How to clear a listFragments ArrayAdapter (subcalss) and display emptyView

Question

I am working on a basic file manager and would like to know how i can clear an ArrayAdapter subclass (namely my coustom FileListAdapter) and still get the emptyView to display. here is my current way of making the ArrayAdapter if there are no files:

if(selectedFile.listFiles() == null){
    mAdapter = new FileListAdapter(getActivity(), R.layout.file_item_layout, new File[0]);
    mListView.setAdapter(mAdapter);

This is the emptyView

mListView.setEmptyView(getActivity().findViewById(android.R.id.empty)); setEmptyText("Empty folder");

Here is my coustom adapter:

public class FileListAdapter extends ArrayAdapter<File> {

private File[] folderContents;
private LayoutInflater inflater;

public FileListAdapter(Context context, int resource, File[] fileList) {
    super(context, resource, fileList);
    folderContents = fileList;
    inflater = LayoutInflater.from(context);
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    View itemView = convertView;
    if(itemView == null){
        itemView = inflater.inflate(R.layout.file_item_layout, parent, false);
    }

    //find the file
    File currentFile = folderContents[position];

    //fill the view
    ImageView iconImage = (ImageView) itemView.findViewById(R.id.file_icon);
    iconImage.setImageResource(FileType.getTypeImage(FileType.parseType(currentFile)));

    String fileName = currentFile.getName();
    TextView fileNameText = (TextView) itemView.findViewById(R.id.file_name);
    fileNameText.setText(fileName);

    String fileType = FileType.parse(currentFile);
    TextView fileTypeText = (TextView) itemView.findViewById(R.id.file_type);
    fileTypeText.setText(fileType);

    String fileSizeText;

    if(!currentFile.isDirectory()){
        long fileSize = currentFile.length();
        if(fileSize < 1024){
            fileSizeText = fileSize + " Bytes";
        } else if(fileSize >= 1024 && fileSize < 1048576){
            //fileSizeText = (fileSize/1024) + "KB";
            fileSizeText = String.format("%.2f KB", (float)(fileSize/1024.0));
        } else if(fileSize >= 1048576 && fileSize < 1073741824){
            //fileSizeText = (fileSize/1048576) + "MB";
            fileSizeText = String.format("%.2f MB", (float)(fileSize/1048576.0));
        } else {
            //fileSizeText = (fileSize/1073741824) + "GB";
            fileSizeText = String.format("%.2f GB", (float)(fileSize/1073741824.0));
        }
    }
    else{
        File[] dirContents = currentFile.listFiles();
        if(dirContents == null){
            fileSizeText = "N/A";
        } else {
            if(dirContents.length == 1){
                fileSizeText ="1 item";
            }
            else{
                fileSizeText = dirContents.length + " items";
            }
        }
    }
    TextView fileSizeTextView = (TextView)itemView.findViewById(R.id.file_size);
    fileSizeTextView.setText(fileSizeText);

    Date lastModifiedDate = new Date(currentFile.lastModified());
    String lastModifiedText = "<" +lastModifiedDate.getMonth() + "/" + lastModifiedDate.getDate() + "/" + (lastModifiedDate.getYear() + 1900) + ">";
    TextView lastModifiedDateText = (TextView) itemView.findViewById(R.id.last_modified);
    lastModifiedDateText.setText(lastModifiedText);

    return itemView;
}

}

Here is the layout for lists (replace listview with gridview to get the other one)

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
    android:layout_height="match_parent" tools:context="com.pcgeekbrain.madfiles.FileViewFragment">

<ListView android:id="@android:id/list" android:layout_width="match_parent"
    android:layout_height="match_parent" />

<TextView android:id="@android:id/empty" android:layout_width="match_parent"
    android:layout_height="match_parent" android:gravity="center" />

</FrameLayout>

what I get is a blank screen. How can I make the emptyView appear when there is no files in the folder?

Thanks in advance.

you can check : mAdapter .add(null); or mAdapter = new FileListAdapter(getActivity(), R.layout.file_item_layout, null); — QuestionAndroid, May 21 '15 at 02:25
you can create Model(is File[] of you) ,after mAdapter .add(new Model()); — QuestionAndroid, May 21 '15 at 02:33

score 0 · Answer 1 · edited May 23 '17 at 12:14

0

UPDATE 3

Put this on your adapter

@Override
public int getCount() {
    return folderContents.length;
}

UPDATE 2

// method setEmptyView on ListView

@android.view.RemotableViewMethod
public void setEmptyView(View emptyView) {
    mEmptyView = emptyView;

    // If not explicitly specified this view is important for accessibility.
    if (emptyView != null
            && emptyView.getImportantForAccessibility() == IMPORTANT_FOR_ACCESSIBILITY_AUTO) {
        emptyView.setImportantForAccessibility(IMPORTANT_FOR_ACCESSIBILITY_YES);
    }

    final T adapter = getAdapter();
    final boolean empty = ((adapter == null) || adapter.isEmpty()); // <- see that
    updateEmptyStatus(empty);
}

// meanwhile, on ArrayAdapter...
// adapter.isEmpty returns getCount!

public boolean isEmpty() {
    return getCount() == 0;
}

UPDATE

Try implement this on your FileListAdapter:

public void removeAll() {
    this.folderContents = new File[]{};
}

And turn empty like this:

adapterInstance.removeAll();
adapterInstance.notifyDataChanged();

You need remove the itens ans call notifyDataChanged(). Check this answer for more details.

edited May 23 '17 at 12:14

Community

1
1

answered May 21 '15 at 02:31

Luis Felipe Kaufmann da silva

148
5

you ever considered that your "emptyView" may not be appearing? sometimes I put my "listView" with height "match_parent" and this hide the "emptyView". Can you check this? – Luis Felipe Kaufmann da silva May 21 '15 at 04:03
the fragments views were generated with match parent. – Menachem Hornbacher May 21 '15 at 04:14
try make the emptyView appear without the listView (you must change id to this test) – Luis Felipe Kaufmann da silva May 21 '15 at 04:15
You do not put a text! Try add `android:text="lorem ipsum"` on textView please. – Luis Felipe Kaufmann da silva May 21 '15 at 04:30
so, now is working? to show on center use `layout_gravity='center'` or change `framelayout` to `relative` ;) – Luis Felipe Kaufmann da silva May 21 '15 at 04:39
I only want to see it when it is empty. Not all the time – Menachem Hornbacher May 21 '15 at 04:41
the ListView has itens and emptView is Visible? – Luis Felipe Kaufmann da silva May 21 '15 at 04:52

dora · Answer 2 · 2015-05-21T06:06:54.943

0

search for your empty view in fragment like below

 @Override
public void onViewCreated(View view, Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);
    ListView listView = (ListView)view.findViewById(android.R.id.list);
    listView.setEmptyView(view.findViewById(android.R.id.empty));

    ArrayAdapter<Session> adapter1 = new ArrayAdapter<Session>(this, android.R.layout.simple_list_item_1, 
            android.R.id.text1, MainController.getInstanz().getItems());
    listView.setAdapter(adapter1);
}

edited May 21 '15 at 06:06

answered May 21 '15 at 03:26

dora

2,047
3
18
20

No change. still gives me blank screen – Menachem Hornbacher May 21 '15 at 03:33
Are you extending ListFragment? Have you used any custom layout for the fragment? – dora May 21 '15 at 03:34
No i am not and no, i just did a new fragment(list) in android studio – Menachem Hornbacher May 21 '15 at 03:42
post your layout containing listview and the empty view. – dora May 21 '15 at 04:07
Please do check above – Menachem Hornbacher May 21 '15 at 04:23
i think you are searching for the empty view in activity.instead you should be searching for the empty view in onViewCreated(View view, Bundle savedInstanceState) callback. i have shown it in my edited answer.Hope it helps. – dora May 21 '15 at 05:15
no, it was not i was doing. BTW. I have worked around the problem and am now facing a similar but different issue. Thanks for trying to help me though. – Menachem Hornbacher May 22 '15 at 01:10

score 0 · Answer 3 · answered May 21 '15 at 10:52

I believe that there are many places where its activity / fragment may be having trouble, so I'm pasting an example of how it should be implemented an adapter to "listView" and "emptyView"

HomeActivity.java

package br.com.luiskaufmannsilva.examplefilemanager;

import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;


public class HomeActivity extends ActionBarActivity {

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


        getSupportFragmentManager()
                .beginTransaction()
                .replace(R.id.content, new FileListFragment())
                .commit();
    }




}

FileListFragment.java

package br.com.luiskaufmannsilva.examplefilemanager;


import android.content.Context;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;

import java.io.File;


/**
 * A simple {@link Fragment} subclass.
 */
public class FileListFragment extends Fragment {


    private ListView listView = null;
    private FileListAdapter adapter = null;

    public FileListFragment() {}


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View view = inflater.inflate(R.layout.fragment_file_list, container, false);

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

        listView.setEmptyView(view.findViewById(android.R.id.empty));

        final File file = Environment.getExternalStorageDirectory();
        adapter = new FileListAdapter(getActivity().getApplicationContext(), file.listFiles());

        listView.setAdapter(adapter);

        new Handler()
                .postDelayed(new Runnable() {
                    @Override
                    public void run() {
                        adapter.clear();
                        adapter.notifyDataSetChanged();

                        new Handler()
                                .postDelayed(new Runnable() {
                                    @Override
                                    public void run() {
                                        adapter.setFiles(file.listFiles());
                                        adapter.notifyDataSetChanged();
                                    }
                                }, 5 * 1000);


                    }
                }, 5 * 1000);

        return view;
    }


    class FileListAdapter extends ArrayAdapter<File>{

        private LayoutInflater inflater;
        private File[] files;

        public FileListAdapter(Context context, File[] objects) {
            super(context, R.layout.file_item, objects);
            this.files = objects;
            this.inflater = LayoutInflater.from(context);
        }

        public void setFiles(File[] files) {
            this.files = files;
        }

        @Override
        public int getCount() {
            return files.length;
        }

        @Override
        public void clear() {
            files = new File[]{};
        }

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

            convertView = inflater.inflate(R.layout.file_item, parent, false);

            //find the file
            File currentFile = files[position];

            //fill the view
            ImageView iconImage = (ImageView) convertView.findViewById(R.id.file_icon);
            iconImage.setImageResource(R.mipmap.ic_launcher); // do not

            TextView fileNameView = (TextView) convertView.findViewById(R.id.file_name);
            fileNameView.setText(currentFile.getName());

            return convertView;
        }
    }

}

activity_home.xml

<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin"
    tools:context=".HomeActivity">

    <LinearLayout
        android:orientation="vertical"
        android:id="@+id/content"
        android:layout_width="match_parent"
        android:layout_height="match_parent"></LinearLayout>

</RelativeLayout>

fragment_file_list.xml

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="br.com.luiskaufmannsilva.examplefilemanager.FileListFragment">

    <ListView
        android:id="@android:id/list"
        android:layout_width="match_parent"
        android:layout_height="match_parent"></ListView>

    <TextView
        android:id="@android:id/empty"
        android:text="No itens"
        android:layout_gravity="center"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

</FrameLayout>

file_item.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"

    android:orientation="horizontal"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ImageView
        android:id="@+id/file_icon"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <TextView
        android:textColor="#ff000000"
        android:id="@+id/file_name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

</LinearLayout>

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="br.com.luiskaufmannsilva.examplefilemanager" >

    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".HomeActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

The above example produces this:

initial: initial

past five seconds after 5 seconds

past five seconds again after 5 seconds again

is not importante, i use it only to display after 5 seconds, this [link](http://developer.android.com/reference/android/os/Handler.html) explain what is it. — Luis Felipe Kaufmann da silva, May 21 '15 at 14:22
No it does not do that. now all the text is suddenly white, it seams like there is another fragment on top of it. and the text still shows all the time. Thank you for breaking my app. — Menachem Hornbacher, May 21 '15 at 19:01
also if i go into a folder with the usable fragment the top one stays there. why is the text white? — Menachem Hornbacher, May 21 '15 at 19:07

How to clear a listFragments ArrayAdapter (subcalss) and display emptyView

3 Answers3