在使用ListFragment的setEmptyText时报java.lang.IllegalStateException: Can't be used with a custom content view错误

今天搞了好久, 才基本解决了这个问题. 

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >
    
    <ListView 
        android:id="@android:id/list"  <!--这样命名我就不多说了-->
        style="@style/MyListView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

    <TextView 
        android:id="@android:id/empty"  <!-- 为什么这样命名,且看下文 -->
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"/>
        
</FrameLayout>

//且看源码ListFragment


 1 private void ensureList() {
        if (mList != null) {
            return;
        }
        View root = getView();
        if (root == null) {
            throw new IllegalStateException("Content view not yet created");
        }
        if (root instanceof ListView) {
            mList = (ListView)root;
        } else {
            mStandardEmptyView = (TextView)root.findViewById(INTERNAL_EMPTY_ID);
            if (mStandardEmptyView == null) {
                mEmptyView = root.findViewById(android.R.id.empty);  //且看这里
            } else {
                mStandardEmptyView.setVisibility(View.GONE);
            }
            mProgressContainer = root.findViewById(INTERNAL_PROGRESS_CONTAINER_ID);
            mListContainer = root.findViewById(INTERNAL_LIST_CONTAINER_ID);
            View rawListView = root.findViewById(android.R.id.list);
            if (!(rawListView instanceof ListView)) {
                if (rawListView == null) {
                    throw new RuntimeException(
                            "Your content must have a ListView whose id attribute is " +
                            "'android.R.id.list'");
                }
                throw new RuntimeException(
                        "Content has view with id attribute 'android.R.id.list' "
                        + "that is not a ListView class");
            }
            mList = (ListView)rawListView;
            if (mEmptyView != null) {
                mList.setEmptyView(mEmptyView);
            } else if (mEmptyText != null) {
                mStandardEmptyView.setText(mEmptyText);
                mList.setEmptyView(mStandardEmptyView);
            }
        }
        mListShown = true;
        mList.setOnItemClickListener(mOnClickListener);
        if (mAdapter != null) {
            ListAdapter adapter = mAdapter;
            mAdapter = null;
            setListAdapter(adapter);
        } else {
            // We are starting without an adapter, so assume we won't
            // have our data right away and start with the progress indicator.
            if (mProgressContainer != null) {
                setListShown(false, false);
            }
        }
        mHandler.post(mRequestFocus);
    }

在程序中重写

@Override
public void setEmptyText(CharSequence text) {
    TextView emptyView = (TextView)getListView().getEmptyView();
    emptyView.setVisibility(View.GONE);
    emptyView.setText(text);
}

然后就可以

setEmptyText(getString(R.string.list_no_data));

这样就成功了.

setEmptyText(CharSequence text) 只能用在ListFragment默认视图. 其背后还是用的ListView的setEmptyView()所以可以通过getEmptyView获取这个视图.