RecyclerView
已经取代了旧的ListView
和GridView
的功能。我正在寻找一个非常基本的示例,展示使用RecyclerView
进行最小网格设置的方法。我不需要冗长的教程风格解释,只需要一个最简单的例子即可。我想象中最简单的网格将模仿旧的GridView,并具备以下特点:
- 每行多个单元格
- 每个单元格中仅包含一个视图
- 响应点击事件
RecyclerView
已经取代了旧的ListView
和GridView
的功能。我正在寻找一个非常基本的示例,展示使用RecyclerView
进行最小网格设置的方法。我不需要冗长的教程风格解释,只需要一个最简单的例子即可。我想象中最简单的网格将模仿旧的GridView,并具备以下特点:
对于那些已经熟悉如何设置RecyclerView
以生成列表的人,好消息是制作网格基本相同。当您设置RecyclerView
时,只需使用GridLayoutManager
而不是LinearLayoutManager
。
recyclerView.setLayoutManager(new GridLayoutManager(this, numberOfColumns));
如果你需要比这更多的帮助,可以查看以下示例。
以下是一个最小化的示例,它将看起来像下面的图片。
从一个空活动开始。您将执行以下任务,添加 RecyclerView
网格。您只需要在每个部分中复制并粘贴代码即可。稍后,您可以将其自定义以适应您的需求。
确保以下依赖项在您的应用程序 gradle.build
文件中:
compile 'com.android.support:appcompat-v7:27.1.1'
compile 'com.android.support:recyclerview-v7:27.1.1'
您可以将版本号更新为最新版本。
创建活动布局
将RecyclerView
添加到您的xml布局中。
activity_main.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">
<android.support.v7.widget.RecyclerView
android:id="@+id/rvNumbers"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</RelativeLayout>
我们的RecyclerView
网格中每个单元格只会有一个TextView
。创建一个新的布局资源文件。
recyclerview_item.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:padding="5dp"
android:layout_width="50dp"
android:layout_height="50dp">
<TextView
android:id="@+id/info_text"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"
android:background="@color/colorAccent"/>
</LinearLayout>
RecyclerView
需要一个适配器来用您的数据填充每个单元格中的视图。创建一个新的java文件。
MyRecyclerViewAdapter.java
public class MyRecyclerViewAdapter extends RecyclerView.Adapter<MyRecyclerViewAdapter.ViewHolder> {
private String[] mData;
private LayoutInflater mInflater;
private ItemClickListener mClickListener;
// data is passed into the constructor
MyRecyclerViewAdapter(Context context, String[] data) {
this.mInflater = LayoutInflater.from(context);
this.mData = data;
}
// inflates the cell layout from xml when needed
@Override
@NonNull
public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View view = mInflater.inflate(R.layout.recyclerview_item, parent, false);
return new ViewHolder(view);
}
// binds the data to the TextView in each cell
@Override
public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
holder.myTextView.setText(mData[position]);
}
// total number of cells
@Override
public int getItemCount() {
return mData.length;
}
// stores and recycles views as they are scrolled off screen
public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
TextView myTextView;
ViewHolder(View itemView) {
super(itemView);
myTextView = itemView.findViewById(R.id.info_text);
itemView.setOnClickListener(this);
}
@Override
public void onClick(View view) {
if (mClickListener != null) mClickListener.onItemClick(view, getAdapterPosition());
}
}
// convenience method for getting data at click position
String getItem(int id) {
return mData[id];
}
// allows clicks events to be caught
void setClickListener(ItemClickListener itemClickListener) {
this.mClickListener = itemClickListener;
}
// parent activity will implement this method to respond to click events
public interface ItemClickListener {
void onItemClick(View view, int position);
}
}
注意事项
GridView
中可用并且是一个常见需求。如果您不需要此功能,可以将该代码删除。将以下代码添加到您的主活动中。
MainActivity.java
public class MainActivity extends AppCompatActivity implements MyRecyclerViewAdapter.ItemClickListener {
MyRecyclerViewAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// data to populate the RecyclerView with
String[] data = {"1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12", "13", "14", "15", "16", "17", "18", "19", "20", "21", "22", "23", "24", "25", "26", "27", "28", "29", "30", "31", "32", "33", "34", "35", "36", "37", "38", "39", "40", "41", "42", "43", "44", "45", "46", "47", "48"};
// set up the RecyclerView
RecyclerView recyclerView = findViewById(R.id.rvNumbers);
int numberOfColumns = 6;
recyclerView.setLayoutManager(new GridLayoutManager(this, numberOfColumns));
adapter = new MyRecyclerViewAdapter(this, data);
adapter.setClickListener(this);
recyclerView.setAdapter(adapter);
}
@Override
public void onItemClick(View view, int position) {
Log.i("TAG", "You clicked number " + adapter.getItem(position) + ", which is at cell position " + position);
}
}
注意,该活动实现了我们在适配器中定义的ItemClickListener。这允许我们在onItemClick中处理单元格点击事件。
就是这样。您现在应该能够运行您的项目,并获得类似于顶部图像的东西。
圆角
自适应列数
这是一种仅使用XML的简单方法
spanCount用于指定列数
layoutManager用于将其设置为网格或线性(垂直或水平)
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/personListRecyclerView"
android:layout_width="0dp"
android:layout_height="0dp"
app:layoutManager="androidx.recyclerview.widget.GridLayoutManager"
app:spanCount="2" />
虽然我喜欢并赞赏Suragch的答案,但我想留个注释,因为我发现编写适配器 (MyRecyclerViewAdapter
) 来定义和公开监听器方法 onItemClick
并不是最好的方式,因为它未正确使用类封装。所以我的建议是让适配器仅处理监听操作(这是它的目的!),并将其与使用适配器(MainActivity
)的活动分离。下面是我如何设置适配器类:
MyRecyclerViewAdapter.java
public class MyRecyclerViewAdapter extends RecyclerView.Adapter<MyRecyclerViewAdapter.ViewHolder> {
private String[] mData = new String[0];
private LayoutInflater mInflater;
// Data is passed into the constructor
public MyRecyclerViewAdapter(Context context, String[] data) {
this.mInflater = LayoutInflater.from(context);
this.mData = data;
}
// Inflates the cell layout from xml when needed
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = mInflater.inflate(R.layout.recyclerview_item, parent, false);
ViewHolder viewHolder = new ViewHolder(view);
return viewHolder;
}
// Binds the data to the textview in each cell
@Override
public void onBindViewHolder(ViewHolder holder, int position) {
String animal = mData[position];
holder.myTextView.setText(animal);
}
// Total number of cells
@Override
public int getItemCount() {
return mData.length;
}
// Stores and recycles views as they are scrolled off screen
public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
public TextView myTextView;
public ViewHolder(View itemView) {
super(itemView);
myTextView = (TextView) itemView.findViewById(R.id.info_text);
itemView.setOnClickListener(this);
}
@Override
public void onClick(View view) {
onItemClick(view, getAdapterPosition());
}
}
// Convenience method for getting data at click position
public String getItem(int id) {
return mData[id];
}
// Method that executes your code for the action received
public void onItemClick(View view, int position) {
Log.i("TAG", "You clicked number " + getItem(position).toString() + ", which is at cell position " + position);
}
}
请注意在MyRecyclerViewAdapter
中现在定义了onItemClick
方法,这是您想编写事件/操作任务的位置。MyRecyclerViewAdapter.ItemClickListener
。这将是最终的修改:
MainActivity.javapublic class MainActivity extends AppCompatActivity {
MyRecyclerViewAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// data to populate the RecyclerView with
String[] data = {"1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12", "13", "14", "15", "16", "17", "18", "19", "20", "21", "22", "23", "24", "25", "26", "27", "28", "29", "30", "31", "32", "33", "34", "35", "36", "37", "38", "39", "40", "41", "42", "43", "44", "45", "46", "47", "48"};
// set up the RecyclerView
RecyclerView recyclerView = (RecyclerView) findViewById(R.id.rvNumbers);
int numberOfColumns = 6;
recyclerView.setLayoutManager(new GridLayoutManager(this, numberOfColumns));
adapter = new MyRecyclerViewAdapter(this, data);
adapter.setClickListener(this);
recyclerView.setAdapter(adapter);
}
}
你需要将你的 RecyclerView
的 LayoutManager
模式设置为 Gridlayout 模式。当你想要设置 RecyclerView
的 LayoutManager
时,只需更改你的代码:
recyclerView.setLayoutManager(new GridLayoutManager(getActivity(), numberOfColumns));
There are 2 ways to achieve this
- In Xml
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/list_amenities"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginTop="@dimen/_8sdp"
android:nestedScrollingEnabled="false"
app:layoutManager="androidx.recyclerview.widget.GridLayoutManager"
app:spanCount="2"
app:layout_constraintEnd_toEndOf="@+id/text_parking_lot_amenities" app:layout_constraintStart_toStartOf="@+id/text_parking_lot_amenities" app:layout_constraintTop_toBottomOf="@id/text_parking_lot_amenities" />
span count 用于网格列的设置。
- 在活动中使用。
listAmenities.layoutManager = GridLayoutManager(this, TWO)
here TWO indicates number of grid columns
在初始化RecyclerView
时设置
recyclerView.setLayoutManager(new GridLayoutManager(this, 4));
如果您想在xml文件中为RecyclerView设置网格布局,则可以将以下两个内容放入RecyclerView xml中。
app:layoutManager="androidx.recyclerview.widget.GridLayoutManager"
app:spanCount=numberOfItemsInSignleRow
recyclerView.setLayoutManager(new GridLayoutManager(getActivity(), numberOfItemsInSignleRow));
recyclerView = findViewById(R.id.recycler_view);
recyclerView.setHasFixedSize(true);
//recyclerView.setLayoutManager(new LinearLayoutManager(this));
recyclerView.setLayoutManager(new GridLayoutManager(this, 2));
recyclerView.setLayoutManager(new GridLayoutManager(this, numberOfColumns));
。 - olfek