Android的搜索栏preference

我目前正在使用的http://android-journey.blogspot.com/2010/01/for-almost-any-application-we-need-to.html教程，RelativeLayout的。第一个问题是TextView的preferenceText没有显示在所有。 第二个问题是吧，不能滑动像常规preferences（如媒体音量条）？

I'm currently trying to implement SeekBarPreference class using http://android-journey.blogspot.com/2010/01/for-almost-any-application-we-need-to.html tutorial with RelativeLayout. First problem is TextView preferenceText isn't showing at all. Second problem is the bar can't be slided like those in regular preferences (like media volume bar)?

public class SeekBarPreference extends Preference implements
    OnSeekBarChangeListener {

public static int maximum    = 100;
public static int interval   = 5;
private float oldValue = 25;
private TextView Indicator;

public SeekBarPreference(Context context) {
    super(context);
}

public SeekBarPreference(Context context, AttributeSet attrs) {
    super(context, attrs);
}

public SeekBarPreference(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
}

@Override
protected View onCreateView(ViewGroup parent) {

    float scale = getContext().getResources().getDisplayMetrics().density;

    RelativeLayout layout = new RelativeLayout(getContext());

    RelativeLayout.LayoutParams textParams = new RelativeLayout.LayoutParams(
            RelativeLayout.LayoutParams.WRAP_CONTENT,
            RelativeLayout.LayoutParams.WRAP_CONTENT);

    RelativeLayout.LayoutParams sbarParams = new RelativeLayout.LayoutParams(
            Math.round(scale * 160),
            RelativeLayout.LayoutParams.WRAP_CONTENT);

    RelativeLayout.LayoutParams indParams = new RelativeLayout.LayoutParams(
            RelativeLayout.LayoutParams.WRAP_CONTENT,
            RelativeLayout.LayoutParams.WRAP_CONTENT);

    TextView preferenceText = new TextView(getContext());
    preferenceText.setId(0);
    preferenceText.setText(getTitle());
    preferenceText.setTextSize(18);
    preferenceText.setTypeface(Typeface.SANS_SERIF, Typeface.BOLD);


    SeekBar sbar = new SeekBar(getContext());
    sbar.setId(1);
    sbar.setMax(maximum);
    sbar.setProgress((int)this.oldValue);
    sbar.setOnSeekBarChangeListener(this);

    this.Indicator = new TextView(getContext());
    this.Indicator.setTextSize(12);
    this.Indicator.setTypeface(Typeface.MONOSPACE, Typeface.ITALIC);
    this.Indicator.setText("" + sbar.getProgress());

    textParams.addRule(RelativeLayout.ALIGN_PARENT_LEFT);
    sbarParams.addRule(RelativeLayout.RIGHT_OF, preferenceText.getId());
    indParams.setMargins(Math.round(20*scale), 0, 0, 0);
    indParams.addRule(RelativeLayout.RIGHT_OF, sbar.getId());

    preferenceText.setLayoutParams(textParams);
    sbar.setLayoutParams(sbarParams);
    this.Indicator.setLayoutParams(indParams);
    layout.addView(preferenceText);
    layout.addView(this.Indicator);
    layout.addView(sbar);
    layout.setId(android.R.id.widget_frame);

    return layout;
}

@Override
public void onProgressChanged(SeekBar seekBar, int progress,
        boolean fromUser) {
    progress = Math.round(((float) progress)/interval) * interval;

    if(!callChangeListener(progress)) {
        seekBar.setProgress((int) this.oldValue);
        return;
    }

    seekBar.setProgress(progress);
    this.oldValue = progress;
    this.Indicator.setText("" + progress);
    updatePreference(progress);

    notifyChanged();
}

@Override
public void onStartTrackingTouch(SeekBar seekBar) {
}

@Override
public void onStopTrackingTouch(SeekBar seekBar) {
}

@Override
protected Object onGetDefaultValue(TypedArray ta, int index) {
    int dValue = ta.getInt(index, 25);

    return validateValue(dValue);
}

@Override
protected void onSetInitialValue(boolean restoreValue,
        Object defaultValue) {
    int temp = restoreValue ? getPersistedInt(25) : (Integer)defaultValue;
    if(!restoreValue)
        persistInt(temp);

    this.oldValue = temp;
}

private int validateValue(int value) {
    if(value > maximum) 
        value = maximum;
    else if (value < 0)
        value = 0;
    else if (value % interval != 0)
        value = Math.round(((float) value)/interval) * interval;

    return value;
}

private void updatePreference(int newValue) {
    SharedPreferences.Editor editor = getEditor();
    editor.putInt(getKey(), newValue);
    editor.commit();
}

}