如何添加一個按鈕到我的EmptyView？

Question

嗨我試圖插入Button到EmptyView。我似乎可以開始工作的唯一東西是EmptyText，其中當列表爲空時顯示文本值。此代碼僅適用於顯示textview。我如何成功地將一個按鈕添加到視圖？

import java.util.ArrayList; 

import android.annotation.TargetApi; 
import android.content.Intent; 
import android.os.Build; 
import android.os.Bundle; 
import android.support.v4.app.ListFragment; 
import android.text.format.DateFormat; 
import android.view.ActionMode; 
import android.view.ContextMenu; 
import android.view.ContextMenu.ContextMenuInfo; 
import android.view.LayoutInflater; 
import android.view.Menu; 
import android.view.MenuInflater; 
import android.view.MenuItem; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.view.ViewGroup; 
import android.widget.AbsListView.MultiChoiceModeListener; 
import android.widget.AdapterView; 
import android.widget.AdapterView.AdapterContextMenuInfo; 
import android.widget.ArrayAdapter; 
import android.widget.Button; 
import android.widget.CheckBox; 
import android.widget.ListAdapter; 
import android.widget.ListView; 
import android.widget.TextView; 

import com.robertrichardson.crimeproofassistant.R.string; 

public class crimeListFragment extends ListFragment { 

    private ArrayList<crime> mcrime; 
    private boolean mSubtitleVisible; 
    public static final String TAG = "crimeListFragment"; 

    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setHasOptionsMenu(true); 
     getActivity().setTitle(R.string.app_name); 
     mcrime = crimeLab.get(getActivity()).getcrime(); 
     crimeAdapter adapter = new crimeAdapter(mcrime); 
     setListAdapter(adapter); 
     setRetainInstance(true); 
     mSubtitleVisible = false; 
    } 

    @Override 
    public void onViewCreated(View view, Bundle savedInstanceState) { 
     super.onViewCreated(view, savedInstanceState); 

     setEmptyText(getResources().getString(string.new_crime_attack_empty_desc)); 

     registerForContextMenu(getListView()); 
     setHasOptionsMenu(true); 
} 


    @TargetApi(11) 
    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup parent, 
      Bundle savedInstanceState) { 
      View v = super.onCreateView(inflater, parent, savedInstanceState); 

     if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) { 
      if (mSubtitleVisible) { 
       getActivity().getActionBar().setSubtitle(R.string.subtitle); 
      } 
     } 

     ListView listView = (ListView)v.findViewById(android.R.id.list); 

     if (Build.VERSION.SDK_INT < Build.VERSION_CODES.HONEYCOMB) { 
      // Use floating point context menus on Froyer and Gingerbread 
      registerForContextMenu(listView); 
     } else { 
      // Use contextual action bar on Honeycomb and higher 
      listView.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE_MODAL); 
      listView.setMultiChoiceModeListener(new MultiChoiceModeListener() { 

      // ActionMode.Callback methods 
      public boolean onCreateActionMode(ActionMode mode, Menu menu) { 
       MenuInflater inflater = mode.getMenuInflater(); 
       inflater.inflate(R.menu.crime_list_item_context, menu); 
       return true; 
      } 

      public void onItemCheckedStateChanged(ActionMode mode, int position, 
        long id, boolean checked) { 
      // required but not used in this implementation 
      } 

      public boolean onActionItemClicked(ActionMode mode, MenuItem item) { 
       switch (item.getItemId()) { 
       case R.id.menu_item_delete_crime: 
        crimeAdapter adapter = (crimeAdapter)getListAdapter(); 
        crimeLab crimeLab = crimeLab.get(getActivity()); 
        for (int i = adapter.getCount() - 1; i >= 0; i--) { 
         if (getListView().isItemChecked(i)) { 
          crimeLab.deletecrime(adapter.getItem(i)); 
         } 
        } 
        mode.finish(); 
        adapter.notifyDataSetChanged(); 
        return true; 
       default: 
        return false; 
       } 

      } 

      public boolean onPrepareActionMode(ActionMode mode, Menu menu) { 
       return false; 
      // Required, but not used in this implementation 
      } 

      public void onDestroyActionMode(ActionMode mode) { 

      } 
     }); 
    } 
     return v; 
    } 

    public void onListItemClick(ListView l, View v, int position, long id) { 
     crime c = ((crimeAdapter)getListAdapter()).getItem(position); 
     // Start crime Activity 
     Intent i = new Intent(getActivity(), crimePagerActivity.class); 
     i.putExtra(crimeFragment.EXTRA_crime_ID, c.getId()); 
     startActivity(i); 
    } 

    @Override 
    public void onActivityResult(int requestCode, int resultCode, Intent data) { 
     ((crimeAdapter)getListAdapter()).notifyDataSetChanged(); 
    } 

    @Override 
    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) { 
     super.onCreateOptionsMenu(menu, inflater); 
     inflater.inflate(R.menu.fragment_crime_list, menu); 
     MenuItem showSubtitle = menu.findItem(R.id.menu_item_show_subtitle); 
     if (mSubtitleVisible && showSubtitle != null) { 
      showSubtitle.setTitle(R.string.hide_subtitle); 
     } 
    } 

    @TargetApi(11) 
    @Override 
    public boolean onOptionsItemSelected(MenuItem item) { 
     switch (item.getItemId()) { 
     case R.id.menu_item_new_crime: 
      crime crime = new crime(); 
      crimeLab.get(getActivity()).addcrime(crime); 
      Intent i = new Intent(getActivity(), crimePagerActivity.class); 
      i.putExtra(crimeFragment.EXTRA_crime_ID, crime.getId()); 
      startActivityForResult(i,0); 
      return true; 
     case R.id.menu_item_show_subtitle: 
      if (getActivity().getActionBar().getSubtitle() != null) { 
       getActivity().getActionBar().setSubtitle(R.string.subtitle); 
       mSubtitleVisible = true; 
       item.setTitle(R.string.hide_subtitle); 
      } else { 
       getActivity().getActionBar().setSubtitle(null); 
       mSubtitleVisible = false; 
       item.setTitle(R.string.show_subtitle); 
      } 
      return true; 
     default: 
      return super.onOptionsItemSelected(item); 
     } 
    } 

    @Override 
    public void onCreateContextMenu(ContextMenu menu,View v, ContextMenuInfo menuInfo) { 
     getActivity().getMenuInflater().inflate(R.menu.crime_list_item_context, menu); 
    } 

    @Override 
    public boolean onContextItemSelected(MenuItem item) { 
     AdapterContextMenuInfo info = (AdapterContextMenuInfo)item.getMenuInfo(); 
     int position = info.position; 
     crimeAdapter adapter = (crimeAdapter)getListAdapter(); 
     crime crime = adapter.getItem(position); 

     switch (item.getItemId()) { 
      case R.id.menu_item_delete_crime: 
       crimeLab.get(getActivity()).deletecrime(crime); 
       adapter.notifyDataSetChanged(); 
       return true; 
     } 
     return super.onContextItemSelected(item); 
    } 

    private class crimeAdapter extends ArrayAdapter<crime> { 
     public crimeAdapter(ArrayList<crime> crime) { 
      super(getActivity(), 0, crime); 
     } 

    @Override 
    public View getView(int position, View convertView, ViewGroup parent) { 

     // If we weren't given a view, inflate one 
     if (convertView == null) { 
      convertView = getActivity().getLayoutInflater() 
        .inflate(R.layout.list_item_crime, null); 
     } 

     // Enter the view of this crime Attack 
     crime c = getItem(position); 

     TextView titleTextView = 
       (TextView)convertView.findViewById(R.id.crime_list_item_titleTextView); 
     titleTextView.setText(c.getTitle()); 
     TextView dateTextView = 
       (TextView)convertView.findViewById(R.id.crime_list_item_dateTextView); 
     dateTextView.setText(DateFormat.format("EEEE, MMM dd, yyyy hh : mm a", c.getDate()).toString()); 

     CheckBox resolvedCheckBox = 
       (CheckBox)convertView.findViewById(R.id.crime_list_item_resolvedCheckBox); 
     resolvedCheckBox.setChecked(c.isResolved()); 

     return convertView; 
    } 
} 

    @Override 
    public void onResume() { 
     super.onResume(); 
     ((crimeAdapter)getListAdapter()).notifyDataSetChanged(); 
    } 
}  


Here's my XML: 

<?xml version="1.0" encoding="utf-8"?> 
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:background="#f2f3f4" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    > 
<ListView 
    android:id="@android:id/list" 
    android:background="#f2f3f4" 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" 
    > 
</ListView> 
<linearLayout 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:background="#f2f3f4" 
    android:orientation="vertical" 
    > 
<TextView 
    android:id="@android:id/empty" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:paddingLeft="4dp" 
    android:paddingRight="4dp" 
    android:text="@string/new__empty_desc" 
    /> 
<Button 
    android:id="@+id/addButton" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:paddingLeft="4dp" 
    android:paddingRight="4dp" 
    android:text="@string/new_attack_empty" 
    /> 
</linearLayout> 
</FrameLayout> 

Answer 1

的ListFragment的默認實現包括設置一個TextView作爲列表中的空視圖。

http://developer.android.com/reference/android/app/ListFragment.html#setEmptyText(java.lang.CharSequence)

您可以通過擴展Fragment改變這一點，在裏面創建自己的ListView。如果您喜歡它提供的一些東西，則可以使用ListFragment中的代碼。

作爲替代方案，您可以嘗試執行getListView().setEmptyView()並設置您需要的視圖。再看看他們是如何做到這一點在ListFragment的代碼，並用不同的視圖複製它（而不是TextView的使用任何你需要一個按鈕或ImageButton的）

http://grepcode.com/file/repository.grepcode.com/java/ext/com.google.android/android/4.0.1_r1/android/app/ListFragment.java

Answer 2

public class MainActivity extends Activity { 

    private CustomBaseAdapter customBaseAdapter; 
    private ListView lv; 
    private Button btn; 



    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 

     FrameLayout fl = new FrameLayout(this); 
     btn = new Button(this); 
     btn.setText("Hit me"); 

     lv = new ListView(this); 

     customBaseAdapter = new CustomBaseAdapter(this); 
     lv.setAdapter(customBaseAdapter); 

     fl.addView(lv); 
     fl.addView(btn); 
     setContentView(fl); 

     handleVisbility(); 
    } 

    public void handleVisbility() { 
     if (customBaseAdapter.getCount() == 0) { 
      lv.setVisibility(View.GONE); 
      btn.setVisibility(View.VISIBLE); 
     } else { 
      lv.setVisibility(View.VISIBLE); 
      btn.setVisibility(View.GONE); 
     } 
    } 

    public class CustomBaseAdapter extends BaseAdapter { 

     private Context context; 
     View superView; 

     public CustomBaseAdapter(Context context) { 
      this.context = context; 
     } 

     @Override 
     public int getCount() { 
      return 1; 
     } 

     @Override 
     public Object getItem(int arg0) { 
      return new Object(); 
     } 

     @Override 
     public long getItemId(int arg0) { 
      return 0; 
     } 

     @Override 
     public View getView(int arg0, View arg1, ViewGroup arg2) { 

      FrameLayout fl = new FrameLayout(context); 

      Button btn = new Button(context); 
      btn.setText("Hello, im a Button"); 

      btn.setOnClickListener(new OnClickListener() { 

       @Override 
       public void onClick(View v) { 
        Toast.makeText(context, "Yay hit me again", Toast.LENGTH_LONG).show(); 
       } 
      }); 

      fl.addView(btn); 

      return fl; 
     } 

    } 

} 

好吧，這是有點什麼你想在這裏做。它顯示一個ListView，如果List中有一個Item，並且如果List是空的，將顯示Button。唯一需要做的，是每次更改ListViews內容時調用handleVisbility（）。尤其是在向列表添加內容之後。