从数据库加载详细信息时光标出现java错误

4 月，1 周 Questions & Answers 59

我目前正在完成一个学校项目，试图创建一个童子军小组经理。这是我第一次使用Java、XML或Android Studio，所以进展有点慢，但我正在努力。我现在面临的问题是从数据库中提取侦察机的详细信息，以便将它们放在微调器中。然后，领导者将从微调器中按名称选择他们想要邀请的侦察员。导致错误的代码（在数据库处理程序类中）如下所示：

public Cursor GetAllScouts()
{
    String whereClause = COLUMN_SECTION + "=?";
    String[] whereArgs = new String[]{"Beavers","Cubs","Scouts","Explorers","Network","Leaders"};
    String[] columns = new String[]{COLUMN_SCID + " AS " + BaseColumns._ID, COLUMN_FNAME, COLUMN_LNAME, COLUMN_SECTION};
    return db.query(TABLE_SCOUTS,columns,whereClause,whereArgs,null,null,null);//Error is being thrown up here
}

来自logcat的信息如下所示：

01-24 18:39:38.228 18179-18179/com.example.atomi.scoutmanagerprototype E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.atomi.scoutmanagerprototype, PID: 18179
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.atomi.scoutmanagerprototype/com.example.atomi.scoutmanagerprototype.frmCreateEvent2}: java.lang.IllegalArgumentException: Cannot bind argument at index 6 because the index is out of range.  The statement has 1 parameters.
    at 安卓.app.ActivityThread.performLaunchActivity(ActivityThread.java:2314)
    at 安卓.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2386)
    at 安卓.app.ActivityThread.access$800(ActivityThread.java:148)
    at 安卓.app.ActivityThread$H.handleMessage(ActivityThread.java:1292)
    at 安卓.os.Handler.dispatchMessage(Handler.java:102)
    at 安卓.os.Looper.loop(Looper.java:135)
    at 安卓.app.ActivityThread.main(ActivityThread.java:5310)
    at java.lang.reflect.Method.invoke(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:372)
    at com.安卓.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:901)
    at com.安卓.internal.os.ZygoteInit.main(ZygoteInit.java:696)
 Caused by: java.lang.IllegalArgumentException: Cannot bind argument at index 6 because the index is out of range.  The statement has 1 parameters.
    at 安卓.database.sqlite.SQLiteProgram.bind(SQLiteProgram.java:212)
    at 安卓.database.sqlite.SQLiteProgram.bindString(SQLiteProgram.java:166)
    at 安卓.database.sqlite.SQLiteProgram.bindAllArgsAsStrings(SQLiteProgram.java:200)
    at 安卓.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:47)
    at 安卓.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1316)
    at 安卓.database.sqlite.SQLiteDatabase.queryWithFactory(SQLiteDatabase.java:1163)
    at 安卓.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1034)
    at 安卓.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1202)
    at com.example.atomi.scoutmanagerprototype.databaseHandler.GetAllScouts(databaseHandler.java:395)
    at com.example.atomi.scoutmanagerprototype.frmCreateEvent2.loadSpinnerData(frmCreateEvent2.java:87)
    at com.example.atomi.scoutmanagerprototype.frmCreateEvent2.onCreate(frmCreateEvent2.java:82)
    at 安卓.app.Activity.performCreate(Activity.java:5953)
    at 安卓.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1128)
    at 安卓.app.ActivityThread.performLaunchActivity(ActivityThread.java:2267)
    at 安卓.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2386) 
    at 安卓.app.ActivityThread.access$800(ActivityThread.java:148) 
    at 安卓.app.ActivityThread$H.handleMessage(ActivityThread.java:1292) 
    at 安卓.os.Handler.dispatchMessage(Handler.java:102) 
    at 安卓.os.Looper.loop(Looper.java:135) 
    at 安卓.app.ActivityThread.main(ActivityThread.java:5310) 
    at java.lang.reflect.Method.invoke(Native Method) 
    at java.lang.reflect.Method.invoke(Method.java:372) 
    at com.安卓.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:901) 
    at com.安卓.internal.os.ZygoteInit.main(ZygoteInit.java:696)

任何帮助都将不胜感激。提前谢谢

# 3 楼答案

列表是否需要可变？如果没有，您可以在资源中的strings.xml文件中指定一个字符串数组，如下所示：

字符串。xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string-array
        name="scout_categories">
        <item>Beavers</item>
        <item>Cubs</item>
        <item>Scouts</item>
        <item>Explorers</item>
        <item>Network</item>
        <item>Leaders</item>
    </string-array>
</resources>

然后，无论您在哪里设置Spinner对象：

一些活动。java

Spinner spinner=(Spinner)findViewById(R.id.spinner);

String[] scoutCategories = getResources().getStringArray(R.array.scout_categories);        

ArrayAdapter<String> adapter=new ArrayAdapter<String>(this, R.layout.spinner_layout, R.id.text, countries);

spinner.setAdapter(adapter);

*参见here了解ArrayAdapter

现在，如果它确实需要一个可变列表，那么我建议研究Android的Room Persistence Library。这是一种更容易建立和运行数据库的方法，它可以为您处理大量的样板代码

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从数据库加载详细信息时光标出现java错误

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