问题描述
我正在尝试用一个 xml 文件填充一个 xml(聊天记录),以及一个可以从中获取消息文本的类。
我正在使用 ArrayAdapter 和通货膨胀。我有 2 个 XML 文件,其中一个是“messageother”,用于其他人的消息,“messageme”用于用户自己写的消息。
public class MsgAdapter extends ArrayAdapter<Msg> {
private final Context context;
private final ArrayList<Msg> msgList;
private TextView tvText;
public MsgAdapter(Context context,ArrayList<Msg> messages) {
super(context,R.layout.activ,messages);
this.context=context;
this.msgList=messages;
}
@Override
public View getView(int position,View convertView,ViewGroup parent) {
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View rowView = inflater.inflate(R.layout.messageother,parent,false);
return rowView;
}
}
现在,这只会复制“messageother”的相同 xml 文件,直到完成。 相反,id喜欢在ListView中一一进行,检查Msg.getmine() = true; 如果是这样,id 喜欢用 xml "messageme" 来膨胀那个:
View rowView = inflater.inflate(R.layout.messageme,false);
这样的事情我怎么办?
解决方法
public static class MsgAdapter extends ArrayAdapter<Msg> {
private static final class ViewHolders {
View mMessageOthersView;
View mMessageMeView;
private ViewHolders(@NonNull final LayoutInflater layoutInflater,@NonNull View parent) {
this.mMessageOthersView = layoutInflater.inflate(R.layout.messageother,parent,false);
this.mMessageMeView = layoutInflater.inflate(R.layout.messageme,false);
}
}
private final ArrayList<Msg> msgList;
private final LayoutInflater mLayoutInflater;
public MsgAdapter(Context context,ArrayList<Msg> messages) {
super(context,R.layout.activ,messages);
this.msgList = messages;
this.mLayoutInflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
@Override
public View getView(final int position,View convertView,final ViewGroup parent) {
final ViewHolders cViewHolders;
if (convertView == null) {
cViewHolders = new ViewHolders(this.mLayoutInflater,parent);
convertView.setTag(cViewHolders);
} else {
cViewHolders = (ViewHolders)convertView.getTag();
}
final View finalView;
final Msg cMsg = this.getItem(position);
if (cMsg.getMine()) finalView = cViewHolders.mMessageMeView;
else finalView = cViewHolders.mMessageOthersView;
//"finalView" is the final inflated Layout
finalView.findViewById(....)
return finalView;
}
}
进一步的步骤可能是为每个布局缓存所有需要的视图,避免为每个项目做一个完整的“findById()”......