direction

I have a class that extends SimpleOnPageChangeListener and in my onPageScrollStateChanged method I want to be able to determine whether the user has swiped forwards or backwards through the ViewPager. I.e. Whether they have swiped left-to-right or right-to-left. I've done a lot of googling on this but I can't find anything about it. I was expecting the onPageScrollStateChanged method would provide a parameter stating which direction the swipe was but it doesn't. @Override public void onPageScrollStateChanged(int state) { // Determine whether the user is swiping forwards or backwards through

I'm building a mobile app for IOS, with html5. I'm using "-webkit-overflow-scrolling: touch" to get the native inertia scrolling, but it's very buggy. I've solved the issues with content not rendering until the scrolling stops, but one persistent bug is this: When I try to scroll up and down, nothing happens, but when I try to scroll horizontally, the content scrolls vertically (90 degrees off axis). If I navigate around my app and come back to the page, it will sometimes be fixed. Also, sometimes it won't scroll at all, despite being full of content. From what I've googled, the consensus

Could someone explain what is the cause of the severe slowdown when iterating bash arrays backwards? Example: time bash -c 'arr=();for i in {1..100000}; do arr+=( $i );done; echo "Straight"; i=0;while (( $i < 100000 )); do current_element=${arr[$i]}; ((i++));done' Straight real 0m0.270s user 0m0.269s sys 0m0.002s time bash -c 'arr=();for i in {1..100000}; do arr+=( $i );done; echo "Reverse"; i=99999;while (( $i > 0 )); do current_element=${arr[$i]}; ((i--));done' Reverse real 0m25.569s user 0m25.589s sys 0m0.008s Also ${arr[i-1]} + ${arr[i]} is much faster than ${arr[i]} + ${arr[i-1]} Thanks

最基础的LED跑马灯效果：从一侧到另一侧，然后返回 byte ledPin[] = { 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 }; //为LED引脚创建数组 int ledDelay( 65 ); //变化之间的延时 int direction = 1 ; int currentLED = 0 ; unsigned long changeTime; void setup() { for ( int x = 0 ; x < 10 ; x++) { pinMode(ledPin[x], OUTPUT); //设置所有引脚为输出模式 } changeTime = millis(); } void loop() { //如果距离最后一次变灯已经过去ledDelay毫秒 if ( (millis()-changeTime) > ledDelay) { changeLED(); //判断LED距离上次改变的时间是否超过一段确定的时间，是为了在需要时允许其他代码在主程序运行。 changeTime = millis(); } void changeLED() { for ( int x = 0 ; x< 10 ; x++) { digitalWrite(ledPin[x], LOW); //关闭所有LED } digitalWrite(ledPin

I have seen a few examples of this but am not sure exactly how to implement it, (such as iPhone Compass GPS Direction ) in do I need to call calcBearingWithLatitude in (void)startup? All I am trying to do is have the compass pull a point from memory and use that point as its "north" so to speak and point to it, no need for distance or anything like that. My implementation file as of now looks like @implementation TrackerViewController @synthesize locationManager; @synthesize compass; @synthesize headingLabel; - (void)viewWillAppear:(BOOL)animated { [super viewWillAppear:animated]; if (

Hi I would like to in my application display something like: you're destination is 400 ft north west. I currently use the getDistanceFrom method but that only gives me the feet between 2 locations. Thanks for your help. You probably should simply use Latitude Longitude equations to calculate the bearing and then set certain ranges of bearings to be SW,S,SE, etc. http://www.movable-type.co.uk/scripts/latlong.html 来源： https://stackoverflow.com/questions/2630789/how-to-get-directions-on-the-iphone-or-ipad