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I'm using a custom list view and after running the application, everything works fine, but while scrolling the list, the view becomes messy. I've pasted screen shots, followed by the code below.

How can I fix this?

Initial screen:

enter image description here

After and while scrolling: enter image description here

MyList.java:

import java.util.ArrayList;

import android.content.Context;
import android.graphics.Typeface;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;

public class MyList extends Fragment {

    ListView list;
    MediaPlayer mp;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedinstanceState)
    {
        mp=MediaPlayer.create(getActivity(), R.raw.wave1);

        return inflater.inflate(R.layout.mylistview, container, false);

    }

    @Override
    public void onStart() {

        super.onStart();
        list=(ListView)getView().findViewById(R.id.listView1);
        list.setAdapter(new MyListAdapter(getActivity()));


        list.setOnItemClickListener(new OnItemClickListener(){

            @Override
            public void onItemClick(AdapterView<?> arg0, View arg1, int position,
                    long arg3) 
            {
                switch(position)
                    {
                    case 0:
                        mp.release();
                        mp=MediaPlayer.create(getActivity(), R.raw.wave1);
                        mp.start(); 

                    break;

                    case 1:
                        mp.release();
                        mp=MediaPlayer.create(getActivity(), R.raw.wave2);
                        mp.start(); 
                        break;

                    case 2:
                        mp.release();
                        mp=MediaPlayer.create(getActivity(), R.raw.wave3);
                        mp.start();     
                        break;

                    case 3:
                        mp.release();
                        mp=MediaPlayer.create(getActivity(), R.raw.wave4);
                        mp.start(); 
                        break;

                    case 4:
                        mp.release();
                        mp=MediaPlayer.create(getActivity(), R.raw.wave5);
                        mp.start(); 
                        break;
                    }

             }
            });
    }
}

    class MyListAdapter extends BaseAdapter
    {
        ArrayList<SingleRow> list;
        Context context;
        MyListAdapter(Context c)
        {
            context=c;
            list=new ArrayList<SingleRow>();

        //  Resources res=c.getResources();
        //  String[] text=res.getStringArray(R.array.text);

            int[] images={R.drawable.ic_launcher,
                    R.drawable.ic_launcher,
                    R.drawable.ic_launcher,
                    R.drawable.ic_launcher,
                    R.drawable.ic_launcher,
                    R.drawable.ic_launcher,
                    R.drawable.ic_launcher,
                    R.drawable.ic_launcher,
                    R.drawable.ic_launcher,
                    R.drawable.ic_launcher,
                    R.drawable.ic_launcher,
                    R.drawable.ic_launcher,
                    R.drawable.ic_launcher,
                    R.drawable.ic_launcher,
                    R.drawable.ic_launcher,
                    R.drawable.ic_launcher,
                    R.drawable.ic_launcher,
                    R.drawable.ic_launcher,
                    R.drawable.ic_launcher,
                    R.drawable.ic_launcher,
                        };
            for(int i=0;i<19;i++)
            {
                list.add(new SingleRow(images[i]));
            }
        }

        @Override
        public int getCount() {
            // TODO Auto-generated method stub
            return list.size();
        }

        @Override
        public Object getItem(int position) {
            // TODO Auto-generated method stub
            return list.get(position);
        }

        @Override
        public long getItemId(int position) {

            return position;
        }

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


            LayoutInflater inflater=(LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            View row1=inflater.inflate(R.layout.mylist_rows, parent, false);
            TextView text=(TextView)row1.findViewById(R.id.textView1);
            ImageView image=(ImageView)row1.findViewById(R.id.imageView1);

            SingleRow temp=list.get(position);

            text.setText(temp.description);
            image.setImageResource(temp.image);

            Typeface font = Typeface.createFromAsset(text.getContext().getAssets(), "fonts/OpenSans.ttf");

            text.setTypeface(font);

            return row1;
        }


    class SingleRow
    {
        String description;
        int image;
        SingleRow( int image)
        {
            //this.description=description;
            this.image=image;
        }
    }

    }

MainActivity.java :

import java.util.ArrayList;

import android.content.res.Configuration;
import android.content.res.TypedArray;
import android.os.Bundle;
import android.support.v4.app.ActionBarDrawerToggle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.widget.DrawerLayout;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;

public class MainActivity extends FragmentActivity {
    private DrawerLayout mDrawerLayout;
    private ListView mDrawerList;
    private ActionBarDrawerToggle mDrawerToggle;

    // nav drawer title
    private CharSequence mDrawerTitle;

    // used to store app title
    private CharSequence mTitle;

    // slide menu items
    private String[] navMenuTitles;
    private TypedArray navMenuIcons;

    private ArrayList<NavDrawerItem> navDrawerItems;
    private NavDrawerListAdapter adapter;

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

        mTitle = mDrawerTitle = getTitle();

        // load slide menu items
        navMenuTitles = getResources().getStringArray(R.array.nav_drawer_items);

        // nav drawer icons from resources
        navMenuIcons = getResources()
                .obtainTypedArray(R.array.nav_drawer_icons);

        mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
        mDrawerList = (ListView) findViewById(R.id.list_slidermenu);

        navDrawerItems = new ArrayList<NavDrawerItem>();

        // adding nav drawer items to array
        // Home
        navDrawerItems.add(new NavDrawerItem(navMenuTitles[0], navMenuIcons.getResourceId(0, -1)));
        // Find People
        navDrawerItems.add(new NavDrawerItem(navMenuTitles[1], navMenuIcons.getResourceId(1, -1)));
        // Photos
        navDrawerItems.add(new NavDrawerItem(navMenuTitles[2], navMenuIcons.getResourceId(2, -1)));
        // Communities, Will add a counter here
        navDrawerItems.add(new NavDrawerItem(navMenuTitles[3], navMenuIcons.getResourceId(3, -1), true, "22"));
        // Pages
        navDrawerItems.add(new NavDrawerItem(navMenuTitles[4], navMenuIcons.getResourceId(4, -1)));
        // What's hot, We  will add a counter here
        navDrawerItems.add(new NavDrawerItem(navMenuTitles[5], navMenuIcons.getResourceId(5, -1), true, "50+"));


        // Recycle the typed array
        navMenuIcons.recycle();

        mDrawerList.setOnItemClickListener(new SlideMenuClickListener());

        // setting the nav drawer list adapter
        adapter = new NavDrawerListAdapter(getApplicationContext(),
                navDrawerItems);
        mDrawerList.setAdapter(adapter);

        // enabling action bar app icon and behaving it as toggle button
        getActionBar().setDisplayHomeAsUpEnabled(true);
        getActionBar().setHomeButtonEnabled(true);

        mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout,
                R.drawable.ic_navigation_drawer, //nav menu toggle icon
                R.string.app_name, // nav drawer open - description for accessibility
                R.string.app_name // nav drawer close - description for accessibility
        ) {
            public void onDrawerClosed(View view) {
                getActionBar().setTitle(mTitle);
                // calling onPrepareOptionsMenu() to show action bar icons
                invalidateOptionsMenu();
            }

            public void onDrawerOpened(View drawerView) {
                getActionBar().setTitle(mDrawerTitle);
                // calling onPrepareOptionsMenu() to hide action bar icons
                invalidateOptionsMenu();
            }
        };
        mDrawerLayout.setDrawerListener(mDrawerToggle);

        if (savedInstanceState == null) {
            // on first time display view for first nav item
            displayView(0);
        }
    }

    /**
     * Slide menu item click listener
     * */
    private class SlideMenuClickListener implements
            ListView.OnItemClickListener {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position,
                long id) {
            // display view for selected nav drawer item
            displayView(position);
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // toggle nav drawer on selecting action bar app icon/title
        if (mDrawerToggle.onOptionsItemSelected(item)) {
            return true;
        }
        // Handle action bar actions click
        switch (item.getItemId()) {
        case R.id.action_settings:
            return true;
        default:
            return super.onOptionsItemSelected(item);
        }
    }

    /***
     * Called when invalidateOptionsMenu() is triggered
     */
    @Override
    public boolean onPrepareOptionsMenu(Menu menu) {
        // if nav drawer is opened, hide the action items
        boolean drawerOpen = mDrawerLayout.isDrawerOpen(mDrawerList);
        menu.findItem(R.id.action_settings).setVisible(!drawerOpen);
        return super.onPrepareOptionsMenu(menu);
    }

    /**
     * Diplaying fragment view for selected nav drawer list item
     * */
    private void displayView(int position) {

        Fragment fragment = null;
        // update the main content by replacing fragments
        switch (position) {
        case 0:
            fragment = new MyList();
            break;  

        } 

        if (fragment != null) {
        android.support.v4.app.FragmentManager fragmentManager = getSupportFragmentManager();
        fragmentManager.beginTransaction()
        .replace(R.id.frame_container, fragment).commit();

        mDrawerList.setItemChecked(position, true);
        mDrawerList.setSelection(position);
        setTitle(navMenuTitles[position]);
        mDrawerLayout.closeDrawer(mDrawerList);
        } 

    }

    @Override
    public void setTitle(CharSequence title) {
        mTitle = title;
        getActionBar().setTitle(mTitle);
    }

    /**
     * When using the ActionBarDrawerToggle, you must call it during
     * onPostCreate() and onConfigurationChanged()...
     */

    @Override
    protected void onPostCreate(Bundle savedInstanceState) {
        super.onPostCreate(savedInstanceState);
        // Sync the toggle state after onRestoreInstanceState has occurred.
        mDrawerToggle.syncState();
    }

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        // Pass any configuration change to the drawer toggls
        mDrawerToggle.onConfigurationChanged(newConfig);
    }

}
Cœur
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rajagrawal
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4 Answers4

0

Update your getView() method, it will work more faster.

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        View row1 = null;

        if(convertView == null){
            LayoutInflater inflater=(LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            View row1=inflater.inflate(R.layout.mylist_rows, parent, false);
        }else{
            row1 = convertView;
        }
        TextView text=(TextView)row1.findViewById(R.id.textView1);
        ImageView image=(ImageView)row1.findViewById(R.id.imageView1);

        SingleRow temp=list.get(position);

        text.setText(temp.description);
        image.setImageResource(temp.image);

        Typeface font = Typeface.createFromAsset(text.getContext().getAssets(), "fonts/OpenSans.ttf");

        text.setTypeface(font);

        return row1;
    }

Also you can optimize some things:

1 if your image will always the same you can put code to if block

if(convertView == null){
    LayoutInflater inflater=(LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    View row1=inflater.inflate(R.layout.mylist_rows, parent, false);

    ImageView image=(ImageView)row1.findViewById(R.id.imageView1);

    SingleRow temp=list.get(position);
    image.setImageResource(temp.image);
}else{

2 if your Your font will always the same you can also put it to if block

if(convertView == null){
    // inflating...

    TextView text=(TextView)row1.findViewById(R.id.textView1);
    Typeface font = Typeface.createFromAsset(text.getContext().getAssets(), "fonts/OpenSans.ttf");

    text.setTypeface(font);
}else{
Roman Black
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0

try

list.setCacheColorHint(Color.TRANSPARENT);
Fahriyal Afif
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0

Modify your getView():

 @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            View row1 = null;

            if(convertView == null){
                LayoutInflater inflater=(LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                View row1=inflater.inflate(R.layout.mylist_rows, parent, false);
                convertView.setTag(row1);
            }else{
                 row1= (View) convertView.getTag();
            }
            TextView text=(TextView)row1.findViewById(R.id.textView1);
            ImageView image=(ImageView)row1.findViewById(R.id.imageView1);

            SingleRow temp=list.get(position);

    text.setText(temp.description);
    image.setImageResource(temp.image);

    Typeface font = Typeface.createFromAsset(text.getContext().getAssets(), "fonts/OpenSans.ttf");

    text.setTypeface(font);

    return row1;
}

Let me know if it will not work.

Neha Agarwal
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  • I tried code you shared. The app crashed with a NullPointer. However, before running the app, the compiler warned about convertView.setTag(row1) as "Null pointer access: The variable convertView can only be null at this location" – rajagrawal Feb 14 '14 at 09:37
  • Change: `View row1 = null;` to `SingleRow row1 = new SingleRow();` – Neha Agarwal Feb 14 '14 at 09:48
  • Got red lines over **new SingleRow()** saying "The constructor MyListAdapter.SingleRow() is undefined". And red lines everywhere row1 was used. – rajagrawal Feb 14 '14 at 09:55
0

Solved. Turns out I had two declarations of the Fragments. One tag declaration inside the activitymain.xml and fragment transaction in the MainActivity.java. According to http://developer.android.com/guide/components/fragments.html you can declare fragments in either of them, but not both. This is why I was getting double views.

rajagrawal
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