使用RecyclerView时出错:指定的子代已经有一个父代 [英] Error using the RecyclerView: The specified child already has a parent
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问题描述
我正在尝试使用新的RecyvlerView适配器创建listView.我已按照android开发人员资源中提供的确切指南进行操作.但这给了我一个奇怪的错误: 指定的孩子已经有一个父母.您必须先在孩子的父母上调用removeView(). 我有最新的SDK.我还在gradle中定义了依赖项.
I am trying to create a listView with a new RecyvlerView Adapter. I have followed the exact guide present on android developer resources. But this is giving me a strange error: The specified child already has a parent. You must call removeView() on the child's parent first. I have the latest SDK. I also define dependencies in gradle.
MyActivity (主要活动):
public class MyActivity extends Activity {
private RecyclerView mRecyclerView;
private RecyclerView.Adapter mAdapter;
private RecyclerView.LayoutManager mLayoutManager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_my);
mRecyclerView = (RecyclerView) findViewById(R.id.my_recycler_view);
// use this setting to improve performance if you know that changes
// in content do not change the layout size of the RecyclerView
mRecyclerView.setHasFixedSize(true);
// use a linear layout manager
mRecyclerView.setLayoutManager(new LinearLayoutManager(this));
mRecyclerView.setItemAnimator(new DefaultItemAnimator());
// specify an adapter (see also next example)
mAdapter = new MyAdapter(new String[]{"Zain", "Nadeem"});
mRecyclerView.setAdapter(mAdapter);
}
}
MyAdapter:
MyAdapter :
public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> {
private String[] mDataset;
// Provide a reference to the views for each data item
// Complex data items may need more than one view per item, and
// you provide access to all the views for a data item in a view holder
// Provide a suitable constructor (depends on the kind of dataset)
public MyAdapter(String[] myDataset) {
mDataset = myDataset;
}
// Create new views (invoked by the layout manager)
@Override
public MyAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
// create a new view
LayoutInflater inflater = LayoutInflater.from(parent.getContext());
View v = inflater.inflate(R.layout.my_text_view, parent, true);
ViewHolder vh = new ViewHolder(v);
return vh;
}
// Replace the contents of a view (invoked by the layout manager)
@Override
public void onBindViewHolder(ViewHolder holder, int position) {
// - get element from your dataset at this position
// - replace the contents of the view with that element
holder.mTextView.setText(mDataset[position]);
}
// Return the size of your dataset (invoked by the layout manager)
@Override
public int getItemCount() {
return mDataset.length;
}
public static class ViewHolder extends RecyclerView.ViewHolder {
// each data item is just a string in this case
public TextView mTextView;
public ViewHolder(View v) {
super(v);
mTextView = (TextView) v.findViewById(R.id.item_title);
}
}
}
my_text_view.xml(列表项的布局):
my_text_view.xml (layout for list items):
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="80dp"
>
<!-- title -->
<TextView
android:id="@+id/item_title"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:textColor="@android:color/darker_gray"
android:layout_marginLeft="8dp"
android:layout_marginRight="8dp"
android:layout_marginTop="8dp"
android:textSize="22dp" />
</RelativeLayout>
activity_my.xml(主要活动):
activity_my.xml (main activity):
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:card_view="http://schemas.android.com/apk/res-auto"
android:layout_height="fill_parent"
android:layout_width="fill_parent"
android:background="@android:color/holo_orange_light"
>
<!-- A CardView that contains a TextView -->
<android.support.v7.widget.RecyclerView
android:id="@+id/my_recycler_view"
android:scrollbars="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MyActivity"/>
</LinearLayout>
这是logcat的输出:
And here is the logcat output:
10-28 01:20:30.287 22729-22729/osman.zaingz.com.lollipop E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: osman.zaingz.com.lollipop, PID: 22729
java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first.
at android.view.ViewGroup.addViewInner(ViewGroup.java:3562)
at android.view.ViewGroup.addView(ViewGroup.java:3415)
at android.view.ViewGroup.addView(ViewGroup.java:3360)
at android.support.v7.widget.RecyclerView$4.addView(RecyclerView.java:322)
at android.support.v7.widget.ChildHelper.addView(ChildHelper.java:79)
at android.support.v7.widget.RecyclerView$LayoutManager.addViewInt(RecyclerView.java:4845)
at android.support.v7.widget.RecyclerView$LayoutManager.addView(RecyclerView.java:4803)
at android.support.v7.widget.RecyclerView$LayoutManager.addView(RecyclerView.java:4791)
at android.support.v7.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1316)
at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1265)
at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:522)
at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:1918)
at android.support.v7.widget.RecyclerView.onLayout(RecyclerView.java:2155)
at android.view.View.layout(View.java:14817)
at android.view.ViewGroup.layout(ViewGroup.java:4631)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1671)
at android.widget.LinearLayout.layoutHorizontal(LinearLayout.java:1660)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1436)
at android.view.View.layout(View.java:14817)
at android.view.ViewGroup.layout(ViewGroup.java:4631)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453)
at android.widget.FrameLayout.onLayout(FrameLayout.java:388)
at android.view.View.layout(View.java:14817)
at android.view.ViewGroup.layout(ViewGroup.java:4631)
at com.android.internal.widget.ActionBarOverlayLayout.onLayout(ActionBarOverlayLayout.java:374)
at android.view.View.layout(View.java:14817)
at android.view.ViewGroup.layout(ViewGroup.java:4631)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453)
at android.widget.FrameLayout.onLayout(FrameLayout.java:388)
at android.view.View.layout(View.java:14817)
at android.view.ViewGroup.layout(ViewGroup.java:4631)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:1983)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1740)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:996)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5600)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:761)
at android.view.Choreographer.doCallbacks(Choreographer.java:574)
at android.view.Choreographer.doFrame(Choreographer.java:544)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:747)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5001)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
推荐答案
膨胀时，您不应将视图附加到其父视图. 你写道:
when inflating you shouldn't attach the view to its parent. you wrote:
View v = inflater.inflate(R.layout.my_text_view, parent, true);
应为:
View v = inflater.inflate(R.layout.my_text_view, parent, false);
这篇关于使用RecyclerView时出错:指定的子代已经有一个父代的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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