How to use shared Preferences on Android?

Question

I am creating a very simple application that only has a seek bar that the user can use. My code looks like this :

    @Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    int number=50;
    SeekBar sb = (SeekBar)findViewById(R.id.slider);
    sb.setMax(100);
    sb.setProgress(number);
    sb.setOnSeekBarChangeListener(this);
}

@Override
public void onProgressChanged(SeekBar v, int progress, boolean isUser) {
    TextView tv = (TextView)findViewById(R.id.percent);
    tv.setText(Integer.toString(progress)+"%");


}

What i want to do is store the seek bars state and when the application is killed and the user opens it again , the last change is displayed on the seek bar and not the default. So i must use shared preferences on my int number variable? I cant understand how i can do that since when the application starts again the line int number=50 will be run again , so the value will go to 50 again.

Answer 1

something like this ought to work:

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    SharedPreferences sp;
    SharedPreferences.Editor spe;


    sp = PreferenceManager.getDefaultSharedPreferences(this);
    spe = sp.edit();


    int number= sp.getInt("seekNum", 50);
    SeekBar sb = (SeekBar)findViewById(R.id.slider);
    sb.setMax(100);
    sb.setProgress(number);
    sb.setOnSeekBarChangeListener(this);
}

@Override
public void onProgressChanged(SeekBar v, int progress, boolean isUser) {
    TextView tv = (TextView)findViewById(R.id.percent);
    tv.setText(Integer.toString(progress)+"%");


}


@Override
public void onStop(){
    super.onStop();

    spe.putInt("seekNum", sb.getProgress());
    spe.commit();
}