Bugdr0id Bugdr0id - 4 months ago 47
Android Question

Android - Seekbar with text following

I want to create a custom SeekBar with following text that updates its position (and progress) according to where the thumb is positioned.

What do I need to achieve:

Seekbar with text following

Assumptions:


  1. Min value = 1000

  2. Max Value = 30000



Case 1:
The progress is on 0% (or min value = 1000) and the text should align to the left border of thumb.

Case 2:
The progress text is displayed above Thumb drawable and centered since it has space to draw itself.

Case 3:
The progress is on 100% (or max value = 3000) and the text should align to the right border of Thumb.

What do i already have:

public class CustomSeekBar extends SeekBar {
private Paint paint;
private int[] coordCenterTemp = new int[]{0, 0};

// .....

private void init() {
paint = new Paint();
paint.setColor(Color.BLACK);
paint.setStyle(Paint.Style.STROKE);
paint.setTextSize(sp2px(20));
paint.setTextAlign(Paint.Align.CENTER);
}

private int sp2px(int sp) {
return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP, sp, getResources().getDisplayMetrics());
}

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

String str = String.valueOf(getProgress());

int thumb_x = (int) (( (double)this.getProgress()/this.getMax() ) * (double)(this.getWidth()));
int thumb_y = 30;

int textMeasure = (int) paint.measureText(str, 0, str.length());

if ((textMeasure / 2) + thumb_x <= getRight()) {
coordCenterTemp[0] = thumb_x;
coordCenterTemp[1] = thumb_y;
}
canvas.drawText(str, coordCenterTemp[0], coordCenterTemp[1], paint);
}
}


This is working for when the progress is 50%. As soon as I slide to right or left, the Text is painted with some offset to wrong direction.

How can I accomplish this?

Answer

I do this recently in my project and this is my code:

first define a ThumbTextView which is TextView above you Seekbar like this:

public class ThumbTextView extends TextView {

    private LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);
    private int width = 0;

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

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

    public void attachToSeekBar(SeekBar seekBar) {
        String content = getText().toString();
        if (TextUtils.isEmpty(content) || seekBar == null)
            return;
        float contentWidth = this.getPaint().measureText(content);
        int realWidth = width - seekBar.getPaddingLeft() - seekBar.getPaddingRight();
        int maxLimit = (int) (width - contentWidth - seekBar.getPaddingRight());
        int minLimit = seekBar.getPaddingLeft();
        float percent = (float) (1.0 * seekBar.getProgress() / seekBar.getMax());
        int left = minLimit + (int) (realWidth * percent - contentWidth / 2.0);
        left = left <= minLimit ? minLimit : left >= maxLimit ? maxLimit : left;
        lp.setMargins(left, 0, 0, 0);
        setLayoutParams(lp);

    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        if (width == 0)
            width = MeasureSpec.getSize(widthMeasureSpec);
    }
}

Then define your ThumbTextSeekBar which contains Seekbar & ThumbSeekbar like this:

public class ThumbTextSeekBar extends LinearLayout {

    public ThumbTextView tvThumb;
    public SeekBar seekBar;
    private SeekBar.OnSeekBarChangeListener onSeekBarChangeListener;

    public ThumbTextSeekBar(Context context) {
        super(context);
        init();
    }

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

    private void init() {
        LayoutInflater.from(getContext()).inflate(R.layout.view_thumb_text_seekbar, this);
        setOrientation(LinearLayout.VERTICAL);
        tvThumb = (ThumbTextView) findViewById(R.id.tvThumb);
        seekBar = (SeekBar) findViewById(R.id.sbProgress);
        seekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
            @Override
            public void onStopTrackingTouch(SeekBar seekBar) {
                if (onSeekBarChangeListener != null)
                    onSeekBarChangeListener.onStopTrackingTouch(seekBar);
            }

            @Override
            public void onStartTrackingTouch(SeekBar seekBar) {
                if (onSeekBarChangeListener != null)
                    onSeekBarChangeListener.onStartTrackingTouch(seekBar);
            }

            @Override
            public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
                if (onSeekBarChangeListener != null)
                    onSeekBarChangeListener.onProgressChanged(seekBar, progress, fromUser);
                tvThumb.attachToSeekBar(seekBar);
            }
        });

    }

    public void setOnSeekBarChangeListener(SeekBar.OnSeekBarChangeListener l) {
        this.onSeekBarChangeListener = l;
    }

    public void setThumbText(String text) {
        tvThumb.setText(text);
    }

    public void setProgress(int progress) {
        if (progress == seekBar.getProgress() && progress == 0) {
            seekBar.setProgress(1);
            seekBar.setProgress(0);
        } else {
            seekBar.setProgress(progress);
        }
    }
}

Use it with something like this:

thumbTextSeekbar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
            @Override
            public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {

                thumbTextSeekbar.setThumbText(seekBar.getProgress()));

            }

            @Override
            public void onStartTrackingTouch(SeekBar seekBar) {
                thumbTextSeekbar.showTxt();
            }

            @Override
            public void onStopTrackingTouch(SeekBar seekBar) {
                thumbTextSeekbar.hideTxt();
            }
        });

The output:

enter image description here