在列表视图中显示数据库值时出现CursorIndexOutOfBoundsException错误

Question

我是android mobile开发新手。我创建了一个名为EmployeeList的数据库，它位于我的Assets文件夹中。我想从那里获取数据并在我的活动中以列表视图格式显示它。该应用程序不断崩溃，我不知道为什么。感谢您的帮助。

这是一个在线和我自己的样本代码组合。

DatabaseHelper.java

import android.content.Context; 
import android.database.Cursor; 
import android.database.SQLException; 
import android.database.sqlite.SQLiteDatabase; 
import android.database.sqlite.SQLiteException; 
import android.database.sqlite.SQLiteOpenHelper; 

import java.io.FileOutputStream; 
import java.io.IOException; 
import java.io.InputStream; 
import java.io.OutputStream; 

/** 
* Created by ahadagali on 6/15/2017. 
*/ 

public class DataBaseHelper extends SQLiteOpenHelper { 

    //The Android's default system path of your application database. 
    private static String DB_PATH = "/data/data/com.example.ahadagali.fivesdyag/databases/"; 

    private static String DB_NAME = "EmployeeList"; 

    private SQLiteDatabase myDataBase; 

    private final Context myContext; 

    /** 
    * Constructor 
    * Takes and keeps a reference of the passed context in order to access to the application assets and resources. 
    * @param context 
    */ 
    public DataBaseHelper(Context context) { 

     super(context, DB_NAME, null, 1); 
     this.myContext = context; 
    } 

    /** 
    * Creates a empty database on the system and rewrites it with your own database. 
    * */ 
    public void createDataBase() throws IOException{ 

     boolean dbExist = checkDataBase(); 

     if(dbExist){ 
      //do nothing - database already exist 
     }else{ 

      //By calling this method and empty database will be created into the default system path 
      //of your application so we are gonna be able to overwrite that database with our database. 
      this.getReadableDatabase(); 

      try { 

       copyDataBase(); 

      } catch (IOException e) { 

       throw new Error("Error copying database"); 

      } 
     } 

    } 

    /** 
    * Check if the database already exist to avoid re-copying the file each time you open the application. 
    * @return true if it exists, false if it doesn't 
    */ 
    private boolean checkDataBase(){ 

     SQLiteDatabase checkDB = null; 

     try{ 
      String myPath = DB_PATH + DB_NAME; 
      checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY); 

     }catch(SQLiteException e){ 

      //database does't exist yet. 

     } 

     if(checkDB != null){ 

      checkDB.close(); 

     } 

     return checkDB != null ? true : false; 
    } 

    /** 
    * Copies your database from your local assets-folder to the just created empty database in the 
    * system folder, from where it can be accessed and handled. 
    * This is done by transfering bytestream. 
    * */ 
    private void copyDataBase() throws IOException { 

     //Open your local db as the input stream 
     InputStream myInput = myContext.getAssets().open(DB_NAME); 

     // Path to the just created empty db 
     String outFileName = DB_PATH + DB_NAME; 

     //Open the empty db as the output stream 
     OutputStream myOutput = new FileOutputStream(outFileName); 

     //transfer bytes from the inputfile to the outputfile 
     byte[] buffer = new byte[1024]; 
     int length; 
     while ((length = myInput.read(buffer))>0){ 
      myOutput.write(buffer, 0, length); 
     } 

     //Close the streams 
     myOutput.flush(); 
     myOutput.close(); 
     myInput.close(); 

    } 

    public void openDataBase() throws SQLException { 

     //Open the database 
     String myPath = DB_PATH + DB_NAME; 
     myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY); 

    } 

    @Override 
    public synchronized void close() { 

     if(myDataBase != null) 
      myDataBase.close(); 

     super.close(); 

    } 

    @Override 
    public void onCreate(SQLiteDatabase db) { 

    } 

    @Override 
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { 

    } 

    // Add your public helper methods to access and get content from the database. 
    // You could return cursors by doing "return myDataBase.query(....)" so it'd be easy 
    // to you to create adapters for your views. 

    public Cursor fetchAll() { 
     Cursor myCursor; 
     myCursor = getReadableDatabase().rawQuery("select * from EmployeeList", null); 
     //myDataBase = this.getReadableDatabase(); 
     if (myDataBase != null) { 
      myCursor = getReadableDatabase().rawQuery("select * from EmployeeList", null); 
     } 
     return myCursor; 
    } 

} 

activityThree.java

import android.content.Context; 
import android.database.Cursor; 
import android.database.SQLException; 
import android.support.v7.app.AppCompatActivity; 
import android.os.Bundle; 
import android.widget.ListAdapter; 
import android.widget.ListView; 
import android.widget.SimpleCursorAdapter; 
import android.widget.TextView; 


import java.io.IOException; 

public class activityThree extends AppCompatActivity { 
    Context context; 

    TextView name; 
    TextView phoneNum; 
    TextView jobPos; 
    TextView availability; 

    ListView listView; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_three); 

     name = (TextView)findViewById(R.id.tv_fullName); 
     phoneNum = (TextView)findViewById(R.id.tv_phoneNum); 
     jobPos = (TextView)findViewById(R.id.tv_jobPosition); 
     availability = (TextView) findViewById(R.id.tv_availability); 

     DataBaseHelper myDbHelper = new DataBaseHelper(context); 
     myDbHelper = new DataBaseHelper(this); 

     try { 

      myDbHelper.createDataBase(); 

     } catch (IOException ioe) { 

      throw new Error("Unable to create database"); 

     } 

     try { 

      myDbHelper.openDataBase(); 

     }catch(SQLException sqle){ 

      throw sqle; 

     } 

     Cursor AllEmployees = myDbHelper.fetchAll(); 



     AllEmployees.moveToFirst(); 
     while (!AllEmployees.isAfterLast()){ 
      AllEmployees.moveToNext(); 
     } 

     String[] from = {AllEmployees.getString(1), AllEmployees.getString(2), AllEmployees.getString(3), AllEmployees.getString(4)}; 
     int [] to = {R.id.tv_fullName, R.id.tv_phoneNum, R.id.tv_jobPosition, R.id.tv_availability}; 
     ListAdapter adapter = new SimpleCursorAdapter(this, R.layout.item_listview, AllEmployees, from, to, 0); 
     ListView myList = (ListView)findViewById(R.id.listView); 
     myList.setAdapter(adapter); 


    } 
} 

activity_three.xml

<?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="match_parent" 
    android:orientation="vertical"> 

    <ListView 
     android:id="@+id/listView" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" /> 
</LinearLayout> 

item_listview.xml

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:orientation="vertical" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:background="#FFFFFF" 
    android:paddingBottom="5dp" 
    android:paddingLeft="10dp" 
    android:paddingRight="10dp" 
    android:paddingTop="10dp"> 

    <TextView 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:id="@+id/tv_fullName" 
     android:text="Name" 
     android:textColor="#4bb6d6" 
     android:textSize="20dp"/> 
    <TextView 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:id="@+id/tv_phoneNum" 
     android:text="734" 
     android:textColor="#b30000" 
     android:textSize="18dp"/> 
    <TextView 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:id="@+id/tv_jobPosition" 
     android:text="Job Position" 
     android:textSize="16dp"/> 
    <TextView 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:id="@+id/tv_availability" 
     android:text="Availability" 
     android:textSize="16dp"/> 

</LinearLayout> 

错误日志

06-15 07:09:00.579 27137-27165/com.example.ahadagali.fivesdyag I/OpenGLRenderer: Initialized EGL, version 1.4 
06-15 07:09:00.579 27137-27165/com.example.ahadagali.fivesdyag D/OpenGLRenderer: Swap behavior 1 
06-15 07:09:00.579 27137-27165/com.example.ahadagali.fivesdyag W/OpenGLRenderer: Failed to choose config with EGL_SWAP_BEHAVIOR_PRESERVED, retrying without... 
06-15 07:09:00.579 27137-27165/com.example.ahadagali.fivesdyag D/OpenGLRenderer: Swap behavior 0 
06-15 07:09:00.591 1296-1406/? D/gralloc_ranchu: gralloc_alloc: format 1 and usage 0x900 imply creation of host color buffer 
06-15 07:09:00.631 1296-1406/? D/gralloc_ranchu: gralloc_alloc: format 1 and usage 0x900 imply creation of host color buffer 
06-15 07:09:00.695 27137-27137/com.example.ahadagali.fivesdyag W/art: Before Android 4.1, method int android.support.v7.widget.ListViewCompat.lookForSelectablePosition(int, boolean) would have incorrectly overridden the package-private method in android.widget.ListView 
06-15 07:09:00.782 1540-1598/system_process I/ActivityManager: Displayed com.example.ahadagali.fivesdyag/.MainActivity: +678ms 
06-15 07:09:00.818 1296-1296/? W/SurfaceFlinger: couldn't log to binary event log: overflow. 
06-15 07:09:00.969 1540-1598/system_process D/gralloc_ranchu: gralloc_unregister_buffer: exiting HostConnection (is buffer-handling thread) 
06-15 07:09:01.903 1655-1655/com.android.inputmethod.latin I/LatinIME: Starting input. Cursor position = 0,0 
06-15 07:09:01.909 1296-3089/? D/gralloc_ranchu: gralloc_alloc: format 1 and usage 0x900 imply creation of host color buffer 
06-15 07:09:01.933 1296-3089/? D/gralloc_ranchu: gralloc_alloc: format 1 and usage 0x900 imply creation of host color buffer 
06-15 07:09:01.973 1296-3089/? D/gralloc_ranchu: gralloc_alloc: format 1 and usage 0x900 imply creation of host color buffer 
06-15 07:09:03.531 1655-1655/com.android.inputmethod.latin I/LatinIME: Starting input. Cursor position = 0,0 
06-15 07:09:03.536 27137-27137/com.example.ahadagali.fivesdyag W/IInputConnectionWrapper: finishComposingText on inactive InputConnection 
06-15 07:09:04.350 1540-2981/system_process I/ActivityManager: START u0 {cmp=com.example.ahadagali.fivesdyag/.activityTwo (has extras)} from uid 10073 on display 0 
06-15 07:09:04.389 1296-1336/? D/gralloc_ranchu: gralloc_alloc: format 1 and usage 0x900 imply creation of host color buffer 
06-15 07:09:04.416 1296-1337/? D/gralloc_ranchu: gralloc_alloc: format 1 and usage 0x900 imply creation of host color buffer 
06-15 07:09:04.452 1296-1337/? D/gralloc_ranchu: gralloc_alloc: format 1 and usage 0x900 imply creation of host color buffer 
06-15 07:09:04.588 1540-1598/system_process I/ActivityManager: Displayed com.example.ahadagali.fivesdyag/.activityTwo: +232ms 
06-15 07:09:04.591 27137-27137/com.example.ahadagali.fivesdyag W/IInputConnectionWrapper: finishComposingText on inactive InputConnection 
06-15 07:09:04.591 27137-27137/com.example.ahadagali.fivesdyag W/IInputConnectionWrapper: finishComposingText on inactive InputConnection 
06-15 07:09:06.247 1540-1554/system_process I/ActivityManager: START u0 {cmp=com.example.ahadagali.fivesdyag/.activityThree} from uid 10073 on display 0 
06-15 07:09:06.280 27137-27137/com.example.ahadagali.fivesdyag D/AndroidRuntime: Shutting down VM 
06-15 07:09:06.281 27137-27137/com.example.ahadagali.fivesdyag E/AndroidRuntime: FATAL EXCEPTION: main 
                       Process: com.example.ahadagali.fivesdyag, PID: 27137 
                       java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.ahadagali.fivesdyag/com.example.ahadagali.fivesdyag.activityThree}: android.database.CursorIndexOutOfBoundsException: Index 4 requested, with a size of 4 
                        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2665) 
                        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2726) 
                        at android.app.ActivityThread.-wrap12(ActivityThread.java) 
                        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1477) 
                        at android.os.Handler.dispatchMessage(Handler.java:102) 
                        at android.os.Looper.loop(Looper.java:154) 
                        at android.app.ActivityThread.main(ActivityThread.java:6119) 
                        at java.lang.reflect.Method.invoke(Native Method) 
                        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886) 
                        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776) 
                        Caused by: android.database.CursorIndexOutOfBoundsException: Index 4 requested, with a size of 4 
                        at android.database.AbstractCursor.checkPosition(AbstractCursor.java:460) 
                        at android.database.AbstractWindowedCursor.checkPosition(AbstractWindowedCursor.java:136) 
                        at android.database.AbstractWindowedCursor.getString(AbstractWindowedCursor.java:50) 
                        at com.example.ahadagali.fivesdyag.activityThree.onCreate(activityThree.java:68) 
                        at android.app.Activity.performCreate(Activity.java:6679) 
                        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1118) 
                        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2618) 
                        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2726)  
                        at android.app.ActivityThread.-wrap12(ActivityThread.java)  
                        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1477)  
                        at android.os.Handler.dispatchMessage(Handler.java:102)  
                        at android.os.Looper.loop(Looper.java:154)  
                        at android.app.ActivityThread.main(ActivityThread.java:6119)  
                        at java.lang.reflect.Method.invoke(Native Method)  
                        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)  
                        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)  
06-15 07:09:06.282 1540-2982/system_process W/ActivityManager: Force finishing activity com.example.ahadagali.fivesdyag/.activityThree 
06-15 07:09:06.286 1540-2982/system_process W/ActivityManager: Force finishing activity com.example.ahadagali.fivesdyag/.activityTwo 
06-15 07:09:06.294 1302-1422/? D/AudioFlinger: mixer(0xa6403a40) throttle end: throttle time(43) 
06-15 07:09:06.328 1296-1337/? D/gralloc_ranchu: gralloc_alloc: format 1 and usage 0x900 imply creation of host color buffer 

Answer 1

根本原因是：android.database.CursorIndexOutOfBoundsException：

致索引4 要求，与大小为4

将您的索引请求更改为3（最大）。 索引是基于零的。

大概在此行代码的

：

String[] from = {AllEmployees.getString(1), AllEmployees.getString(2), AllEmployees.getString(3), AllEmployees.getString(4)}; 

尝试0至3（通过4 insted的1）。我猜你只有最多四列或其他东西。

编辑 尝试改变注释下面的代码（评论说，我下面注释行） 我相信你迭代的数据的末尾，以便你的光标是过去所有的数据尝试读取之前。

AllEmployees.moveToFirst(); 
     // while (!AllEmployees.isAfterLast()){ 
     // AllEmployees.moveToNext(); 
     // } 

     String[] from = {AllEmployees.getString(1), AllEmployees.getString(2), AllEmployees.getString(3), AllEmployees.getString(4)}; 
     int [] to = {R.id.tv_fullName, R.id.tv_phoneNum, R.id.tv_jobPosition, R.id.tv_availability}; 
     ListAdapter adapter = new SimpleCursorAdapter(this, R.layout.item_listview, AllEmployees, from, to, 0); 
     ListView myList = (ListView)findViewById(R.id.listView); 
     myList.setAdapter(adapter); 

EDIT 2

尝试用我的更换你的代码（以下3行））：

ListAdapter adapter = new SimpleCursorAdapter(this, R.layout.item_listview, AllEmployees, from, to, 0); 
     ListView myList = (ListView)findViewById(R.id.listView); 
     myList.setAdapter(adapter); 

新代码

String[]values={"Android","iOS","Windows Phone","Other Stuff"}; 
      ArrayAdapter<String> adapter=new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1, android.R.id.text1,values); 
      myList.setAdapter(adapter); 

如果一切正常，则尝试跟随运行的代码（这会从您的数据库中添加值）后NG代码：

while (!AllEmployees.isAfterLast()){ 
       AllEmployees.moveToNext(); 
       adapter.add(AllEmployees.getString(0); 
      } 
adapter.notifyDataSetChanged(); // updates the list in UI 

另一部分作品后，只添加这第二部分。 这不完全正确，但在此之后，您应该可以通过它。