@Override public int getItemCount() { return data.size(); } public class MyViewHolder extends RecyclerView.ViewHolder { public TextView name_textview,hexadecimal_textview; public MyViewHolder(@NonNull View itemView) { super(itemView); name_textview = itemView.findViewById(R.id.name_textview); hexadecimal_textview = itemView.findViewById(R.id.hexadecimal_textview);
时间: 2024-03-11 10:43:55 浏览: 104
这段代码是一个 RecyclerView 的适配器(Adapter)的实现代码。其中,`getItemCount()` 方法返回数据源中数据项的数量,即列表中需要展示的自定义按钮的数量。`MyViewHolder` 是一个自定义的 ViewHolder 类,其中包含展示列表项中名称和十六进制颜色代码的 TextView。在 MyViewHolder 构造函数中,通过 `findViewById()` 方法将布局文件中对应的 TextView 实例化并赋值给类成员变量。这样做的目的是为了避免每次展示列表项时都需要调用 `findViewById()` 方法,从而提高列表的性能。
相关问题
public class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyViewHolder> { private List<MyData> mDataList; private Context mContext; public MyAdapter(List<MyData> dataList, Context context) { mDataList = dataList; mContext = context; } @Override public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_layout, parent, false); return new MyViewHolder(view); } @Override public void onBindViewHolder(MyViewHolder holder, int position) { MyData data = mDataList.get(position); holder.bindData(data); holder.itemView.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { // item 被点击了 Intent intent = new Intent(mContext, DetailActivity.class); intent.putExtra("data", data); mContext.startActivity(intent); } }); } @Override public int getItemCount() { return mDataList.size(); } static class MyViewHolder extends RecyclerView.ViewHolder { private TextView mTextView; public MyViewHolder(View itemView) { super(itemView); mTextView = itemView.findViewById(R.id.text_view); } public void bindData(MyData data) { mTextView.setText(data.getText()); } }}中的data.getText()怎么编写
这里的 `data` 是一个 `MyData` 对象,它有一个名为 `getText()` 的方法可以获取其中的文本内容。因此,`data.getText()` 就是调用 `MyData` 对象中的 `getText()` 方法获取文本内容。
假设 `MyData` 类中有一个名为 `getText()` 的方法,它返回一个字符串类型的文本内容,那么 `MyAdapter` 类中的 `data.getText()` 可以这样编写:
```
public void bindData(MyData data) {
mTextView.setText(data.getText());
}
```
在这个方法中,我们调用 `MyData` 对象中的 `getText()` 方法获取文本内容,并将其设置到 `TextView` 中显示。这样,每次调用 `bindData()` 方法时,都会根据传入的 `MyData` 对象获取其中的文本内容,并将其显示在对应的 `TextView` 中。
能否帮我完善下面代码中的点击项事件 ,显示短的toast .谢放。代码如下:package com.blog; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.TextView; import androidx.annotation.NonNull; import androidx.recyclerview.widget.RecyclerView; import com.blog.R; public class SimpleAdapter extends RecyclerView.Adapter<SimpleAdapter.ViewHolder> { private String[] examples; public interface ViewHolderListener { void onItemClicked(View view, int adapterPosition); } private final ViewHolderListener viewHolderListener; public SimpleAdapter(String[] strs, ViewHolderListener viewHolderListener) { examples = strs; this.viewHolderListener = viewHolderListener; } @NonNull @Override public SimpleAdapter.ViewHolder onCreateViewHolder (@NonNull ViewGroup parent, int viewType) { View view = LayoutInflater.from(parent.getContext()) .inflate(R.layout.list_item_layout, parent, false); return new SimpleAdapter.ViewHolder(view, viewHolderListener); } @Override public void onBindViewHolder(@NonNull SimpleAdapter.ViewHolder holder, int position) { holder.tvContent.setText(examples[position]); } @Override public int getItemCount() { return examples.length; } static class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener { private final TextView tvContent; private final ViewHolderListener viewHolderListener; ViewHolder(View itemView, ViewHolderListener viewHolderListener) { super(itemView); tvContent = itemView.findViewById(R.id.tv_content); this.viewHolderListener = viewHolderListener; itemView.findViewById(R.id.all_layout).setOnClickListener(this); } @Override public void onClick(View view) { if (null != viewHolderListener) { viewHolderListener.onItemClicked(view, getAdapterPosition()); } } } }
当用户点击列表项时,显示短时长的 Toast,你可以在 `ViewHolder` 类的 `onClick` 方法中添加以下代码:
```java
@Override
public void onClick(View view) {
if (null != viewHolderListener) {
viewHolderListener.onItemClicked(view, getAdapterPosition());
Toast.makeText(view.getContext(), "你点击了第 " + (getAdapterPosition() + 1) + " 个列表项", Toast.LENGTH_SHORT).show();
}
}
```
这样,当用户点击列表项时,就会显示一个短时长的 Toast,提示用户点击了哪个列表项。完整的 `SimpleAdapter` 类如下:
```java
package com.blog;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import android.widget.Toast;
import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;
import com.blog.R;
public class SimpleAdapter extends RecyclerView.Adapter<SimpleAdapter.ViewHolder> {
private String[] examples;
public interface ViewHolderListener {
void onItemClicked(View view, int adapterPosition);
}
private final ViewHolderListener viewHolderListener;
public SimpleAdapter(String[] strs, ViewHolderListener viewHolderListener) {
examples = strs;
this.viewHolderListener = viewHolderListener;
}
@NonNull
@Override
public SimpleAdapter.ViewHolder onCreateViewHolder
(@NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext())
.inflate(R.layout.list_item_layout, parent, false);
return new SimpleAdapter.ViewHolder(view, viewHolderListener);
}
@Override
public void onBindViewHolder(@NonNull SimpleAdapter.ViewHolder holder, int position) {
holder.tvContent.setText(examples[position]);
}
@Override
public int getItemCount() {
return examples.length;
}
static class ViewHolder extends RecyclerView.ViewHolder implements
View.OnClickListener {
private final TextView tvContent;
private final ViewHolderListener viewHolderListener;
ViewHolder(View itemView, ViewHolderListener viewHolderListener) {
super(itemView);
tvContent = itemView.findViewById(R.id.tv_content);
this.viewHolderListener = viewHolderListener;
itemView.findViewById(R.id.all_layout).setOnClickListener(this);
}
@Override
public void onClick(View view) {
if (null != viewHolderListener) {
viewHolderListener.onItemClicked(view, getAdapterPosition());
Toast.makeText(view.getContext(), "你点击了第 " + (getAdapterPosition() + 1) + " 个列表项", Toast.LENGTH_SHORT).show();
}
}
}
}
```
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