Android获取窗体信息的Util方法

package com.wangyi.tools;import android.app.Activity;import android.util.DisplayMetrics;public class DisplayUtils {    private static DisplayUtils instance;  private Activity mActivity;  private DisplayUtils(Activity mActivity){    this.mActivity=mActivity;  }  public static DisplayUtils getInstance(Activity mActivity){    if(instance==null){      instance=new DisplayUtils(mActivity);    }    return instance;  }  public final int[] getScreenSize(){    int[] size=new int[2];    DisplayMetrics dm = new DisplayMetrics();    mActivity.getWindowManager().getDefaultDisplay().getMetrics(dm);    size[0]=dm.widthPixels;    size[1]=dm.heightPixels;    return size;  }  public final static int getWindowWidth(Activity mActivity) {    DisplayMetrics dm = new DisplayMetrics();    mActivity.getWindowManager().getDefaultDisplay().getMetrics(dm);    return dm.widthPixels;  }  public final static int getWindowHeight(Activity mActivity) {    DisplayMetrics dm = new DisplayMetrics();    mActivity.getWindowManager().getDefaultDisplay().getMetrics(dm);    return dm.heightPixels;  }}