10.自定义Indicator

在内置Indicator不满足需求时可以通过自定义IndicatorView实现,例子将实现一个如下图所示的IndicatorView。

Custom IndicatorView

（1）自定义View并继承BaseIndicatorView，根据需求进行指示器的绘制。

public class FigureIndicatorView extends BaseIndicatorView {

    private int radius = DpUtils.dp2px(20);

    private int backgroundColor = Color.parseColor("#88FF5252");

    private int textColor = Color.WHITE;

    private int textSize=DpUtils.dp2px(13);

    public FigureIndicatorView(Context context) {
        this(context, null);
    }

    public FigureIndicatorView(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public FigureIndicatorView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        mPaint = new Paint();
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        setMeasuredDimension(2 * radius, 2 * radius);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        mPaint.setColor(backgroundColor);
        canvas.drawCircle(getWidth() / 2, getHeight() / 2, radius, mPaint);
        mPaint.setColor(textColor);
        mPaint.setTextSize(textSize);
        String text = currentPosition + 1 + "/" + pageSize;
        int textWidth = (int) mPaint.measureText(text);
        Paint.FontMetricsInt fontMetricsInt = mPaint.getFontMetricsInt();
        int baseline = (getMeasuredHeight() - fontMetricsInt.bottom + fontMetricsInt.top) / 2 - fontMetricsInt.top;
        canvas.drawText(text, (getWidth() - textWidth) / 2, baseline, mPaint);
    }

    public void setRadius(int radius) {
        this.radius = radius;
    }

    @Override
    public void setBackgroundColor(@ColorInt int backgroundColor) {
        this.backgroundColor = backgroundColor;
    }

    public void setTextSize(int textSize) {
        this.textSize = textSize;
    }

    public void setTextColor(int textColor) {
        this.textColor = textColor;
    }
}

（2）设置自定义指示器

    FigureIndicatorView indicatorView = new FigureIndicatorView(mContext);
    indicatorView.setRadius(getResources().getDimensionPixelOffset(R.dimen.dp_18));
    indicatorView.setTextSize(getResources().getDimensionPixelSize(R.dimen.sp_13));
    indicatorView.setBackgroundColor(Color.parseColor("#aa118EEA"));

    mViewPager.setAdapter(adapter)
              .setIndicatorView(indicatorView)
              .create(getPicList(4));