如何解决如何将此列表视图中可以添加的最大项目数限制为 10?
所以我正在处理一个列表,我希望用户可以放入列表的最大项目数为 10。但是,我无法理解如何在这里执行此操作...我不知道'不希望列表是无限的。我尝试了很多诸如循环之类的东西,但是我在实现它时遇到了麻烦。这个问题最有效的解决方案是什么?
这是我的适配器的代码:
// full subtask adapter code
package com.example.taskmasterv3;
import android.content.Context;
import android.content.Intent;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import java.util.ArrayList;
public class SubtaskAdapter extends ArrayAdapter<subtask> {
private final Context context;
private ArrayList<subtask> values;
public SubtaskAdapter(Context context,ArrayList<subtask> list) {
//since your are using custom view,pass zero and inflate the custom view by overriding getview
super(context,list);
this.context = context;
this.values = list;
}
@Override
public View getView(int position,@Nullable View convertView,@NonNull ViewGroup parent) {
//check if its null,if so inflate it,else simply reuse it
if (convertView == null) {
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.subtask_item,parent,false);
}
//use convertView to refer the childviews to populate it with data
TextView tvSubtaskName = convertView.findViewById(R.id.tvSubtaskName);
ImageView ivPri = convertView.findViewById(R.id.ivPri);
ImageView ivTime = convertView.findViewById(R.id.ivTime);
ImageView ivDelete = convertView.findViewById(R.id.ivDelete);
ivDelete.setTag(position);
ivDelete.setonClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
int position = (Integer) v.getTag();
remove(values.remove(position));
notifyDataSetChanged();
}
});
tvSubtaskName.setText(values.get(position).getSubtaskName());
if (values.get(position).isPriHigh()) {
ivPri.setimageResource(R.drawable.priority_high);
} else if (values.get(position).isPriMed()) {
ivPri.setimageResource(R.drawable.priority_med);
} else if (values.get(position).isPriLow()) {
ivPri.setimageResource(R.drawable.priority_low);
}
if (values.get(position).isTimeMore()) {
ivTime.setimageResource(R.drawable.time_symbol_more);
} else if (values.get(position).isTimeMed()) {
ivTime.setimageResource(R.drawable.time_symbol_med);
} else if (values.get(position).isTimeLess()) {
ivTime.setimageResource(R.drawable.time_symbol_less);
}
// Delete button for subtasks (NOT WORKING)
//return the view you inflated
return convertView;
}
//to keep adding the new subtasks try the following
public void addANewSubTask(subtask newSubTask){
ArrayList<subtask> newvalues = new ArrayList<>(this.values);
newvalues.add(newSubTask);
this.values = newvalues;
notifyDataSetChanged();
}
}
解决方法
只需覆盖适配器中的 getCount()
@Override
public int getCount() {
if(this.values.size()>10)
{
return 10;
}
else {
return super.getCount();
}
}
,
你可以试试这样的
if(newvalues.size() < 10) {
newvalues.add(newsubtask)
} else {
// dont add values,show user the size is 10
}
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