Android - 打開從片段中的對話框發射的第三個選項卡

Question

我有ALr.java類和FragHandler。 FragHandler有Tablayout和viewpager。 ALR和FragHandler代碼在下面寫成。我想通過調用activatealert方法來打開FragHandler中第三個選項卡的Settings選項卡，從ALR即rl.setonclicklisterner中單擊。

MyFragHandler類

public class FragHandler extends AppCompatActivity 
    TabLayout tabLayout; 
    Toolbar customtoolbar; 
    SharedPreferences sharedPreferences; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.alstabopener); 

     sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this); 



     tabLayout = (TabLayout) findViewById(R.id.tab_layout); 
     tabLayout.addTab(tabLayout.newTab().setText("1")); 
     tabLayout.addTab(tabLayout.newTab().setText("2")); 
     tabLayout.addTab(tabLayout.newTab().setText("Settings")); 
     tabLayout.setTabGravity(TabLayout.GRAVITY_FILL); 




     final ViewPager viewPager = (ViewPager) findViewById(R.id.pager); 
     final AlsViewChanger adapter = new AlsViewChanger(getSupportFragmentManager(), tabLayout.getTabCount()); 
     viewPager.setAdapter(adapter); 

     viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout)); 
     tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() { 
      @Override 
      public void onTabSelected(TabLayout.Tab tab) { 
       viewPager.setCurrentItem(tab.getPosition()); 
      } 

      @Override 
      public void onTabUnselected(TabLayout.Tab tab) { 

      } 

      @Override 
      public void onTabReselected(TabLayout.Tab tab) { 

      } 
     }); 


    } 





} 

，並從那裏我米試圖打開標籤我ALR.java 3.

public class ALR extends Fragment { 


    TextView rl, 




    @Nullable 
    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) throws NullPointerException { 
     View view = inflater.inflate(R.layout.ar, container, false); 



     rl = (TextView) view.findViewById(R.id.reto); 


       rl.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View view) { 


        activatealert(); 

       });  
    public void activatealert() { 
     MaterialDialog activateald = new MaterialDialog.Builder(getActivity()) 
       .content("In order to use these services, please click settings and set appropriate options to activate Where R U feature.") 
       .title("Activate Where R U") 
       .positiveColor(Color.BLUE) 
       .negativeColor(Color.RED) 
       .positiveText("Settings") 
       .negativeText("Cancel") 
       .onPositive(new MaterialDialog.SingleButtonCallback() { 
        @Override 
        public void onClick(@NonNull MaterialDialog dialog, @NonNull DialogAction which) { 
         Intent intent = new Intent(getActivity(),FragHandler.class); 
         intent.putExtra("Settings",2); 
         startActivity(intent); 

        } 
       }) 
       .show(); 
    } 
} 

它打開所需的選項卡式activitiy但第一個標籤不三分之一。請指導。

Answer 1

編輯基於您的代碼：

刪除OnTabSelectedListener，你不需要它。

只需添加

tabLayout.setupWithViewPager(viewPager); 

下面是完整的代碼：

public class FragHandler extends AppCompatActivity 
    TabLayout tabLayout; 
    Toolbar customtoolbar; 
    SharedPreferences sharedPreferences; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.alstabopener); 

     sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this); 

     tabLayout = (TabLayout) findViewById(R.id.tab_layout); 
     tabLayout.addTab(tabLayout.newTab().setText("1")); 
     tabLayout.addTab(tabLayout.newTab().setText("2")); 
     tabLayout.addTab(tabLayout.newTab().setText("Settings")); 
     tabLayout.setTabGravity(TabLayout.GRAVITY_FILL); 

     final ViewPager viewPager = (ViewPager) findViewById(R.id.pager); 
     final AlsViewChanger adapter = new AlsViewChanger(getSupportFragmentManager(), tabLayout.getTabCount()); 
     viewPager.setAdapter(adapter); 

     tabLayout.setupWithViewPager(viewPager); 
     int tabToSelect = getIntent().getIntExtra("Settings」, 0); 
     viewPager.setCurrentItem(tabToSelect); 
    } 

} 

請檢查

int tabToSelect = getIntent().getIntExtra("Settings」, 0); 

，如果你想這樣做，我只是假設。如果你不需要它，請改變它。

很難沒有太多的細節來回答，但這裏是基於假設我的一些建議：

1）要啓動它有多個選項卡的活動FragHandler。 TabLayout與ViewPager相關聯。所以在這種情況下，在將適配器設置爲ViewPager後，請撥打viewPager.setCurrentItem(2)。如果你只有標籤，那麼你可以試試tabLayout.getTabAt(2).select()。這應該會觸發OnTabSelectedListener，您可能已經有用於替換片段的代碼。

2）有對話的片段在同一個TabLayout裏面，你要求的第三個標籤是。在這種情況下，把下面的代碼中設置按鈕的onClick：

// If ViewPager, then make it public in YourActivity 
((YourActivity)getActivity()).viewPager.setCurrentItem(2); 

// If TabLayout without ViewPager, then also make it public 
((YourActivity)getActivity()).tabLayout.getTabAt(2).select(); 

和後期儘可能多的細節可能讓你可以得到正確的答案