从SQLite检索到有错误的Array

时间：2012-03-05 17:21:54

标签： android sqlite

当我尝试从SQLite检索到数组时出现错误。 我在for循环中找出了错误原因，声明中的错误

urlString[i] = allrows.getString(0);

我试图调试它，但我仍然不知道如何解决它。方法如下：

public String[] getImgURL(){
        mydb = localContext.openOrCreateDatabase(DBNAME, Context.MODE_PRIVATE,null);
        Cursor allrows  = mydb.rawQuery("SELECT ImgURL FROM "+  TABLE, null);
        String[] urlString = new String[allrows.getCount()-1];
        for (int i = 1; i < allrows.getCount(); i++) {
            urlString[i] = allrows.getString(0);
            allrows.moveToNext();               
        }
        allrows.close();    
        mydb.close();
        return urlString;
}

日志如下

03-06 01:26:05.479: W/dalvikvm(27671): threadid=1: thread exiting with uncaught exception (group=0x4001d5a0)    
03-06 01:26:05.479: E/AndroidRuntime(27671): FATAL EXCEPTION: main    
03-06 01:26:05.479: E/AndroidRuntime(27671): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.test.testing/com.ip.scan.MainActivity}: android.database.CursorIndexOutOfBoundsException: Index -1 requested, with a size of 5    
03-06 01:26:05.479: E/AndroidRuntime(27671):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java)    
03-06 01:26:05.479: E/AndroidRuntime(27671):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java)    
03-06 01:26:05.479: E/AndroidRuntime(27671):    at android.app.ActivityThread.access$1500(ActivityThread.java)    
03-06 01:26:05.479: E/AndroidRuntime(27671):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java)    
03-06 01:26:05.479: E/AndroidRuntime(27671):    at android.os.Handler.dispatchMessage(Handler.java)    
03-06 01:26:05.479: E/AndroidRuntime(27671):    at android.os.Looper.loop(Looper.java)    
03-06 01:26:05.479: E/AndroidRuntime(27671):    at android.app.ActivityThread.main(ActivityThread.java)
03-06 01:26:05.479: E/AndroidRuntime(27671):    at java.lang.reflect.Method.invokeNative(Native Method)
03-06 01:26:05.479: E/AndroidRuntime(27671):    at java.lang.reflect.Method.invoke(Method.java:507)
03-06 01:26:05.479: E/AndroidRuntime(27671):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java)
03-06 01:26:05.479: E/AndroidRuntime(27671):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java)
03-06 01:26:05.479: E/AndroidRuntime(27671):    at dalvik.system.NativeStart.main(Native Method)
03-06 01:26:05.479: E/AndroidRuntime(27671): Caused by: android.database.CursorIndexOutOfBoundsException: Index -1 requested, with a size of 5
03-06 01:26:05.479: E/AndroidRuntime(27671):    at android.database.AbstractCursor.checkPosition(AbstractCursor.java)
03-06 01:26:05.479: E/AndroidRuntime(27671):    at android.database.AbstractWindowedCursor.checkPosition(AbstractWindowedCursor.java)
03-06 01:26:05.479: E/AndroidRuntime(27671):    at android.database.AbstractWindowedCursor.getString(AbstractWindowedCursor.java)
03-06 01:26:05.479: E/AndroidRuntime(27671):    at com.ip.scan.LocalSQLite.getImgURL(LocalSQLite.java:57)
03-06 01:26:05.479: E/AndroidRuntime(27671):    at com.ip.scan.MainActivity.onCreate(MainActivity.java:32)
03-06 01:26:05.479: E/AndroidRuntime(27671):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java)
03-06 01:26:05.479: E/AndroidRuntime(27671):    ... 12 more
03-06 01:26:05.549: D/dalvikvm(27671): GC_CONCURRENT freed 220K, 41% free 3334K/5639K, external 0K/0K, paused 3ms+2ms
03-06 01:26:05.549: E/Database(27671): close() was never explicitly called on database '/data/data/com.test.testing/databases/vege.db' 
03-06 01:26:05.549: E/Database(27671): android.database.sqlite.DatabaseObjectNotClosedException: Application did not close the cursor or database object that was opened here
03-06 01:26:05.549: E/Database(27671):  at android.database.sqlite.SQLiteDatabase.<init>(SQLiteDatabase.java)
03-06 01:26:05.549: E/Database(27671):  at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java)
03-06 01:26:05.549: E/Database(27671):  at android.database.sqlite.SQLiteDatabase.openOrCreateDatabase(SQLiteDatabase.java)
03-06 01:26:05.549: E/Database(27671):  at android.database.sqlite.SQLiteDatabase.openOrCreateDatabase(SQLiteDatabase.java)
03-06 01:26:05.549: E/Database(27671):  at android.app.ContextImpl.openOrCreateDatabase(ContextImpl.java)
03-06 01:26:05.549: E/Database(27671):  at android.content.ContextWrapper.openOrCreateDatabase(ContextWrapper.java)
03-06 01:26:05.549: E/Database(27671):  at com.ip.scan.LocalSQLite.getImgURL(LocalSQLite.java:53)
03-06 01:26:05.549: E/Database(27671):  at com.ip.scan.MainActivity.onCreate(MainActivity.java:32)
03-06 01:26:05.549: E/Database(27671):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java)
03-06 01:26:05.549: E/Database(27671):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java)
03-06 01:26:05.549: E/Database(27671):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java)
03-06 01:26:05.549: E/Database(27671):  at android.app.ActivityThread.access$1500(ActivityThread.java)
03-06 01:26:05.549: E/Database(27671):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java)
03-06 01:26:05.549: E/Database(27671):  at android.os.Handler.dispatchMessage(Handler.java)
03-06 01:26:05.549: E/Database(27671):  at android.os.Looper.loop(Looper.java)
03-06 01:26:05.549: E/Database(27671):  at android.app.ActivityThread.main(ActivityThread.java)
03-06 01:26:05.549: E/Database(27671):  at java.lang.reflect.Method.invokeNative(Native Method)
03-06 01:26:05.549: E/Database(27671):  at java.lang.reflect.Method.invoke(Method.java:507)
03-06 01:26:05.549: E/Database(27671):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java)
03-06 01:26:05.549: E/Database(27671):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java)
03-06 01:26:05.549: E/Database(27671):  at dalvik.system.NativeStart.main(Native Method)

4 个答案:

答案 0 :(得分：1)

试试这个，

 public String[] getImgURL(){
    mydb = localContext.openOrCreateDatabase(DBNAME, Context.MODE_PRIVATE,null);
    Cursor allrows  = mydb.rawQuery("SELECT ImgURL FROM "+  TABLE, null);
    String[] urlString = new String[allrows.getCount()-1];

    allrows.moveToFirst();

    for (int i = 1; i < allrows.getCount(); i++) {
        urlString[i] = allrows.getString(0);
        allrows.moveToNext();               
    }
    allrows.close();    
    mydb.close();
    return urlString;

}

答案 1 :(得分：0)

如果您的错误是一个超出范围的索引，我的猜测是您正在创建一个大小为n -1的数组，然后将n个元素放入其中。它应该是

String[] urlString = new String[allrows.getCount()];

这样，数组足够大，可以容纳你放入的元素数量。如果这是错误的，请发布一个堆栈跟踪，在黑暗中刺伤并不是很有趣。

答案 2 :(得分：0)

在开始使用光标操作之前，您需要拨打allrows.moveToFirst。

答案 3 :(得分：0)

这里有两个问题。

首先，您必须先移动光标。 moveToFirst或moveToNext很好。

其次，数组中的索引以及数组的大小不正确。

这样做的正确和最新情况如下：

mydb = localContext.openOrCreateDatabase(DBNAME, Context.MODE_PRIVATE,null);
Cursor allrows  = mydb.rawQuery("SELECT ImgURL FROM "+  TABLE, null);
List<String> result = new ArrayList<String>();
while (allrows.moveToNext()) {
    result.add(allrows.getString(0));
}
allrows.close();    
mydb.close();
return allrows.toArray(new String[0]);
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