每当用户点击我的RecyclerView项目时，我都会尝试启动一项新活动。这就是我的活动看起来我的logcat显示错误
的方式package com.example.nikit.phyprac4.ui;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import com.example.nikit.phyprac4.R;
import com.example.nikit.phyprac4.adapter.ListAdapter;
import com.example.nikit.phyprac4.model.ListData;
import com.example.nikit.phyprac4.model.ListItem;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity {
private RecyclerView recyclerView;
private ListAdapter listAdapter;
private ArrayList myData;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
myData=(ArrayList) ListData.getListData();
recyclerView=(RecyclerView)findViewById(R.id.ReList);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
listAdapter=new ListAdapter(myData,this);
recyclerView.setAdapter(listAdapter);
}
}
activity_main.xml中
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.nikit.phyprac4.ui.MainActivity">
<android.support.v7.widget.RecyclerView
android:id="@+id/ReList"
android:layout_width="match_parent"
android:layout_height="wrap_content"
>
</android.support.v7.widget.RecyclerView>
</RelativeLayout>
logcat错误看起来像这样
03-12 00:53:17.306 9776-9776/? I/art: Late-enabling -Xcheck:jni
03-12 00:53:17.329 9776-9783/? I/art: Debugger is no longer active
03-12 00:53:17.329 9776-9783/? I/art: Starting a blocking GC Instrumentation
03-12 00:53:17.366 9776-9776/? W/System: ClassLoader referenced unknown path: /data/app/com.example.nikit.phyprac4-2/lib/arm
03-12 00:53:17.382 9776-9776/? I/InstantRun: Instant Run Runtime started. Android package is com.example.nikit.phyprac4, real application class is null.
03-12 00:53:17.944 9776-9776/? W/System: ClassLoader referenced unknown path: /data/app/com.example.nikit.phyprac4-2/lib/arm
03-12 00:53:18.123 9776-9776/? W/art: Before Android 4.1, method android.graphics.PorterDuffColorFilter android.support.graphics.drawable.VectorDrawableCompat.updateTintFilter(android.graphics.PorterDuffColorFilter, android.content.res.ColorStateList, android.graphics.PorterDuff$Mode) would have incorrectly overridden the package-private method in android.graphics.drawable.Drawable
03-12 00:53:18.346 9776-9776/com.example.nikit.phyprac4 D/AndroidRuntime: Shutting down VM
03-12 00:53:18.347 9776-9776/com.example.nikit.phyprac4 E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.nikit.phyprac4, PID: 9776
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.nikit.phyprac4/com.example.nikit.phyprac4.ui.MainActivity}: java.lang.ClassCastException: android.widget.RelativeLayout cannot be cast to android.support.v7.widget.RecyclerView
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2659)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2724)
at android.app.ActivityThread.-wrap12(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1473)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6123)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:757)
Caused by: java.lang.ClassCastException: android.widget.RelativeLayout cannot be cast to android.support.v7.widget.RecyclerView
at com.example.nikit.phyprac4.ui.MainActivity.onCreate(MainActivity.java:29)
at android.app.Activity.performCreate(Activity.java:6672)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1140)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2612)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2724)
at android.app.ActivityThread.-wrap12(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1473)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6123)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:757)
请同时查看我的适配器
package com.example.nikit.phyprac4.adapter;
import android.content.Context;
import android.content.Intent;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;
import com.example.nikit.phyprac4.R;
import com.example.nikit.phyprac4.model.ListItem;
import com.example.nikit.phyprac4.ui.FirstActivity;
import com.example.nikit.phyprac4.ui.MainActivity;
import com.example.nikit.phyprac4.ui.SecondActivity;
import java.util.List;
/**
* Created by nikit on 11/3/17.
*/
public class ListAdapter extends RecyclerView.Adapter<ListAdapter.ListHolder> {
private List<ListItem> ListData;
private LayoutInflater inflater;
private Context context;
//private Button load;
public ListAdapter(List<ListItem>ListData, Context c)
{
this.inflater=LayoutInflater.from(c);
this.ListData=ListData;
}
@Override
public ListHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view=inflater.inflate(R.layout.list_item,parent,false);
return new ListHolder(view);
}
@Override
public void onBindViewHolder(ListHolder holder, int position) {
ListItem item=ListData.get(position);
holder.title.setText(item.getTitle());
holder.icon.setImageResource(item.getImageResId());
}
@Override
public int getItemCount() {
return ListData.size();
}
class ListHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
private TextView title;
private ImageView icon;
private View container;
public ListHolder(View itemView) {
super(itemView);
title=(TextView)itemView.findViewById(R.id.lbl_item_text);
icon=(ImageView)itemView.findViewById(R.id.im_item_icon);
container=itemView.findViewById(R.id.cont_item_root);
context = itemView.getContext();
//load=(Button)itemView.findViewById(R.id.btn_card_load);
container.setOnClickListener(this);
}
@Override
public void onClick(View v) {
if(v.getId()==R.id.cont_item_root)
{
final Intent intent;
switch (getAdapterPosition()){
case 0:
intent = new Intent(context, FirstActivity.class);
break;
case 1:
intent = new Intent(context, SecondActivity.class);
break;
default:
intent = new Intent(context, MainActivity.class);
break;
}
context.startActivity(intent);
}
}
}
}
只要FirstActivity和SecondActivity为空，应用程序就可以正常运行，但只要我将textview放入其中就会崩溃 请帮我。我是业余开发人员。
答案 0 :(得分：0)
评论此行myData =（ArrayList）ListData.getListData（）; 在MainActivity解决了这个问题，当然在列表适配器中我们将传递ListData.getListData（）而不是myData