Utils.java

package com.yalantis.ucrop.util;

import android.content.Context;
import android.content.res.Resources;
import android.util.DisplayMetrics;

/**
 * author：luck
 * project：LoveCare
 * package：com.tongyu.luck.lovecare.util
 * email：893855882@qq.com
 * data：16/8/10
 */
public class Utils {
    /**
     * This method converts  dp unit to equivalent pixels, depending on device density.
     *
     * @param dp      A value in dp (density independent pixels) unit. Which we need to convert into pixels
     * @param context Context to get resources and device specific display metrics
     * @return A float value to represent px equivalent to dp depending on device density
     */
    public static float convertDpToPixel(float dp, Context context) {
        Resources resources = context.getResources();
        DisplayMetrics metrics = resources.getDisplayMetrics();
        float px = dp * (metrics.densityDpi / 160f);
        return px;
    }

    /**
     * This method converts device specific pixels to density independent pixels.
     *
     * @param px      A value in px (pixels) unit. Which we need to convert into db
     * @param context Context to get resources and device specific display metrics
     * @return A float value to represent dp equivalent to px value
     */
    public static float convertPixelsToDp(float px, Context context) {
        Resources resources = context.getResources();
        DisplayMetrics metrics = resources.getDisplayMetrics();
        float dp = px / (metrics.densityDpi / 160f);
        return dp;
    }


    /**
     * dpתpx
     */
    public static int dip2px(Context ctx, float dpValue) {
        final float scale = ctx.getResources().getDisplayMetrics().density;
        return (int) (dpValue * scale + 0.5f);
    }


    /**
     * pxתdp
     */
    public static int px2dip(Context ctx, float pxValue) {
        final float scale = ctx.getResources().getDisplayMetrics().density;
        return (int) (pxValue / scale + 0.5f);
    }

    /**
     * 防止连续点击跳转两个页面
     */
    public static long lastClickTime;

    public static boolean isFastDoubleClick() {
        long time = System.currentTimeMillis();
        if (time - lastClickTime < 800) {
            return true;
        }
        lastClickTime = time;
        return false;
    }

    /**
     * 防止连续点击跳转两个页面
     */
    public static long lastClickTime2;

    public static boolean isFastDoubleClick2() {
        long time = System.currentTimeMillis();
        if (time - lastClickTime < 800) {
            return true;
        }
        lastClickTime2 = time;
        return false;
    }

    /**
     * 判断 一个字段的值否为空
     *
     * @param s
     * @return
     * @author Michael.Zhang 2013-9-7 下午4:39:00
     */
    public static boolean isNull(String s) {
        if (null == s || s.equals("") || s.equalsIgnoreCase("null")) {
            return true;
        }

        return false;
    }
}