Android 判断app是否在前台还是在后台运行

Android 断定app是不是在前台还是在后台运行，直接看代码，可直接应用。

public static boolean isBackground(Context context) {
		ActivityManager activityManager = (ActivityManager) context
				.getSystemService(Context.ACTIVITY_SERVICE);
		List<RunningAppProcessInfo> appProcesses = activityManager
				.getRunningAppProcesses();
		for (RunningAppProcessInfo appProcess : appProcesses) {
			if (appProcess.processName.equals(context.getPackageName())) {
				/*
				BACKGROUND=400 EMPTY=500 FOREGROUND=100
				GONE=1000 PERCEPTIBLE=130 SERVICE=300 ISIBLE=200
				 */
				Log.i(context.getPackageName(), "此appimportace ="
						+ appProcess.importance
						+ ",context.getClass().getName()="
						+ context.getClass().getName());
				if (appProcess.importance != RunningAppProcessInfo.IMPORTANCE_FOREGROUND) {
					Log.i(context.getPackageName(), "处于后台"
							+ appProcess.processName);
					return true;
				} else {
					Log.i(context.getPackageName(), "处于前台"
							+ appProcess.processName);
					return false;
				}
			}
		}
		return false;
	}public st