Android/Java错误：“Java.lang.IllegalStateException:指定的子级已具有父级”
我正在建造一个简单的回收器，并尝试测试我目前所拥有的。对于android，我已经研究过了，我认为错误在于MainActivity.java或适配器MyAdapter.java，但我无法解决它。任何输入都将是惊人的。我在日志中收到此错误：Android/Java错误：“Java.lang.IllegalStateException:指定的子级已具有父级”,java,android,Java,Android,我正在建造一个简单的回收器，并尝试测试我目前所拥有的。对于android，我已经研究过了，我认为错误在于MainActivity.java或适配器MyAdapter.java，但我无法解决它。任何输入都将是惊人的。我在日志中收到此错误： 07-16 15:15:55.743 2997-2997/com.example.duncan.recyclerviewproject E/AndroidRuntime: FATAL EXCEPTION: main
07-16 15:15:55.743 2997-2997/com.example.duncan.recyclerviewproject E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.duncan.recyclerviewproject, PID: 2997
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:3949)
at android.view.ViewGroup.addView(ViewGroup.java:3799)
at android.view.ViewGroup.addView(ViewGroup.java:3740)
at android.support.v7.widget.RecyclerView$5.addView(RecyclerView.java:727)
at android.support.v7.widget.ChildHelper.addView(ChildHelper.java:107)
at android.support.v7.widget.RecyclerView$LayoutManager.addViewInt(RecyclerView.java:7921)
at android.support.v7.widget.RecyclerView$LayoutManager.addView(RecyclerView.java:7879)
at android.support.v7.widget.RecyclerView$LayoutManager.addView(RecyclerView.java:7867)
at android.support.v7.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1556)
at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1502)
at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:595)
at android.support.v7.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:3625)
at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:3354)
at android.support.v7.widget.RecyclerView.onLayout(RecyclerView.java:3886)
at android.view.View.layout(View.java:16067)
at android.view.ViewGroup.layout(ViewGroup.java:5051)
at android.support.constraint.ConstraintLayout.onLayout(ConstraintLayout.java:1197)
at android.view.View.layout(View.java:16067)
at android.view.ViewGroup.layout(ViewGroup.java:5051)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:579)
at android.widget.FrameLayout.onLayout(FrameLayout.java:514)
at android.view.View.layout(View.java:16067)
at android.view.ViewGroup.layout(ViewGroup.java:5051)
at android.support.v7.widget.ActionBarOverlayLayout.onLayout(ActionBarOverlayLayout.java:434)
at android.view.View.layout(View.java:16067)
at android.view.ViewGroup.layout(ViewGroup.java:5051)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:579)
at android.widget.FrameLayout.onLayout(FrameLayout.java:514)
at android.view.View.layout(View.java:16067)
at android.view.ViewGroup.layout(ViewGroup.java:5051)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1703)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1557)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1466)
at android.view.View.layout(View.java:16067)
at android.view.ViewGroup.layout(ViewGroup.java:5051)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:579)
at android.widget.FrameLayout.onLayout(FrameLayout.java:514)
at android.view.View.layout(View.java:16067)
at android.view.ViewGroup.layout(ViewGroup.java:5051)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2122)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1879)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1090)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5982)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:781)
at android.view.Choreographer.doCallbacks(Choreographer.java:592)
at android.view.Choreographer.doFrame(Choreographer.java:560)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:767)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5484)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:984)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:779)
package com.example.duncan.recyclerviewproject;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity {
private RecyclerView recyclerView;
private RecyclerView.Adapter adapter;
private List<ListItem> listItems;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
recyclerView = (RecyclerView) findViewById(R.id.recyclerView);
recyclerView.setHasFixedSize(true);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
listItems = new ArrayList<>();
for(int i = 0; i<=10; i++){
ListItem listItem = new ListItem(
"heading " + (i+1),
"Lorem ipsum dummy text"
);
listItems.add(listItem);
}
adapter = new MyAdapter(listItems, this);
recyclerView.setAdapter(adapter);
}
}
package com.example.duncan.recyclerviewproject;
import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import java.util.List;
/**
* Created by Duncan on 7/16/17.
*/
public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> {
private List<ListItem> listItems;
private Context context;
public MyAdapter(List<ListItem> listItems, Context context) {
this.listItems = listItems;
this.context = context;
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext())
.inflate(R.layout.list_item, parent);
return new ViewHolder(v);
}
@Override
public void onBindViewHolder(ViewHolder holder, int position) {
ListItem listItem = listItems.get(position);
holder.textViewHead.setText(listItem.getHead());
holder.textViewDesc.setText(listItem.getDesc());
}
@Override
public int getItemCount() {
return listItems.size();
}
public class ViewHolder extends RecyclerView.ViewHolder {
public TextView textViewHead;
public TextView textViewDesc;
public ViewHolder(View itemView) {
super(itemView);
textViewHead = (TextView) itemView.findViewById(R.id.textViewHead);
textViewDesc = (TextView) itemView.findViewById(R.id.textViewDesc);
}
}
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<android.support.v7.widget.CardView
android:layout_width="match_parent"
android:layout_height="wrap_content">
<LinearLayout
android:padding="16dp"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:id="@+id/textViewHead"
android:text="Heading"
android:textAppearance="@style/Base.TextAppearance.AppCompat.Large"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<TextView
android:id="@+id/textViewDesc"
android:text="Body"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>
</android.support.v7.widget.CardView>
</LinearLayout>
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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"
tools:context="com.example.duncan.recyclerviewproject.MainActivity">
<android.support.v7.widget.RecyclerView
android:id="@+id/recyclerView"
android:layout_width="784dp"
android:layout_height="1127dp"
tools:layout_editor_absoluteY="8dp"
tools:layout_editor_absoluteX="8dp"></android.support.v7.widget.RecyclerView>
</android.support.constraint.ConstraintLayout>
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_item, parent);
添加适配器class@OussemaAroua我添加了适配器myadapter.java您是如何导致错误的？你的应用程序启动后是否立即崩溃？当我尝试通过USB/android在我的设备上运行应用程序时，会发生此错误studio@Code-学徒澄清：是的，我的应用程序在启动后立即崩溃。这解决了问题。谢谢
View v = LayoutInflater.from(context).inflate(R.layout.list_item, parent, false);