPreferences() {
    Log.i(TAG, "Initializing shared preferences ...");
    Editor editor = sharedPreferences.edit();

    editor.putInt(MARV_INIT, 1);
    editor.putString(MARV_LAT, ((Double) SG_LATITUDE).toString());
    editor.putString(MARV_LON, ((Double) SG_LONGITUDE).toString());
    editor.putFloat(MARV_ZOOM, (float) DEFAULT_ZOOM);
    editor.putString(MARV_PDFL, getString(R.string.default_poi_list));
    editor.putBoolean(MARV_PRON, true);
    editor.putFloat(MARV_LTRD, (float) LocationAlertService.DEFAULT_RADIUS);

    editor.commit();
}

private void saveSharedPreferences() {

    // Update global variables first
    updateCameraProperties();

    // Now save global variables into shared preferences
    Editor editor = sharedPreferences.edit();

    editor.putString(MARV_LAT,
            ((Double) lastCameraPosition.latitude).toString());
    editor.putString(MARV_LON,
            ((Double) lastCameraPosition.longitude).toString());
    editor.putFloat(MARV_ZOOM, lastCameraZoom);
    editor.putString(MARV_PDFL, poiDocFileListUrl);
    editor.putBoolean(MARV_PRON, proximityAlertsOn);
    editor.putFloat(MARV_LTRD, lastRadiusUsed);

    editor.commit();
}

private void loadSharedPreferences() {

    lastCameraPosition = new LatLng(Double.parseDouble(sharedPreferences
            .getString(MARV_LAT, ((Double) SG_LATITUDE).toString())),
            Double.parseDouble(sharedPreferences.getString(MARV_LON,
                    ((Double) SG_LONGITUDE).toString())));
    lastCameraZoom = sharedPreferences.getFloat(MARV_ZOOM, DEFAULT_ZOOM);
    poiDocFileListUrl = sharedPreferences.getString(MARV_PDFL,
            getString(R.string.default_poi_list));
    proximityAlertsOn = sharedPreferences.getBoolean(MARV_PRON, true);
    lastRadiusUsed = sharedPreferences.getFloat(MARV_LTRD, LocationAlertService.DEFAULT_RADIUS);            
}