[英]How to pass context to Picasso
您好,我尝试使用Picasso添加图像,但是当我使用以下视图持有人时,在适配器中获取Picasso的上下文时遇到问题:
这是我的适配器
public class DataAdapter extends
RecyclerView.Adapter<DataAdapter.ViewHolder> {
private ArrayList<String>
al_prod_name,al_prod_price,al_prod_id,
al_prod_image;
public DataAdapter(ArrayList<String> al_prod_id,
ArrayList<String> al_prod_name,
ArrayList<String> al_prod_price,
ArrayList<String> al_prod_image) {
this.al_prod_id = al_prod_id;
this.al_prod_price = al_prod_price;
this.al_prod_name = al_prod_name;
this.al_prod_image = al_prod_image
}
public DataAdapter.ViewHolder
onCreateViewHolder(ViewGroup viewGroup, int i) {
View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.cardrow, viewGroup,
false);
return new ViewHolder(view);
}
public void onBindViewHolder(DataAdapter.ViewHolder
viewHolder, int i) {
viewHolder.tv_prod_name.setText
(al_prod_name.get(i));
viewHolder.tv_prod_price.setText
(al_prod_price.get(i));
Picasso.with().load(al_prod_image.get(i))
.placeholder(R.drawable.floatingicon)
.error(R.drawable.floatingicon).
.into(viewHolder.img_prod);
}
public int getItemCount() {
return al_prod_id.size();
}
public class ViewHolder extends RecyclerView.ViewHolder{
private TextView tv_prod_name,tv_prod_price;
private ImageView img_prod;
public ViewHolder(View view) {
super(view);
tv_prod_name = (TextView)view
.findViewById(R.id.tv_prod_name);
tv_prod_price = (TextView)view
.findViewById(R.id.tv_prod_price);
img_prod = (ImageView)view
.findViewById(R.id.img_prod);
}
}
}
请帮助获取上下文。这是我设置适配器的方式:
RecyclerView.Adapter adapter = new
DataAdapter(al_prod_id,al_prod_name,
al_prod_price,al_prod_image);
最简单的解决方案是使用viewHolder.itemView.getContext()
Picasso.with(viewHolder.itemView.getContext()).load(al_prod_image.get(i))
.placeholder(R.drawable.floatingicon)
.error(R.drawable.floatingicon).
.into(viewHolder.img_prod);
将您的构造函数更改为
private Context context;
public DataAdapter(Context context, ArrayList<String> al_prod_id,
ArrayList<String> al_prod_name,
ArrayList<String> al_prod_price,
ArrayList<String> al_prod_image) {
this.context = context;
this.al_prod_id = al_prod_id;
this.al_prod_price = al_prod_price;
this.al_prod_name = al_prod_name;
this.al_prod_image = al_prod_image
}
现在将您的适配器称为
RecyclerView.Adapter adapter = new
DataAdapter(context, al_prod_id,al_prod_name,
al_prod_price,al_prod_image);
这里的上下文是您的活动参考。 希望对您有帮助。
将您的活动上下文传递给DataAdapter
RecyclerView.Adapter adapter = new DataAdapter(yourActivity.this,al_prod_id,al_prod_name,
al_prod_price,al_prod_image);
数据适配器
private Context mContext;
private ArrayList<String> al_prod_name,al_prod_price,al_prod_id,al_prod_image;
public DataAdapter(Context mContext,ArrayList<String> al_prod_id, ArrayList<String> al_prod_name,ArrayList<String> al_prod_price, ArrayList<String> al_prod_image)
{
this.mContext=mContext;
this.al_prod_id = al_prod_id;
this.al_prod_price = al_prod_price;
this.al_prod_name = al_prod_name;
this.al_prod_image = al_prod_image
}
//set image
Picasso.with(mContext).load(al_prod_image.get(i))
.placeholder(R.drawable.floatingicon)
.error(R.drawable.floatingicon).
.into(viewHolder.img_prod);
在您的适配器上下文上下文中声明一个数据成员; 这样编写适配器的构造函数,
DataAdapter(Context context, otherAurguments);
并且在创建适配器时
DataAdapter adapter = new DataAdapter(yourActivityName.this , otherAurguments);
每个视图都有上下文。 我建议您使用getApplicationContext()
防止活动上下文为空时应用崩溃
Picasso.with(itemView.getContext()).load(al_prod_image.get(i))
要么
Picasso.with(itemView.getContext().getApplicationContext()).load(al_prod_image.get(i))
在活动中,
RecyclerView.Adapter adapter = new DataAdapter(YOUR_ACTIVITY.this, al_prod_id,al_prod_name, al_prod_price,al_prod_image);
在适配器中
private Context context;
public DataAdapter(Context mContext, ArrayList<String> al_prod_id, ArrayList<String> al_prod_name, ArrayList<String> al_prod_price, ArrayList<String> al_prod_image) {
this.context= mContext;
this.al_prod_id = al_prod_id;
this.al_prod_price = al_prod_price;
this.al_prod_name = al_prod_name;
this.al_prod_image = al_prod_image
}
结合使用毕加索的上下文
Picasso.with(context).load(al_prod_image.get(i))
.placeholder(R.drawable.floatingicon)
.error(R.drawable.floatingicon).
.into(viewHolder.img_prod);
像这样更改您的DataAdapter构造函数,在您的适配器类中创建一个Context对象,并像这样更改您的构造函数
public DataAdapter(Context context,ArrayList<String> al_prod_id,
ArrayList<String> al_prod_name,
ArrayList<String> al_prod_price,
ArrayList<String> al_prod_image) {
this.al_prod_id = al_prod_id;
this.al_prod_price = al_prod_price;
this.al_prod_name = al_prod_name;
this.al_prod_image = al_prod_image;
this.mContext = context;
}
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