Question

我在android中使用SQLite数据库的简单函数来返回一些记录的计数。

public int getThreadMessagesCount(int thread_id){

    int mThreadCount = 0 ;

    Cursor cur = db.rawQuery("select count(*) as ThreadCount from tbl_messaging where thread_id = ?", new String[]{thread_id+""});
    Log.d("xxx", "query executed");

    if (cur.getCount()<=0)
        mThreadCount = 0 ;
        else
            mThreadCount = cur.getInt(cur.getColumnIndex("ThreadCount")) ;

    return mThreadCount ;



}

但是当执行函数向我抛出赎罪时。

记录：

03-02 12:09:03.210: E/AndroidRuntime(32360): FATAL EXCEPTION: main
03-02 12:09:03.210: E/AndroidRuntime(32360): android.database.CursorIndexOutOfBoundsException: Index -1 requested, with a size of 1
03-02 12:09:03.210: E/AndroidRuntime(32360):    at android.database.AbstractCursor.checkPosition(AbstractCursor.java:418)
03-02 12:09:03.210: E/AndroidRuntime(32360):    at android.database.AbstractWindowedCursor.checkPosition(AbstractWindowedCursor.java:136)
03-02 12:09:03.210: E/AndroidRuntime(32360):    at android.database.AbstractWindowedCursor.getInt(AbstractWindowedCursor.java:68)
03-02 12:09:03.210: E/AndroidRuntime(32360):    at com.example.tawasol1.cls_database.getThreadMessagesCount(cls_database.java:460)
03-02 12:09:03.210: E/AndroidRuntime(32360):    at com.example.tawasol1.Cls_act_check_account$5.onClick(Cls_act_check_account.java:377)
03-02 12:09:03.210: E/AndroidRuntime(32360):    at android.view.View.performClick(View.java:4261)
03-02 12:09:03.210: E/AndroidRuntime(32360):    at android.view.View$PerformClick.run(View.java:17356)
03-02 12:09:03.210: E/AndroidRuntime(32360):    at android.os.Handler.handleCallback(Handler.java:615)
03-02 12:09:03.210: E/AndroidRuntime(32360):    at android.os.Handler.dispatchMessage(Handler.java:92)
03-02 12:09:03.210: E/AndroidRuntime(32360):    at android.os.Looper.loop(Looper.java:137)
03-02 12:09:03.210: E/AndroidRuntime(32360):    at android.app.ActivityThread.main(ActivityThread.java:4921)
03-02 12:09:03.210: E/AndroidRuntime(32360):    at java.lang.reflect.Method.invokeNative(Native Method)
03-02 12:09:03.210: E/AndroidRuntime(32360):    at java.lang.reflect.Method.invoke(Method.java:511)
03-02 12:09:03.210: E/AndroidRuntime(32360):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1038)
03-02 12:09:03.210: E/AndroidRuntime(32360):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:805)
03-02 12:09:03.210: E/AndroidRuntime(32360):    at dalvik.system.NativeStart.main(Native Method)

Answer 1

试试此代码

public int getThreadMessagesCount(int thread_id){

int mThreadCount = 0 ;

Cursor cur = db.rawQuery("select count(*) as ThreadCount from tbl_messaging where thread_id = ?", new String[]{thread_id+""});
Log.d("xxx", "query executed");

if (cur.getCount()<=0)
    mThreadCount = 0 ;
    else{
        cur.moveToNext();
        mThreadCount = cur.getInt(cur.getColumnIndex("ThreadCount")) ;}

return mThreadCount ;

}`

Sqlite - 简单的函数返回计数

1 个答案: