Question

我有以下代码。我从db查询中获取了一个游标对象，该查询实际上返回一个整数值。我需要从游标对象获取整数值。我正在尝试以下方法，它返回一个异常。任何人都可以告诉我如何从光标中获取整数值。查询是正确的我使用一些数据库工具尝试了相同的查询，我得到了所需的值。请帮我解决这个问题：

我的数据库查询：

public int getTaskUID(String taskName) {


     Cursor cursor = db.rawQuery("SELECT _id FROM DataTable WHERE Task_name = ' " +taskName + "'" , null);

       int count = Integer.parseInt(String.valueOf(cursor)) ;
       Log.d("Pana", "the value of count is " + count);

return count;

   }

我的adb追踪：

    --------- beginning of crash
03-12 11:23:29.392    1129-1129/com.ms.t.tms E/AndroidRuntime﹕ FATAL EXCEPTION: main
    Process: com.ms.t.tms, PID: 1129
    java.lang.IllegalStateException: Could not execute method of the activity
            at android.view.View$1.onClick(View.java:4007)
            at android.view.View.performClick(View.java:4756)
            at android.view.View$PerformClick.run(View.java:19749)
            at android.os.Handler.handleCallback(Handler.java:739)
            at android.os.Handler.dispatchMessage(Handler.java:95)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5221)
            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:899)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
     Caused by: java.lang.reflect.InvocationTargetException
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at android.view.View$1.onClick(View.java:4002)
            at android.view.View.performClick(View.java:4756)
            at android.view.View$PerformClick.run(View.java:19749)
            at android.os.Handler.handleCallback(Handler.java:739)
            at android.os.Handler.dispatchMessage(Handler.java:95)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5221)
            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:899)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
     Caused by: java.lang.NumberFormatException: Invalid int: "android.database.sqlite.SQLiteCursor@59327fe"
            at java.lang.Integer.invalidInt(Integer.java:138)
            at java.lang.Integer.parse(Integer.java:410)
            at java.lang.Integer.parseInt(Integer.java:367)
            at java.lang.Integer.parseInt(Integer.java:334)
            at com.ms.t.tms.SQLiteDataBaseAdapter.getTaskUID(SQLiteDataBaseAdapter.java:382)
            at com.ms.t.tms.InsertSubTaskActivity.addUser(InsertSubTaskActivity.java:502)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at android.view.View$1.onClick(View.java:4002)
            at android.view.View.performClick(View.java:4756)
            at android.view.View$PerformClick.run(View.java:19749)
            at android.os.Handler.handleCallback(Handler.java:739)
            at android.os.Handler.dispatchMessage(Handler.java:95)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5221)
            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:899)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)

我的数据库架构：

public static final String CREATE_TABLE = " CREATE TABLE " + TABLE_NAME +
            "(" + UID + " INTEGER PRIMARY KEY AUTOINCREMENT, " + TASK_NAME + " VARCHAR(250)," + CONTACT_NAME + " VARCHAR(250)," + CONTACT_NUMBER + " VARCHAR(250),"
            + CONTACT_EMAIL + " VARCHAR(250)," + DESCRIPTION + " VARCHAR(250), " + REMARKS + " VARCHAR(250),"
            + DATE + " VARCHAR(250)," + TIME + " VARCHAR(250)," + ESTIMATED_COMPLETION_DATE + " VARCHAR(250), " + ESTIMATED_COMPLETION_TIME + " VARCHAR(250), "
            + ACTUAL_COMPLETION_DATE + " VARCHAR(250), " + ACTUAL_COMPLETION_TIME + " VARCHAR(250), " + NOTIFY_DATE + " VARCHAR(250), " + NOTIFY_TIME + " VARCHAR(250), " +  SUB_TASK_NUMBER + " VARCHAR(250) );";

如何将游标对象转换为int值。请帮忙。

Answer 1

你可以从光标获得价值，如

 int count = Integer.parseInt(cursor.getString(0)) ;

或者

 int count = cursor.getInt(cursor.getColumnIndex("db_column_name"));

Answer 2

您无法将游标值转换为整数作为结果持有者对象。您可以尝试从游标中提取值并将其解析为整数。

类似的东西：

int count = cursor.getCount();//to get number of rows your query gave

或者，如果您想要请求结果，那么：

int count = cursor.getInt(cursor.getColumnIndex("_id"));

Answer 3

你不能这样做：

  int count = Integer.parseInt(String.valueOf(cursor)) ;
  Log.d("Pana", "the value of count is " + count);

在您的代码中执行以下操作：

  Cursor cursor = db.rawQuery("SELECT _id FROM DataTable WHERE Task_name = ' " +taskName + "'" , null);

    if(cursor != null && cursor.getCount > 0) {
       cursor.moveToFirst()
    }

  long id = cursor.getLong(cursor.getColumnIndex("_id"));

使用以下代码从光标

获取值

 // Reading Long Value
 long id = cursor.getLong(cursor.getColumnIndex("_id"));

 //Reading String value
 String name = cursor.getString(cursor.getColumnIndex("table_column_name"));

 //Reading Double value
 String name = cursor.getDouble(cursor.getColumnIndex("table_column_name"));

//Reading Integer value
 String name = cursor.getInt(cursor.getColumnIndex("table_column_name"));

计算游标中的记录数

 int count = (cursor != null && cursor.getCount() > 0) ? cursor.getCount() : 0;

Java.Lang.NumberFormatException：如何格式化游标对象以获取int值

3 个答案:

或者