android - 回收站 View : scrollToPosition not working

Question

我有一个显示用户短信的简单项目。我目前无法将 RecyclerView 滚动到最后收到的短信。
我的 recyclerView 在一个使用 Coordinator 布局的非常简单的 Activity 中:

<android.support.design.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
android:background="@color/background"
tools:context="com.myproject.myproject.MessageActivity">

<android.support.design.widget.AppBarLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:theme="@style/AppTheme.AppBarOverlay">

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        android:background="?attr/colorPrimary"
        app:popupTheme="@style/AppTheme.PopupOverlay"/>

</android.support.design.widget.AppBarLayout>

<include layout="@layout/content_message" />
</android.support.design.widget.CoordinatorLayout>

和 content_message.xml:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:descendantFocusability="beforeDescendants"
android:focusable="true"
android:focusableInTouchMode="true"
android:orientation="vertical"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:context="com.textbutler.textbutler.MessageActivity"
tools:showIn="@layout/activity_message">

<!-- some views here -->

<android.support.v7.widget.RecyclerView
    android:id="@+id/content_text"
    android:layout_width="match_parent"
    android:layout_height="0dp"
    android:layout_weight="1"
    android:scrollbars="vertical" />

<!-- some views here -->
</LinearLayout>

Activity 通过基本加载程序加载数据。我强制访问 UI 线程上的 recyclerview 并延迟(以防万一)

public class MessageActivity extends AppCompatActivity {
private static final int URL_LOADER = 0;

private RecyclerView recyclerView;
private LinearLayoutManager layoutManager;
private MessageAdapter adapter;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_message);

    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);
    getSupportActionBar().setDisplayHomeAsUpEnabled(true);

    initializeList(savedInstanceState);
}

private void initializeList(Bundle savedInstanceState) {
    if (recyclerView == null) {
        recyclerView = (RecyclerView) findViewById(R.id.content_text);

        if (recyclerView == null)
            return;

        if (layoutManager == null) {
            layoutManager = new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false);
            layoutManager.setReverseLayout(true);
            layoutManager.setStackFromEnd(true);
        }

        recyclerView.setLayoutManager(layoutManager);

        final Activity me = this;

        if (adapter == null) {
            adapter = new MessageAdapter(new ObservableCallback() {
                @Override
                public void callback() {
                    // this function is called right after the recyclerview received notifyDataSetChanged
                    new Handler().postDelayed(new Runnable() {
                        @Override
                        public void run() {

                            me.runOnUiThread(new Runnable() {
                                @Override
                                public void run() {
                                    Log.d("ScrollingUI", "scrolltoposition " + adapter.getItemCount());
                                    recyclerView.scrollToPosition(adapter.getItemCount() - 1);
                                }
                            });
                        }
                    }, 1000);
                }
            });
            SMSByUserLoader loader = new SMSByUserLoader(this, adapter);
            getSupportLoaderManager().initLoader(URL_LOADER, savedInstanceState, loader);
        }

        recyclerView.setAdapter(adapter);
    }
}

当我运行这段代码时，RecyclerView 被完美填充。一秒钟后，我有了正确的日志，但 View 没有改变。 我已经找到了这个问题的各种答案，但它们似乎都不适用于我的情况。
在 RecyclerView 中滚动非常有效。

Answer 1

我有同样的问题，smoothScrollToPosition 方法解决了它:

 RecyclerView.smoothScrollToPosition(postion);