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OnProgressChanged () SeekBar is called twice

I created a Custom SeekBarPreference

so that it displays the time range to be selected (say 0.2

sec to 2.2

sec). My problem is onProgressChanged () is being called twice - once with progress = 0

and the second time with progress = "actual value"

. I store the value in SharedPreference

so that I can later use it in my application.
Here is my code snippet -

@Override
protected View onCreateDialogView() {
    LayoutInflater inflator = ((PreferenceActivity) mContext)
            .getLayoutInflater();
    View view = inflator.inflate(R.layout.seek_bar, null);

    mCurrentValue = PreferenceManager.getDefaultSharedPreferences(mContext)
            .getFloat(this.getKey(), mDefaultValue);
    ......
    SeekBar mSeekBar = (SeekBar) view.findViewById(R.id.seekbar);
    mSeekBar.setOnSeekBarChangeListener(this);

    mSeekBar.setMax(20);
    mSeekBar.setProgress((int) ((mCurrentValue - mMinValue)
            / (mMaxValue - mMinValue) * 20)); // 20 = progress bar max value.
    return view;
}

@Override
public void onProgressChanged(SeekBar seekBar, int progress,
        boolean fromUser) {
    if (progress != 0) {
        mCurrentValue = (float) ((float) progress / 20
                * (mMaxValue - mMinValue) + mMinValue);
    }
    mValueText.setText(Float.toString(mCurrentValue)); 
    /* mValueText is a TextBox where I display my Current Value */
}

Here I have checked the progress value so that it is not equal to 0

and therefore it avoids the first call. However, a side effect of this is that I cannot install anything for 0

.

Why can this be done?

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3 answers


The callback method onProgressChanged()

has a parameter boolean

fromUser

.
Using this parameter , we can determine if the changes come from the Framework or are made by the user .

So an implementation like -

@Override
public void onProgressChanged(SeekBar seekBar, int progress,
        boolean fromUser) {
    if (fromUser) { // If the changes are from the User only then accept the
                    // changes
    /* Instead of -> if (progress != 0) { */

        mCurrentValue = (float) ((float) progress / 20
                * (mMaxValue - mMinValue) + mMinValue);
        mCurrentValue *= 10;
        mCurrentValue = Math.round(mCurrentValue);
        mCurrentValue /= 10;
    }

    mValueText.setText(Float.toString(mCurrentValue));
}


sets the value TextView

only when it is changed by the user.

+5


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you can use follwing method for OnSeekBarChangeListener.



public void onStopTrackingTouch(SeekBar seekBar) {
     int progress=seekBar.getProgress();

}
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I have another problem today (Custom SeekBar and PreferenceFragment). I don't know why, but the code below only works twice: on start, touch and stop:

    mTextViewValue = (TextView) view.findViewById(R.id.seekbar_value);
    mSeekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
        @Override
        public void onProgressChanged(@NonNull SeekBar seekBar, int progress, boolean fromUser) {
                mTextViewValue.setText(String.valueOf(newValue));
            }

Finally, I have a solution. It works:

    final TextView valueTextView = (TextView) view.findViewById(R.id.seekbar_value);
    mSeekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
        @Override
        public void onProgressChanged(@NonNull SeekBar seekBar, int progress, boolean fromUser) {
                valueTextView.setText(String.valueOf(newValue));
            }

Maybe it helps someone.

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