CODEWITHSUNDEEP
javaandroid
zyMacro
zyMacro

Reputation: 695

SharedPreference between activity and service

I want to make a step counter on Android with TYPE_STEP_COUNTER.As you know, TYPE_STEP_COUNTER will reset when you re-boot the device.So I should conserve the steps.I decide to use SharedPreference to conserve it. The project structure as follows: enter image description here

In the MainActivity.java，

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        text_step = (TextView) findViewById(R.id.main_text_step);
        delayHandler = new Handler(this);
        Toolbar toolbar=(Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        SharedPreferences.Editor editor=getSharedPreferences("DateStep",MODE_PRIVATE).edit();
    }

But ,when I put data in StepService.java,it failed. //StepService.java

editor.putInt("step",StepDetector.CURRENT_STEP); editor.putString("date",current_Date);

It says can't resolve symbol editor. can you give me some advive what should I do to conserve data in StepService.java?

When I declared in service.java,it shows as follows: enter image description here

Upvotes: 1

Views: 2139

Answers (3)

Daniel Luque
Daniel Luque

Reputation: 116

I would use an interface to communicate Activity and Service: it's makes code cleaner, easier to read and test. If you have never used them, it may be a bit confusing, but take a minute to understand the code:

ServiceCallback.java 

public interface ServiceCallback {
    void updateStepValue(int value, String date);
}

StepService.java

public class StepService extends Service {
   ServiceCallback mCallback;

   public void bindCallback(ServiceCallback callback) {
       mCallback = callback;
   }

   public void unbindCallback() { 
       mCallback = null; 
   }

   // Somewhere in your code, call callback method to send data to Activity
   ...
   mCallback.updateStepValue(5, "15-07-2017");
}

Activity.java

public class Activity implements ServiceCallback {
    SharedPreferences.Editor editor;
    StepService service;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        ...
        editor = context.getSharedPreferences("preferences_key", Context.MODE_PRIVATE).edit();
        // Once your service is running and assigned to service variable
        // bind activity to it to listen service callbacks
        service.bindCallback(this);
    }

    @Override
    protected void onResume() {
        super.onResume();
        service.unbindCallback();
    }

    @Override
    void updateStepValue(int value, String date) {
         editor.putInt("step",value);
         editor.putString("date",date);
         editor.apply();
    }
}

Upvotes: 2

Eselfar
Eselfar

Reputation: 3869

You need to commit your changes.

editor.putInt("step",StepDetector.CURRENT_STEP);
editor.putString("date",current_Date);
editor.apply(); // <-- Save the data in the Shared Preferences.

Then in your service you can get the Shared Preferences again and get the values. You don't need to share the editor across the two classes. In the StepService just request the Shared Preferences again:

Context mContext = context;
// ...

mContext.getSharedPreferences("DateStep",MODE_PRIVATE).edit();
// Then get the data you want.

Edit

// In StepService

Editor mEditor;

@Override
public void onCreate() {
    super.onCreate(); 
    mEditor = getApplicationContext().getSharedPreferences("DateStep",MODE_PRIVATE).edit();
    // Then get the data you want anywhere in your Service
}

Upvotes: 2

Pavneet_Singh
Pavneet_Singh

Reputation: 37404

you need to declare your editor outside onCreate to make it visible to other methods because currently the declaration limits it's scope to only inside onCreate method , in short it's a Local reference variable

  SharedPreferences.Editor editor; 
  // ^^^^^^^^^^  declare it outside

  protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        text_step = (TextView) findViewById(R.id.main_text_step);
        delayHandler = new Handler(this);
        Toolbar toolbar=(Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        editor=getSharedPreferences("DateStep",MODE_PRIVATE).edit();
        // initialize editor
    }

To use editor in other class then declare and initialize it as shown above while using the same file name DateStep to save data in that file.

In Service class , override onCreate in service and apply the same approach

SharedPreferences.Editor editor; 
// ^^^^^^^^^^  declare it outside

@Override
public void onCreate() {
    super.onCreate();
    editor=getSharedPreferences("DateStep",MODE_PRIVATE).edit();
        // initialize editor
}

Upvotes: 2

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