我想要做的是处理滚动 NestedScrollView。但是当我“setOnScrollChangedListener”到它，然后我滚动视图时，什么也没有发生，甚至没有调用“setOnScrollChangedListener”方法......谁能告诉我为什么？什么时候会调用“setOnScrollChangedListener”方法？
<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:fitsSystemWindows="true">
<android.support.design.widget.AppBarLayout
android:id="@+id/MyAppbar"
android:layout_width="match_parent"
android:layout_height="256dp"
android:fitsSystemWindows="true">
<android.support.design.widget.CollapsingToolbarLayout
android:id="@+id/collapse_toolbar"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_scrollFlags="scroll|exitUntilCollapsed"
android:background="@color/material_deep_teal_500"
android:fitsSystemWindows="true">
<ImageView
android:id="@+id/bgheader"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scaleType="centerCrop"
android:fitsSystemWindows="true"
android:background="@drawable/example"
app:layout_collapseMode="parallax" />
</android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>
<android.support.v4.widget.NestedScrollView
android:id="@+id/scroll"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="fill_vertical"
app:layout_behavior="@string/appbar_scrolling_view_behavior">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:paddingTop="24dp">
<android.support.v7.widget.CardView
android:layout_marginLeft="10dp"
android:layout_marginRight="10dp"
android:layout_marginTop="10dp"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textColor="@color/error_color"
android:textSize="20sp"
android:text="This text is part of first Cardview\n\n"/>
</LinearLayout>
</android.support.v7.widget.CardView>
<android.support.v7.widget.CardView
android:layout_marginLeft="10dp"
android:layout_marginRight="10dp"
android:layout_marginTop="10dp"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textSize="20sp"
android:textColor="@color/abc_search_url_text"
android:text="This text is part of second Cardview\n\n"/>
</LinearLayout>
</android.support.v7.widget.CardView>
</LinearLayout>
</android.support.v4.widget.NestedScrollView>
</android.support.design.widget.CoordinatorLayout>
在 MainActivity 中，我想听滚动。我确实喜欢这样：
public class MainActivity extends AppCompatActivity {
private NestedScrollView nestedScrollView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
nestedScrollView = (NestedScrollView) findViewById(R.id.scroll);
nestedScrollView.setOnScrollChangeListener(new NestedScrollView.OnScrollChangeListener() {
@Override
public void onScrollChange(NestedScrollView v, int scrollX, int scrollY, int oldScrollX, int oldScrollY) {
System.out.println("I am scrolling the view...");
}
});
}
}