滚动时有两个 xml 变化的 Listview

Question

目前我正在为我的应用程序处理消息传递页面。问题是我在列表视图中使用了两个不同的 xml。现在我可以让数据以正确的顺序显示在页面上，但是，当我滚动时，数据仍然以正确的顺序显示，但样式不同。例如，在滚动最后一条消息之前，如果我向上滚动则使用 messagesent.xml，然后向下滚动相同的消息现在具有 message.xml 样式。我目前使用的代码如下。

public class MessagingAdapter extends ArrayAdapter<MessagingObject> {


private static final String userID = "USERID";
private static final int TYPE_ITEM1 = 0;
private static final int TYPE_ITEM2 = 1;

public String newid;
public Context context;
public ArrayList<MessagingObject> object = new ArrayList<MessagingObject>();

int type;

public MessagingAdapter(Context context, int textViewResourceId, ArrayList<MessagingObject> objects) {
    super(context, textViewResourceId, objects);
    this.context = context;
    this.object = objects;
}

@Override
public int getItemViewType(int position) {

    if (userID.equals(newid)) {
        type = TYPE_ITEM1;
    } else {
        type = TYPE_ITEM2;
    }
    return type;
}

@Override
public int getViewTypeCount() {

    return 2;
}

@Override
public View getView(int position, View convertview, ViewGroup parent) {


    MessagingObject i = object.get(position);
    newid = i.getMessageID();

    LayoutInflater inflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    convertview = inflater.inflate(R.layout.messagesright_layout, null);

    if (convertview == null) {
        convertview = inflater.inflate(R.layout.messagesright_layout, null);
    }

    if (type == TYPE_ITEM1) {
       convertview = inflater.inflate(R.layout.messagesright_layout, null);
       TextView sentmessage = (TextView) convertview.findViewById(R.id.messagesent_text);
       sentmessage.setText(object.get(position).getMessage());

       TextView senttime = (TextView) convertview.findViewById(R.id.messagesentTime);
       String senttimestring = new String().valueOf(object.get(position).getTimeStamp());
       senttime.setText(senttimestring);

      } else {
       convertview = inflater.inflate(R.layout.messages_layout, null);
       TextView message = (TextView) convertview.findViewById(R.id.message_text);
       message.setText(object.get(position).getMessage());

       TextView time = (TextView) convertview.findViewById(R.id.messageTime);
       String timestring = new String().valueOf(object.get(position).getTimeStamp());
       time.setText(timestring);
     }
    return convertview;
}

现在我知道这与 Listview 回收有关，但是，我尝试了一些我在其他堆栈溢出帖子上找到的解决方案，但没有运气，而且我无法找到很多解决这个问题的方法2个xml。

感谢您的观看！

Answer 1

我编写了一个列表，其中包含 2 个 xml 用于列表中不同行的布局，但我没有看到这个问题。

我不会将视图类型存储在局部变量中，而是我总是在“getView”的开头调用“getItemViewType”，因此我可以保证获得当前位置的正确视图类型，请参阅我对您的调整下面的代码（我没有检查这个编译）

---

public class MessagingAdapter extends ArrayAdapter<MessagingObject> {


private static final String userID = "USERID";
private static final int TYPE_ITEM1 = 0;
private static final int TYPE_ITEM2 = 1;

public String newid;
public Context context;
public ArrayList<MessagingObject> object = new ArrayList<MessagingObject>();

int type;

public MessagingAdapter(Context context, int textViewResourceId, ArrayList<MessagingObject> objects) {
    super(context, textViewResourceId, objects);
    this.context = context;
    this.object = objects;
}

@Override
public int getItemViewType(int position) {

    if (userID.equals(newid)) {
        return = TYPE_ITEM1;
    } else {
        return = TYPE_ITEM2;
    }
}

@Override
public int getViewTypeCount() {

    return 2;
}

@Override
public View getView(int position, View convertview, ViewGroup parent) {


    MessagingObject i = object.get(position);
    newid = i.getMessageID();

    LayoutInflater inflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);

    if (getItemViewType(position) == TYPE_ITEM1) {
       convertview = inflater.inflate(R.layout.messagesright_layout, null);
       TextView sentmessage = (TextView) convertview.findViewById(R.id.messagesent_text);
       sentmessage.setText(object.get(position).getMessage());

       TextView senttime = (TextView) convertview.findViewById(R.id.messagesentTime);
       String senttimestring = new String().valueOf(object.get(position).getTimeStamp());
       senttime.setText(senttimestring);

      } else {
       convertview = inflater.inflate(R.layout.messages_layout, null);
       TextView message = (TextView) convertview.findViewById(R.id.message_text);
       message.setText(object.get(position).getMessage());

       TextView time = (TextView) convertview.findViewById(R.id.messageTime);
       String timestring = new String().valueOf(object.get(position).getTimeStamp());
       time.setText(timestring);
     }
    return convertview;

Answer 2

您的getView 错误。只有当convertView 为空时，您才应该询问该位置的类型并膨胀视图。

@Override
public View getView(int position, View convertview, ViewGroup parent) {


MessagingObject i = object.get(position);
newid = i.getMessageID();
int type = getItemViewType(position);

if (convertview == null) {
    LayoutInflater inflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    if (type == TYPE_ITEM1) {
       convertview = inflater.inflate(R.layout.messagesright_layout, null);
    } else if (type == TYPE_ITEM2) {
       convertview = inflater.inflate(R.layout.messages_layout, null);
    }
}

if (type == TYPE_ITEM1) {
   TextView sentmessage = (TextView) convertview.findViewById(R.id.messagesent_text);
   sentmessage.setText(object.get(position).getMessage());

   TextView senttime = (TextView) convertview.findViewById(R.id.messagesentTime);
   String senttimestring = new String().valueOf(object.get(position).getTimeStamp());
   senttime.setText(senttimestring);

  } else {

   TextView message = (TextView) convertview.findViewById(R.id.message_text);
   message.setText(object.get(position).getMessage());

   TextView time = (TextView) convertview.findViewById(R.id.messageTime);
   String timestring = new String().valueOf(object.get(position).getTimeStamp());
   time.setText(timestring);
 }
return convertview;
}

Answer 3

try this:

if (convertview == null) {

if (type == TYPE_ITEM1) {
   convertview = inflater.inflate(R.layout.messagesright_layout, null);
   TextView sentmessage = (TextView) convertview.findViewById(R.id.messagesent_text);
   sentmessage.setText(object.get(position).getMessage());

   TextView senttime = (TextView) convertview.findViewById(R.id.messagesentTime);
   String senttimestring = new String().valueOf(object.get(position).getTimeStamp());
   senttime.setText(senttimestring);

  } else {
   convertview = inflater.inflate(R.layout.messages_layout, null);
   TextView message = (TextView) convertview.findViewById(R.id.message_text);
   message.setText(object.get(position).getMessage());

   TextView time = (TextView) convertview.findViewById(R.id.messageTime);
   String timestring = new String().valueOf(object.get(position).getTimeStamp());
   time.setText(timestring);
 }