我創建的一個程序,第一個 activity 從數據庫中獲取隨機值然後作為一個字符串傳遞到下一個activity 中。
我知道在 sql 中如何實現這個功能:
SELECT column FROM table
ORDER BY RANDOM()
LIMIT 1
一些嘗試後我在程序中使用:
Cursor send = database.query(TABLE_NAME, new String[] { COLUMN_NAME }, null, null, null, null, "RANDOM() LIMIT 1");
Bundle b = new Bundle();
b.putString("description", send.getString(send.getColumnIndex(COLUMN_NAME)));
當我點擊按鈕打開第二個 activity 時,最後一行中有錯誤。
Log:
05-22 22:14:24.202: E/AndroidRuntime(14259): FATAL EXCEPTION: main
05-22 22:14:24.202: E/AndroidRuntime(14259): android.database.CursorIndexOutOfBoundsException: Index 1 requested, with a size of 1
05-22 22:14:24.202: E/AndroidRuntime(14259): at android.database.AbstractCursor.checkPosition(AbstractCursor.java:400)
05-22 22:14:24.202: E/AndroidRuntime(14259): at android.database.AbstractWindowedCursor.checkPosition(AbstractWindowedCursor.java:136)
05-22 22:14:24.202: E/AndroidRuntime(14259): at android.database.AbstractWindowedCursor.getString(AbstractWindowedCursor.java:50)
05-22 22:14:24.202: E/AndroidRuntime(14259): at com.example.ListAction$1.onItemClick(ListAction.java:90)
05-22 22:14:24.202: E/AndroidRuntime(14259): at android.widget.AdapterView.performItemClick(AdapterView.java:292)
05-22 22:14:24.202: E/AndroidRuntime(14259): at android.widget.AbsListView.performItemClick(AbsListView.java:1177)
05-22 22:14:24.202: E/AndroidRuntime(14259): at android.widget.AbsListView$PerformClick.run(AbsListView.java:2705)
05-22 22:14:24.202: E/AndroidRuntime(14259): at android.widget.AbsListView$1.run(AbsListView.java:3458)
05-22 22:14:24.202: E/AndroidRuntime(14259): at android.os.Handler.handleCallback(Handler.java:605)
05-22 22:14:24.202: E/AndroidRuntime(14259): at android.os.Handler.dispatchMessage(Handler.java:92)
05-22 22:14:24.202: E/AndroidRuntime(14259): at android.os.Looper.loop(Looper.java:137)
05-22 22:14:24.202: E/AndroidRuntime(14259): at android.app.ActivityThread.main(ActivityThread.java:4507)
05-22 22:14:24.202: E/AndroidRuntime(14259): at java.lang.reflect.Method.invokeNative(Native Method)
05-22 22:14:24.202: E/AndroidRuntime(14259): at java.lang.reflect.Method.invoke(Method.java:511)
05-22 22:14:24.202: E/AndroidRuntime(14259): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:790)
05-22 22:14:24.202: E/AndroidRuntime(14259): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:557)
05-22 22:14:24.202: E/AndroidRuntime(14259): at dalvik.system.NativeStart.main(Native Method)
如何獲取復選框偏好價值?
數組越界了,可能是query用法有問題,導致沒有數據查詢出來,sqlite跟sql的用法可能有出入.