Multiple Listviews in single Activity in Android?

问题:

I want to have multiple listviews in single activity. But only one listview should be displayed at one time. The listviews will be loaded dynamically. So, how can I fill all the four listviews at the same time and display only one?

回答1:

Instead of using all that code to flip between listviews why not put all your listviews inside a ViewFlipper? It the easiest way an required almost 1 line of code! :)

-Moto

回答2:

You can do one thing for your problem. The reason you will only see the one list view, may be because one list will have the fill parent paramter value for its height. What you have to do is, use absolute layout or just fix the height for each layout. Also use the scrollview to place the controls. Moreover, if you post your XML layout here, then it will be easier to answer your query as to where you need to make changes.

回答3:

You should use a FrameLayout; it allows z ordering of its child views which means that you can have your ListView stacked one above the other. You can then toggle visibility of each of these ListViews from your code using View#setVisibility() method. You would create appropriate adapters for each of these ListViews and whenever a ListView is to be drawn the framwork will call getView() method of the required adapter.

回答4:

I have used mostly the same way of showing multiple listviews as you suggested i.e. using setvisibility.

But now what I want is to have the Bitmap image of all the four listviews. Suppose, my activity starts and the data are loaded into all four listviews by binding them to their respective adapters. Now, when I am trying to fetch the Bitmap using getDrawingCache() it always returns null to me.

So, can you let me know how can I fetch the Bitmap of all the four listviews?

public class HomeScreenActivity extends Activity { private ImageView imgBabble = null; private ListView listBabble = null; private ListView listVille = null; private ListView listPrivateMsgs = null; private ListView listBookmarks = null; private List<String> tempBabble = null; private List<String> tempVille = null; private List<String> tempPrivateMsgs = null; private List<String> tempBookmarks = null;  //RelativeLayouts private RelativeLayout babbleLayout = null; private RelativeLayout villeLayout = null; private RelativeLayout privateMsgsLayout = null; private RelativeLayout bookmarksLayout = null;  //Bitmap private Bitmap babbleShrunkView = null; private Bitmap villeShrunkView = null; private Bitmap privateMsgsShrunkView = null; private Bitmap bookmarksShrunkView = null;  /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState)  {     super.onCreate(savedInstanceState);     requestWindowFeature(Window.FEATURE_CUSTOM_TITLE);     setContentView(R.layout.homescreen);     getWindow().setFeatureInt(Window.FEATURE_CUSTOM_TITLE, R.layout.customtitle);      imgBabble = (ImageView) findViewById(R.id.imgBtnBabble);     Bitmap bitmapOrg = BitmapFactory.decodeResource(getResources(),R.drawable.babble_top_logo);     BitmapDrawable bmpDrawable = new BitmapDrawable(bitmapOrg);     imgBabble.setBackgroundDrawable(bmpDrawable);      //Initialize the layouts for Babble, Ville, Private Messages and Bookmarks     babbleLayout = (RelativeLayout) findViewById(R.id.babbleLayout);     babbleLayout.setDrawingCacheEnabled(true);      villeLayout = (RelativeLayout) findViewById(R.id.villeLayout);     villeLayout.setDrawingCacheEnabled(true);      privateMsgsLayout = (RelativeLayout) findViewById(R.id.privatemsgsLayout);     privateMsgsLayout.setDrawingCacheEnabled(true);      bookmarksLayout = (RelativeLayout) findViewById(R.id.bookmarksLayout);     bookmarksLayout.setDrawingCacheEnabled(true);      //Babble     tempBabble = new ArrayList<String>();     tempBabble.add("First Babble");     tempBabble.add("Second Babble");     tempBabble.add("Third Babble");      listBabble = (ListView) findViewById(R.id.listBabble);     listBabble.setAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_list_item_multiple_choice, tempBabble));     //babbleShrunkView = babbleLayout.getDrawingCache();      //babbleLayout = (RelativeLayout) findViewById(R.id.listLayout);      if(babbleShrunkView == null)     {         System.out.println("Babble View is null");     }      //Ville     tempVille = new ArrayList<String>();     tempVille.add("First Ville");     tempVille.add("Second Ville");     tempVille.add("Third Ville");      listVille = (ListView) findViewById(R.id.listVille);     //listVille.setDrawingCacheEnabled(true);     listVille.setAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_list_item_multiple_choice, tempVille));     //villeShrunkView = villeLayout.getDrawingCache();      if(villeShrunkView == null)     {         System.out.println("Ville View is null");     }      //listVille.setVisibility(View.GONE);      //Private Messages     tempPrivateMsgs = new ArrayList<String>();     tempPrivateMsgs.add("First PM");     tempPrivateMsgs.add("Second PM");     tempPrivateMsgs.add("Third PM");      listPrivateMsgs = (ListView) findViewById(R.id.listPrivateMessages);     //listPrivateMsgs.setDrawingCacheEnabled(true);     listPrivateMsgs.setAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_list_item_multiple_choice, tempPrivateMsgs));     //privateMsgsShrunkView = privateMsgsLayout.getDrawingCache();      if(privateMsgsShrunkView == null)     {         System.out.println("Private Messages View is null");     }      //listPrivateMsgs.setVisibility(View.GONE);      //Bookmarks     tempBookmarks = new ArrayList<String>();     tempBookmarks.add("First Bookmarks");     tempBookmarks.add("Second Bookmarks");     tempBookmarks.add("Third Bookmarks");      listBookmarks = (ListView) findViewById(R.id.listBookmarks);     //listBookmarks.setDrawingCacheEnabled(true);     listBookmarks.setAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_list_item_multiple_choice, tempBookmarks));     //bookmarksShrunkView = bookmarksLayout.getDrawingCache();      if(bookmarksShrunkView == null)     {         System.out.println("Bookmarks Messages View is null");     }      //listBookmarks.setVisibility(View.GONE);      imgBabble.setOnClickListener(new View.OnClickListener()      {         @Override         public void onClick(View v)          {             System.out.println("Babble Clicked");              babbleShrunkView = babbleLayout.getDrawingCache();             villeShrunkView = villeLayout.getDrawingCache();             privateMsgsShrunkView = privateMsgsLayout.getDrawingCache();             bookmarksShrunkView = bookmarksLayout.getDrawingCache();              BabbleVilleShrinkView.addBitmap(0, resizeBitmap(200, 200, babbleShrunkView));             BabbleVilleShrinkView.addBitmap(1, resizeBitmap(200, 200, villeShrunkView));             BabbleVilleShrinkView.addBitmap(2, resizeBitmap(200, 200, privateMsgsShrunkView));             BabbleVilleShrinkView.addBitmap(3, resizeBitmap(200, 200, bookmarksShrunkView));              Gallery gallery = new Gallery(getApplicationContext());             gallery.setAdapter(new ImageAdapter(getApplicationContext()));         }     }); } // End of class 

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