AlertDialog Holoeverywhere崩潰？

Question

我是學holoeverywhere庫>>https://github.com/Prototik/HoloEverywhere/ 我正在嘗試alertdialog，但我得到崩潰..

這個錯誤..........

01-25 10:45:52.799: E/AndroidRuntime(12308): FATAL EXCEPTION: main 
01-25 10:45:52.799: E/AndroidRuntime(12308): java.lang.NullPointerException 
01-25 10:45:52.799: E/AndroidRuntime(12308): at org.holoeverywhere.widget.AlertController.setupContent(AlertController.java:681) 
01-25 10:45:52.799: E/AndroidRuntime(12308): at org.holoeverywhere.widget.AlertController.setupView(AlertController.java:745) 
01-25 10:45:52.799: E/AndroidRuntime(12308): at org.holoeverywhere.widget.AlertController.installContent(AlertController.java:469) 
01-25 10:45:52.799: E/AndroidRuntime(12308): at org.holoeverywhere.app.AlertDialog.onCreate(AlertDialog.java:411) 
01-25 10:45:52.799: E/AndroidRuntime(12308): at android.app.Dialog.dispatchOnCreate(Dialog.java:307) 
01-25 10:45:52.799: E/AndroidRuntime(12308): at android.app.Dialog.show(Dialog.java:225) 
01-25 10:45:52.799: E/AndroidRuntime(12308): at com.droidersuin.project.setting.SettingAppSystem.ClearChace(SettingAppSystem.java:196) 
01-25 10:45:52.799: E/AndroidRuntime(12308): at com.droidersuin.project.setting.SettingAppSystem$2.onItemClick(SettingAppSystem.java:137) 
01-25 10:45:52.799: E/AndroidRuntime(12308): at android.widget.AdapterView.performItemClick(AdapterView.java:284) 
01-25 10:45:52.799: E/AndroidRuntime(12308): at android.widget.ListView.performItemClick(ListView.java:3755) 
01-25 10:45:52.799: E/AndroidRuntime(12308): at org.holoeverywhere.widget.ListView.performItemClick(ListView.java:635) 
01-25 10:45:52.799: E/AndroidRuntime(12308): at android.widget.AbsListView$PerformClick.run(AbsListView.java:1964) 
01-25 10:45:52.799: E/AndroidRuntime(12308): at android.os.Handler.handleCallback(Handler.java:587) 
01-25 10:45:52.799: E/AndroidRuntime(12308): at android.os.Handler.dispatchMessage(Handler.java:92) 
01-25 10:45:52.799: E/AndroidRuntime(12308): at android.os.Looper.loop(Looper.java:130) 
01-25 10:45:52.799: E/AndroidRuntime(12308): at android.app.ActivityThread.main(ActivityThread.java:3687) 
01-25 10:45:52.799: E/AndroidRuntime(12308): at java.lang.reflect.Method.invokeNative(Native Method) 
01-25 10:45:52.799: E/AndroidRuntime(12308): at java.lang.reflect.Method.invoke(Method.java:507) 
01-25 10:45:52.799: E/AndroidRuntime(12308): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867) 
01-25 10:45:52.799: E/AndroidRuntime(12308): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:625) 
01-25 10:45:52.799: E/AndroidRuntime(12308): at dalvik.system.NativeStart.main(Native Method) 

這是我的代碼.........

import org.holoeverywhere.app.Activity; 
import org.holoeverywhere.app.AlertDialog; 

public class SettingAppSystem extends Activity { 
//... 
public void onCreate(Bundle savedInstanceState) { 
//..... 
     AlertDialog.Builder builder = new AlertDialog.Builder(this); 
     builder.setMessage("Delete Cache?") 
       .setCancelable(false) 
       .setPositiveButton("Yes", new DialogInterface.OnClickListener() { 
        public void onClick(DialogInterface dialog, int id) { 
         final ProgressDialog progressDialog = ProgressDialog.show(SettingAppSystem.this, "", "Delete Cache..."); 
         new Thread() { 
           public void run() { 
            try { 
            ImageLoader imgLoader = new ImageLoader(getBaseContext()); 
            ImageLoaderDetailImage imgLoaderDetailImage = new ImageLoaderDetailImage(getBaseContext()); 
            imgLoader.clearCache(); 
            imgLoaderDetailImage.clearCache(); 
            } catch (Exception e) { 
             Log.e("tag", e.getMessage()); 
            } 
            progressDialog.dismiss(); 
           Thread.currentThread().interrupt(); 
           } 
          }.start(); 

        } 
       }) 
       .setNegativeButton("No", new DialogInterface.OnClickListener() { 
        public void onClick(DialogInterface dialog, int id) { 
         dialog.cancel(); 
        } 
       }); 
     AlertDialog alert = builder.create(); 
     alert.show(); 
} 
} 

當我點擊logcat中，錯誤的是alert.show（）;，如何解決？對不起，我的英語

Answer 1

嘗試通過作爲上下文。聲明在您的活動如下：

final Context context = this; 

然後改變：

new AlertDialog.Builder(this); 

要：

new AlertDialog.Builder(context); 

---------- OLD答案---- -----

更改

AlertDialog alert = builder.create(); 
    alert.show(); 

要

builder.show(); 

由於新警報您創建爲空。