MotionLayout 我无法将我的回收器视图滚动到第一个位置

Question

我有一个activity_motion_sec.xml文件，如下所示。与此样品几乎相同https://riggaroo.dev/android-motionlayout-tutorial-collapsing-view/.我添加了一个简单的向上箭头按钮。我希望我的回收视图滚动到0。按下向上箭头按钮时的位置。

activity_motion_sec.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.motion.widget.MotionLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
app:layoutDescription="@xml/base_scroll_scene"
app:showPaths="false">
<ImageView
android:id="@+id/imageViewAvatar"
android:layout_width="140dp"
android:layout_height="0dp"
android:layout_marginStart="16dp"
android:layout_marginTop="16dp"
android:scaleType="centerCrop"
app:layout_constraintDimensionRatio="h,1:1"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
android:src="@drawable/bursa" />

<TextView
android:id="@+id/textViewName"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="16dp"
android:layout_marginBottom="8dp"
android:fontFamily="@font/raleway_semibold"
android:text="Veruca Salt "
android:textAppearance="@style/TextAppearance.AppCompat.Display1"
app:layout_constraintBottom_toTopOf="@+id/space"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toEndOf="@+id/imageViewAvatar"
app:layout_constraintTop_toTopOf="@+id/imageViewAvatar" />

<androidx.recyclerview.widget.RecyclerView
android:id="@+id/recyclerViewStatus"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/imageViewAvatar"
>
</androidx.recyclerview.widget.RecyclerView>

<View
android:id="@+id/my_view"
android:layout_width="0dp"
android:layout_height="30dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="@id/space"
app:layout_constraintStart_toStartOf="parent"
android:background="@drawable/bottom_gradient_mask"
android:visibility="gone"/>
<ImageView
android:id="@+id/up_arrow"
android:layout_width="30dp"
android:layout_height="30dp"
android:src="@drawable/ic_arrow_upward_black_24dp"
android:visibility="gone"
app:layout_constraintEnd_toEndOf="@+id/space"
app:layout_constraintTop_toTopOf="@+id/space"/>

<Space
android:id="@+id/space"
android:layout_width="match_parent"
android:layout_height="8dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="@+id/imageViewAvatar"
app:layout_constraintTop_toBottomOf="@id/imageViewAvatar" />
</androidx.constraintlayout.motion.widget.MotionLayout>

在base_scroll_scene.xml文件中，我可以处理向上箭头按钮的点击事件。当按钮被点击时，动画运行，但我无法设置回收视图的位置。

base_scroll_scene.xml

<?xml version="1.0" encoding="utf-8"?>
<MotionScene xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
<Transition
app:constraintSetEnd="@id/end"
app:constraintSetStart="@id/start"
app:duration="1000">
<OnSwipe
app:dragDirection="dragUp"
app:touchAnchorId="@+id/recyclerViewStatus"
app:touchAnchorSide="top" />
<OnClick
app:targetId="@id/up_arrow"
app:clickAction="transitionToStart"/>
</Transition>
<ConstraintSet android:id="@+id/start">
<Constraint
android:id="@+id/recyclerViewStatus"
/>
</ConstraintSet>
<ConstraintSet android:id="@+id/end">
<Constraint
android:id="@id/imageViewAvatar"
android:layout_width="40dp"
android:layout_height="40dp"
android:layout_marginStart="16dp"
android:layout_marginTop="16dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
/>
<Constraint
android:id="@id/space"
android:layout_width="match_parent"
android:layout_height="30dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="@+id/imageViewAvatar"
app:layout_constraintTop_toBottomOf="@id/imageViewAvatar"/>
<Constraint
android:id="@+id/up_arrow"
android:layout_width="30dp"
android:layout_height="30dp"
android:src="@drawable/ic_arrow_upward_black_24dp"
android:visibility="visible"
app:layout_constraintEnd_toEndOf="@+id/space"
app:layout_constraintTop_toTopOf="@+id/space"/>
<Constraint
android:id="@+id/my_view"
android:layout_width="0dp"
android:layout_height="30dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="@id/space"
app:layout_constraintStart_toStartOf="parent"
android:background="@drawable/bottom_gradient_mask"
android:visibility="visible"/>
</ConstraintSet>
</MotionScene>

我曾尝试在我的java文件中设置一个ClickListener，但没有成功。视图不侦听我在MotionActivitySec.java中设置的事件侦听器和MotionActivitySec.java

public class MotionActivitySec extends Activity {

@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_motion_sec);
MyListData[] myListData = new MyListData[] {
new MyListData("Email", android.R.drawable.ic_dialog_email),
new MyListData("Info", android.R.drawable.ic_dialog_info),
new MyListData("Delete", android.R.drawable.ic_delete),
new MyListData("Dialer", android.R.drawable.ic_dialog_dialer),
new MyListData("Alert", android.R.drawable.ic_dialog_alert),
new MyListData("Map", android.R.drawable.ic_dialog_map),
new MyListData("Email", android.R.drawable.ic_dialog_email),
new MyListData("Info", android.R.drawable.ic_dialog_info),
new MyListData("Delete", android.R.drawable.ic_delete),
new MyListData("Dialer", android.R.drawable.ic_dialog_dialer),
new MyListData("Alert", android.R.drawable.ic_dialog_alert),
new MyListData("Map", android.R.drawable.ic_dialog_map),
};
final RecyclerView recyclerView = findViewById(R.id.recyclerViewStatus);
MyAdapter adapter = new MyAdapter(myListData);
recyclerView.setHasFixedSize(true);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
recyclerView.setAdapter(adapter);
ImageView imageView = findViewById(R.id.up_arrow);
imageView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(MotionActivitySec.this, "clicked", Toast.LENGTH_SHORT).show();
recyclerView.scrollToPosition(0);
}
});

}
}

Answer 1

执行以下操作：

1.删除

<OnClick
app:targetId="@id/up_arrow"
app:clickAction="transitionToStart"/>

2.在活动中，处理按钮点击本身

upArrow.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
root.transitionToEnd();
//root.transitionToStart();
recyclerViewStatus.getLayoutManager().scrollToPosition(0);
}
});