Artificial QQ Space Parallax Effect, Listview.setheader ()

Dynamically set the width of the picture above the ListView according to the Finger Movement event of the ListView, and when the finger is released

Animating a picture (animated values over time) Valueanimator.ofint ()

ImportAndroid.animation.ValueAnimator;ImportAndroid.content.Context;ImportAndroid.graphics.Bitmap;ImportAndroid.util.AttributeSet;ImportAndroid.util.Log;Importandroid.view.MotionEvent;ImportAndroid.view.ViewGroup;ImportAndroid.view.animation.OvershootInterpolator;ImportAndroid.widget.ImageView;ImportAndroid.widget.ListView;/*** Created by Lxj on 2017/1/5.*/ Public classParallaxlistviewextendsListView { PublicParallaxlistview (Context context) {Super(context); }     PublicParallaxlistview (Context context, AttributeSet attrs) {Super(context, attrs); }     PublicParallaxlistview (context context, AttributeSet attrs,intdefstyleattr) {        Super(context, attrs, defstyleattr); }    intOriginalHeight;//The initial height is 120dp.ImageView image; intMaxHeight;//The maximum height of a child is set to the height of the image itself.     Public voidsetparallaximage (ImageView image) { This. Image =image; //reads the value of Image_height from the Dimens file and automatically transitions to pixelsOriginalHeight =getresources (). Getdimensionpixelsize (R.dimen.image_height); MaxHeight= This. Image.getdrawable (). Getintrinsicheight (); }    /*** This method is executed when the ListView is sliding to the head and can get the distance to the finger movement in the method *@paramDeltaY The distance the finger moves, the top end is a negative value, and the bottom end is a positive value *@paramscrolly scrollto Scrolling coordinates *@parammaxoverscrolly The maximum distance that the ListView can continue to slide after sliding to the head *@paramIstouchevent Whether the finger is dragged to the head, true: Yes, false: Indicates that the head is sliding by inertia *@return     */@Overrideprotected BooleanOverscrollby (intDeltaX,intDeltaY,intSCROLLX,intscrolly,intScrollrangex,intScrollrangey,intMAXOVERSCROLLX,intmaxoverscrolly,Booleanistouchevent) {        //if the finger is dragged to the head, and is the top of the head, the other ignores not handling        if(Istouchevent && deltay<0){            //let the height of the imageview increase with the finger movement            intNewheight = image.getheight () + math.abs (DeltaY)/3; //Limit Newheight            if(newheight>maxheight) {Newheight=MaxHeight; } viewgroup.layoutparams params=Image.getlayoutparams (); Params.height=Newheight;        Image.setlayoutparams (params); }        return Super. Overscrollby (DeltaX, DeltaY, Scrollx, scrolly, Scrollrangex,
Scrollrangey, Maxoverscrollx, maxoverscrolly, istouchevent); } @Override Public Booleanontouchevent (motionevent ev) {if(ev.getaction () = =motionevent.action_up) {            //slowly restores the imageview height to the initial 120 .Valueanimator animator =Valueanimator.ofint (Image.getheight (), originalheight); //listen to changes in animation values to implement your own animation logicAnimator.addupdatelistener (NewValueanimator.animatorupdatelistener () {@Override Public voidonanimationupdate (valueanimator animation) {intValue = (int) Animation.getanimatedvalue (); //we need to set the value to the heightViewgroup.layoutparams params =Image.getlayoutparams (); Params.height=value;                Image.setlayoutparams (params);            }            }); Animator.setinterpolator (Newovershootinterpolator ()); Animator.setduration (500);        Animator.start (); }        return Super. ontouchevent (EV); }}

Importandroid.support.v7.app.AppCompatActivity;ImportAndroid.os.Bundle;ImportAndroid.view.View;ImportAndroid.widget.AbsListView;ImportAndroid.widget.ArrayAdapter;ImportAndroid.widget.ImageView; Public classMainactivityextendsappcompatactivity {PrivateParallaxlistview ListView; @Overrideprotected voidonCreate (Bundle savedinstancestate) {Super. OnCreate (savedinstancestate);        Setcontentview (R.layout.activity_main); ListView=(Parallaxlistview) Findviewbyid (R.id.listview); //Remove the blue shadow of the edge when the ListView slides to the headListview.setoverscrollmode (Abslistview.over_scroll_never); //Add HeaderView Header = View.inflate ( This, R.layout.header,NULL); ImageView Image=(ImageView) Header.findviewbyid (r.id.image);        Listview.addheaderview (header); //Set ImageViewlistview.setparallaximage (image); Listview.setadapter (NewArrayadapter<string> ( This, Android.    R.layout.simple_list_item_1, Constant.names)); }}

<?xml version= "1.0" encoding= "Utf-8"? ><relativelayout xmlns:android= "http://schemas.android.com/apk/res/ Android "    xmlns:tools=" Http://schemas.android.com/tools "android:id=" @+id/activity_main     " Android:layout_width= "Match_parent" android:layout_height= "match_parent"    tools:context= " Com.zh.parallax97.MainActivity ">    <com.itheima.parallax97.ParallaxListView        android:id=" @ +id/listview "        android:layout_width=" Match_parent "        android:layout_height=" Match_ Parent "/></relativelayout>

Artificial QQ Space Parallax Effect, Listview.setheader ()