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package de.danoeh.antennapod.view;
import android.content.Context;
import android.content.res.TypedArray;
import android.database.DataSetObserver;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.View;
import androidx.annotation.Nullable;
import androidx.vectordrawable.graphics.drawable.ArgbEvaluator;
import androidx.viewpager.widget.ViewPager;
public class PagerIndicatorView extends View {
private final Paint paint = new Paint();
private float position = 0;
private int numPages = 0;
private int disabledPage = -1;
private int circleColor = 0;
private int circleColorHighlight = -1;
public PagerIndicatorView(Context context) {
super(context);
setup();
}
public PagerIndicatorView(Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
setup();
}
public PagerIndicatorView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
setup();
}
private void setup() {
paint.setAntiAlias(true);
paint.setStyle(Paint.Style.FILL);
int[] colorAttrs = new int[] { android.R.attr.textColorSecondary };
TypedArray a = getContext().obtainStyledAttributes(colorAttrs);
circleColorHighlight = a.getColor(0, 0xffffffff);
circleColor = (Integer) new ArgbEvaluator().evaluate(0.8f, 0x00ffffff, circleColorHighlight);
a.recycle();
}
public void setViewPager(ViewPager pager) {
numPages = pager.getAdapter().getCount();
pager.getAdapter().registerDataSetObserver(new DataSetObserver() {
@Override
public void onChanged() {
numPages = pager.getAdapter().getCount();
invalidate();
}
});
pager.addOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
PagerIndicatorView.this.position = position + positionOffset;
invalidate();
}
});
}
public void setDisabledPage(int disabledPage) {
this.disabledPage = disabledPage;
invalidate();
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
for (int i = 0; i < numPages; i++) {
if ((int) Math.floor(position) == i) {
// This is the current dot
drawCircle(canvas, i, (float) (1 - (position - Math.floor(position))));
} else if ((int) Math.ceil(position) == i) {
// This is the next dot
drawCircle(canvas, i, (float) (position - Math.floor(position)));
} else {
drawCircle(canvas, i, 0);
}
}
}
private void drawCircle(Canvas canvas, int position, float frac) {
float circleRadiusSmall = canvas.getHeight() * 0.26f;
float circleRadiusBig = canvas.getHeight() * 0.35f;
float circleRadiusDelta = (circleRadiusBig - circleRadiusSmall);
float start = 0.5f * (canvas.getWidth() - numPages * 1.5f * canvas.getHeight());
paint.setStrokeWidth(canvas.getHeight() * 0.3f);
if (position == disabledPage) {
paint.setStyle(Paint.Style.STROKE);
} else {
paint.setStyle(Paint.Style.FILL_AND_STROKE);
}
paint.setColor((Integer) new ArgbEvaluator().evaluate(frac, circleColor, circleColorHighlight));
canvas.drawCircle(start + (position * 1.5f + 0.75f) * canvas.getHeight(), 0.5f * canvas.getHeight(),
circleRadiusSmall + frac * circleRadiusDelta, paint);
}
}
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