SimpleFooter.java

package zrc.widget;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Paint.Align;
import android.graphics.Paint.Style;
import android.util.TypedValue;

public class SimpleFooter implements Footable {
    private float PI = (float) Math.PI;
    private int mPice = 6;
    private Paint mPaint;
    private int mTime = 0;
    private int mCircleColor;
    private int mHeight;

    public SimpleFooter(Context context) {
        mPaint = new Paint();
        mPaint.setAntiAlias(true);
        mPaint.setStyle(Style.FILL);
        int fontSize = (int) TypedValue
                .applyDimension(TypedValue.COMPLEX_UNIT_SP, 20, context.getResources()
                        .getDisplayMetrics());
        mPaint.setTextSize(fontSize);
        mPaint.setTextAlign(Align.CENTER);
        mCircleColor = 0xffffffff;
        mHeight = (int) TypedValue
                .applyDimension(TypedValue.COMPLEX_UNIT_DIP, 30, context.getResources()
                        .getDisplayMetrics());
    }

    public void setCircleColor(int color) {
        mCircleColor = color;
    }

    @Override
    public boolean draw(Canvas canvas, int left, int top, int right, int bottom) {
        final int width = right - left;
        final int height = mHeight;
        final int viewHeight = bottom - top;
        canvas.save();
        canvas.clipRect(left + 5, top + 1, right + 5, bottom - 1);
        mPaint.setColor(mCircleColor);
        for (int i = 0; i < mPice; i++) {
            int angleParam = mTime * 5;
            float angle = -(i * (360 / mPice) - angleParam) * PI / 180;
            float radius = height / 4;
            float x = (float) (width / 2 + radius * Math.cos(angle));
            float y = (float) (top + Math.max(height, viewHeight) / 2 + radius * Math.sin(angle));
            canvas.drawCircle(x, y, height / 15, mPaint);
        }
        mTime++;
        canvas.restore();
        return true;
    }

    @Override
    public int getHeight() {
        return mHeight;
    }
}