uu-android/WeiChat/src/main/java/com/xzjmyk/pm/activity/util/DisplayUtil.java

package com.xzjmyk.pm.activity.util;

import android.app.Activity;
import android.content.Context;
import android.view.WindowManager;

public class DisplayUtil {

	public static final int voice_view_max_width = 165;// dp
	public static final int voice_view_min_width = 30;// dp
	public static final float voice_max_length = 30 ;// 声音最长可以表现为多少毫秒（实际本程序是60s,但是如果这里是60s的话，当时间很短，就没啥差别

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

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

	public static int getVoiceViewWidth(Context context, int seconds) {
		if (seconds >= voice_max_length) {
			return dip2px(context, voice_view_max_width);
		}
		final int dpLen = (int) ((seconds / voice_max_length) * (voice_view_max_width - voice_view_min_width)) + voice_view_min_width;
		return dip2px(context, dpLen);
	}

	/**
	 * 将px值转换为sp值，保证文字大小不变
	 *
	 * @param pxValue
	 * @param （DisplayMetrics类中属性scaledDensity）
	 * @return
	 */
	public static int px2sp(Context context, float pxValue) {
		final float fontScale = context.getResources().getDisplayMetrics().scaledDensity;
		return (int) (pxValue / fontScale + 0.5f);
	}

	/**
	 * 设置添加屏幕的背景透明度
	 *
	 * @param bgAlpha
	 */
	public static void backgroundAlpha(Activity activity, float bgAlpha) {
		WindowManager.LayoutParams lp = activity.getWindow().getAttributes();
		lp.alpha = bgAlpha; //0.0-1.0
		activity.getWindow().setAttributes(lp);
	}
}