диалоговое окно предупреждения в фрагментах

Question

Я сделал этот код, чтобы отобразить диалоговое окно предупреждения в фрагменте, но когда я нажимаю на кнопку, приложение вылетает. спасибо за помощь в любом случае.

fragment_disconnect.xml:

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent" 
    android:orientation="vertical" 
    android:gravity="center_horizontal" 
    android:background="#EBB917" > 

    <Button 
    android:layout_margin="20dip" 
    android:id="@+id/button_disconnect_alert" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="Disconnect" 
    android:onClick="onClick" /> 

</LinearLayout> 

код:

package com.example.poca2; 

import android.app.AlertDialog; 
import android.app.Fragment; 
import android.content.DialogInterface; 
import android.content.Intent; 
import android.os.Bundle; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.ViewGroup; 

public class DisconnectFragment extends Fragment { 
public DisconnectFragment(){} 


public void onClick(View view) 
{ 
    AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(getActivity()); 
    // set Title 
    alertDialogBuilder.setTitle("Disconnecting User"); 
    //set Message 
    alertDialogBuilder.setMessage("Are You Sure You Want To Disconnect ? ").setCancelable(false).setPositiveButton("Yes",new DialogInterface.OnClickListener() { 
     public void onClick(DialogInterface dialog, int id){ 
      // if button is clicked ,then go to into activity 
      //Intent intent = new Intent(getActivity(), IntroActivity.class); 
      //startActivity(intent); 
     } 
    }).setNegativeButton("No", new DialogInterface.OnClickListener() { 
     public void onClick(DialogInterface dialog,int id){ 
      // if button is clicked then close the alert box 

      dialog.cancel(); 
     } 
    }); 
    //create alert dialog 
    AlertDialog alertDialog = alertDialogBuilder.create(); 
    //show alert box 
    alertDialog.show(); 
}  




@Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, 
     Bundle savedInstanceState) { 
    View rootView = inflater.inflate(R.layout.fragment_disconnect, container, false); 
    return rootView; 
    } 
} 

журнала:

04-03 11:37:22.684: D/skia(23439): new locale en-Latn-GB 
04-03 11:37:22.854: D/libEGL(23439): loaded /vendor/lib/egl/libEGL_adreno.so 
04-03 11:37:22.854: D/libEGL(23439): loaded /vendor/lib/egl/libGLESv1_CM_adreno.so 
04-03 11:37:22.864: D/libEGL(23439): loaded /vendor/lib/egl/libGLESv2_adreno.so 
04-03 11:37:22.864: I/Adreno-EGL(23439): <qeglDrvAPI_eglInitialize:316>: EGL 1.4 QUALCOMM build: (CL4169980) 
04-03 11:37:22.864: I/Adreno-EGL(23439): OpenGL ES Shader Compiler Version: 17.01.10.SPL 
04-03 11:37:22.864: I/Adreno-EGL(23439): Build Date: 09/26/13 Thu 
04-03 11:37:22.864: I/Adreno-EGL(23439): Local Branch: 
04-03 11:37:22.864: I/Adreno-EGL(23439): Remote Branch: 
04-03 11:37:22.864: I/Adreno-EGL(23439): Local Patches: 
04-03 11:37:22.864: I/Adreno-EGL(23439): Reconstruct Branch: 
04-03 11:37:22.914: D/OpenGLRenderer(23439): Enabling debug mode 0 
04-03 11:37:39.971: D/AndroidRuntime(23439): Shutting down VM 
04-03 11:37:39.971: W/dalvikvm(23439): threadid=1: thread exiting with uncaught exception (group=0x41b2b898) 
04-03 11:37:39.981: E/AndroidRuntime(23439): FATAL EXCEPTION: main 
04-03 11:37:39.981: E/AndroidRuntime(23439): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.poca2/com.example.poca2.RegisterActivity}: java.lang.NullPointerException 
04-03 11:37:39.981: E/AndroidRuntime(23439): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2295) 
04-03 11:37:39.981: E/AndroidRuntime(23439): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2349) 
04-03 11:37:39.981: E/AndroidRuntime(23439): at android.app.ActivityThread.access$700(ActivityThread.java:159) 
04-03 11:37:39.981: E/AndroidRuntime(23439): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1316) 
04-03 11:37:39.981: E/AndroidRuntime(23439): at android.os.Handler.dispatchMessage(Handler.java:99) 
04-03 11:37:39.981: E/AndroidRuntime(23439): at android.os.Looper.loop(Looper.java:137) 
04-03 11:37:39.981: E/AndroidRuntime(23439): at android.app.ActivityThread.main(ActivityThread.java:5419) 
04-03 11:37:39.981: E/AndroidRuntime(23439): at java.lang.reflect.Method.invokeNative(Native Method) 
04-03 11:37:39.981: E/AndroidRuntime(23439): at java.lang.reflect.Method.invoke(Method.java:525) 
04-03 11:37:39.981: E/AndroidRuntime(23439): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1187) 
04-03 11:37:39.981: E/AndroidRuntime(23439): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1003) 
04-03 11:37:39.981: E/AndroidRuntime(23439): at dalvik.system.NativeStart.main(Native Method) 
04-03 11:37:39.981: E/AndroidRuntime(23439): Caused by: java.lang.NullPointerException 
04-03 11:37:39.981: E/AndroidRuntime(23439): at com.example.poca2.RegisterActivity.onCreate(RegisterActivity.java:33) 
04-03 11:37:39.981: E/AndroidRuntime(23439): at android.app.Activity.performCreate(Activity.java:5372) 
04-03 11:37:39.981: E/AndroidRuntime(23439): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1104) 
04-03 11:37:39.981: E/AndroidRuntime(23439): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2257) 
04-03 11:37:39.981: E/AndroidRuntime(23439): ... 11 more 
04-03 11:37:44.545: D/skia(23761): new locale en-Latn-GB 
04-03 11:37:44.776: D/libEGL(23761): loaded /vendor/lib/egl/libEGL_adreno.so 
04-03 11:37:44.786: D/libEGL(23761): loaded /vendor/lib/egl/libGLESv1_CM_adreno.so 
04-03 11:37:44.786: D/libEGL(23761): loaded /vendor/lib/egl/libGLESv2_adreno.so 
04-03 11:37:44.786: I/Adreno-EGL(23761): <qeglDrvAPI_eglInitialize:316>: EGL 1.4 QUALCOMM build: (CL4169980) 
04-03 11:37:44.786: I/Adreno-EGL(23761): OpenGL ES Shader Compiler Version: 17.01.10.SPL 
04-03 11:37:44.786: I/Adreno-EGL(23761): Build Date: 09/26/13 Thu 
04-03 11:37:44.786: I/Adreno-EGL(23761): Local Branch: 
04-03 11:37:44.786: I/Adreno-EGL(23761): Remote Branch: 
04-03 11:37:44.786: I/Adreno-EGL(23761): Local Patches: 
04-03 11:37:44.786: I/Adreno-EGL(23761): Reconstruct Branch: 
04-03 11:37:44.836: D/OpenGLRenderer(23761): Enabling debug mode 0 
04-03 11:37:48.069: D/AndroidRuntime(23761): Shutting down VM 
04-03 11:37:48.069: W/dalvikvm(23761): threadid=1: thread exiting with uncaught exception (group=0x41b2b898) 
04-03 11:37:48.069: E/AndroidRuntime(23761): FATAL EXCEPTION: main 
04-03 11:37:48.069: E/AndroidRuntime(23761): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.poca2/com.example.poca2.RegisterActivity}: java.lang.NullPointerException 
04-03 11:37:48.069: E/AndroidRuntime(23761): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2295) 
04-03 11:37:48.069: E/AndroidRuntime(23761): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2349) 
04-03 11:37:48.069: E/AndroidRuntime(23761): at android.app.ActivityThread.access$700(ActivityThread.java:159) 
04-03 11:37:48.069: E/AndroidRuntime(23761): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1316) 
04-03 11:37:48.069: E/AndroidRuntime(23761): at android.os.Handler.dispatchMessage(Handler.java:99) 
04-03 11:37:48.069: E/AndroidRuntime(23761): at android.os.Looper.loop(Looper.java:137) 
04-03 11:37:48.069: E/AndroidRuntime(23761): at android.app.ActivityThread.main(ActivityThread.java:5419) 
04-03 11:37:48.069: E/AndroidRuntime(23761): at java.lang.reflect.Method.invokeNative(Native Method) 
04-03 11:37:48.069: E/AndroidRuntime(23761): at java.lang.reflect.Method.invoke(Method.java:525) 
04-03 11:37:48.069: E/AndroidRuntime(23761): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1187) 
04-03 11:37:48.069: E/AndroidRuntime(23761): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1003) 
04-03 11:37:48.069: E/AndroidRuntime(23761): at dalvik.system.NativeStart.main(Native Method) 
04-03 11:37:48.069: E/AndroidRuntime(23761): Caused by: java.lang.NullPointerException 
04-03 11:37:48.069: E/AndroidRuntime(23761): at com.example.poca2.RegisterActivity.onCreate(RegisterActivity.java:33) 
04-03 11:37:48.069: E/AndroidRuntime(23761): at android.app.Activity.performCreate(Activity.java:5372) 
04-03 11:37:48.069: E/AndroidRuntime(23761): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1104) 
04-03 11:37:48.069: E/AndroidRuntime(23761): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2257) 
04-03 11:37:48.069: E/AndroidRuntime(23761): ... 11 more 
04-03 11:37:54.265: I/Process(23761): Sending signal. PID: 23761 SIG: 9 

сбой приложения о том, когда я нажимаю на кнопку. Thnx за помощью

Answer 1

Попробуйте это:

Предположит, что это ваш фрагмент:

public class SomeFragment extends Fragment { 

    public SomeFragment() { 
    } 

    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, 
      Bundle savedInstanceState) { 

     View rootView = inflater.inflate(R.layout.activity_main, container, 
       false); 

     return rootView; 
    } 

    @Override 
public void onActivityCreated(Bundle savedInstanceState) { 
    // TODO Auto-generated method stub 
    super.onActivityCreated(savedInstanceState); 

    Button btn = (Button) getActivity().findViewById(
      button_disconnect_alert); 

    btn.setOnClickListener(new OnClickListener() { 

     @Override 
     public void onClick(View v) { 
      // TODO Auto-generated method stub 

      AlertDialog.Builder builder = new AlertDialog.Builder(
        getActivity()); 
      builder.setIcon(getResources().getDrawable(
        R.drawable.ic_launcher)); 
      builder.setTitle("Some title"); 
      builder.setMessage("Some Message"); 
      builder.setPositiveButton("Yes", 
        new DialogInterface.OnClickListener() { 

         @Override 
         public void onClick(DialogInterface dialog, 
           int which) { 

          Toast.makeText(getActivity(), 
            "Positive clicked", Toast.LENGTH_SHORT) 
            .show(); 

          Intent intent = new Intent(getActivity(), 
            IntroActivity.class); 
          getActivity().startActivity(intent); 

         } 
        }); 
      builder.setNegativeButton("No", 
        new DialogInterface.OnClickListener() { 

         @Override 
         public void onClick(DialogInterface dialog, 
           int which) { 

          Toast.makeText(getActivity(), 
            "Negative clicked", Toast.LENGTH_SHORT) 
            .show(); 

         } 
        }); 
      builder.setCancelable(false); 
      AlertDialog alert = builder.create(); 
      alert.show(); 
     } 
    }); 

} 

} 

Надеется, что это помогает .. :)

Answer 2

У вас есть нулевой указатель исключение @ RegisterActivity.onCreate(), RegisterActivity.java линии 33

Независимо от переменных вы обращающиеся здесь, вам нужно проверить, если они равны нулю перед их использованием.

Основным методом отладки было бы сделать что-то подобное для каждой ссылки/переменной, используемой в этой строке.

if (variable == null) 
{ 
    Log.d(TAG, "variable is null") 
} 

когда вы узнали, что имеет нулевое значение, то вы можете выяснить, почему, и как только вы знаете, почему, вы можете это исправить, и извлечь уроки из опыта.