Android Development: Parallax effect of Scrollerview, adapted from Parallaxlistview

Recently in the project, useful to a follow the path of the parallax effect, hard to search, on GitHub, there is a similar effect, but the ListView, plus a top of the headerview, to achieve the effect, But what I need is scrollerview, so the code is modified to achieve the scrollerview below the parallax effect, refer to the following:

Before reading the code below, you can check the source above GitHub

I have a lot of limitations on the original code, only to achieve the effect I need, it seems easy to understand, the most afraid of the kind of around the code, look at the core implementation code:

public class Parallaxscollview extends ScrollView implements Onscrolllistener {public final static double no_zoom = 1;    Public final static Double zoom_x2 = 2;    Private ImageView Mimageview;    private int mimageviewheight =-1;    private int mdefaultimageviewheight = 0;    private int originimageviewheight;    private int mmaxheight;                                    Private interface Onoverscrollbylistener {public boolean overscrollby (int deltax, int deltay, int scrollx, int scrolly, int scrollrangex, int scrollrangey, int maxove    RSCROLLX, int maxoverscrolly, Boolean istouchevent);    } Private interface Ontoucheventlistener {public void ontouchevent (motionevent ev);        } public Parallaxscollview (context context, AttributeSet attrs, int defstyle) {        Super (context, attrs, Defstyle);    Init (context);     } public Parallaxscollview (context context, AttributeSet Attrs) {   Super (context, attrs);    Init (context);        } public Parallaxscollview (context context) {super (context);    Init (context); } public void init (context context) {mdefaultimageviewheight = Context.getresources (). Getdimensionpixelsize (R.D        Imen.size_default_height);    Originimageviewheight = Context.getresources (). Getdimensionpixelsize (R.dimen.size_default_height); } @Override public void onscrollstatechanged (Abslistview view, int scrollstate) {} @Override protected Boo Lean Overscrollby (int deltax, int deltay, int scrollx, int scrolly, int scrollrangex, in T scrollrangey, int maxoverscrollx, int maxoverscrolly, Boolean istouchevent) {b                Oolean iscollapseanimation = false; Iscollapseanimation = Scrollbylistener.overscrollby (DeltaX, DeltaY, Scrollx, scrolly, Scrollrangex, ScrollR Angey, MAXOVERSCROLLX, maxoverscrolly, IStouchevent) | |        Iscollapseanimation; /*return iscollapseanimation?                True:super.overScrollBy (DeltaX, DeltaY, Scrollx, scrolly, Scrollrangex, Scrollrangey, MAXOVERSCROLLX,    0, istouchevent); */return false; } @Override public void onscroll (Abslistview view, int firstvisibleitem, int Visibleitemcoun    T, int totalitemcount) {} @Override protected void onmeasure (int widthmeasurespec, int heightmeasurespec) {    Super.onmeasure (Widthmeasurespec, Heightmeasurespec); } @Override protected void onscrollchanged (int l, int t, int oldl, int Oldt) {super.onscrollchanged (L, T, OL        DL, Oldt);        View Firstview = (view) mimageview.getparent (); Firstview.gettop < getpaddingtop means mimageview would be covered by top padding//So we can layout it to M Ake it shorter if (Firstview.gettop () < Getpaddingtop () && mimageview.getheight () > MimageViewheight) {mimageview.getlayoutparams (). Height = Math.max (mimageview.getheight ()-(Getpaddingtop ()-FirstV            Iew.gettop ()), mimageviewheight); The to set of the Firstview.mtop to 0,///maybe Use view.settop () are more easy, but it just support from Android 3.            0 (API one) firstview.layout (Firstview.getleft (), 0, Firstview.getright (), Firstview.getheight ());        Mimageview.requestlayout ();        }} @Override public boolean ontouchevent (motionevent ev) {touchlistener.ontouchevent (EV);    return super.ontouchevent (EV);        } public void Setparallaximageview (ImageView iv) {Mimageview = IV;    Mimageview.setscaletype (ImageView.ScaleType.CENTER_CROP); } public void Setviewsbounds (double zoomratio) {if (mimageviewheight = =-1) {mimageviewheight = MIm            Ageview.getheight ();            if (mimageviewheight <= 0) {mimageviewheight = Mdefaultimageviewheight;    }        Double ratio = (double) mimageview.getdrawable (). Getintrinsicwidth ())/((double) mimageview.getwidth ());  }} private Onoverscrollbylistener Scrollbylistener = new Onoverscrollbylistener () {@Override public Boolean Overscrollby (int deltax, int deltay, int scrollx, int scrolly, int scrollrange            X, int scrollrangey, int maxoverscrollx, int maxoverscrolly, Boolean istouchevent) { if (istouchevent) {if (true) {Mimageview.getlayoutparams (). Height = Mimag                        Eview.getheight ()-DELTAY/2;                Mimageview.requestlayout ();        }} return false;    }    }; Private Ontoucheventlistener Touchlistener = new Ontoucheventlistener () {@Override public void ontouchevent (Motionevent ev) {if (ev.getaction () = = motionevent.action_up) {if (mimageviewheight -1 < Mimageview.getheight ()) {resetanimimation animation = new Resetanimimation (                    Mimageview, Mimageviewheight);                    Animation.setduration (300);                Mimageview.startanimation (animation);    }            }        }    };        public class Resetanimimation extends Animation {int targetheight;        int originalheight;        int extraheight;        View MView;            Protected resetanimimation (view view, int targetheight) {This.mview = view;            This.targetheight = Targetheight;            OriginalHeight = View.getheight ();            Extraheight = This.originalheight-originimageviewheight;        LOG.I ("Debug", "Target heitht" + targetheight + "original height" + originalheight + "Extraheight" + extraheight);            } @Override protected void applytransformation (float interpolatedtime, transformation t) {            int newheight; NeWheight = (int) (Originimageviewheight + extraheight * (1-interpolatedtime));            Mview.getlayoutparams (). height = newheight;        Mview.requestlayout (); }    }}

Second cloth: In XML, refer to the Parallaxscollview:

<com.gnod.parallaxlistview.parallaxscollview xmlns:android= "Http://schemas.android.com/apk/res/android" Android:id= "@+id/parallax_scroll_view" android:layout_width= "match_parent" android:layout_height= "Match_parent" a ndroid:orientation= "vertical" android:overscrollmode= "never" > <linearlayout android:layout_width= "MATC            H_parent "android:layout_height=" match_parent "android:orientation=" vertical "> <linearlayout Android:layout_width= "Match_parent" android:layout_height= "Wrap_content" Android:orientati on= "Horizontal" > <imageview android:id= "@+id/headview" Android:layout_widt                H= "Match_parent" android:layout_height= "120DP" android:scaletype= "Centercrop" android:src= "@drawable/img_header"/> </LinearLayout> <textview android:id= "@+id/tex TView1 "Android:layout_wiDth= "Wrap_content" android:layout_height= "wrap_content" android:layout_margin= "15DP" Android            oid:text= "Large text" android:textappearance= "? Android:attr/textappearancelarge"/> <textview Android:layout_width= "Wrap_content" android:layout_height= "Wrap_content" Android:layout_margi        N= "15DP" android:text= "Large text" android:textappearance= "? Android:attr/textappearancelarge"/>            <textview android:layout_width= "wrap_content" android:layout_height= "Wrap_content" Android:layout_margin= "15DP" android:text= "Large text" android:textappearance= "? Android:attr/tex Tappearancelarge "/> <textview android:layout_width=" Wrap_content "Android:layout_heigh t= "Wrap_content" android:layout_margin= "15DP" android:text= "Large text" Android:textappea Rance= "? Android:attr/texTappearancelarge "/> <textview android:layout_width=" Wrap_content "Android:layout_heigh t= "Wrap_content" android:layout_margin= "15DP" android:text= "Large text" Android:textappea            Rance= "Android:attr/textappearancelarge"/> <textview android:layout_width= "Wrap_content"            android:layout_height= "Wrap_content" android:layout_margin= "15DP" android:text= "Large text" Android:textappearance= "? Android:attr/textappearancelarge"/> <textview Android:layout_widt H= "Wrap_content" android:layout_height= "wrap_content" android:layout_margin= "15DP" Androi            d:text= "Large text" android:textappearance= "? Android:attr/textappearancelarge"/> <textview Android:layout_width= "Wrap_content" android:layout_height= "Wrap_content" android:layout_margin= "15DP" Android:text= "Large text" android:textappearance= "? Android:attr/textappearancelarge"/> <textview Android:layout_width= "Wrap_content" android:layout_height= "Wrap_content" android:layout_margin=        "15DP" android:text= "Large text" android:textappearance= "Android:attr/textappearancelarge"/>            <textview android:layout_width= "wrap_content" android:layout_height= "Wrap_content" Android:layout_margin= "15DP" android:text= "Large text" android:textappearance= "? Android:attr/texta Ppearancelarge "/> <textview android:layout_width=" Wrap_content "android:layout_height= "Wrap_content" android:layout_margin= "15DP" android:text= "Large text" Android:textappeara Nce= "? Android:attr/textappearancelarge"/> </linearlayout></ Com.gnod.parallaxlistview.parallaxscollview>

The last step, in activity, refers to Parallaxscrollerview and sets ImageView:

Mimageview = (ImageView) Findviewbyid (R.id.headview);        ScrollView = (Parallaxscollview) Findviewbyid (R.id.parallax_scroll_view);        Scrollview.setparallaximageview (Mimageview);

You can also achieve cool parallax effect on Scrollerview.

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Android Development: Parallax effect of Scrollerview, adapted from Parallaxlistview