ViewDragHelper (CommonLib API)

java.lang.Object
- apublic.lg.com.commonlib.swipeback.ViewDragHelper

```
public class ViewDragHelper
extends Object
```
ViewDragHelper is a utility class for writing custom ViewGroups. It offers a number of useful operations and state tracking for allowing a user to drag and reposition views within their parent ViewGroup.

嵌套类概要

嵌套类
限定符和类型类和说明

static class ViewDragHelper.Callback
A Callback is used as a communication channel with the ViewDragHelper back to the parent view using it.

嵌套类
限定符和类型	类和说明
`static class`	`ViewDragHelper.Callback` A Callback is used as a communication channel with the ViewDragHelper back to the parent view using it.

字段概要

字段
限定符和类型	字段和说明
`static int`	`DIRECTION_ALL` Indicates that a check should occur along all axes
`static int`	`DIRECTION_HORIZONTAL` Indicates that a check should occur along the horizontal axis
`static int`	`DIRECTION_VERTICAL` Indicates that a check should occur along the vertical axis
`static int`	`EDGE_ALL` Edge flag set indicating all edges should be affected.
`static int`	`EDGE_BOTTOM` Edge flag indicating that the bottom edge should be affected.
`static int`	`EDGE_LEFT` Edge flag indicating that the left edge should be affected.
`static int`	`EDGE_RIGHT` Edge flag indicating that the right edge should be affected.
`static int`	`EDGE_SIZE`
`static int`	`EDGE_TOP` Edge flag indicating that the top edge should be affected.
`static int`	`INVALID_POINTER` A null/invalid pointer ID.
`static int`	`STATE_DRAGGING` A view is currently being dragged.
`static int`	`STATE_IDLE` A view is not currently being dragged or animating as a result of a fling/snap.
`static int`	`STATE_SETTLING` A view is currently settling into place as a result of a fling or predefined non-interactive motion.

方法概要

所有方法静态方法实例方法具体方法
限定符和类型	方法和说明
`void`	`abort()` `cancel()`, but also abort all motion in progress and snap to the end of any animation.
`void`	`cancel()` The result of a call to this method is equivalent to `processTouchEvent(MotionEvent)` receiving an ACTION_CANCEL event.
`protected boolean`	`canScroll(android.view.View v, boolean checkV, int dx, int dy, int x, int y)` Tests scrollability within child views of v given a delta of dx.
`void`	`captureChildView(android.view.View childView, int activePointerId)` Capture a specific child view for dragging within the parent.
`boolean`	`checkTouchSlop(int directions)` Check if any pointer tracked in the current gesture has crossed the required slop threshold.
`boolean`	`checkTouchSlop(int directions, int pointerId)` Check if the specified pointer tracked in the current gesture has crossed the required slop threshold.
`boolean`	`continueSettling(boolean deferCallbacks)` Move the captured settling view by the appropriate amount for the current time.
`static ViewDragHelper`	`create(android.view.ViewGroup forParent, float sensitivity, ViewDragHelper.Callback cb)` Factory method to create a new ViewDragHelper.
`static ViewDragHelper`	`create(android.view.ViewGroup forParent, ViewDragHelper.Callback cb)` Factory method to create a new ViewDragHelper.
`android.view.View`	`findTopChildUnder(int x, int y)` Find the topmost child under the given point within the parent view's coordinate system.
`void`	`flingCapturedView(int minLeft, int minTop, int maxLeft, int maxTop)` Settle the captured view based on standard free-moving fling behavior.
`int`	`getActivePointerId()`
`android.view.View`	`getCapturedView()`
`int`	`getEdgeSize()` Return the size of an edge.
`float`	`getMinVelocity()` Return the currently configured minimum velocity.
`int`	`getTouchSlop()`
`int`	`getViewDragState()` Retrieve the current drag state of this helper.
`boolean`	`isCapturedViewUnder(int x, int y)` Determine if the currently captured view is under the given point in the parent view's coordinate system.
`boolean`	`isEdgeTouched(int edges)` Check if any of the edges specified were initially touched in the currently active gesture.
`boolean`	`isEdgeTouched(int edges, int pointerId)` Check if any of the edges specified were initially touched by the pointer with the specified ID.
`boolean`	`isPointerDown(int pointerId)` Check if the given pointer ID represents a pointer that is currently down (to the best of the ViewDragHelper's knowledge).
`boolean`	`isViewUnder(android.view.View view, int x, int y)` Determine if the supplied view is under the given point in the parent view's coordinate system.
`void`	`processTouchEvent(android.view.MotionEvent ev)` Process a touch event received by the parent view.
`void`	`setEdgeSize(int size)` Set the size of an edge.
`void`	`setEdgeTrackingEnabled(int edgeFlags)` Enable edge tracking for the selected edges of the parent view.
`void`	`setMinVelocity(float minVel)` Set the minimum velocity that will be detected as having a magnitude greater than zero in pixels per second.
`boolean`	`settleCapturedViewAt(int finalLeft, int finalTop)` Settle the captured view at the given (left, top) position.
`boolean`	`shouldInterceptTouchEvent(android.view.MotionEvent ev)` Check if this event as provided to the parent view's onInterceptTouchEvent should cause the parent to intercept the touch event stream.
`boolean`	`smoothSlideViewTo(android.view.View child, int finalLeft, int finalTop)` Animate the view `child` to the given (left, top) position.

从类继承的方法 java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- 字段详细资料
  - INVALID_POINTER
```
public static final int INVALID_POINTER
```
    A null/invalid pointer ID.
    
    另请参阅:
    
    常量字段值
  - STATE_IDLE
```
public static final int STATE_IDLE
```
    A view is not currently being dragged or animating as a result of a fling/snap.
    
    另请参阅:
    
    常量字段值
  - STATE_DRAGGING
```
public static final int STATE_DRAGGING
```
    A view is currently being dragged. The position is currently changing as a result of user input or simulated user input.
    
    另请参阅:
    
    常量字段值
  - STATE_SETTLING
```
public static final int STATE_SETTLING
```
    A view is currently settling into place as a result of a fling or predefined non-interactive motion.
    
    另请参阅:
    
    常量字段值
  - EDGE_LEFT
```
public static final int EDGE_LEFT
```
    Edge flag indicating that the left edge should be affected.
    
    另请参阅:
    
    常量字段值
  - EDGE_RIGHT
```
public static final int EDGE_RIGHT
```
    Edge flag indicating that the right edge should be affected.
    
    另请参阅:
    
    常量字段值
  - EDGE_TOP
```
public static final int EDGE_TOP
```
    Edge flag indicating that the top edge should be affected.
    
    另请参阅:
    
    常量字段值
  - EDGE_BOTTOM
```
public static final int EDGE_BOTTOM
```
    Edge flag indicating that the bottom edge should be affected.
    
    另请参阅:
    
    常量字段值
  - EDGE_ALL
```
public static final int EDGE_ALL
```
    Edge flag set indicating all edges should be affected.
    
    另请参阅:
    
    常量字段值
  - DIRECTION_HORIZONTAL
```
public static final int DIRECTION_HORIZONTAL
```
    Indicates that a check should occur along the horizontal axis
    
    另请参阅:
    
    常量字段值
  - DIRECTION_VERTICAL
```
public static final int DIRECTION_VERTICAL
```
    Indicates that a check should occur along the vertical axis
    
    另请参阅:
    
    常量字段值
  - DIRECTION_ALL
```
public static final int DIRECTION_ALL
```
    Indicates that a check should occur along all axes
    
    另请参阅:
    
    常量字段值
  - EDGE_SIZE
```
public static final int EDGE_SIZE
```
    另请参阅:
    
    常量字段值
- 方法详细资料
  - create
```
public static ViewDragHelper create(android.view.ViewGroup forParent,
                                    ViewDragHelper.Callback cb)
```
    Factory method to create a new ViewDragHelper.
    
    参数:
    
    forParent - Parent view to monitor
    
    cb - Callback to provide information and receive events
    
    返回:
    
    a new ViewDragHelper instance
  - create
```
public static ViewDragHelper create(android.view.ViewGroup forParent,
                                    float sensitivity,
                                    ViewDragHelper.Callback cb)
```
    Factory method to create a new ViewDragHelper.
    
    参数:
    
    forParent - Parent view to monitor
    
    sensitivity - Multiplier for how sensitive the helper should be about detecting the start of a drag. Larger values are more sensitive. 1.0f is normal.
    
    cb - Callback to provide information and receive events
    
    返回:
    
    a new ViewDragHelper instance
  - setMinVelocity
```
public void setMinVelocity(float minVel)
```
    Set the minimum velocity that will be detected as having a magnitude greater than zero in pixels per second. Callback methods accepting a velocity will be clamped appropriately.
    
    参数:
    
    minVel - Minimum velocity to detect
  - getMinVelocity
```
public float getMinVelocity()
```
    Return the currently configured minimum velocity. Any flings with a magnitude less than this value in pixels per second. Callback methods accepting a velocity will receive zero as a velocity value if the real detected velocity was below this threshold.
    
    返回:
    
    the minimum velocity that will be detected
  - getViewDragState
```
public int getViewDragState()
```
    Retrieve the current drag state of this helper. This will return one of STATE_IDLE, STATE_DRAGGING or STATE_SETTLING.
    
    返回:
    
    The current drag state
  - setEdgeTrackingEnabled
```
public void setEdgeTrackingEnabled(int edgeFlags)
```
    Enable edge tracking for the selected edges of the parent view. The callback's and methods will only be invoked for edges for which edge tracking has been enabled.
    
    参数:
    
    edgeFlags - Combination of edge flags describing the edges to watch
    
    另请参阅:
    
    EDGE_LEFT, EDGE_TOP, EDGE_RIGHT, EDGE_BOTTOM
  - getEdgeSize
```
public int getEdgeSize()
```
    Return the size of an edge. This is the range in pixels along the edges of this view that will actively detect edge touches or drags if edge tracking is enabled.
    
    返回:
    
    The size of an edge in pixels
    
    另请参阅:
    
    setEdgeTrackingEnabled(int)
  - setEdgeSize
```
public void setEdgeSize(int size)
```
    Set the size of an edge. This is the range in pixels along the edges of this view that will actively detect edge touches or drags if edge tracking is enabled.
    
    参数:
    
    size - The size of an edge in pixels
  - captureChildView
```
public void captureChildView(android.view.View childView,
                             int activePointerId)
```
    Capture a specific child view for dragging within the parent. The callback will be notified but will not be asked permission to capture this view.
    
    参数:
    
    childView - Child view to capture
    
    activePointerId - ID of the pointer that is dragging the captured child view
  - getCapturedView
```
public android.view.View getCapturedView()
```
    返回:
    
    The currently captured view, or null if no view has been captured.
  - getActivePointerId
```
public int getActivePointerId()
```
    返回:
    
    The ID of the pointer currently dragging the captured view, or INVALID_POINTER.
  - getTouchSlop
```
public int getTouchSlop()
```
    返回:
    
    The minimum distance in pixels that the user must travel to initiate a drag
  - cancel
```
public void cancel()
```
    The result of a call to this method is equivalent to processTouchEvent(MotionEvent) receiving an ACTION_CANCEL event.
  - abort
```
public void abort()
```
    cancel(), but also abort all motion in progress and snap to the end of any animation.
  - smoothSlideViewTo
```
public boolean smoothSlideViewTo(android.view.View child,
                                 int finalLeft,
                                 int finalTop)
```
    Animate the view child to the given (left, top) position. If this method returns true, the caller should invoke continueSettling(boolean) on each subsequent frame to continue the motion until it returns false. If this method returns false there is no further work to do to complete the movement.
    This operation does not count as a capture event, though getCapturedView() will still report the sliding view while the slide is in progress.
    
    参数:
    
    child - Child view to capture and animate
    
    finalLeft - Final left position of child
    
    finalTop - Final top position of child
    
    返回:
    
    true if animation should continue through continueSettling(boolean) calls
  - settleCapturedViewAt
```
public boolean settleCapturedViewAt(int finalLeft,
                                    int finalTop)
```
    Settle the captured view at the given (left, top) position. The appropriate velocity from prior motion will be taken into account. If this method returns true, the caller should invoke continueSettling(boolean) on each subsequent frame to continue the motion until it returns false. If this method returns false there is no further work to do to complete the movement.
    
    参数:
    
    finalLeft - Settled left edge position for the captured view
    
    finalTop - Settled top edge position for the captured view
    
    返回:
    
    true if animation should continue through continueSettling(boolean) calls
  - flingCapturedView
```
public void flingCapturedView(int minLeft,
                              int minTop,
                              int maxLeft,
                              int maxTop)
```
    Settle the captured view based on standard free-moving fling behavior. The caller should invoke continueSettling(boolean) on each subsequent frame to continue the motion until it returns false.
    
    参数:
    
    minLeft - Minimum X position for the view's left edge
    
    minTop - Minimum Y position for the view's top edge
    
    maxLeft - Maximum X position for the view's left edge
    
    maxTop - Maximum Y position for the view's top edge
  - continueSettling
```
public boolean continueSettling(boolean deferCallbacks)
```
    Move the captured settling view by the appropriate amount for the current time. If continueSettling returns true, the caller should call it again on the next frame to continue.
    
    参数:
    
    deferCallbacks - true if state callbacks should be deferred via posted message. Set this to true if you are calling this method from View.computeScroll() or similar methods invoked as part of layout or drawing.
    
    返回:
    
    true if settle is still in progress
  - isPointerDown
```
public boolean isPointerDown(int pointerId)
```
    Check if the given pointer ID represents a pointer that is currently down (to the best of the ViewDragHelper's knowledge).
    The state used to report this information is populated by the methods shouldInterceptTouchEvent(MotionEvent) or processTouchEvent(MotionEvent). If one of these methods has not been called for all relevant MotionEvents to track, the information reported by this method may be stale or incorrect.
    
    参数:
    
    pointerId - pointer ID to check; corresponds to IDs provided by MotionEvent
    
    返回:
    
    true if the pointer with the given ID is still down
  - canScroll
```
protected boolean canScroll(android.view.View v,
                            boolean checkV,
                            int dx,
                            int dy,
                            int x,
                            int y)
```
    Tests scrollability within child views of v given a delta of dx.
    
    参数:
    
    v - View to test for horizontal scrollability
    
    checkV - Whether the view v passed should itself be checked for scrollability (true), or just its children (false).
    
    dx - Delta scrolled in pixels along the X axis
    
    dy - Delta scrolled in pixels along the Y axis
    
    x - X coordinate of the active touch point
    
    y - Y coordinate of the active touch point
    
    返回:
    
    true if child views of v can be scrolled by delta of dx.
  - shouldInterceptTouchEvent
```
public boolean shouldInterceptTouchEvent(android.view.MotionEvent ev)
```
    Check if this event as provided to the parent view's onInterceptTouchEvent should cause the parent to intercept the touch event stream.
    
    参数:
    
    ev - MotionEvent provided to onInterceptTouchEvent
    
    返回:
    
    true if the parent view should return true from onInterceptTouchEvent
  - processTouchEvent
```
public void processTouchEvent(android.view.MotionEvent ev)
```
    Process a touch event received by the parent view. This method will dispatch callback events as needed before returning. The parent view's onTouchEvent implementation should call this.
    
    参数:
    
    ev - The touch event received by the parent view
  - checkTouchSlop
```
public boolean checkTouchSlop(int directions)
```
    Check if any pointer tracked in the current gesture has crossed the required slop threshold.
    This depends on internal state populated by shouldInterceptTouchEvent(MotionEvent) or processTouchEvent(MotionEvent). You should only rely on the results of this method after all currently available touch data has been provided to one of these two methods.
    
    参数:
    
    directions - Combination of direction flags, see DIRECTION_HORIZONTAL, DIRECTION_VERTICAL, DIRECTION_ALL
    
    返回:
    
    true if the slop threshold has been crossed, false otherwise
  - checkTouchSlop
```
public boolean checkTouchSlop(int directions,
                              int pointerId)
```
    Check if the specified pointer tracked in the current gesture has crossed the required slop threshold.
    This depends on internal state populated by shouldInterceptTouchEvent(MotionEvent) or processTouchEvent(MotionEvent). You should only rely on the results of this method after all currently available touch data has been provided to one of these two methods.
    
    参数:
    
    directions - Combination of direction flags, see DIRECTION_HORIZONTAL, DIRECTION_VERTICAL, DIRECTION_ALL
    
    pointerId - ID of the pointer to slop check as specified by MotionEvent
    
    返回:
    
    true if the slop threshold has been crossed, false otherwise
  - isEdgeTouched
```
public boolean isEdgeTouched(int edges)
```
    Check if any of the edges specified were initially touched in the currently active gesture. If there is no currently active gesture this method will return false.
    
    参数:
    
    edges - Edges to check for an initial edge touch. See EDGE_LEFT, EDGE_TOP, EDGE_RIGHT, EDGE_BOTTOM and EDGE_ALL
    
    返回:
    
    true if any of the edges specified were initially touched in the current gesture
  - isEdgeTouched
```
public boolean isEdgeTouched(int edges,
                             int pointerId)
```
    Check if any of the edges specified were initially touched by the pointer with the specified ID. If there is no currently active gesture or if there is no pointer with the given ID currently down this method will return false.
    
    参数:
    
    edges - Edges to check for an initial edge touch. See EDGE_LEFT, EDGE_TOP, EDGE_RIGHT, EDGE_BOTTOM and EDGE_ALL
    
    返回:
    
    true if any of the edges specified were initially touched in the current gesture
  - isCapturedViewUnder
```
public boolean isCapturedViewUnder(int x,
                                   int y)
```
    Determine if the currently captured view is under the given point in the parent view's coordinate system. If there is no captured view this method will return false.
    
    参数:
    
    x - X position to test in the parent's coordinate system
    
    y - Y position to test in the parent's coordinate system
    
    返回:
    
    true if the captured view is under the given point, false otherwise
  - isViewUnder
```
public boolean isViewUnder(android.view.View view,
                           int x,
                           int y)
```
    Determine if the supplied view is under the given point in the parent view's coordinate system.
    
    参数:
    
    view - Child view of the parent to hit test
    
    x - X position to test in the parent's coordinate system
    
    y - Y position to test in the parent's coordinate system
    
    返回:
    
    true if the supplied view is under the given point, false otherwise
  - findTopChildUnder
```
public android.view.View findTopChildUnder(int x,
                                           int y)
```
    Find the topmost child under the given point within the parent view's coordinate system. The child order is determined using .
    
    参数:
    
    x - X position to test in the parent's coordinate system
    
    y - Y position to test in the parent's coordinate system
    
    返回:
    
    The topmost child view under (x, y) or null if none found.

类 ViewDragHelper

嵌套类概要

字段概要

方法概要

从类继承的方法 java.lang.Object

字段详细资料

INVALID_POINTER

STATE_IDLE

STATE_DRAGGING

STATE_SETTLING

EDGE_LEFT

EDGE_RIGHT

EDGE_TOP

EDGE_BOTTOM

EDGE_ALL

DIRECTION_HORIZONTAL

DIRECTION_VERTICAL

DIRECTION_ALL

EDGE_SIZE

方法详细资料

create

create

setMinVelocity

getMinVelocity

getViewDragState

setEdgeTrackingEnabled

getEdgeSize

setEdgeSize

captureChildView

getCapturedView

getActivePointerId

getTouchSlop

cancel

abort

smoothSlideViewTo

settleCapturedViewAt

flingCapturedView

continueSettling

isPointerDown

canScroll

shouldInterceptTouchEvent

processTouchEvent

checkTouchSlop

checkTouchSlop

isEdgeTouched

isEdgeTouched

isCapturedViewUnder

isViewUnder

findTopChildUnder