java - 尝试向 recyclerview 添加元素(ConcurrentModificationException)

Question

我正在尝试将项目添加到列表中，但出现错误，我不知道如何解决它。
下面是添加的示例:

for (Object object : mData) {
    if (object instanceof BaseAdapter.ChoseFriendItem) {
               mAdapter.addItem(1, object);
    }
}

其中 mDate - arraylist
执行代码后出现以下错误:

FATAL EXCEPTION: main
Process: com.akbars.bankok, PID: 15263    java.util.ConcurrentModificationException
at java.util.ArrayList$ArrayListIterator.next(ArrayList.java:573)
at com.akbars.bankok.v2.ActivityChoseFriends.onClick(ActivityChoseFriends.java:311)
at android.view.View.performClick(View.java:5198)
at android.view.View$PerformClick.run(View.java:21147)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

然后我尝试使用迭代器。但为什么它只添加一个元素而不是从列表的开头添加，这是一个例子:

for (ListIterator<Object> iterator = mData.listIterator(); iterator.hasNext();) {
     if (iterator.next() instanceof BaseAdapter.ChoseFriendItem){
         mAdapter.addItem(1, iterator.next());
         return;
     }
}

也许有人知道如何修复这个错误？

Answer 1

这段代码你的代码应该是这样的:

for (ListIterator<Object> iterator = mData.listIterator(); iterator
                                .hasNext();) {
                            Object item = iterator.next();
                            if (item instanceof BaseAdapter.ChoseFriendItem){
                                mAdapter.addItem(1, item);
                                //return; There should be no return statement here.
                            }
                        }

You called iterator.next() two times which will one element each time and give incorrect results.