通过一个加入按钮来给list添加item,但是每次添加后的item都会左移,应该怎么解决

item 的布局代码

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:orientation="vertical"
    android:layout_height="wrap_content">
    <androidx.cardview.widget.CardView
        android:layout_width="1000dp"
        app:cardBackgroundColor="@color/teal_200"
        android:layout_height="1dp">
    </androidx.cardview.widget.CardView>
<LinearLayout
    android:layout_gravity="center"
    android:gravity="center"
    android:layout_width="match_parent"
    android:orientation="vertical"
    android:layout_height="wrap_content">


        <LinearLayout

            android:layout_width="match_parent"
            android:orientation="vertical"
            android:layout_height="wrap_content">
            <LinearLayout
                android:layout_width="match_parent"
                android:orientation="horizontal"
                android:layout_height="wrap_content">
                <TextView
                    android:layout_width="wrap_content"
                    android:textColor="@color/black"
                    android:textSize="20sp"
                    android:text="班级:"
                    android:layout_height="wrap_content">

                </TextView>
                <TextView
                    android:id="@+id/name_tv"
                    android:layout_width="match_parent"
                    android:layout_marginLeft="20dp"
                    android:text="xxx"
                    android:textStyle="bold"
                    android:textSize="20sp"
                    android:layout_height="wrap_content">

                </TextView>
            </LinearLayout>
            <LinearLayout
                android:layout_width="match_parent"
                android:orientation="horizontal"
                android:layout_height="wrap_content">
                <TextView
                    android:layout_width="wrap_content"
                    android:textColor="@color/black"
                    android:textSize="20sp"
                    android:text="姓名:"
                    android:layout_height="wrap_content">

                </TextView>
                <TextView
                    android:id="@+id/class_tv"
                    android:layout_width="wrap_content"
                    android:layout_marginLeft="20dp"
                    android:text="高三八班"
                    android:textStyle="bold"
                    android:textSize="20sp"
                    android:layout_height="wrap_content">

                </TextView>
            </LinearLayout>
            <LinearLayout
                android:layout_width="match_parent"
                android:orientation="horizontal"
                android:layout_height="wrap_content">
                <TextView
                    android:layout_width="wrap_content"
                    android:textColor="@color/black"
                    android:textSize="20sp"
                    android:text="学号:"
                    android:layout_height="wrap_content">

                </TextView>
                <TextView
                    android:id="@+id/number_tv"
                    android:layout_width="match_parent"
                    android:layout_marginLeft="20dp"
                    android:text="20211157"
                    android:textStyle="bold"
                    android:textSize="20sp"
                    android:layout_height="wrap_content">

                </TextView>
            </LinearLayout>
            <LinearLayout
                android:layout_width="match_parent"
                android:orientation="horizontal"
                android:layout_height="wrap_content">
                <TextView
                    android:layout_width="wrap_content"
                    android:textColor="@color/black"
                    android:textSize="20sp"
                    android:text="分数:"
                    android:layout_height="wrap_content">

                </TextView>
                <TextView
                    android:id="@+id/score_tv"
                    android:layout_width="match_parent"
                    android:layout_marginLeft="20dp"
                    android:text="98分"
                    android:textStyle="bold"
                    android:textSize="20sp"
                    android:layout_height="wrap_content">

                </TextView>
            </LinearLayout>
        </LinearLayout>

</LinearLayout>
    <androidx.cardview.widget.CardView
        android:layout_width="1000dp"
        app:cardBackgroundColor="@color/teal_200"
        android:layout_height="1dp">
    </androidx.cardview.widget.CardView>
</LinearLayout>

2.Recycleviewadapter代码

public class RecycleviewAdapter extends RecyclerView.Adapter<RecycleviewAdapter.InnerHolder> {
   private List<DataBeans> mDataBeans;
    private  TextView mName;
    private  TextView mClass;
    private  TextView mNumber;
    private  TextView mScore;
    private  DataBeans mBeans =new DataBeans();
    private Map<Integer,DataBeans> mBeansMap =new HashMap<>();
    public RecycleviewAdapter(List<DataBeans> data){
        Log.d("adapter---","data---"+data);
        this.mDataBeans =data;

      mBeansMap.put(data.size(),mBeans);
        Log.d("adapter---","map---"+mBeansMap);

    }
    @NonNull
    @Override
    public InnerHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = View.inflate(parent.getContext(), R.layout.item_msg, null);
        return new InnerHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull InnerHolder holder, int position) {

        holder.setData(mDataBeans.get(position));

    }


    @Override
    public int getItemCount() {
        if (mDataBeans!=null){
            Log.d("adapter---","databenas---"+mDataBeans.size());
            return mDataBeans.size();
        }
        return 0;
    }

    public class InnerHolder extends RecyclerView.ViewHolder {
        public InnerHolder(@NonNull View itemView) {
            super(itemView);
            mName = itemView.findViewById(R.id.name_tv);
            mClass = itemView.findViewById(R.id.class_tv);
            mNumber = itemView.findViewById(R.id.number_tv);
            mScore = itemView.findViewById(R.id.score_tv);

        }

        public void setData(DataBeans dataBeans) {
               mName.setText(dataBeans.getName());
               mClass.setText(dataBeans.getmClass());
               mScore.setText(dataBeans.getScore());
               mNumber.setText(dataBeans.getNumber());

        }
    }
}

3.Acvivity

public class EditMsgActivity extends AppCompatActivity {

    private EditText mClass_ip;
    private EditText mName_ip;
    private EditText mNumber_ip;
    private EditText mScore_ip;
    private Button mAdd_btn;
    private RecyclerView mRecyclerView;
    private String MClass;
    private String mName;
    private String mScore;
    private String mNumber;
  private List<DataBeans> mData=new ArrayList<>();
  private DataBeans mDataBeans;
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_msgshow);
        initview();

        setOnClickListener();

    }

    private void setOnClickListener() {
        mAdd_btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
            mRecyclerView.setHasFixedSize(true);
                getEtmsg();
        setdata();
                setListviewEvent();
                mClass_ip.getText().clear();
                mName_ip.getText().clear();
                mScore_ip.getText().clear();
                mNumber_ip.getText().clear();
            }
        });
    }

    private void setdata() {
        int count=0;
        if (mName!=null&&MClass!=null&&mNumber!=null&&mScore!=null){
        mDataBeans=new DataBeans();
        mDataBeans.setName(mName);
        mDataBeans.setmClass(MClass);
        mDataBeans.setNumber(mNumber);
        mDataBeans.setScore(mScore);
        Log.d("EditActivity----","databeans-------"+mDataBeans.toString());

        if (mDataBeans!=null){
        mData.add(mDataBeans);

        Log.d("EditActivity----","data-------"+mData);


        }
        }

    }

    private void setListviewEvent() {

            RecycleviewAdapter adapter = new RecycleviewAdapter(mData);
            mRecyclerView.addItemDecoration(new SpaceItemDecoration(0,15));
        LinearLayoutManager layoutManager = new LinearLayoutManager(this);
        mRecyclerView.setLayoutManager(layoutManager);
            mRecyclerView.setAdapter(adapter);
            mRecyclerView.setHasFixedSize(true);
    }

    private void getEtmsg() {

        MClass = mClass_ip.getText().toString();

        Log.d("EditActivity----","class----"+MClass);
        mName = mName_ip.getText().toString();
        mScore = mScore_ip.getText().toString();
        mNumber = mNumber_ip.getText().toString();

    }

    private void initview() {
        mClass_ip = this.findViewById(R.id.class_input);
        mName_ip = this.findViewById(R.id.name_input);
        mNumber_ip = this.findViewById(R.id.number_input);
        mScore_ip = this.findViewById(R.id.score_input);
        mAdd_btn = this.findViewById(R.id.add_btn);
        mRecyclerView = this.findViewById(R.id.list_view);

    }
    //设置边距
    public static class SpaceItemDecoration extends RecyclerView.ItemDecoration {

        private final int normal;
        private final int margin;

        @Override
        public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
            super.getItemOffsets(outRect, view, parent, state);

            outRect.top = normal;
            outRect.bottom = normal;
            if (parent.getChildAdapterPosition(view) % 3 == 0) {
                outRect.right = normal;
                outRect.left = margin;
            } else if (parent.getChildAdapterPosition(view) % 3 == 1) {
                outRect.right = margin;
                outRect.left = margin;
            } else if (parent.getChildAdapterPosition(view) % 3 == 2) {
                outRect.right = normal;
                outRect.left = margin;
            }

        }

        public SpaceItemDecoration(int normal, int margin) {
            this.normal = normal;
            this.margin = margin;
        }
    }