Add dynamic text over Android SeekBar thumb

问题

I'm trying to make this custom SeekBar in Android 2.2 and everything I do seems to be wrong! I'm trying to display the value of the seekbar over the thumb image of the SeekBar. Does anybody have some experiences with this?

回答1:

I have followed a different approach which provides more possibilities to customize the thumb. Final output will look like following:

First you have to design the layout which will be set as thumb drawable.

layout_seekbar_thumb.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:orientation="vertical">

    <LinearLayout
        android:layout_width="@dimen/seekbar_thumb_size"
        android:layout_height="@dimen/seekbar_thumb_size"
        android:background="@drawable/ic_seekbar_thumb_back"
        android:gravity="center"
        android:orientation="vertical">

        <TextView
            android:id="@+id/tvProgress"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="0"
            android:textColor="#000000"
            android:textSize="14sp" />

    </LinearLayout>

</LinearLayout>

Here seekbar_thumb_size can be any small size as per your requirement. I have used 30dp here. For background you can use any drawable/icon of your choice.

Now you need this view to be set as thumb drawable so get it with following code:

View thumbView = LayoutInflater.from(YourActivity.this).inflate(R.layout.layout_seekbar_thumb, null, false);

Here I suggest to initialize this view in onCreate() so no need to inflate it again and again.

Now set this view as thumb drawable when seekBar progress is changed. Add the following method in your code:

public Drawable getThumb(int progress) {
        ((TextView) thumbView.findViewById(R.id.tvProgress)).setText(progress + "");

        thumbView.measure(View.MeasureSpec.UNSPECIFIED, View.MeasureSpec.UNSPECIFIED);
        Bitmap bitmap = Bitmap.createBitmap(thumbView.getMeasuredWidth(), thumbView.getMeasuredHeight(), Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(bitmap);
        thumbView.layout(0, 0, thumbView.getMeasuredWidth(), thumbView.getMeasuredHeight());
        thumbView.draw(canvas);

        return new BitmapDrawable(getResources(), bitmap);
}

Now call this method from onProgressChanged().

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

                // You can have your own calculation for progress                    
                seekBar.setThumb(getThumb(progress));
            }

            @Override
            public void onStartTrackingTouch(SeekBar seekBar) {

            }

            @Override
            public void onStopTrackingTouch(SeekBar seekBar) {

            }
        });

Note: Also call getThumb() method when you initialize seekBar to initialize it with default value.

With this approach, you can have any custom view on progress change.

回答2:

I assume you've already extended the base class, so you have something like:

public class SeekBarHint extends SeekBar {
  public SeekBarHint (Context context) {
      super(context);
  }

  public SeekBarHint (Context context, AttributeSet attrs, int defStyle) {
      super(context, attrs, defStyle);
  }

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

Now you override the onDraw method with some of your own code. Insert the following:

@Override
protected void onDraw(Canvas c) {
    super.onDraw(c);
}

Now, you want to draw some text near the thumb, but there isn't a convenient way to get the thumb's x-position. We just need a little math.

@Override
protected void onDraw(Canvas c) {
    super.onDraw(c);
    int thumb_x = ( (double)this.getProgress()/this.getMax() ) * (double)this.getWidth();
    int middle = this.getHeight()/2;
    // your drawing code here, ie Canvas.drawText();
}

回答3:

seekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
            @Override
            public void onProgressChanged(SeekBar seekBar, int progress, boolean b) {
                int val = (progress * (seekBar.getWidth() - 2 * seekBar.getThumbOffset())) / seekBar.getMax();
                text_seekbar.setText("" + progress);
                text_seekbar.setX(seekBar.getX() + val + seekBar.getThumbOffset() / 2);
            }

            @Override
            public void onStartTrackingTouch(SeekBar seekBar) {
                text_seekbar.setVisibility(View.VISIBLE);

            }

            @Override
            public void onStopTrackingTouch(SeekBar seekBar) {
                text_seekbar.setVisibility(View.GONE);
            }
        });

回答4:

This worked for me

@Override
public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
int val = (progress * (seekBar.getWidth() - 2 * seekBar.getThumbOffset())) / seekBar.getMax();
_testText.setText("" + progress);
_testText.setX(seekBar.getX() + val + seekBar.getThumbOffset() / 2);
}

回答5:

Hey I found another solution, seems simpler:

 private void setText(){
    int progress = mSeekBar.getProgress();
    int max= mSeekBar.getMax();
    int offset = mSeekBar.getThumbOffset();
    float percent = ((float)progress)/(float)max;
    int width = mSeekBar.getWidth() - 2*offset;

    int answer =((int)(width*percent +offset - mText.getWidth()/2));
    mText.setX(answer);

}


@Override
public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
    setText();
    mText.setText(""+progress);
}

回答6:

This follow code aligns your TextView center to your SeekBar thumb center. YOUR_TEXT_VIEW width must be wrap_content in xml.

Hope this code will help you.

@Override
public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
       YOUR_TEXT_VIEW.setText(Integer.toString(progress));
       double pourcent = progress / (double) seekBar.getMax();
       int offset = seekBar.getThumbOffset();
       int seekWidth = seekBar.getWidth();
       int val = (int) Math.round(pourcent * (seekWidth - 2 * offset));
       int labelWidth = YOUR_TEXT_VIEW.getWidth();
       YOUR_TEXT_VIEW.setX(offset + seekBar.getX() + val
                 - Math.round(pourcent * offset)
                 - Math.round(pourcent * labelWidth/2));
}

回答7:

I used this library to create drawable text view and put that drawable into thumb programmatically.

https://github.com/amulyakhare/TextDrawable

Code is something like this:

seekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
        @Override
        public void onStartTrackingTouch(SeekBar seekBar) {
        }
        @Override
        public void onProgressChanged(SeekBar seekBar, int progress, boolean fromTouch) {
            String dynamicText = String.valueOf(progress);
            TextDrawable drawable = TextDrawable.builder()
                    .beginConfig()
                    .endConfig()
                    .buildRoundRect(dynamicText , Color.WHITE ,20);
            seekBar.setThumb(drawable);

        }
        @Override
        public void onStopTrackingTouch(SeekBar seekBar) {

        }
    });

回答8:

Works not bad for me
there is a little hardcode)
please write improvements which smbd may has

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.support.v7.widget.AppCompatSeekBar;
import android.util.AttributeSet;
import android.util.TypedValue;

public class CustomSeekBar extends AppCompatSeekBar {

    @SuppressWarnings("unused")
    private static final String TAG = CustomSeekBar.class.getSimpleName();

    private Paint paint;
    private Rect bounds;

    public String dimension;

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

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

    public CustomSeekBar(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        init();
    }

    private void init(){
        paint = new Paint();
        paint.setColor(Color.WHITE);
        paint.setStyle(Paint.Style.STROKE);
        paint.setTextSize(sp2px(14));

        bounds = new Rect();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        String label = String.valueOf(getProgress()) + dimension;
        paint.getTextBounds(label, 0, label.length(), bounds);
        float x = (float) getProgress() * (getWidth() - 2 * getThumbOffset()) / getMax() +
            (1 - (float) getProgress() / getMax()) * bounds.width() / 2 - bounds.width() / 2
            + getThumbOffset() / (label.length() - 1);
        canvas.drawText(label, x, paint.getTextSize(), paint);
    }

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

回答9:

IMO best way is to do it through code. It is really not that scary and we are all programmers after all :)

class ThumbDrawable(context: Context) : Drawable() {

    private val paint = Paint(Paint.ANTI_ALIAS_FLAG)
    private val textPaint = Paint(Paint.ANTI_ALIAS_FLAG)
    private val textBounds = Rect()

    private var shadowColor = context.resources.getColor(R.color.wallet_screen_option_shadow)
    private val size = context.resources.getDimensionPixelSize(R.dimen.thumbRadius).toFloat()
    private val textSize = context.resources.getDimensionPixelSize(R.dimen.thumbTextSize).toFloat()
    var progress: Int = 0

    init {
        textPaint.typeface = Typeface.createFromAsset(context.assets, "font/avenir_heavy.ttf")
        val accentColor = context.resources.getColor(R.color.accent)
        paint.color = accentColor
        textPaint.color = accentColor
        textPaint.textSize = textSize
        paint.setShadowLayer(size / 2, 0f, 0f, shadowColor)
    }

    override fun draw(canvas: Canvas) {
        Timber.d("bounds: $bounds")
        val progressAsString = progress.toString()
        canvas.drawCircle(bounds.left.toFloat(), bounds.top.toFloat(), size, paint)
        textPaint.getTextBounds(progressAsString, 0, progressAsString.length, textBounds)
        //0.6f is cause of the avenirs spacing, should be .5 for proper font
        canvas.drawText(progressAsString, bounds.left.toFloat() - textBounds.width() * 0.6f, bounds.top.toFloat() - size * 2, textPaint)
    }

    override fun setAlpha(alpha: Int) {
    }

    override fun getOpacity(): Int {
        return PixelFormat.OPAQUE
    }

    override fun setColorFilter(colorFilter: ColorFilter?) {
    }

}

and in your seekbar implementation

class CustomSeekBar @JvmOverloads constructor(context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0) :
        SeekBar(context, attrs, defStyleAttr) {

    init {
        thumb = ThumbDrawable(context)
        setPadding(0, 0, 0, 0);
    }

    override fun invalidate() {
        super.invalidate()
        if (thumb is ThumbDrawable) (thumb as ThumbDrawable).progress = progress

    }



}

final result is something like this

回答10:

I created this example to show how textview should be supported to different types of screen size and how to calculate the real position of Thumb because sometimes the position could be 0.

public class CustomProgressBar extends RelativeLayout implements AppCompatSeekBar.OnSeekBarChangeListener {

    @BindView(R.id.userProgressBar)
    protected AppCompatSeekBar progressSeekBar;
    @BindView(R.id.textPorcent)
    protected TextView porcent;
    @BindView(R.id.titleIndicator)
    protected TextView title;

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

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

    private void init() {
        LayoutInflater inflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        inflater.inflate(R.layout.custom_progressbar_view, this, true);
        ButterKnife.bind(this);
        setColors(R.color.green, R.color.progress_bar_remaining);
        progressSeekBar.setPadding(0, 0, 0, 0);
        progressSeekBar.setOnSeekBarChangeListener(this);
    }

    private void setPorcentTextViewPosition(float widthView) {
        int width = CoreUtils.getScreenSize().x;
        float xPosition = ((float) progressSeekBar.getProgress() / 100) * width;
        float finalPosition = xPosition - (widthView / 2f);
        if (width - xPosition < widthView) {
            porcent.setX(width - widthView);
        } else if (widthView < finalPosition) {
            porcent.setX(finalPosition);
        }
    }

    public void setColors(int progressDrawable, int remainingDrawable) {
        LayerDrawable layer = (LayerDrawable) progressSeekBar.getProgressDrawable();
        Drawable background = layer.getDrawable(0);
        Drawable progress = layer.getDrawable(1);

        background.setColorFilter(ContextCompat.getColor(getContext(), remainingDrawable), PorterDuff.Mode.SRC_IN);
        progress.setColorFilter(ContextCompat.getColor(getContext(), progressDrawable), PorterDuff.Mode.SRC_IN);
    }

    public void setValues(int progress, int remaining) {
        int value = (progress * remaining) / 100;
        progressSeekBar.setMax(remaining);
        porcent.setText(String.valueOf(value).concat("%"));

        porcent.post(new Runnable() {
            @Override
            public void run() {
                setPorcentTextViewPosition(porcent.getWidth());
            }
        });
        progressSeekBar.setProgress(value);
    }

    public void setTitle(String title) {
        this.title.setText(title);
    }

    @Override
    public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
    }

    @Override
    public void onStartTrackingTouch(SeekBar seekBar) {
    }

    @Override
    public void onStopTrackingTouch(SeekBar seekBar) {
    }
}

回答11:

Add a TextView to your layout. Add onSeekBarChangeListener.

You will want precision so that the text is exactly in the middle of your seek bar thumb, you have to a little calculation. This is because the width of the text is different. Say, you want to show numbers from 0 to 150. Width of 188 will be different from 111. Because of this, the text you are showing will always tilt to some side.

The way to solve it is to measure the width of the text, remove that from the width of the seekbar thumb, divide it by 2, and add that to the result that was given in the accepted answer. Now you would not care about how large the number range. Here is the code:

 override fun onProgressChanged(seekBar: SeekBar, progress: Int, fromUser: Boolean) {
                    val value = progress * (seekBar.width - 2 * seekBar.thumbOffset) / seekBar.max
                    label.text = progress.toString()
                    label.measure(0, 0)
                    val textWidth =  label.measuredWidth
                    val firstRemainder = seekThumbWidth - textWidth
                    val result = firstRemainder / 2
                    label.x = (seekBar.x + value + result)
                }

来源：https://stackoverflow.com/questions/10722746/add-dynamic-text-over-android-seekbar-thumb