在android活動的子菜單項中創建對話框片段時出錯

Question

我創建了一個對話框片段。當我按下子菜單項時，我需要讓這個對話框來到我目前的活動。所以我創建並聲明瞭AlertDialog.Builder builde;在我的活動開始之前。

public class Placed_Product_Details extends Activity { 
String usrnme,name,proid; 
AlertDialog.Builder builde; 

其代碼如下。

public Dialog onCreateDialog(Bundle savedInstanceState) { 
    // TODO Auto-generated method stub 
    builde = new AlertDialog.Builder(Placed_Product_Details.this); 
    LayoutInflater inflater = Placed_Product_Details.this.getLayoutInflater(); 
     // Inflate and set the layout for the dialog 
    // Pass null as the parent view because its going in the dialog layout 
    builde.setView(inflater.inflate(R.layout.updateproductname, null)) 
    // Add action buttons 
      .setPositiveButton("OK", new DialogInterface.OnClickListener() { 
       @Override 
       public void onClick(DialogInterface dialog, int id) { 
        // sign in the user ... 
       } 
      }); 

    return builde.create(); 

} 

這是子菜單代碼的一部分。

public boolean onOptionsItemSelected(MenuItem item) { 
    // TODO Auto-generated method stub 
    switch (item.getItemId()) { 
    case R.id.delete: 
    { 

     //here i have the code for deleting from the database 

     break; 
    } 
    case R.id.updateproductname: 
    { 

       //here I have created a dialog and called it here. The code 
       //of the dialog is posted above 
     AlertDialog ab=builde.create(); 
     ab.show(); 
     break; 
    } 
    default: 
     break; 
    } 
    return super.onOptionsItemSelected(item); 

} 

這是我在我的項目的res/layout /文件夾中創建的對話框updateproductname.xml的佈局。

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
android:layout_width="fill_parent" 
android:layout_height="fill_parent" 
android:orientation="vertical" > 

<TextView 
    android:id="@+id/textView1" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_marginLeft="45dp" 
    android:layout_marginTop="30dp" 
    android:text="Update Product Name" 
    android:textAppearance="?android:attr/textAppearanceLarge" /> 

<EditText 
    android:id="@+id/productnameedittext" 
    android:layout_width="match_parent" 
    android:layout_marginLeft="0dp" 
    android:layout_marginTop="30dp" 
    android:hint="Enter new product name here" 
    android:layout_height="wrap_content" 
    android:ems="10" > 

    <requestFocus /> 
</EditText> 

<Button 
    android:id="@+id/productnamebutton" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_marginLeft="50dp" 
    android:layout_marginTop="30dp" 
    android:text="Change Product Name" /> 

</LinearLayout> 

當我點擊子菜單時，我的應用程序強制突然關閉。我不知道爲什麼？我將顯示顯示錯誤的logcat。這是因爲我錯誤地創建了對話框片段。有人可以告訴我錯誤在我的應用程序中。

編輯：這是我的錯誤的完整的日誌..

02-17 10:50:23.267: D/AndroidRuntime(687): Shutting down VM 
02-17 10:50:23.318: W/dalvikvm(687): threadid=1: thread exiting with uncaught exception (group=0x40015560) 
02-17 10:50:23.416: E/AndroidRuntime(687): FATAL EXCEPTION: main 
02-17 10:50:23.416: E/AndroidRuntime(687): java.lang.NullPointerException 
02-17 10:50:23.416: E/AndroidRuntime(687): at com.example.onlineauction.Placed_Product_Details.onOptionsItemSelected(Placed_Product_Details.java:188) 
02-17 10:50:23.416: E/AndroidRuntime(687): at android.app.Activity.onMenuItemSelected(Activity.java:2205) 
02-17 10:50:23.416: E/AndroidRuntime(687): at com.android.internal.policy.impl.PhoneWindow.onMenuItemSelected(PhoneWindow.java:748) 
02-17 10:50:23.416: E/AndroidRuntime(687): at com.android.internal.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:143) 
02-17 10:50:23.416: E/AndroidRuntime(687): at com.android.internal.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:855) 
02-17 10:50:23.416: E/AndroidRuntime(687): at com.android.internal.view.menu.MenuDialogHelper.onClick(MenuDialogHelper.java:137) 
02-17 10:50:23.416: E/AndroidRuntime(687): at com.android.internal.app.AlertController$AlertParams$3.onItemClick(AlertController.java:873) 
02-17 10:50:23.416: E/AndroidRuntime(687): at android.widget.AdapterView.performItemClick(AdapterView.java:284) 
02-17 10:50:23.416: E/AndroidRuntime(687): at android.widget.ListView.performItemClick(ListView.java:3513) 
02-17 10:50:23.416: E/AndroidRuntime(687): at android.widget.AbsListView$PerformClick.run(AbsListView.java:1812) 
02-17 10:50:23.416: E/AndroidRuntime(687): at android.os.Handler.handleCallback(Handler.java:587) 
02-17 10:50:23.416: E/AndroidRuntime(687): at android.os.Handler.dispatchMessage(Handler.java:92) 
02-17 10:50:23.416: E/AndroidRuntime(687): at android.os.Looper.loop(Looper.java:123) 
02-17 10:50:23.416: E/AndroidRuntime(687): at android.app.ActivityThread.main(ActivityThread.java:3683) 
02-17 10:50:23.416: E/AndroidRuntime(687): at java.lang.reflect.Method.invokeNative(Native Method) 
02-17 10:50:23.416: E/AndroidRuntime(687): at java.lang.reflect.Method.invoke(Method.java:507) 
02-17 10:50:23.416: E/AndroidRuntime(687): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 
02-17 10:50:23.416: E/AndroidRuntime(687): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 
02-17 10:50:23.416: E/AndroidRuntime(687): at dalvik.system.NativeStart.main(Native Method) 
02-17 10:50:27.746: I/Process(687): Sending signal. PID: 687 SIG: 9 

第二編輯：這裏是顯示錯誤的第二logcat的。

02-17 12:07:11.577: E/AndroidRuntime(769): FATAL EXCEPTION: main 
02-17 12:07:11.577: E/AndroidRuntime(769): java.lang.NullPointerException 
02-17 12:07:11.577: E/AndroidRuntime(769): at com.example.onlineauction.Placed_Product_Details$1.onClick(Placed_Product_Details.java:212) 
02-17 12:07:11.577: E/AndroidRuntime(769): at com.android.internal.app.AlertController$ButtonHandler.handleMessage(AlertController.java:159) 
02-17 12:07:11.577: E/AndroidRuntime(769): at android.os.Handler.dispatchMessage(Handler.java:99) 
02-17 12:07:11.577: E/AndroidRuntime(769): at android.os.Looper.loop(Looper.java:123) 
02-17 12:07:11.577: E/AndroidRuntime(769): at android.app.ActivityThread.main(ActivityThread.java:3683) 
02-17 12:07:11.577: E/AndroidRuntime(769): at java.lang.reflect.Method.invokeNative(Native Method) 
02-17 12:07:11.577: E/AndroidRuntime(769): at java.lang.reflect.Method.invoke(Method.java:507) 
02-17 12:07:11.577: E/AndroidRuntime(769): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 
02-17 12:07:11.577: E/AndroidRuntime(769): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 
02-17 12:07:11.577: E/AndroidRuntime(769): at dalvik.system.NativeStart.main(Native Method) 
02-17 12:07:15.667: I/Process(769): Sending signal. PID: 769 SIG: 9 

Answer 1

第一變量builder未初始化爲onCreateDialog()不叫任何地方......

你也許會想，你是壓倒一切的ActivityonCreateDialog()方法，但實際上不是。

看到onCreateDialog()的定義Activity

protected Dialog onCreateDialog(int); 
protected Dialog onCreateDialog(int,Bundle); 

僅供參考...這兩種方法已被棄用。

，但你寫

protected Dialog onCreateDialog(Bundle); 

不覆蓋的Activity任何方法...（使用Override註釋知道你實際上是覆蓋或沒有）

您可以從onCreateDialog()刪除Bundle參數方法，因爲你沒有使用它。

public Dialog onCreateDialog() { 
    // TODO Auto-generated method stub 
    builde = new AlertDialog.Builder(Placed_Product_Details.this); 
    LayoutInflater inflater = Placed_Product_Details.this 
      .getLayoutInflater(); 
    // Inflate and set the layout for the dialog 
    // Pass null as the parent view because its going in the dialog layout 
    builde.setView(inflater.inflate(R.layout.updateproductname, null)) 
    // Add action buttons 
      .setPositiveButton("OK", new DialogInterface.OnClickListener() { 
       @Override 
       public void onClick(DialogInterface dialog, int id) { 
        // sign in the user ... 
       } 
      }); 

    return builde.create(); 
} 

，並點擊相應的MenuItem時調用此方法...

case R.id.updateproductname:{ 

    //here I have created a dialog and called it here. The code 
    //of the dialog is posted above 
    onCreateDialog().show(); 
    break; 
}