ScrollView滚动视图.docx

ScrollView滚动视图.docx

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ScrollView滚动视图

ScrollView滚动视图

extendsFrameLayout

java.lang.Object

↳android.view.View

↳android.view.ViewGroup

↳android.widget.FrameLayout

↳android.widget.ScrollView

ClassOverview

Layoutcontainerforaviewhierarchythatcanbescrolledbytheuser,allowingittobelargerthanthephysicaldisplay.AScrollViewisaFrameLayout,meaningyoushouldplaceonechildinitcontainingtheentirecontentstoscroll;thischildmayitselfbealayoutmanagerwithacomplexhierarchyofobjects.AchildthatisoftenusedisaLinearLayoutinaverticalorientation,presentingaverticalarrayoftop-levelitemsthattheusercanscrollthrough.

YoushouldneveruseaScrollViewwithaListView,becauseListViewtakescareofitsownverticalscrolling.Mostimportantly,doingthisdefeatsalloftheimportantoptimizationsinListViewfordealingwithlargelists,sinceiteffectivelyforcestheListViewtodisplayitsentirelistofitemstofilluptheinfinitecontainersuppliedbyScrollView.

TheTextViewclassalsotakescareofitsownscrolling,sodoesnotrequireaScrollView,butusingthetwotogetherispossibletoachievetheeffectofatextviewwithinalargercontainer.

ScrollViewonlysupportsverticalscrolling.Forhorizontalscrolling,useHorizontalScrollView.

Summary

XMLAttributes

AttributeNameRelatedMethodDescription

android:

fillViewportsetFillViewport（boolean）Defineswhetherthescrollviewshouldstretchitscontenttofilltheviewport.

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InheritedXMLAttributes

Fromclassandroid.widget.FrameLayout

Fromclassandroid.view.ViewGroup

Fromclassandroid.view.View

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InheritedConstants

Fromclassandroid.view.ViewGroup

Fromclassandroid.view.View

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InheritedFields

Fromclassandroid.view.View

PublicConstructors

ScrollView（Contextcontext）

ScrollView（Contextcontext,AttributeSetattrs）

ScrollView（Contextcontext,AttributeSetattrs,intdefStyleAttr）

ScrollView（Contextcontext,AttributeSetattrs,intdefStyleAttr,intdefStyleRes）

PublicMethods

voidaddView（Viewchild,intindex）

Addsachildview.

voidaddView（Viewchild,intindex,ViewGroup.LayoutParamsparams）

Addsachildviewwiththespecifiedlayoutparameters.

voidaddView（Viewchild）

Addsachildview.

voidaddView（Viewchild,ViewGroup.LayoutParamsparams）

Addsachildviewwiththespecifiedlayoutparameters.

booleanarrowScroll（intdirection）

Handlescrollinginresponsetoanupordownarrowclick.

voidcomputeScroll（）

CalledbyaparenttorequestthatachildupdateitsvaluesformScrollXandmScrollYifnecessary.

booleandispatchKeyEvent（KeyEventevent）

Dispatchakeyeventtothenextviewonthefocuspath.

voiddraw（Canvascanvas）

Manuallyrenderthisview（andallofitschildren）tothegivenCanvas.

booleanexecuteKeyEvent（KeyEventevent）

Youcancallthisfunctionyourselftohavethescrollviewperformscrollingfromakeyevent,justasiftheeventhadbeendispatchedtoitbytheviewhierarchy.

voidfling（intvelocityY）

Flingthescrollview

booleanfullScroll（intdirection）

Handlesscrollinginresponsetoa"home/end"shortcutpress.

CharSequencegetAccessibilityClassName（）

Returntheclassnameofthisobjecttobeusedforaccessibilitypurposes.

intgetMaxScrollAmount（）

booleanisFillViewport（）

IndicateswhetherthisScrollView'scontentisstretchedtofilltheviewport.

booleanisSmoothScrollingEnabled（）

booleanonGenericMotionEvent（MotionEventevent）

Implementthismethodtohandlegenericmotionevents.

booleanonInterceptTouchEvent（MotionEventev）

Implementthismethodtointerceptalltouchscreenmotionevents.

booleanonNestedFling（Viewtarget,floatvelocityX,floatvelocityY,booleanconsumed）

Requestaflingfromanestedscroll.

voidonNestedScroll（Viewtarget,intdxConsumed,intdyConsumed,intdxUnconsumed,intdyUnconsumed）

Reacttoanestedscrollinprogress.

voidonNestedScrollAccepted（Viewchild,Viewtarget,intaxes）

Reacttothesuccessfulclaimingofanestedscrolloperation.

booleanonStartNestedScroll（Viewchild,Viewtarget,intnestedScrollAxes）

Reacttoadescendantviewinitiatinganestablescrolloperation,claimingthenestedscrolloperationifappropriate.

voidonStopNestedScroll（Viewtarget）

Reacttoanestedscrolloperationending.

booleanonTouchEvent（MotionEventev）

Implementthismethodtohandletouchscreenmotionevents.

booleanpageScroll（intdirection）

Handlesscrollinginresponsetoa"pageup/down"shortcutpress.

voidrequestChildFocus（Viewchild,Viewfocused）

Calledwhenachildofthisparentwantsfocus

booleanrequestChildRectangleOnScreen（Viewchild,Rectrectangle,booleanimmediate）

Calledwhenachildofthisgroupwantsaparticularrectangletobepositionedontothescreen.

voidrequestDisallowInterceptTouchEvent（booleandisallowIntercept）

CalledwhenachilddoesnotwantthisparentanditsancestorstointercepttoucheventswithonInterceptTouchEvent（MotionEvent）.

voidrequestLayout（）

Callthiswhensomethinghaschangedwhichhasinvalidatedthelayoutofthisview.

voidscrollTo（intx,inty）

Setthescrolledpositionofyourview.

Thisversionalsoclampsthescrollingtotheboundsofourchild.

voidsetFillViewport（booleanfillViewport）

IndicatesthisScrollViewwhetheritshouldstretchitscontentheighttofilltheviewportornot.

voidsetOverScrollMode（intmode）

Settheover-scrollmodeforthisview.

voidsetSmoothScrollingEnabled（booleansmoothScrollingEnabled）

Setwhetherarrowscrollingwillanimateitstransition.

booleanshouldDelayChildPressedState（）

ReturntrueifthepressedstateshouldbedelayedforchildrenordescendantsofthisViewGroup.

finalvoidsmoothScrollBy（intdx,intdy）

LikescrollBy（int,int）,butscrollsmoothlyinsteadofimmediately.

finalvoidsmoothScrollTo（intx,inty）

LikescrollTo（int,int）,butscrollsmoothlyinsteadofimmediately.

ProtectedMethods

intcomputeScrollDeltaToGetChildRectOnScreen（Rectrect）

ComputetheamounttoscrollintheYdirectioninordertogetarectanglecompletelyonthescreen（or,iftallerthanthescreen,atleastthefirstscreensizechunkofit）.

intcomputeVerticalScrollOffset（）

Computetheverticaloffsetoftheverticalscrollbar'sthumbwithinthehorizontalrange.

intcomputeVerticalScrollRange（）

Thescrollrangeofascrollviewistheoverallheightofallofitschildren.

floatgetBottomFadingEdgeStrength（）

Returnsthestrength,orintensity,ofthebottomfadededge.

floatgetTopFadingEdgeStrength（）

Returnsthestrength,orintensity,ofthetopfadededge.

voidmeasureChild（Viewchild,intparentWidthMeasureSpec,intparentHeightMeasureSpec）

Askoneofthechildrenofthisviewtomeasureitself,takingintoaccountboththeMeasureSpecrequirementsforthisviewanditspadding.

voidmeasureChildWithMargins（Viewchild,intparentWidthMeasureSpec,intwidthUsed,intparentHeightMeasureSpec,intheightUsed）

Askoneofthechildrenofthisviewtomeasureitself,takingintoaccountboththeMeasureSpecrequirementsforthisviewanditspaddingandmargins.

voidonDetachedFromWindow（）

Thisiscalledwhentheviewisdetachedfromawindow.

voidonLayout（booleanchanged,intl,intt,intr,intb）

Calledfromlayoutwhenthisviewshouldassignasizeandpositiontoeachofitschildren.

voidonMeasure（intwidthMeasureSpec,intheightMeasureSpec）

Measuretheviewanditscontenttodeterminethemeasuredwidthandthemeasuredheight.

voidonOverScrolled（intscrollX,intscrollY,booleanclampedX,booleanclampedY）

CalledbyoverScrollBy（int,int,int,int,int,int,int,int,boolean）torespondtotheresultsofanover-scrolloperation.

booleanonRequestFocusInDescendants（intdirection,RectpreviouslyFocusedRect）

Whenlookingforfocusinchildrenofascrollview,needtobealittlemorecarefulnottogivefocustosomethingthatisscrolledoffscreen.

voidonRestoreInstanceState（Parcelablestate）

Hookallowingaviewtore-applyarepresentationofitsinternalstatethathadpreviouslybeengeneratedbyonSaveInstanceState（）.

ParcelableonSaveInstanceState（）

Hookallowingaviewtogeneratearepresentationofitsinternalstatethatcanlaterbeusedtocreateanewinstancewiththatsamestate.

voidonSizeChanged（intw,inth,intoldw,intoldh）

Thisiscalledduringlayoutwhenthesizeofthisviewhaschanged.

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InheritedMethods

Fromclassandroid.widget.FrameLayout

Fromclassandroid.view.ViewGroup

Fromclassandroid.view.View

Fromclassjava.lang.Object

Frominterfaceandroid.view.ViewParent

Frominterfaceandroid.view.ViewManager

Frominterfaceandroid.graphics.drawable.Drawable.Callback

Frominterfaceandroid.view.KeyEvent.Callback

Frominterfaceandroid.view.accessibility.AccessibilityEventSource

XMLAttributes

android:

fillViewport

Defineswhetherthescrollviewshouldstretchitscontenttofilltheviewport.

Mustbeabooleanvalue,either"true"or"false".

Thismayalsobeareferencetoaresource（intheform"@[package:

]type:

name"）orthemeattribute（intheform"?

[package:

][type:

]name"）containingavalueofthistype.

ThiscorrespondstotheglobalattributeresourcesymbolfillViewport.

RelatedMethods

setFillViewport（boolean）

PublicConstructors

publicScrollView（Contextcontext）

AddedinAPIlevel1

publicScrollView（Contextcontext,AttributeSetattrs）

AddedinAPIlevel1

publicScrollView（Contextcontext,AttributeSetattrs,intdefStyleAttr）

AddedinAPIlevel1

publicScrollView（Contextcontext,AttributeSetattrs,intdefStyleAttr,intdefStyleRes）

AddedinAPIlevel21

PublicMethods

publicvoidaddView（Viewchild,intindex）

AddedinAPIlevel1

Addsachildview.Ifnolayoutparametersarealreadysetonthechild,thedefaultparametersforthisViewGrouparesetonth