Assistance - Data Not Displaying In Activity / View

[ShatterStar]

Hi All,

I have an activity with a fragment, I have a cursorloader in the fragment, all my code seems to be fine but for some reason in my onLoadFinished event the view just shows a loading circle and none of the contacts from the phone are displayed - here's my code

PS. There are alot of comments from android documentation as I am still learning so bear with me

SelectContactActivity.java

package myrappah.com.myrapp;

//import android.app.FragmentManager;
import android.Manifest;
import android.annotation.TargetApi;
import android.content.ContentResolver;
import android.content.pm.PackageManager;
import android.database.Cursor;
import android.os.Build;
import android.provider.ContactsContract;
import android.support.annotation.NonNull;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;

import java.util.ArrayList;
import java.util.List;

import static android.Manifest.permission.READ_CONTACTS;

public class SelectContactActivity extends AppCompatActivity {

    // The ListView
    private ListView lstNames;

    // Request code for READ_CONTACTS. It can be any number > 0.
    private static final int PERMISSIONS_REQUEST_READ_CONTACTS = 100;

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

        FragmentManager fm = getSupportFragmentManager();
        FragmentTransaction ft = fm.beginTransaction();

        SelectContactFragment selectContactFragment = new SelectContactFragment();
        ft.add(R.id.fragment, selectContactFragment);
        ft.commit();

        //showContacts();
    }


}

SelectContactFragment.java

package myrappah.com.myrapp;

import android.annotation.SuppressLint;
import android.database.Cursor;
import android.net.Uri;
import android.os.Build;
import android.support.v4.app.LoaderManager;
import android.support.v4.content.CursorLoader;
import android.support.v4.content.Loader;
import android.support.v4.widget.SimpleCursorAdapter;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

import android.provider.ContactsContract;
import android.support.v4.app.Fragment;
import android.support.v4.app.LoaderManager.LoaderCallbacks;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ListView;

public class SelectContactFragment extends Fragment implements
        LoaderManager.LoaderCallbacks<Cursor>,
        AdapterView.OnItemClickListener {

    @SuppressLint("InlinedApi")
    private final static String[] FROM_COLUMNS = {
            Build.VERSION.SDK_INT
                    >= Build.VERSION_CODES.HONEYCOMB ?
                    ContactsContract.Contacts.DISPLAY_NAME_PRIMARY :
                    ContactsContract.Contacts.DISPLAY_NAME
    };

    private final static int[] TO_IDS = {
            android.R.id.text1
    };

    @SuppressLint("InlinedApi")
    private static final String[] PROJECTION =
            {
                    ContactsContract.Contacts._ID,
                    ContactsContract.Contacts.LOOKUP_KEY,
                    Build.VERSION.SDK_INT
                            >= Build.VERSION_CODES.HONEYCOMB ?
                            ContactsContract.Contacts.DISPLAY_NAME_PRIMARY :
                            ContactsContract.Contacts.DISPLAY_NAME

            };

    // The column index for the _ID column
    private static final int CONTACT_ID_INDEX = 0;
    // The column index for the LOOKUP_KEY column
    private static final int CONTACT_KEY_INDEX = 1;

    // Defines the text expression
    @SuppressLint("InlinedApi")
    private static final String SELECTION =
            Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB ?
                    ContactsContract.Contacts.DISPLAY_NAME_PRIMARY + " LIKE ?" :
                    ContactsContract.Contacts.DISPLAY_NAME + " LIKE ?";
    // Defines a variable for the search string
    private String mSearchString;
    // Defines the array to hold values that replace the ?
    private String[] mSelectionArgs = { mSearchString };

    ListView mContactsList;
    long mContactId;
    String mContactKey;
    Uri mContactUri;
    private SimpleCursorAdapter mCursorAdapter;

    // Empty public constructor, required by the system
    public SelectContactFragment() {}

    // A UI Fragment must inflate its View
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        // Inflate the fragment layout
        return inflater.inflate(R.layout.contacts_list_view, container, false);
    }

    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);

        // Gets the ListView from the View list of the parent activity
        mContactsList = (ListView)getActivity().findViewById(android.R.id.list);

        // Gets a CursorAdapter
        mCursorAdapter = new SimpleCursorAdapter(
                getActivity(),
                R.layout.contacts_list_item,
                null,
                FROM_COLUMNS, TO_IDS,
                0);
        // Sets the adapter for the ListView
        mContactsList.setAdapter(mCursorAdapter);

        // Set the item click listener to be the current fragment.
        mContactsList.setOnItemClickListener(this);

        getLoaderManager().initLoader(0, null, this);
    }

    @Override
    public Loader<Cursor> onCreateLoader(int id, Bundle args) {

        /*
         * Makes search string into pattern and
         * stores it in the selection array
         */
        mSelectionArgs[0] = "%" + mSearchString + "%";
        // Starts the query
        return new CursorLoader(
                getActivity(),
                ContactsContract.Contacts.CONTENT_URI,
                PROJECTION,
                SELECTION,
                mSelectionArgs,
                null
        );
    }

    @Override
    public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
        mCursorAdapter.swapCursor(data);
        //mCursorAdapter.notifyDataSetChanged();
    }

    @Override
    public void onLoaderReset(Loader<Cursor> loader) {
        mCursorAdapter.swapCursor(null);
    }

    @Override
    public void onItemClick( AdapterView<?> parent, View item, int position, long rowID) {
        // Get the Cursor
        //Cursor cursor = parent.getAdapter().getCursor();
        Cursor cursor = (Cursor) mCursorAdapter.getItem(position);

        // Move to the selected contact
        cursor.moveToPosition(position);
        // Get the _ID value
        mContactId = cursor.getLong(CONTACT_ID_INDEX);
        // Get the selected LOOKUP KEY
        mContactKey = cursor.getString(CONTACT_KEY_INDEX);
        // Create the contact's content Uri
        mContactUri = ContactsContract.Contacts.getLookupUri(mContactId, mContactKey);
        /*
         * You can use mContactUri as the content URI for retrieving
         * the details for a contact.
         */
    }
}

activity_select_contact.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="myrappah.com.myrapp.SelectContactFragment">

    <fragment
        android:id="@+id/fragment"
        android:name="android.support.v4.app.ListFragment"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight="1"
         />
</LinearLayout>

contact_list_view.xml

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

android:layout_width="match_parent"
android:layout_height="match_parent"
    android:id="@android:id/list"

     />

contact_list_item.xml

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@android:id/text1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:clickable="true"/>

 

[Deleted User]

The first thing I would do in this situation, is to set breakpoints in the various cursorAdaptor methods, to verify that these were being called. Crucially the onLoadFinished() method is the key part where your data is connected to the ListView.

 

[ShatterStar]

The first thing I would do in this situation, is to set breakpoints in the various cursorAdaptor methods, to verify that these were being called. Crucially the onLoadFinished() method is the key part where your data is connected to the ListView.

Hi,

I have already done this and ti seems to be hanging on the onloadfinished

 

[Deleted User]

There's only one line in onLoadFinished() and that's

mCursorAdapter.swapCursor(data);

That means swapCursor() isn't returning.
What I would do is set a breakpoint at this line, and step into the method. execute line by line and try to establish what the problem is. When you can pin it down to one specific line causing the problem, then you can try to establish why it's getting stuck.

 

[ShatterStar]

There's only one line in onLoadFinished() and that's

mCursorAdapter.swapCursor(data);

That means swapCursor() isn't returning.
What I would do is set a breakpoint at this line, and step into the method. execute line by line and try to establish what the problem is. When you can pin it down to one specific line causing the problem, then you can try to establish why it's getting stuck.

okay, thanks for the suggestion, I have been banging my head against the wall with this!