使用多个类共享preferences？ [英] Using SharedPreferences across multiple classes?

问题描述

我有一个共享preferences，目前工作在一个班，但第二类不起作用。我想我可能会调用它错了，因为我得到的错误说：

I have a SharedPreferences that currently works in one class but doesn't work in a second class. I think I might be calling it wrong, because the error I get says:

The method getSharedPreferences(String, int) is undefined for the type CheckPreferences

在code与共享prefernces正确的工作原理是这样的：

The code that works correctly with the SharedPrefernces is this:

public void loadApp()
{
    setContentView(shc_BalloonSat.namespace.R.layout.main);
    alert = new AlertDialog.Builder(this).create();
    //String returned = "";
    lastpacketsPHP = "";
    pref = getSharedPreferences("shared_prefs", 1);
    prefEditor = pref.edit();
    //prefEditor.putString(lastpacketsPHP, "/* Insert PHP file location here */");
    //prefEditor.commit();

    // These next two lines are used to test the PHP files on the SHC server by determining if PHP is set up correctly.
    prefEditor.putString(lastpacketsPHP, "/* Insert PHP file location here */");
    prefEditor.commit();   

    if (!isNetworkConnected(this))
    {
    showAlert();
    }

    else
    {
    api = new httpAPI(this);
        map = new mapAPI(this);
        dialog = new runDialog(this, api, new runDialog.OnDataLoadedListener()
        {

            public void dataLoaded(String textViewString)
            {
            infoTV = (TextView)findViewById(shc_BalloonSat.namespace.R.id.info);
                infoTV.setText(textViewString);
                assignInfoToInfoTextView();
                assignInfoToHistoryTextView();
            }
        });

        dialog.execute();
    }

    CheckPreferences cp = new CheckPreferences(this, new CheckPreferences.CheckPreferencesListener()
    {

        public void onSettingsSaved()
        {
            // This function let's the activity know that the user has saved their preferences and
            // that the rest of the app should be now be shown.
            check.saveSettings();               
        }

        public void onCancel()
        {
            Toast.makeText(getApplicationContext(), "Settings dialog cancelled", Toast.LENGTH_LONG).show();
        }
    });

    cp.show();
}

在我的其他类，我不知道如果我只是调用它不正确，或者如果我看着它完全不正确。该类如下所示：

In my other class, I don't know if I'm just calling it incorrectly or if I'm looking at it completely incorrectly. The class is shown below:

package shc_BalloonSat.namespace;
import android.app.Dialog;
import android.content.Context;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.view.View;
import android.widget.CheckBox;

public class CheckPreferences extends Dialog
{
Context shc;
private CheckBox altitudeCheckBox = (CheckBox) findViewById(R.id.altitudeCheckbox);
private CheckBox latitudeCheckbox = (CheckBox) findViewById(R.id.latitudeCheckbox);
private CheckBox longitudeCheckbox = (CheckBox) findViewById(R.id.longitudeCheckbox);
private CheckBox velocityCheckbox = (CheckBox) findViewById(R.id.velocityCheckbox);
private CheckPreferencesListener listener;
SharedPreferences pref;
Editor prefEditor;
String userAltitudePreference;
String userLatitudePreference;
String userLongitudePreference;
String userVelocityPreference;
String userAltitudeChoice;
String userLatitudeChoice;
String userLongitudeChoice;
String userVelocityChoice;

public interface CheckPreferencesListener 
{
public void onSettingsSaved();
public void onCancel();
}

public CheckPreferences(Context context, CheckPreferencesListener l)
{
super(context);
this.setContentView(R.layout.custompreferences);
this.setCancelable(false);
this.setCanceledOnTouchOutside(false);
this.setTitle("Data View Settings");
pref = getSharedPreferences("shared_prefs", 1);
prefEditor = pref.edit();
initOnClick();
}

private void initOnClick()
{
View.OnClickListener click = new View.OnClickListener()
{
    public void onClick(View v)
    {
    switch (v.getId())
    {
            case R.id.saveBtn:
            {
                saveSettings();
                listener.onSettingsSaved();
                dismiss();
                break;
            }

            case R.id.cancelBtn:
            {
                listener.onCancel();
                dismiss();
                break;
            }
    }
    }
};

    // Save Button
    this.findViewById(R.id.saveBtn).setOnClickListener(click);

    // Cancel Button
    this.findViewById(R.id.cancelBtn).setOnClickListener(click);
}

public void saveSettings()
{
// This function is called when the user chooses the save their preferences

if (altitudeCheckBox.isChecked())
{
    userAltitudeChoice = "true";
    prefEditor.putString(userAltitudePreference, userAltitudeChoice);
    prefEditor.commit();   
}

else if (latitudeCheckbox.isChecked())
{
    userLatitudeChoice = "true";
    prefEditor.putString(userLatitudePreference, userLatitudeChoice);
    prefEditor.commit();  
}

else if (longitudeCheckbox.isChecked())
{
    userLongitudeChoice = "true";
    prefEditor.putString(userLongitudePreference, userLongitudeChoice);
    prefEditor.commit();  
}

else if (velocityCheckbox.isChecked())
{
    userVelocityChoice = "true";
    prefEditor.putString(userVelocityPreference, userVelocityChoice);
    prefEditor.commit();  
}

else
{

}

}
}

我上面提到的错误在这条线出现：

The error I mentioned above occurs on this line:

pref = getSharedPreferences("shared_prefs", 1);

任何帮助将大大AP preciated。我很想知道我做错了。

Any help will be greatly appreciated. I'd love to know what I'm doing wrong.

推荐答案

您应该调用通过背景引用变量此方法。

You should have to call this method via context reference variable.

public CheckPreferences(Context context, CheckPreferencesListener l)
{
 super(context);
 shc=context;
 ...
 pref = shc.getSharedPreferences("shared_prefs", 1);
 ...
}

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