我的应用程序应该显示一个 ListView ，每行都有一个 TextView 、复选框和 ImageView 。在为图像添加代码之前一切正常。但现在我总是得到这个异常(exception):
android.widget.LinearLayout$LayoutParams cannot be cast to android.widget.AbsListView$LayoutParams
我猜我在 Adapter 类中的 getView() 方法有问题。我是 android 开发的新手，我很难理解并找到问题。我使用了搜索功能，但找不到解决方案。你能帮帮我吗？
堆栈跟踪:
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example..myapplication, PID: 17373
java.lang.ClassCastException: android.widget.LinearLayout$LayoutParams cannot be cast to android.widget.AbsListView$LayoutParams
at android.widget.ListView.setupChild(ListView.java:1927)
at android.widget.ListView.makeAndAddView(ListView.java:1894)
at android.widget.ListView.fillDown(ListView.java:792)
at android.widget.ListView.fillFromTop(ListView.java:853)
at android.widget.ListView.layoutChildren(ListView.java:1731)
at android.widget.AbsListView.onLayout(AbsListView.java:2279)
at android.view.View.layout(View.java:15047)
at android.view.ViewGroup.layout(ViewGroup.java:4676)
at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1055)
at android.view.View.layout(View.java:15047)
at android.view.ViewGroup.layout(ViewGroup.java:4676)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453)
at android.widget.FrameLayout.onLayout(FrameLayout.java:388)
at android.view.View.layout(View.java:15047)
at android.view.ViewGroup.layout(ViewGroup.java:4676)
at android.support.v7.widget.ActionBarOverlayLayout.onLayout(ActionBarOverlayLayout.java:444)
at android.view.View.layout(View.java:15047)
at android.view.ViewGroup.layout(ViewGroup.java:4676)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453)
at android.widget.FrameLayout.onLayout(FrameLayout.java:388)
at android.view.View.layout(View.java:15047)
at android.view.ViewGroup.layout(ViewGroup.java:4676)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1671)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1525)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1434)
at android.view.View.layout(View.java:15047)
at android.view.ViewGroup.layout(ViewGroup.java:4676)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453)
at android.widget.FrameLayout.onLayout(FrameLayout.java:388)
at android.view.View.layout(View.java:15047)
at android.view.ViewGroup.layout(ViewGroup.java:4676)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2189)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1896)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1103)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6018)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:799)
at android.view.Choreographer.doCallbacks(Choreographer.java:599)
at android.view.Choreographer.doFrame(Choreographer.java:559)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:784)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:157)
at android.app.ActivityThread.main(ActivityThread.java:5872)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:858)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:674)
at dalvik.system.NativeStart.main(Native Method)
主 Activity .java
package com.example.myapplication;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.preference.Preference;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.CheckBox;
import android.widget.ListView;
import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity {
ListView lv;
CheckBox checkBox;
ArrayList<Object> items = new ArrayList<>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//lv mit xml listview verknüpfen
lv = (ListView) findViewById(R.id.list_view_nahrungsmittel);
//checkBox mit xml checkbox verbinden
checkBox = (CheckBox) findViewById(R.id.checkbox);
//Lebensmittel/Aktivitäten erstellen und zur items Liste hinzufügen
ItemList gemuese = new ItemList("Gemüse","100g","Karotte\nWirsing\nKohl",R.drawable.ic_cruciferous_vegetables );
ItemList wasser = new ItemList("Wasser","0,5 Liter","Mineralwasser", R.drawable.ic_beverages);
ItemList supps = new ItemList("Supplements", "Eine Pille", "D3\nK2\nO3", R.drawable.ic_supp);
ItemList sport = new ItemList("Sport", "1h", "Laufen\nCrosstrainer\nFahrrad\nPumpen", R.drawable.ic_exercise);
ItemList meditation = new ItemList("Meditation", "1h", R.drawable.meditation);
items.add("Nahrungsmittel");
items.add(wasser);
items.add(gemuese);
items.add(supps);
items.add("Aktivitäten");
items.add(sport);
items.add(meditation);
//ItemListAdapter: Items Liste mit lv verknüpfen
lv.setAdapter(new ItemListAdapter(this, items, R.layout.row_item ));
//Click on Items
lv.setOnItemClickListener(new AdapterView.OnItemClickListener() { //??
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Object obj = items.get(position);
if (obj instanceof ItemList) {
//Intent erstellen
Intent intent = new Intent(MainActivity.this, DetailActivity.class);
//Informationen aus dem Item Objekt ziehen
ItemList item = (ItemList) obj;
String title = item.getTitle();
String portion = item.getPortion();
String typ = item.getTyp();
//Informationen übergeben
intent.putExtra("EXTRA_TITLE", title);
intent.putExtra("EXTRA_PORTION", portion);
intent.putExtra("EXTRA_TYP", typ);
//neue Aktivität starten
startActivity(intent);
}
}
});
}
}
适配器类
package com.example.myapplication;
import android.content.Context;
import android.provider.ContactsContract;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;
import java.util.ArrayList;
public class ItemListAdapter extends BaseAdapter {
private LayoutInflater inflater;
private ArrayList<Object> itemArray;
int resIdImage;
private static final int TYPE_ListElement = 0;
private static final int TYPE_DIVIDER = 1;
public ItemListAdapter(Context context, ArrayList<Object> itemArray, int resource) {
this.itemArray = itemArray;
this.resIdImage = resource;
this.inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
@Override
public int getCount() {
return itemArray.size();
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public Object getItem(int position) {
return itemArray.get(position);
}
@Override
public int getViewTypeCount() {
// TYPE_PERSON and TYPE_DIVIDER
return 2;
}
@Override
public int getItemViewType(int position) {
if (getItem(position) instanceof ItemList) {
return TYPE_ListElement;
}
return TYPE_DIVIDER;
}
@Override
public boolean isEnabled(int position) {
return (getItemViewType(position) == TYPE_ListElement);
}
public class DataHolder{
ImageView imageView;
TextView textView;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
DataHolder holder = null;
int type = getItemViewType(position);
if (convertView == null) {
switch (type) {
case TYPE_ListElement:
View view = inflater.inflate(resIdImage, parent, false);
convertView = inflater.inflate(R.layout.row_item, (ViewGroup) view, false);
holder = new DataHolder();
holder.imageView = (ImageView) convertView.findViewById(R.id.image);
holder.textView = (TextView) convertView.findViewById(R.id.nameLabel);
convertView.setTag(holder);
break;
case TYPE_DIVIDER:
convertView = inflater.inflate(R.layout.row_header, parent, false);
break;
}
}
else {
holder = (DataHolder)convertView.getTag();
}
switch (type) {
case TYPE_ListElement:
ItemList item = (ItemList) getItem(position);
TextView name = (TextView)convertView.findViewById(R.id.nameLabel);
name.setText(item.getTitle());
holder.textView.setText(item.getTitle());
holder.imageView.setImageResource(item.resIdImage);
break;
case TYPE_DIVIDER:
TextView title = (TextView)convertView.findViewById(R.id.headerTitle);
String titleString = (String)getItem(position);
title.setText(titleString);
break;
}
return convertView;
}
}
行布局
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<ImageView
android:id="@+id/image"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:srcCompat="@mipmap/ic_launcher"
android:layout_gravity="center"
android:layout_margin="20dp"/>
<TextView
android:id="@+id/nameLabel"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="20sp"
android:layout_margin="20dp"
android:text="Name"
android:layout_weight="1"
/>
<CheckBox
android:id="@+id/checkbox"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:checked="false"
android:focusable="false"
android:focusableInTouchMode="false"
android:layout_gravity="right|center"
android:gravity="right|center"
/>
最佳答案
你的 getView() 方法看起来很可疑:
case TYPE_ListElement: View view = inflater.inflate(resIdImage, parent, false); convertView = inflater.inflate(R.layout.row_item, (ViewGroup) view, false); ...
在 getView() 中看到两次调用 inflate() 真的很奇怪。我怀疑您想按如下方式更改它:
case TYPE_ListElement:
convertView = inflater.inflate(resIdImage, parent, false);
...
关于java - LayoutParams 上的 ClassCastException 从 LinearLayout 到 AbsListView，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/52561569/