Simple customized VerticalSeekBar which extends SeekBar also shows how to customize a view class in java.
/** * @author hafsalrahman * */ public class VerticalSeekBar extends SeekBar { public VerticalSeekBar(Context context) { super(context); } public VerticalSeekBar(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); } public VerticalSeekBar(Context context, AttributeSet attrs) { super(context, attrs); } protected void onSizeChanged(int w, int h, int oldw, int oldh) { super.onSizeChanged(h, w, oldh, oldw); } @Override protected synchronized void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(heightMeasureSpec, widthMeasureSpec); setMeasuredDimension(getMeasuredHeight(), getMeasuredWidth()); } protected void onDraw(Canvas c) { c.rotate(-90); c.translate(-getHeight(), 0); super.onDraw(c); } private OnSeekBarChangeListener onChangeListener; @Override public void setOnSeekBarChangeListener(OnSeekBarChangeListener onChangeListener){ this.onChangeListener = onChangeListener; } private int lastProgress = 0; @Override public boolean onTouchEvent(MotionEvent event) { if (!isEnabled()) { return false; } switch (event.getAction()) { case MotionEvent.ACTION_DOWN: onChangeListener.onStartTrackingTouch(this); setPressed(true); setSelected(true); break; case MotionEvent.ACTION_MOVE: super.onTouchEvent(event); int progress = getMax() - (int) (getMax() * event.getY() / getHeight()); // Ensure progress stays within boundaries if(progress < 0) {progress = 0;} if(progress > getMax()) {progress = getMax();} setProgress(progress); // Draw progress if(progress != lastProgress) { // Only enact listener if the progress has actually changed lastProgress = progress; onChangeListener.onProgressChanged(this, progress, true); } onSizeChanged(getWidth(), getHeight() , 0, 0); setPressed(true); setSelected(true); break; case MotionEvent.ACTION_UP: onChangeListener.onStopTrackingTouch(this); setPressed(false); setSelected(false); break; case MotionEvent.ACTION_CANCEL: super.onTouchEvent(event); setPressed(false); setSelected(false); break; } return true; } public synchronized void setProgressAndThumb(int progress) { setProgress(progress); onSizeChanged(getWidth(), getHeight() , 0, 0); if(progress != lastProgress) { // Only enact listener if the progress has actually changed lastProgress = progress; onChangeListener.onProgressChanged(this, progress, true); } } public synchronized void setMaximum(int maximum) { setMax(maximum); } public synchronized int getMaximum() { return getMax(); } }
It can be used from XML as below
<com.hafsal.flag.VerticalSeekBar android:id="@+id/calculatorVerticalSeekBar" android:layout_width="wrap_content" android:layout_height="fill_parent" android:layout_gravity="bottom" android:max="20" android:progress="0" />