android ViewConfiguration
ViewConfiguration
1.有时候要获取一些android UI的中一些默认参数的来进行操作设置,就要用到ViewConfiguration
官方飞解释是:ViewConfiguration 是
Contains methods to standard constants used in the UI for timeouts, sizes, and distances.
解释就是Configuration包含的方法和常量是可用于UI 超时,大小和距离的设置
2.这个类包含的常量有:
1 /** 2 * 包含了方法和标准的常量用来设置UI的超时、大小和距离 3 */ 4 public class ViewConfiguration { 5 // 设定水平滚动条的宽度和垂直滚动条的高度,单位是像素px 6 private static final int SCROLL_BAR_SIZE = 10; 7 8 //定义滚动条逐渐消失的时间,单位是毫秒 9 private static final int SCROLL_BAR_FADE_DURATION = 250; 10 11 // 默认的滚动条多少秒之后消失,单位是毫秒 12 private static final int SCROLL_BAR_DEFAULT_DELAY = 300; 13 14 // 定义边缘地方褪色的长度 15 private static final int FADING_EDGE_LENGTH = 12; 16 17 //定义子控件按下状态的持续事件 18 private static final int PRESSED_STATE_DURATION = 125; 19 20 //定义一个按下状态转变成长按状态的转变时间 21 private static final int LONG_PRESS_TIMEOUT = 500; 22 23 //定义用户在按住适当按钮,弹出全局的对话框的持续时间 24 private static final int GLOBAL_ACTIONS_KEY_TIMEOUT = 500; 25 26 //定义一个touch事件中是点击事件还是一个滑动事件所需的时间,如果用户在这个时间之内滑动,那么就认为是一个点击事件 27 private static final int TAP_TIMEOUT = 115; 28 29 /** 30 * Defines the duration in milliseconds we will wait to see if a touch event 31 * is a jump tap. If the user does not complete the jump tap within this interval, it is 32 * considered to be a tap. 33 */ 34 //定义一个touch事件时候是一个点击事件。如果用户在这个时间内没有完成这个点击,那么就认为是一个点击事件 35 private static final int JUMP_TAP_TIMEOUT = 500; 36 37 //定义双击事件的间隔时间 38 private static final int DOUBLE_TAP_TIMEOUT = 300; 39 40 //定义一个缩放控制反馈到用户界面的时间 41 private static final int ZOOM_CONTROLS_TIMEOUT = 3000; 42 43 /** 44 * Inset in pixels to look for touchable content when the user touches the edge of the screen 45 */ 46 private static final int EDGE_SLOP = 12; 47 48 /** 49 * Distance a touch can wander before we think the user is scrolling in pixels 50 */ 51 private static final int TOUCH_SLOP = 16; 52 53 /** 54 * Distance a touch can wander before we think the user is attempting a paged scroll 55 * (in dips) 56 */ 57 private static final int PAGING_TOUCH_SLOP = TOUCH_SLOP * 2; 58 59 /** 60 * Distance between the first touch and second touch to still be considered a double tap 61 */ 62 private static final int DOUBLE_TAP_SLOP = 100; 63 64 /** 65 * Distance a touch needs to be outside of a window's bounds for it to 66 * count as outside for purposes of dismissing the window. 67 */ 68 private static final int WINDOW_TOUCH_SLOP = 16; 69 70 //用来初始化fling的最小速度,单位是每秒多少像素 71 private static final int MINIMUM_FLING_VELOCITY = 50; 72 73 //用来初始化fling的最大速度,单位是每秒多少像素 74 private static final int MAXIMUM_FLING_VELOCITY = 4000; 75 76 //视图绘图缓存的最大尺寸,以字节表示。在ARGB888格式下,这个尺寸应至少等于屏幕的大小 77 @Deprecated 78 private static final int MAXIMUM_DRAWING_CACHE_SIZE = 320 * 480 * 4; // HVGA screen, ARGB8888 79 80 //flings和scrolls摩擦力度大小的系数 81 private static float SCROLL_FRICTION = 0.015f; 82 83 /** 84 * Max distance to over scroll for edge effects 85 */ 86 private static final int OVERSCROLL_DISTANCE = 0; 87 88 /** 89 * Max distance to over fling for edge effects 90 */ 91 private static final int OVERFLING_DISTANCE = 4; 92 93 }
3.常用方法有:
4.用途:
场景:当你想要在滑动时候设置用户滑动最小速度,和最大速度,滑动的默认距离可以这么设置参数。
1 ViewConfiguration vc = ViewConfiguration.get(context); 2 mSlop = vc.getScaledTouchSlop(); 3 mMinFlingVelocity = vc.getMinimumFlingVelocity(); 4 mMinFlingVelocity = vc.getMaximumFlingVelocity();