Android - 背景延伸而不是在滚动时对齐

Question

我正在尝试创建聊天视图（已发送文本，已接收文本）。背景可绘制（框）与一侧正确对齐。当我滚动时，它会扩展框以适应整个宽度。不知道为什么会这样。有任何想法吗？ The problem i'm talking about How i actually want it(this is before scrolling)

我的自定义适配器类

public class DisplayMessageAdapter extends ArrayAdapter<Message> {

Context context;
int sentResource, rcvdResource;
ArrayList<Message> messages = null;

public DisplayMessageAdapter(Context context, int sentResource, int rcvdResource, ArrayList<Message> messages) {
    super(context, sentResource, rcvdResource, messages);
    this.context = context;
    this.sentResource = sentResource;
    this.rcvdResource = rcvdResource;
    this.messages = messages;
}



@SuppressLint("NewApi")
@Override


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

View row = convertView;
Message message = messages.get(position);

Holder holder = new Holder();



    if(row == null)
    {
        LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        holder = new Holder();
        row = inflater.inflate(R.layout.message_layout, parent, false);
        holder.content  = (TextView) row.findViewById(R.id.message_content);
        row.setTag(holder);
    }
    else
    {
        holder = (Holder) row.getTag();
    }
    if(message.sent != null)
    {
        RelativeLayout.LayoutParams params = (LayoutParams) holder.content.getLayoutParams();
        params.setMargins(30, params.topMargin, params.rightMargin, params.bottomMargin);
        params.addRule(RelativeLayout.ALIGN_PARENT_RIGHT);

        holder.content.setLayoutParams(params);
        holder.content.setBackgroundResource(R.drawable.sent);
        holder.content.setText(message.sent);

    }

    else
    {
        RelativeLayout.LayoutParams params = (LayoutParams) holder.content.getLayoutParams();
        params.setMargins(params.leftMargin, params.topMargin, 30, params.bottomMargin);
        params.addRule(RelativeLayout.ALIGN_PARENT_LEFT);

        holder.content.setLayoutParams(params);
        holder.content.setBackgroundResource(R.drawable.rcvd);
        holder.content.setText(message.received);
    }



return row;
}

我的布局文件

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
>

  <TextView
      android:id="@+id/message_content"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content" 
      android:textColor="#000000"
      android:layout_marginTop="4dp"
      android:layout_marginBottom="4dp"
      android:textSize="15sp"
       />

</RelativeLayout>

我的Drawables - rcvd / send

  <shape android:visible="false" xmlns:android="http://schemas.android.com/apk/res/android">
    <solid android:color="#FFFFFF"/>
    <corners android:radius="3dp" />
    <padding android:left="10dp" android:top="10dp"
        android:right="10dp" android:bottom="10dp"/>
    <stroke android:color="#439CC8" android:width="2dp"/>
</shape>

<shape android:visible="false" xmlns:android="http://schemas.android.com/apk/res/android">
    <solid android:color="#FFFFFF"/>
    <corners android:radius="3dp" />
    <padding android:left="10dp" android:top="10dp"
        android:right="10dp" android:bottom="10dp"/>
    <stroke android:color="#6D4E4E" android:width="2dp"/>
</shape>