在CoordinatorLayout中平滑ImageView滚动
在CoordinatorLayout中平滑ImageView滚动
提问于 2015-10-02 17:18:56
我有一个问题，在我的应用程序中的CoordinatorLayout平滑滚动。
我试图做到这一点：http://wstaw.org/m/2015/10/02/google-scroll.gif
但是我最好的结果是：http://wstaw.org/m/2015/10/02/my-scroll.gif
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/main_content"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:isScrollContainer="true">
<android.support.design.widget.AppBarLayout
android:id="@+id/appbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">
<ImageView
android:id="@+id/imageView"
android:layout_width="match_parent"
android:layout_height="@dimen/detail_image_height"
android:background="?attr/colorPrimary"
android:fitsSystemWindows="true"
android:adjustViewBounds="true"
android:scaleType="centerCrop"
app:layout_scrollFlags="scroll|exitUntilCollapsed" />
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:popupTheme="@style/ThemeOverlay.AppCompat.Light" />
<RelativeLayout
android:id="@+id/relativeLayout"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_marginLeft="@dimen/activity_horizontal_margin"
android:layout_marginRight="@dimen/activity_horizontal_margin"
android:background="?attr/colorPrimary"
android:minHeight="80dp">
(...)
</RelativeLayout>
</android.support.design.widget.AppBarLayout>
<android.support.v4.widget.NestedScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_centerHorizontal="true"
app:layout_behavior="@string/appbar_scrolling_view_behavior">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
(...)
</LinearLayout>
</android.support.v4.widget.NestedScrollView>
</android.support.design.widget.CoordinatorLayout>我做错了什么？提前谢谢。
Stack Overflow用户
发布于 2016-01-01 02:56:51
我不能完全修复这个行为，但我确实找到了一些有助于向上滚动的东西。它是基于一个关于CoordinatorLayout的SO线程中的this answer。首先，创建一个扩展AppBarLayout.Behavior的类。
/**
* This "fixes" the weird scroll behavior with CoordinatorLayouts with NestedScrollViews when scrolling up.
* This is based on https://stackoverflow.com/questions/30923889/flinging-with-recyclerview-appbarlayout
*/
@SuppressWarnings("unused")
public class CoordinatorFlingBehavior extends AppBarLayout.Behavior {
private static final String TAG = "CoordinatorFling";
public CoordinatorFlingBehavior() {
}
public CoordinatorFlingBehavior(Context context, AttributeSet attrs) {
super(context, attrs);
}
@Override
public boolean onNestedFling(CoordinatorLayout coordinatorLayout, AppBarLayout child, View target, float velocityX, float velocityY, boolean consumed) {
// Passing false for consumed will make the AppBarLayout fling everything and pull down the expandable stuff
if (target instanceof NestedScrollView && velocityY < 0) {
final NestedScrollView scrollView = (NestedScrollView) target;
int scrollY = scrollView.getScrollY();
// Note the ! in front
consumed = !(scrollY < target.getContext().getResources().getDimensionPixelSize(R.dimen.flingThreshold) // if below threshold, fling
|| isScrollingUpFast(scrollY, velocityY)); // Or if moving quickly, fling
Log.v(TAG, "onNestedFling: scrollY = " + scrollY + ", velocityY = " + velocityY + ", flinging = " + !consumed);
}
return super.onNestedFling(coordinatorLayout, child, target, velocityX, velocityY, consumed);
}
/**
* This uses the log of the velocity because constants make it too easy to uncouple the CoordinatorLayout - the AppBarLayout and the NestedScrollView - when scrollPosition is small.
*
* @param scrollPosition - of the NestedScrollView target
* @param velocityY - Y velocity. Should be negative, because scrolling up is negative. However, a positive value won't crash this method.
* @return true if scrolling up fast
*/
private boolean isScrollingUpFast(int scrollPosition, float velocityY) {
float positiveVelocityY = Math.abs(velocityY);
double calculation = scrollPosition * Math.log(positiveVelocityY);
return positiveVelocityY > calculation;
}
}然后，将以下行添加到AppBarLayout的xml块中(将companyname和packages替换为您使用的任何内容)：
app:layout_behavior="com.companyname.packages.CoordinatorFlingBehavior"页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/32904110
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