我有一个问题让我发疯。基本上它是一个简单的 RecyclerView,显示卡片视图。已经有很多帖子了,我查了一下。我已经分配了一个 LayoutManager,如此处所示(RecyclerView 不显示任何 CardView 项目),我已经实现了 getItemCount 方法,如此处所述(卡片视图未显示),我更改为以下版本(这里建议更改版本卡片的 RecyclerView 不显示任何内容):
compile 'com.android.support:support-v4:24.0.0'
compile 'com.android.support:cardview-v7:24.0.0'
compile 'com.android.support:recyclerview-v7:24.0.0'
我还执行了notifyDataSetChanged(),如此处所示(RecyclerView 不显示任何 CardView 项目)。然而,没有什么能解决我的问题。
我有一个 Activity,其中包含以下代码(仅相关部分,getDummyData 返回包含 1 个虚拟数据的列表):
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
DatabaseHelper databaseHelper = new DatabaseHelper(getApplicationContext());
setContentView(R.layout.activity_overview);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
RecyclerView rv = (RecyclerView) findViewById(R.id.rv);
rv.setHasFixedSize(true);
LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);
linearLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);
rv.setLayoutManager(linearLayoutManager);
RVAdapter adapter = new RVAdapter(getDummyData());
rv.setAdapter(adapter);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
adapter.notifyDataSetChanged();
}
public class RVAdapter extends RecyclerView.Adapter<RVAdapter.DocumentViewHolder> {
List<Document> DocumentList;
public RVAdapter(List<Document> Documents) {
this.DocumentList = Documents;
}
@Override
public DocumentViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.document_item, parent, false);
DocumentViewHolder pvh = new DocumentViewHolder(v);
return pvh;
}
@Override
public void onBindViewHolder(DocumentViewHolder DocumentViewHolder, int i) {
DocumentViewHolder.Date.setText(DocumentList.get(i).getCreatedFormatted());
DocumentViewHolder.participants.setText(DocumentList.get(i).getParticipants(getApplicationContext()));
DocumentViewHolder.counterOfItems.setText(DocumentList.get(i).getcounterOfItems(getApplicationContext()) + StringUtils.EMPTY);
}
@Override
public void onAttachedToRecyclerView(RecyclerView recyclerView) {
super.onAttachedToRecyclerView(recyclerView);
}
@Override
public int getItemCount() {
//return DocumentList.size();
return 1;
}
public class DocumentViewHolder extends RecyclerView.ViewHolder {
TextView Date;
TextView participants;
TextView ideasPreview;
TextView counterOfItems;
ImageView Photo;
public DocumentViewHolder(View itemView) {
super(itemView);
Date = (TextView) itemView.findViewById(R.id._date);
participants = (TextView) itemView.findViewById(R.id.participants);
ideasPreview = (TextView) itemView.findViewById(R.id.ideas_preview);
counterOfItems = (TextView) itemView.findViewById(R.id.counter_of_items);
Photo = (ImageView) itemView.findViewById(R.id._photo);
}
}
}
我有一个 Document_item - xml:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<android.support.v7.widget.CardView xmlns:card_view="http://schemas.android.com/apk/res-auto"
android:id="@+id/card_view"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
card_view:cardCornerRadius="@dimen/_card_corner">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<ImageView
android:id="@+id/_photo"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="0.25" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center_horizontal"
android:orientation="vertical"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingEnd="@dimen/activity_horizontal_margin"
android:paddingStart="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin">
<TextView
android:id="@+id/_date"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="21st June 2016" />
<TextView
android:id="@+id/participants"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Thomas, Christian and Johann" />
<TextView
android:id="@+id/counter_of_items"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Thomas, Christian and Johann" />
<TextView
android:id="@+id/ideas_preview"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Hello, Test, Test, Test" />
</LinearLayout>
</LinearLayout>
</android.support.v7.widget.CardView>
</LinearLayout>
该活动的 xml 如下所示:
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:context="com.chmaurer.idea.OverviewActivity">
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="@style/AppTheme.AppBarOverlay">
<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/AppTheme.PopupOverlay" />
</android.support.design.widget.AppBarLayout>
<android.support.v7.widget.RecyclerView
android:id="@+id/rv"
android:layout_width="match_parent"
android:layout_height="match_parent">
</android.support.v7.widget.RecyclerView>
<android.support.design.widget.FloatingActionButton
android:id="@+id/fab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|end"
android:layout_margin="@dimen/fab_margin"
android:src="@drawable/ic_playlist_add_white_24dp" />
</android.support.design.widget.CoordinatorLayout>
代码编译执行正常,但是不显示任何卡牌。我现在已经自己尝试了几个小时,但这绝对是我很高兴得到提示的时刻......