Home » Android » android seek bar customization,

android seek bar customization,

Posted by: admin June 15, 2020 Leave a comment

Questions:

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

How to&Answers:

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:
    enter image description here

  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:

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);
                }
            }
        }