安卓 - 自定义适配器，GetView 位置未正确递增

Question

我的自定义适配器包含一个 getView 方法，并且 getView 的位置未正确递增。副作用是所有值都以两种布局（row_chat_me和row_chat_others）呈现。IsMsgFromMe正确识别消息的作者是谁（消息。GetFrom（））。chatMsgList 是一个包含消息对象的 ArrayList。

谢谢！

public class ChatAdapter extends ArrayAdapter<Message> {
public ChatAdapter(Context context, ArrayList<Message> messages) {
    super(context, 0, messages);
}
public boolean IsMsgFromMe(Message message) {
    boolean isSenderMe = ChatFragment.username.equals(message.GetFrom());
    return isSenderMe;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
    ViewHolder holder = null;
    // Get the data item for this position
    Message message = ChatFragment.chatMsgList.get(position);
    if (convertView == null) {
        holder = new ViewHolder();
        //Check who has sent the message me or someone else...
        if (IsMsgFromMe(message)) {
            convertView = LayoutInflater.from(getContext()).inflate(R.layout.row_chat_me, parent, false);
            holder.chatFrom = (TextView) convertView.findViewById(R.id.txt_message_me_from);
            holder.chatMessage = (TextView) convertView.findViewById(R.id.txt_message_me_message);
            holder.chatTime = (TextView) convertView.findViewById(R.id.txt_message_me_time);
        } else {
            convertView = LayoutInflater.from(getContext()).inflate(R.layout.row_chat_others, parent, false);
            holder.chatFrom = (TextView) convertView.findViewById(R.id.txt_message_others_from);
            holder.chatMessage = (TextView) convertView.findViewById(R.id.txt_message_others_message);
            holder.chatTime = (TextView) convertView.findViewById(R.id.txt_message_others_time);
        }
        convertView.setTag(holder);
    } else {
        holder = (ViewHolder) convertView.getTag();
    }
    // Populate the data into the template view using the data object
    holder.chatFrom.setText("From: " + message.GetFrom());
    holder.chatMessage.setText(message.GetMsg());
    holder.chatTime.setText("Date: " + message.GetTime());
    // Return the completed view to render on screen
    return convertView;
}
public static class ViewHolder {
    public TextView chatFrom;
    public TextView chatMessage;
    public TextView chatTime;
}

}

Answer 1

正如上面的代码，在 getView（） 中，当 convertView！=null 时，也许 convertView 是从 R.layout.row_chat_me 而不是R.layout.row_chat_others

膨胀的（和 .

因此，您应该覆盖 getItemType（） 和 getViewTypeCount（） 以在适配器中定义 2（或更多）项视图类型。

您可以在此处阅读更多详细信息：http://android.amberfog.com/?p=296（部分不同列表项的布局）

Answer 2

我的建议是使用传递到适配器的消息列表，而不是引用ChatFragment中的列表。所以我会像这样修改适配器代码：

public class ChatAdapter extends ArrayAdapter<Message> {
private ArrayList<Message> messages;
public ChatAdapter(Context context, ArrayList<Message> messages) {
    super(context, 0, messages);
    this.messages = messages;
}
...

除非您对 2 行聊天有不同的

背景，或者 2 行聊天之间有一些其他主要差异，否则我认为您只需要一行布局。

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    ViewHolder holder = null;
    // Get the data item for this position
    Message message = messages.get(position);
    if (convertView == null) {
        holder = new ViewHolder();
        convertView = LayoutInflater.from(getContext()).inflate(R.layout.row_chat, parent, false);
        holder.chatFrom = (TextView) convertView.findViewById(R.id.txt_message_from);
        holder.chatMessage = (TextView) convertView.findViewById(R.id.txt_message_message);
        holder.chatTime = (TextView) convertView.findViewById(R.id.txt_message_time);
        convertView.setTag(holder);
    } else {
        holder = (ViewHolder) convertView.getTag();
    }
    // Populate the data into the template view using the data object
    holder.chatFrom.setText("From: " + message.GetFrom());
    holder.chatMessage.setText(message.GetMsg());
    holder.chatTime.setText("Date: " + message.GetTime());
    // Return the completed view to render on screen
    return convertView;
}

单行布局示例：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
   android:orientation="vertical"
   android:layout_width="match_parent"
   android:layout_height="match_parent">
    <TextView
       android:id="@+id/txt_message_time"
       android:layout_width="fill_parent"
       android:layout_height="25dp"/>
    <TextView
       android:id="@+id/txt_message_from"
       android:layout_width="fill_parent"
       android:layout_height="25dp"
       android:layout_below="@+id/txt_message_time" />
    <TextView
       android:id="@+id/txt_message_message"
       android:layout_width="fill_parent"
       android:layout_below="@+id/txt_message_from"
       android:layout_height="50dp" />
</RelativeLayout>

我希望这有所帮助。