getScaledTouchSlop() 的返回值为 int 类型，表示一次滑动的距离。一般的用法为：获得�手指的滑动距离，值为 A ，当� A 的大小大于该 API 返回的值时开始滑动控件，反之，控件不移动。
ViewConfiguration 相关属性的获取方式
ViewConfiguration.get(context).getXXX();
ViewConfiguration 滑动参数�类
/**
*Contains methods to standard constants used in the UI for *timeouts, sizes, and distances.
* UI 中时间、大小、距离的常量
*/
public class ViewConfiguration {
// 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
private static final int SCROLL_BAR_SIZE = 10;
//定义滚动条逐渐消失的时间，单位是毫秒
private static final int SCROLL_BAR_FADE_DURATION = 250;
// 默认的滚动条多少秒之后消失，单位是毫秒
private static final int SCROLL_BAR_DEFAULT_DELAY = 300;
// 定义边缘地方褪色的长度
private static final int FADING_EDGE_LENGTH = 12;
//定义子控件按下状态的持续事件
private static final int PRESSED_STATE_DURATION = 125;
//定义一个按下状态转变成长按状态的转变时间
private static final int LONG_PRESS_TIMEOUT = 500;
//定义用户在按住适当按钮，弹出全局的对话框的持续时间
private static final int GLOBAL_ACTIONS_KEY_TIMEOUT = 500;
//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
private static final int TAP_TIMEOUT = 115;
/**
* Defines the duration in milliseconds we will wait to see if a touch event
* is a jump tap. If the user does not complete the jump tap within this interval, it is
* considered to be a tap.
*/
//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
private static final int JUMP_TAP_TIMEOUT = 500;
//定义双击事件的间隔时间
private static final int DOUBLE_TAP_TIMEOUT = 300;
//定义一个缩放控制反馈到用户界面的时间
private static final int ZOOM_CONTROLS_TIMEOUT = 3000;
/**
* Inset in pixels to look for touchable content when the user touches the edge of the screen
*/
private static final int EDGE_SLOP = 12;
/**
* Distance a touch can wander before we think the user is scrolling in pixels
*/
private static final int TOUCH_SLOP = 16;
/**
* Distance a touch can wander before we think the user is attempting a paged scroll
* (in dips)
*/
private static final int PAGING_TOUCH_SLOP = TOUCH_SLOP * 2;
/**
* Distance between the first touch and second touch to still be considered a double tap
*/
private static final int DOUBLE_TAP_SLOP = 100;
/**
* Distance a touch needs to be outside of a window's bounds for it to
* count as outside for purposes of dismissing the window.
*/
private static final int WINDOW_TOUCH_SLOP = 16;
//用来初始化fling的最小速度，单位是每秒多少像素
private static final int MINIMUM_FLING_VELOCITY = 50;
//用来初始化fling的最大速度，单位是每秒多少像素
private static final int MAXIMUM_FLING_VELOCITY = 4000;
//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
@Deprecated
private static final int MAXIMUM_DRAWING_CACHE_SIZE = 320 * 480 * 4; // HVGA screen, ARGB8888
//flings和scrolls摩擦力度大小的系数
private static float SCROLL_FRICTION = 0.015f;
/**
* Max distance to over scroll for edge effects
*/
private static final int OVERSCROLL_DISTANCE = 0;
/**
* Max distance to over fling for edge effects
*/
private static final int OVERFLING_DISTANCE = 4;
