Question

所以我花了将近3个小时来寻找关于如何使用POJO的ArrayAdapter为我的微调器设置值的答案。

这是我的POJO：

public class ArchiveIssueModel implements Serializable {

private String Issues;
private String id;
private String Picture;

public ArchiveIssueModel(String issues, String id, String picture) {
    Issues = issues;
    this.id = id;
    Picture = picture;
}



public ArchiveIssueModel() {
}

public ArchiveIssueModel(String issue) {
    this.Issues = issue;
}

public String getIssues() {
    return Issues;
}

public void setIssues(String issues) {
    Issues = issues;
}

public String getId() {
    return id;
}

public void setId(String id) {
    this.id = id;
}

public String getPicture() {
    return Picture;
}

public void setPicture(String picture) {
    Picture = picture;
}

//to display object as a string in spinner
@Override
public String toString() {
    return Issues;
}

@Override
public boolean equals(Object obj) {
    if(obj instanceof ArchiveIssueModel){
        ArchiveIssueModel c = (ArchiveIssueModel )obj;
        if(c.getIssues().equals(Issues) && c.getId()== id ) return true;
    }

    return false;
}

我知道如何使用String的ArrayAdapter设置值。我这样做了，这很容易理解。

ArrayAdapter<String> spinnerArrayAdapter =
            new ArrayAdapter<>(this,
                    android.R.layout.simple_spinner_item, yearList);
    spinnerArrayAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    sp_year.setAdapter(spinnerArrayAdapter);
    sp_year.setSelection(spinnerArrayAdapter.getPosition(year));

但是我无法弄清楚如何在ArrayAdapter o ArchiveIssueModel（即我的POJO）的情况下为我的微调器设置一个值。任何帮助，将不胜感激。 TY：）

Answer 1

它与您编写的相同，但只是向适配器提供了POJO类的列表。

import android.content.Context
import android.util.AttributeSet
import android.widget.Button

public class ResizableButton(context: Context, attrs: AttributeSet) : Button(context, attrs) {

    override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {
        val width = MeasureSpec.getSize(widthMeasureSpec)
        setMeasuredDimension(width, width)
    }

}

Answer 2

我们需要定义适配器来描述将Java对象转换为View的过程（在getView方法中）。这种天真的方法（没有任何视图缓存）如下所示：

    public class UsersAdapter extends ArrayAdapter<User> {

    // View lookup cache

    private static class ViewHolder {

        TextView name;

        TextView home;

    }



    public UsersAdapter(Context context, ArrayList<User> users) {

       super(context, R.layout.item_user, users);

    }



    @Override

    public View getView(int position, View convertView, ViewGroup parent) {

       // Get the data item for this position

       User user = getItem(position);    

       // Check if an existing view is being reused, otherwise inflate the view

       ViewHolder viewHolder; // view lookup cache stored in tag

       if (convertView == null) {

          // If there's no view to re-use, inflate a brand new view for row

          viewHolder = new ViewHolder();

          LayoutInflater inflater = LayoutInflater.from(getContext());

          convertView = inflater.inflate(R.layout.item_user, parent, false);

          viewHolder.name = (TextView) convertView.findViewById(R.id.tvName);

          viewHolder.home = (TextView) convertView.findViewById(R.id.tvHome);

          // Cache the viewHolder object inside the fresh view

          convertView.setTag(viewHolder);

       } else {

           // View is being recycled, retrieve the viewHolder object from tag

           viewHolder = (ViewHolder) convertView.getTag();

       }

       // Populate the data from the data object via the viewHolder object 

       // into the template view.

       viewHolder.name.setText(user.name);

       viewHolder.home.setText(user.hometown);

       // Return the completed view to render on screen

       return convertView;

   }

}

注意：将用户pojo更改为pojo类。

如何从ArrayAdapter <pojo>动态设置微调器的值

2 个答案: