如何在ListView中獲取所選項目？

Question

這是我的代碼，出於某種原因，當我運行它時（編輯，刪除），我無法在android studio中獲得提示提示。 T` //活動是第一頁，並通過火力

public class mainActivity extends AppCompatActivity { 
    public String username; 
    public String userUid; 
    FirebaseListAdapter<blogContent> adapter; //Declare connection to firebase 
    private FirebaseAuth firebaseAuth; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { //Bsically the main page 

     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 
     username = getIntent().getStringExtra("username"); 
     userUid = getIntent().getStringExtra("userUid"); 
     setTitle("Welcome, " + username); 
     final String user = username; 
     final ListView listView = (ListView) findViewById(R.id.activityList); 
     adapter = new FirebaseListAdapter<blogContent>(this, blogContent.class, R.layout.activity_blog_content, //connects to firebase 
       FirebaseDatabase.getInstance().getReference(userUid)) { //Pulls user ID from firebase 
      @Override 
      protected void populateView(View v, blogContent model, int position) { //checks if user exists in database 
        String checking = model.getUsercheck(); 
       if(user.equals(checking)) { //exists 

         TextView title = (TextView) v.findViewById(R.id.title); 
         ImageView img = (ImageView) v.findViewById(R.id.img); 
         TextView des = (TextView) v.findViewById(R.id.description); 

         byte[] decodedString = Base64.decode(model.getImg(), Base64.DEFAULT); 
         Bitmap bitmap = BitmapFactory.decodeByteArray(decodedString, 0, decodedString.length); 

         title.setText(model.getTitle()); 
         des.setText(model.getDescription()); 
         img.setImageBitmap(bitmap); 
         Log.d("TAG", model.getImg()); 

       }else{ //if doesn't exist 
        Log.d("TAG","no such user found"); 
       } 
      } 

     }; 
     listView.setAdapter(adapter); 
     listView.setOnItemClickListener(new AdapterView.OnItemClickListener() { 
      @Override 
      public void onItemClick(AdapterView<?> parent, View view, int position, long id) { 
       blogContent itemRef = adapter.getItem(position); 

       CharSequence picker[] = new CharSequence[] {"Edit", "Delete"}; 
       AlertDialog.Builder builder = new AlertDialog.Builder(mainActivity.this); 
       builder.setTitle("Choose an Action"); 
       builder.setItems(picker, new DialogInterface.OnClickListener() { 
        @Override 
        public void onClick(DialogInterface dialog, int which) { 
         switch(which){ 
          case 0:{ 
           Toast.makeText(mainActivity.this, "0", Toast.LENGTH_SHORT).show(); 
           break; 
          } 
          case 1:{ 
           Toast.makeText(mainActivity.this, "1", Toast.LENGTH_SHORT).show(); 
           break; 
          } 
          default:{ 
           break; 
          } 
         } 
        } 
       }); 
      } 
     }); 
    } 

    public void addActivityIntent(View view){ //get user and password and sends screen to addactivity 
     Intent intent = new Intent(mainActivity.this, addActivity.class); //declares destination 
     intent.putExtra("username", username); 
     intent.putExtra("userUid", userUid); 
     startActivity(intent); //sends user 
    } 

} 

照顧登錄此外，它不似乎是建立一個數組是可能的，因爲我是從火力地堡，我應該如何解決任何線索提取數據這個？

Answer 1

因爲你應該添加.show（）你可以寫警告對話框像

new AlertDialog.Builder(mainActivity.this); 
      builder.setTitle("Choose an Action"); 
      builder.setItems(picker, new DialogInterface.OnClickListener() { 
       @Override 
       public void onClick(DialogInterface dialog, int which) { 
        switch(which){ 
         case 0:{ 
          Toast.makeText(mainActivity.this, "0", Toast.LENGTH_SHORT).show(); 
          break; 
         } 
         case 1:{ 
          Toast.makeText(mainActivity.this, "1", Toast.LENGTH_SHORT).show(); 
          break; 
         } 
         default:{ 
          break; 
         } 
        } 
       } 
      }).show();