HorizontalScrollHighDownView.java

package com.laotan.easyreader.view;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.support.annotation.Nullable;
import android.util.AttributeSet;
import android.view.View;
import android.view.WindowManager;

/**
 * Created by quantan.liu on 2017/3/4.
 */

public class HorizontalScrollHighDownView extends View {

    private int windowWidth;

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

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

    public HorizontalScrollHighDownView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        WindowManager wm = (WindowManager) getContext()
                .getSystemService(Context.WINDOW_SERVICE);
        windowWidth = wm.getDefaultDisplay().getWidth();//获取屏幕宽度

    }

    @Override
    protected void onDraw(Canvas canvas) {
        Paint mPaint = new Paint();
        mPaint.setStyle(Paint.Style.FILL);
        mPaint.setAntiAlias(true);
        mPaint.setColor(Color.WHITE);
       canvas.drawCircle(windowWidth/2,1050,1000,mPaint);
    }
}