向下滚动时，RecyclerView项之间的间隙较大 [英] Large gap forms between RecyclerView items when scrolling down
问题描述
我正在制作一个待办事项列表应用程序，并且在测试时，由于某种原因，每当我尝试向下滚动时，项目之间就会形成巨大的差距.每当我拖放项目时，它总是会发生，但是我的ItemTouchHelper适配器和回调类看不到任何错误.如果您能帮助我，那就太好了.
I'm making a ToDo list app, and while testing it, for some reason, a huge gap forms between the items whenever I try to scroll down. It always happens whenever I Drag and Drop the items, but I don't see any errors with my ItemTouchHelper adapter and callback class. It would be awesome if you can help me out.
之前:
之后:
RecyclerAdapter.java
RecyclerAdapter.java
public class RecyclerAdapter extends
RecyclerView.Adapter<RecyclerAdapter.RecyclerVH> implements ItemTouchHelperAdapter{
private LayoutInflater layoutInflater;
ArrayList<Info> data;
Context context;
public RecyclerAdapter(Context context) {
layoutInflater = LayoutInflater.from(context);
this.context = context;
}
public void setData(ArrayList<Info> data) {
this.data = data;
notifyDataSetChanged();
}
@Override
public RecyclerVH onCreateViewHolder(ViewGroup viewGroup, int position) {
View view = layoutInflater.inflate(R.layout.custom_row, viewGroup, false);
view.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Log.d("R.A onClick Owen", "onClick method triggered");
}
});
RecyclerVH recyclerVH = new RecyclerVH(view);
return recyclerVH;
}
@Override
public void onBindViewHolder(RecyclerVH recyclerVH, int position) {
Log.d("RecyclerView", "onBindVH called: " + position);
final Info currentObject = data.get(position);
// Current Info object retrieved for current RecyclerView item - USED FOR DELETE
recyclerVH.listTitle.setText(currentObject.title);
recyclerVH.listContent.setText(currentObject.content);
/*recyclerVH.listTitle.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// Open new Activity containing note content
Toast.makeText(this, "Opening: " + currentObject.title, Toast.LENGTH_LONG).show();
}
});*/
}
public void deleteItem(int position) {
DBInfo dbInfo = new DBInfo(context);
dbInfo.deleteNote(data.get(position));
// Deletes RV item/position's Info object
data.remove(position);
// Removes Info object at specified position
notifyItemRemoved(position);
// Notifies the RV that item has been removed
}
@Override
public int getItemCount() {
return data.size();
}
// This is where the Swipe and Drag-And-Drog methods come into place
@Override
public boolean onItemMove(int fromPosition, int toPosition) {
// Swapping positions
// ATTEMPT TO UNDERSTAND WHAT IS GOING ON HERE
Collections.swap(data, fromPosition, toPosition);
notifyItemMoved(fromPosition, toPosition);
return true;
}
@Override
public void onItemDismiss(int position) {
// Deleting item from RV and DB
deleteItem(position);
}
class RecyclerVH extends RecyclerView.ViewHolder implements View.OnClickListener{
// OnClickListener is implemented here
// Can also be added at onBindViewHolder above
TextView listTitle, listContent;
public RecyclerVH(View itemView) {
super(itemView);
listTitle = (TextView) itemView.findViewById(R.id.title);
listContent = (TextView) itemView.findViewById(R.id.content);
listTitle.setOnClickListener(this);
}
@Override
public void onClick(View v) {
Toast.makeText(context, "Opening: Note" + getLayoutPosition(), Toast.LENGTH_SHORT).show();
// PS NEVER ADD listTitle VARIABLE AS PUBLIC VARIABLE ABOVE WHICH IS GIVEN VALUE AT ONBINDVH
// THIS IS BECAUSE THE VALUE WILL CHANGE IF ITEM IS ADDED OR DELETED
}
}
}
activity_main.xml
activity_main.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:fab="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity"
android:orientation="vertical"
android:weightSum="1">
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="@drawable/rounded_corners" />
<FrameLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v7.widget.RecyclerView
android:id="@+id/recyclerList"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<RelativeLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<com.melnykov.fab.FloatingActionButton
android:id="@+id/fab_add"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true"
android:layout_marginBottom="16dp"
android:layout_marginRight="16dp"
android:layout_marginEnd="16dp"
android:gravity="bottom|end"
android:onClick="addNote"
android:src="@drawable/fab_ic_add"
fab:fab_colorNormal="@color/colorPrimary"
fab:fab_colorPressed="@color/colorPrimaryDark"
fab:fab_colorRipple="@color/colorPrimaryDark" />
</RelativeLayout>
</FrameLayout>
</LinearLayout>
custom_row.xml
custom_row.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:id="@+id/main"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<TextView
android:id="@+id/title"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
android:padding="8dp"
android:text="@string/test"
android:textSize="18sp"
android:textStyle="bold" />
</LinearLayout>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/main"
android:paddingLeft="8dp">
<TextView
android:id="@+id/content"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="@string/test"
android:textSize="15sp" />
</LinearLayout>
</RelativeLayout>
非常感谢任何能帮助我的人.输入时我正在拔头发.
Thank you so much to whoever can help me out. I am pulling my hair out as I type.
我已经确认问题不是我的ItemTouchHelper类. (尝试在不调用它的情况下运行，仍然会出现问题.) 另外，似乎显示一个对话框并抬起键盘时，后台的RecyclerView可以自行解决问题.删除对话框后，问题重复出现(例如，滚动会在项目之间放置大量空间)
I have confirmed that it is not my ItemTouchHelper class that's the problem. (Tried running without it being called, problem still occurs.) Also, it seems that when a dialog is shown and the keyboard brought up, the RecyclerView in the background resolves the problem by itself. After dialog is removed, the problem repeats (i.e. Scrolling puts massive space between items)
推荐答案
Luksprog对Gabriele Mariotti的回答起作用.
Luksprog's answer to Gabriele Mariotti's answer works.
根据 doc
在2.3.0版中，LayoutManager API新增了一项令人兴奋的功能: 自动测量！ 这样， RecyclerView 可以根据其内容的大小自行调整大小. >这意味着以前无法使用的方案，例如现在可以使用 WRAP_CONTENT >作为RecyclerView的尺寸. 您会发现所有内置的LayoutManager现在都支持自动测量.
With the release 2.3.0 there is an exciting new feature to the LayoutManager API: auto-measurement! This allows a RecyclerView to size itself based on the size of its contents. >This means that previously unavailable scenarios, such as using WRAP_CONTENT >for a dimension of the RecyclerView, are now possible. You’ll find all built in LayoutManagers now support auto-measurement.
由于此更改，确保再次检查项目视图的布局参数:以前忽略的布局参数(例如 MATCH_PARENT 沿滚动方向)将被完全尊重.
Due to this change, make sure to double check the layout parameters of your item views: previously ignored layout parameters (such as MATCH_PARENT in the scroll direction) will now be fully respected.
在项目布局中，您必须更改:
In your item layout you have to change:
android:layout_height="match_parent"
使用
android:layout_height="wrap_content"
这篇关于向下滚动时，RecyclerView项之间的间隙较大的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
