Scroll in ListView android
Added in API level 1
Summary:
XML Attrs
| Inherited XML Attrs
| Inherited Constants
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ScrollView
Kotlin
|Java
public
class
ScrollView
Show
A view group that allows the view hierarchy placed within it to be scrolled. Scroll view may have only one direct child placed within it. To add multiple views within the scroll view, make the direct child you add a view group, for example LinearLayout, and place additional views within that LinearLayout. Scroll view supports vertical scrolling only. For horizontal scrolling, use HorizontalScrollView instead. Never add a RecyclerView or ListView to a scroll view. Doing so results in poor user interface performance and a poor user experience. For vertical scrolling, consider NestedScrollView instead of scroll view which offers greater user interface flexibility and support for the material design scrolling patterns. Material Design offers guidelines on how the appearance of several UI components, including app bars and banners, should respond to gestures. Summary
XML attributesandroid:fillViewportDefines whether the scrollview should stretch its content to fill the viewport. May be a boolean value, such as "true" or "false". Related methods:
Public constructorsScrollView
Added in API level 1
ScrollView
Added in API level 1
ScrollView
Added in API level 1
ScrollView
Added in API level 21
Public methodsaddView
Added in API level 1
Adds a child view. If no layout parameters are already set on the child, the default parameters for this ViewGroup are set on the child. Note: do not invoke this method from View.draw(android.graphics.Canvas), View.onDraw(android.graphics.Canvas), dispatchDraw(android.graphics.Canvas) or any related method.
addView
Added in API level 1
Adds a child view with the specified layout parameters. Note: do not invoke this method from View.draw(android.graphics.Canvas), View.onDraw(android.graphics.Canvas), dispatchDraw(android.graphics.Canvas) or any related method.
addView
Added in API level 1
Adds a child view with the specified layout parameters. Note: do not invoke this method from View.draw(android.graphics.Canvas), View.onDraw(android.graphics.Canvas), dispatchDraw(android.graphics.Canvas) or any related method.
addView
Added in API level 1
Adds a child view. If no layout parameters are already set on the child, the default parameters for this ViewGroup are set on the child. Note: do not invoke this method from View.draw(android.graphics.Canvas), View.onDraw(android.graphics.Canvas), dispatchDraw(android.graphics.Canvas) or any related method.
arrowScroll
Added in API level 1
Handle scrolling in response to an up or down arrow click.
computeScroll
Added in API level 1
Called by a parent to request that a child update its values for mScrollX and mScrollY if necessary. This will typically be done if the child is animating a scroll using a Scroller object. dispatchKeyEvent
Added in API level 1
Dispatch a key event to the next view on the focus path. This path runs from the top of the view tree down to the currently focused view. If this view has focus, it will dispatch to itself. Otherwise it will dispatch the next node down the focus path. This method also fires any key listeners.
draw
Added in API level 1
Manually render this view (and all of its children) to the given Canvas.
The view must have already done a full layout before this function is
called. When implementing a view, implement
onDraw(android.graphics.Canvas) instead of overriding this method.
If you do need to override this method, call the superclass version.
executeKeyEvent
Added in API level 1
You can call this function yourself to have the scroll view perform scrolling from a key event, just as if the event had been dispatched to it by the view hierarchy.
fling
Added in API level 1
Fling the scroll view
fullScroll
Added in API level 1
Handles scrolling in response to a "home/end" shortcut press. This method will scroll the view to the top or bottom and give the focus to the topmost/bottommost component in the new visible area. If no component is a good candidate for focus, this scrollview reclaims the focus.
getAccessibilityClassName
Added in API level 23
Return the class name of this object to be used for accessibility purposes. Subclasses should only override this if they are implementing something that should be seen as a completely new class of view when used by accessibility, unrelated to the class it is deriving from. This is used to fill in AccessibilityNodeInfo.setClassName.
getBottomEdgeEffectColor
Added in API level 29
Returns the bottom edge effect color.
See also:
getMaxScrollAmount
Added in API level 1
getTopEdgeEffectColor
Added in API level 29
Returns the top edge effect color.
See also:
isFillViewport
Added in API level 1
Indicates whether this ScrollView's content is stretched to fill the viewport. Related XML Attributes:
isSmoothScrollingEnabled
Added in API level 1
onGenericMotionEvent
Added in API level 12
Implement this method to handle generic motion events. Generic motion events describe joystick movements, mouse hovers, track pad touches, scroll wheel movements and other input events. The source of the motion event specifies the class of input that was received. Implementations of this method must examine the bits in the source before processing the event. The following code example shows how this is done. Generic motion events with source class InputDevice#SOURCE_CLASS_POINTER are delivered to the view under the pointer. All other generic motion events are delivered to the focused view. public boolean onGenericMotionEvent(MotionEvent event) { if (event.isFromSource(InputDevice.SOURCE_CLASS_JOYSTICK)) { if (event.getAction() == MotionEvent.ACTION_MOVE) { // process the joystick movement... return true; } } if (event.isFromSource(InputDevice.SOURCE_CLASS_POINTER)) { switch (event.getAction()) { case MotionEvent.ACTION_HOVER_MOVE: // process the mouse hover movement... return true; case MotionEvent.ACTION_SCROLL: // process the scroll wheel movement... return true; } } return super.onGenericMotionEvent(event); }
onInterceptTouchEvent
Added in API level 1
Implement this method to intercept all touch screen motion events. This allows you to watch events as they are dispatched to your children, and take ownership of the current gesture at any point. Using this function takes some care, as it has a fairly complicated interaction with View.onTouchEvent(MotionEvent), and using it requires implementing that method as well as this one in the correct way. Events will be received in the following order:
onNestedFling
Added in API level 21
Request a fling from a nested scroll. This method signifies that a nested scrolling child has detected suitable conditions for a fling. Generally this means that a touch scroll has ended with a velocity in the direction of scrolling that meets or exceeds the minimum fling velocity along a scrollable axis. If a nested scrolling child view would normally fling but it is at the edge of its own content, it can use this method to delegate the fling to its nested scrolling parent instead. The parent may optionally consume the fling or observe a child fling.
onNestedScroll
Added in API level 21
React to a nested scroll in progress. This method will be called when the ViewParent's current nested scrolling child view dispatches a nested scroll event. To receive calls to this method the ViewParent must have previously returned true for a call to onStartNestedScroll(android.view.View, android.view.View, int). Both the consumed and unconsumed portions of the scroll distance are reported to the ViewParent. An implementation may choose to use the consumed portion to match or chase scroll position of multiple child elements, for example. The unconsumed portion may be used to allow continuous dragging of multiple scrolling or draggable elements, such as scrolling a list within a vertical drawer where the drawer begins dragging once the edge of inner scrolling content is reached.
onNestedScrollAccepted
Added in API level 21
React to the successful claiming of a nested scroll operation. This method will be called after onStartNestedScroll returns true. It offers an opportunity for the view and its superclasses to perform initial configuration for the nested scroll. Implementations of this method should always call their superclass's implementation of this method if one is present.
onStartNestedScroll
Added in API level 21
React to a descendant view initiating a nestable scroll operation, claiming the nested scroll operation if appropriate. This method will be called in response to a descendant view invoking View#startNestedScroll(int). Each parent up the view hierarchy will be given an opportunity to respond and claim the nested scrolling operation by returning true. This method may be overridden by ViewParent implementations to indicate when the view is willing to support a nested scrolling operation that is about to begin. If it returns true, this ViewParent will become the target view's nested scrolling parent for the duration of the scroll operation in progress. When the nested scroll is finished this ViewParent will receive a call to onStopNestedScroll(android.view.View).
onStopNestedScroll
Added in API level 21
React to a nested scroll operation ending. Perform cleanup after a nested scrolling operation. This method will be called when a nested scroll stops, for example when a nested touch scroll ends with a MotionEvent#ACTION_UP or MotionEvent#ACTION_CANCEL event. Implementations of this method should always call their superclass's implementation of this method if one is present.
onTouchEvent
Added in API level 1
Implement this method to handle touch screen motion events. If this method is used to detect click actions, it is recommended that the actions be performed by implementing and calling performClick(). This will ensure consistent system behavior, including:
pageScroll
Added in API level 1
Handles scrolling in response to a "page up/down" shortcut press. This method will scroll the view by one page up or down and give the focus to the topmost/bottommost component in the new visible area. If no component is a good candidate for focus, this scrollview reclaims the focus.
requestChildFocus
Added in API level 1
Called when a child of this parent wants focus
requestChildRectangleOnScreen
Added in API level 1
Called when a child of this group wants a particular rectangle to be positioned onto the screen. ViewGroups overriding this can trust that:
ViewGroups overriding this should uphold the contract:
requestDisallowInterceptTouchEvent
Added in API level 1
Called when a child does not want this parent and its ancestors to intercept touch events with ViewGroup#onInterceptTouchEvent(MotionEvent). This parent should pass this call onto its parents. This parent must obey this request for the duration of the touch (that is, only clear the flag after this parent has received an up or a cancel.
requestLayout
Added in API level 1
Call this when something has changed which has invalidated the layout of this view. This will schedule a layout pass of the view tree. This should not be called while the view hierarchy is currently in a layout pass (isInLayout(). If layout is happening, the request may be honored at the end of the current layout pass (and then layout will run again) or after the current frame is drawn and the next layout occurs. Subclasses which override this method should call the superclass method to handle possible request-during-layout errors correctly. If you override this method you must call through to the superclass implementation. scrollTo
Added in API level 1
Set the scrolled position of your view. This will cause a call to onScrollChanged(int, int, int, int) and the view will be invalidated. This version also clamps the scrolling to the bounds of our child.
scrollToDescendant
Added in API level 29
Scrolls the view to the given child.
setBottomEdgeEffectColor
Added in API level 29
Sets the bottom edge effect color.
See also:
setEdgeEffectColor
Added in API level 29
Sets the edge effect color for both top and bottom edge effects.
See also:
setFillViewport
Added in API level 1
Indicates this ScrollView whether it should stretch its content height to fill the viewport or not. Related XML Attributes:
setSmoothScrollingEnabled
Added in API level 1
Set whether arrow scrolling will animate its transition.
setTopEdgeEffectColor
Added in API level 29
Sets the top edge effect color.
See also:
shouldDelayChildPressedState
Added in API level 14
Return true if the pressed state should be delayed for children or descendants of this ViewGroup. Generally, this should be done for containers that can scroll, such as a List. This prevents the pressed state from appearing when the user is actually trying to scroll the content. The default implementation returns true for compatibility reasons. Subclasses that do not scroll should generally override this method and return false.
smoothScrollBy
Added in API level 1
Like View#scrollBy, but scroll smoothly instead of immediately.
smoothScrollTo
Added in API level 1
Like scrollTo(int, int), but scroll smoothly instead of immediately.
Protected methodscomputeScrollDeltaToGetChildRectOnScreen
Added in API level 1
Compute the amount to scroll in the Y direction in order to get a rectangle completely on the screen (or, if taller than the screen, at least the first screen size chunk of it).
computeVerticalScrollOffset
Added in API level 1
Compute the vertical offset of the vertical scrollbar's thumb within the horizontal range. This value is used to compute the position of the thumb within the scrollbar's track. The range is expressed in arbitrary units that must be the same as the units used by computeVerticalScrollRange() and computeVerticalScrollExtent(). The default offset is the scroll offset of this view.
computeVerticalScrollRange
Added in API level 1
The scroll range of a scroll view is the overall height of all of its children.
getBottomFadingEdgeStrength
Added in API level 1
Returns the strength, or intensity, of the bottom faded edge. The strength is a value between 0.0 (no fade) and 1.0 (full fade). The default implementation returns 0.0 or 1.0 but no value in between. Subclasses should override this method to provide a smoother fade transition when scrolling occurs.
getTopFadingEdgeStrength
Added in API level 1
Returns the strength, or intensity, of the top faded edge. The strength is a value between 0.0 (no fade) and 1.0 (full fade). The default implementation returns 0.0 or 1.0 but no value in between. Subclasses should override this method to provide a smoother fade transition when scrolling occurs.
measureChild
Added in API level 1
Ask one of the children of this view to measure itself, taking into account both the MeasureSpec requirements for this view and its padding. The heavy lifting is done in getChildMeasureSpec.
measureChildWithMargins
Added in API level 1
Ask one of the children of this view to measure itself, taking into account both the MeasureSpec requirements for this view and its padding and margins. The child must have MarginLayoutParams The heavy lifting is done in getChildMeasureSpec.
onDetachedFromWindow
Added in API level 1
This is called when the view is detached from a window. At this point it
no longer has a surface for drawing.
onLayout
Added in API level 1
Called from layout when this view should assign a size and position to each of its children. Derived classes with children should override this method and call layout on each of their children.
onMeasure
Added in API level 1
Measure the view and its content to determine the measured width and the measured height. This method is invoked by measure(int, int) and should be overridden by subclasses to provide accurate and efficient measurement of their contents. CONTRACT: When overriding this method, you must call setMeasuredDimension(int, int) to store the measured width and height of this view. Failure to do so will trigger an IllegalStateException, thrown by measure(int, int). Calling the superclass' onMeasure(int, int) is a valid use. The base class implementation of measure defaults to the background size, unless a larger size is allowed by the MeasureSpec. Subclasses should override onMeasure(int, int) to provide better measurements of their content. If this method is overridden, it is the subclass's responsibility to make sure the measured height and width are at least the view's minimum height and width (getSuggestedMinimumHeight() and getSuggestedMinimumWidth()).
onOverScrolled
Added in API level 9
Called by overScrollBy(int, int, int, int, int, int, int, int, boolean) to respond to the results of an over-scroll operation.
onRequestFocusInDescendants
Added in API level 1
When looking for focus in children of a scroll view, need to be a little more careful not to give focus to something that is scrolled off screen. This is more expensive than the default ViewGroup implementation, otherwise this behavior might have been made the default.
onRestoreInstanceState
Added in API level 1
Hook allowing a view to re-apply a representation of its internal state that had previously
been generated by onSaveInstanceState(). This function will never be called with a
null state.
onSaveInstanceState
Added in API level 1
Hook allowing a view to generate a representation of its internal state that can later be used to create a new instance with that same state. This state should only contain information that is not persistent or can not be reconstructed later. For example, you will never store your current position on screen because that will be computed again when a new instance of the view is placed in its view hierarchy.
Some examples of things you may store here: the current cursor position
in a text view (but usually not the text itself since that is stored in a
content provider or other persistent storage), the currently selected
item in a list view.
onSizeChanged
Added in API level 1
This is called during layout when the size of this view has changed. If you were just added to the view hierarchy, you're called with the old values of 0.
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