我的代码严重问题!!由于 IndexOutOfBoundException
，它会因很多错误而崩溃我创建了一个显示来自params的数据的活动......
现在，当我尝试运行我的应用程序（运行该活动）时，它说：
07-16 17:14:42.483 10250-10250/ir.homa E/AndroidRuntime: FATAL EXCEPTION: main
Process: ir.homa, PID: 10250
java.lang.RuntimeException: Unable to start activity ComponentInfo{ir.homa/ir.homa.HotelPageAdapter}: java.lang.IndexOutOfBoundsException: Invalid index 0, size is 0
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2658)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2723)
at android.app.ActivityThread.access$900(ActivityThread.java:172)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1422)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:5832)
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:1399)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1194)
Caused by: java.lang.IndexOutOfBoundsException: Invalid index 0, size is 0
at java.util.ArrayList.throwIndexOutOfBoundsException(ArrayList.java:255)
at java.util.ArrayList.get(ArrayList.java:308)
at ir.homa.HotelPageAdapter.prepareHotels(HotelPageAdapter.java:100)
at ir.homa.HotelPageAdapter.onCreate(HotelPageAdapter.java:61)
at android.app.Activity.performCreate(Activity.java:6221)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1119)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2611)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2723)
at android.app.ActivityThread.access$900(ActivityThread.java:172)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1422)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:5832)
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:1399)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1194) 07-16 17:14:42.513 4085-12738/? E/android.os.Debug: ro.product_ship = true 07-16 17:14:42.513 4085-12738/? E/android.os.Debug: ro.debug_level = 0x4f4c
我认为，因为 preparehotel（），所以应用程序每次都会崩溃......
这是我的活动代码：
package ir.homa;
import android.app.Activity;
import android.content.Context;
import android.content.res.Resources;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.util.TypedValue;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;
import com.bumptech.glide.Glide;
import java.util.ArrayList;
import java.util.List;
/**
* Created by SMQ on 7/13/2016.
*/
public class HotelPageAdapter extends Activity {
private Context mContext;
private RecyclerView recyclerView;
private HotelListAdapter adapter;
private List<HotelList> hotelList;
public String name1;
public int thumbnail1;
public int count1;
public int position1;
public HotelPageAdapter() {
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.hotel_page);
Bundle extras = getIntent().getExtras();
name1 = extras.getString("name");
thumbnail1 = extras.getInt("thumbnail");
count1 = extras.getInt("count");
position1 = extras.getInt("position1");
if ( extras != null ) {
Log.i("LOG", String.valueOf(thumbnail1));
Log.i("LOG", String.valueOf(count1));
Log.i("LOG", String.valueOf(position1));
Log.i("LOG", name1);
}
hotelList = new ArrayList<>();
adapter = new HotelListAdapter(this, hotelList);
final LinearLayoutManager layoutManager = new LinearLayoutManager(mContext);
layoutManager.setOrientation(LinearLayoutManager.VERTICAL);
prepareHotels();
class MyViewHolder extends RecyclerView.ViewHolder {
public TextView name, count;
public ImageView thumbnail;
public MyViewHolder(View view) {
super(view);
count = (TextView) view.findViewById(R.id.count1);
name = (TextView) view.findViewById(R.id.title1);
thumbnail = (ImageView) view.findViewById(R.id.thumbnail1);
}
}
}
private int dpToPx(int dp) {
Resources r = getResources();
return Math.round(TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dp, r.getDisplayMetrics()));
}
public void onBindViewHolder(final HotelListAdapter.MyViewHolder holder, int position) {
this.position1 = position;
final HotelList hotel = hotelList.get(position);
holder.title.setText(name1);
holder.count.setText(count1 + " اتاق");
Glide.with(mContext).load(thumbnail1).into(holder.thumbnail);
}
private void prepareHotels() {
final HotelList hotel = hotelList.get(position1);
int[] covers = new int[] {
R.mipmap.bandar_homa,
R.mipmap.mashhad_homa1,
R.mipmap.mashhad_homa,
R.mipmap.shiraz_homa,
R.mipmap.tehran_homa,
};
HotelList B = new HotelList( name1 , count1, covers[thumbnail1]);
hotelList.add(B);
adapter.notifyDataSetChanged();
}
/**
* RecyclerView item decoration - give equal margin around grid item
*/
public class GridSpacingItemDecoration extends RecyclerView.ItemDecoration {
private int spanCount;
private int spacing;
private boolean includeEdge;
public GridSpacingItemDecoration(int spanCount, int spacing, boolean includeEdge) {
this.spanCount = spanCount;
this.spacing = spacing;
this.includeEdge = includeEdge;
}
}
}
这是同一活动的xml文件：
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:card_view="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:clickable="true">
<android.support.v7.widget.CardView
android:id="@+id/card_view1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="center"
android:layout_margin="@dimen/card_margin"
android:elevation="3dp"
card_view:cardCornerRadius="0dp">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/card"
android:focusable="true"
android:contextClickable="true">
<ImageView
android:id="@+id/thumbnail1"
android:layout_width="match_parent"
android:layout_height="160dp"
android:background="?attr/selectableItemBackgroundBorderless"
android:clickable="true"
android:scaleType="fitXY"
android:contextClickable="true" />
<TextView
android:id="@+id/title1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingLeft="10dp"
android:paddingRight="25dp"
android:paddingTop="10dp"
android:textColor="@color/cardview_dark_background"
android:textSize="15dp"
android:layout_centerVertical="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true" />
<TextView
android:id="@+id/count1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@id/title"
android:paddingBottom="5dp"
android:paddingLeft="10dp"
android:paddingRight="25dp"
android:textSize="12dp" />
<ImageView
android:id="@+id/overflow"
android:layout_width="20dp"
android:layout_height="30dp"
android:layout_alignParentRight="true"
android:layout_below="@id/thumbnail"
android:layout_marginTop="10dp"
android:scaleType="centerCrop"
android:src="@android:drawable/ic_menu_sort_by_size" />
</RelativeLayout>
</android.support.v7.widget.CardView>
</LinearLayout>
我该如何解决？
答案 0 :(得分：2)
您的问题是您正在尝试获取不存在的索引0的值。
通过阅读堆栈跟踪，您可以轻松查看正在发生的行：
ir.homa.HotelPageAdapter.prepareHotels(HotelPageAdapter.java:100)
HotelPageAdapter.java中的 100行prepareHotels您正在调用以下方法：
final HotelList hotel = hotelList.get(position1);
position1为0，但hotelList不包含任何条目。
因此，您需要先添加条目，或在继续之前检查它是否为空：
private void prepareHotels() {
// Check if hotelList is empty. If true, go back, if false, continue.
if(hotelList == null || hotelList.size() == 0) return;
final HotelList hotel = hotelList.get(position1);
// ...
}
如果prepareHotels为空，则hotelList只会执行此操作。否则它会继续正常。
但我建议检查是否可以使用position1，所以请改为写下：
// Check if the index position1 is in the bounds of hotelList, and continue if they are, otherwise go back to prevent a crash.
if(hotelList == null || hotelList.size() <= position1) return;