android seek bar customization,

Question

I need to customize a seek bar in such a way that, at pre determined time say , 30sec, I should have a dot on the seek bar. This duration varies for each and every video, so how to I place a dot point on the seek bar at a particular second

Answer 1

Here're some possibilities:

1. Put 'dot' view just above SeekBar one. Will not explain it here in details, because it's trivial android-layout task;

2. Extend SeekBar, like the following (refer to this good explanation about custom views):

   /**
    * Seek bar with dots on it on specific time / percent
    */
   public class DottedSeekBar extends SeekBar {
   
       /** Int values which corresponds to dots */
       private int[] mDotsPositions = null;
       /** Drawable for dot */
       private Bitmap mDotBitmap = null;
   
       public DottedSeekBar(final Context context) {
           super(context);
           init(null);
       }
   
       public DottedSeekBar(final Context context, final AttributeSet attrs) {
           super(context, attrs);
           init(attrs);
       }
   
       public DottedSeekBar(final Context context, final AttributeSet attrs, final int defStyle) {
           super(context, attrs, defStyle);
           init(attrs);
       }
   
       /**
        * Initializes Seek bar extended attributes from xml
        *
        * @param attributeSet {@link AttributeSet}
        */
       private void init(final AttributeSet attributeSet) {
           final TypedArray attrsArray = getContext().obtainStyledAttributes(attributeSet, R.styleable.DottedSeekBar, 0, 0);
   
           final int dotsArrayResource = attrsArray.getResourceId(R.styleable.DottedSeekBar_dots_positions, 0);
   
           if (0 != dotsArrayResource) {
               mDotsPositions = getResources().getIntArray(dotsArrayResource);
           }
   
           final int dotDrawableId = attrsArray.getResourceId(R.styleable.DottedSeekBar_dots_drawable, 0);
   
           if (0 != dotDrawableId) {
               mDotBitmap = BitmapFactory.decodeResource(getResources(), dotDrawableId);
           }
       }
   
       /**
        * @param dots to be displayed on this SeekBar
        */
       public void setDots(final int[] dots) {
           mDotsPositions = dots;
           invalidate();
       }
   
       /**
        * @param dotsResource resource id to be used for dots drawing
        */
       public void setDotsDrawable(final int dotsResource) {
           mDotBitmap = BitmapFactory.decodeResource(getResources(), dotsResource);
           invalidate();
       }
   
       @Override
       protected synchronized void onDraw(final Canvas canvas) {
           super.onDraw(canvas);
   
           final int width = getMeasuredWidth();
           final int step = width / getMax();
   
           if (null != mDotsPositions && 0 != mDotsPositions.length && null != mDotBitmap) {
               // draw dots if we have ones
               for (int position : mDotsPositions) {
                   canvas.drawBitmap(mDotBitmap, position * step, 0, null);
               }
           }
       }
   }
   

   Don't forget about custom attrs in res/values/attrs.xml:

   <resources>
       <declare-styleable name="DottedSeekBar">
           <attr name="dots_positions" format="reference"/>
           <attr name="dots_drawable" format="reference"/>
       </declare-styleable>
   </resources>
   

   And using the following code:

   setContentView(R.layout.main);
   
   final DottedSeekBar bar = (DottedSeekBar) findViewById(R.id.seekBar);
   
   bar.setDots(new int[] {25, 50, 75});
   bar.setDotsDrawable(R.drawable.dot);
   

   with main.xml layout:

   <LinearLayout
           xmlns:android="http://schemas.android.com/apk/res/android"
           xmlns:custom="http://schemas.android.com/apk/res/com.example.TestApp"
           android:orientation="vertical"
           android:layout_width="match_parent"
           android:layout_height="match_parent">
   
       <com.example.TestApp.DottedSeekBar
           android:layout_width="match_parent"
           android:layout_height="wrap_content"
           android:id="@+id/seekBar" />
   </LinearLayout>
   

   or just single main.xml:

   <LinearLayout
           xmlns:android="http://schemas.android.com/apk/res/android"
           xmlns:custom="http://schemas.android.com/apk/res/com.example.TestApp"
           android:orientation="vertical"
           android:layout_width="match_parent"
           android:layout_height="match_parent">
   
       <com.example.TestApp.DottedSeekBar
           android:layout_width="match_parent"
           android:layout_height="wrap_content"
           android:id="@+id/seekBar"
           custom:dots_positions="@array/dots"
           custom:dots_drawable="@drawable/dot" />
   </LinearLayout>
   

   You could obtain the following image:

3. Refer to this example for more ideas;

Regarding putting dots on specific 'time': SeekBar is not about time, so it's up to You to provide any time-related logic.

Answer 2

The above answer is completely correct but the onDraw method could have been improved a little.

        @Override
        protected synchronized void onDraw(final Canvas canvas) {
            super.onDraw(canvas);

            final float width=getMeasuredWidth()-getPaddingLeft()-getPaddingRight();
            final float step=width/(float)(getMax());

            if (null != mDotsPositions && 0 != mDotsPositions.length && null != mDotBitmap) {
                // draw dots if we have ones
                for (int position : mDotsPositions) {
                    canvas.drawBitmap(mDotBitmap, position * step, 0, null);
                }
            }
        }