Android laggy performance while loading gridview of images

Question

I am implementing a grid view of images which is opened using a button. The issue I am facing is regarding lagging/time delay for opening the gridview. Here is some of code snippets

    import android.os.Bundle;
import android.app.ActionBar;
import android.app.Activity;
import android.app.FragmentManager;
import android.content.Intent;
import android.content.res.Resources;
import android.graphics.drawable.Drawable;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.GridView;

public class Gallery extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_gallery);
        ActionBar ab=getActionBar();
        Resources r=getResources();
        Drawable d=r.getDrawable(R.color.quotescolor);
        ab.setBackgroundDrawable(d);
        GridView gv=(GridView)findViewById(R.id.gridview);
        gv.setAdapter(new ImageAdapter2(this));
        final FragmentManager fm=getFragmentManager();
        gv.setOnItemClickListener(new OnItemClickListener() {

            @Override
            public void onItemClick(AdapterView<?> arg0, View arg1, int position,
                    long arg3) {
                // TODO Auto-generated method stub
                if(position==0)
                {
                    ImageDial1 id1=new ImageDial1();
                    id1.show(fm,"image_title");
                    //Intent i=new Intent(Gallery.this,ImageFrag1.class);
                    //startActivity(i);
                }

and for the images i am using an adapter like this

package com.example.sachinapp;

import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;

public class ImageAdapter2 extends BaseAdapter {

    private Context ctx;

    public ImageAdapter2(Context c)
    {
        ctx=c;
    }
    @Override
    public int getCount() {
        // TODO Auto-generated method stub
        return pics.length;
    }

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

    @Override
    public long getItemId(int position) {
        // TODO Auto-generated method stub
        return 0;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        // TODO Auto-generated method stub
        ImageView iv;
        if (convertView == null) {  // if it's not recycled, initialize some attributes
            iv = new ImageView(ctx);
            iv.setLayoutParams(new GridView.LayoutParams(150,150));
            iv.setScaleType(ImageView.ScaleType.CENTER_CROP);
            iv.setPadding(8, 8, 8, 8);
        } else {
            iv = (ImageView) convertView;
        }

        iv.setImageResource(pics[position]);
        return iv;

    }

    private Integer[] pics={
            R.drawable.s1,R.drawable.s2,
            R.drawable.s3,R.drawable.s4,
            R.drawable.s6,R.drawable.s7,
            R.drawable.s8,R.drawable.s9,
            R.drawable.s10,R.drawable.s11,
            R.drawable.s2,R.drawable.s13,
            R.drawable.s4,R.drawable.s15,
            R.drawable.s6,R.drawable.s7,
            R.drawable.s18,R.drawable.s19,
    };
    }

I am also facing lagging when scrolling through the gridview. How can i improve the performance and make the gridview load faster. I have read that we can use async task for that, but I am not very familiar about how to use it in this case . Is there any other solution as well? Thanks

How large are the drawables? If they are too large and your imageview has to scale them down to your 150dp, that could hurt performance. — Patrick, Jul 12 '13 at 12:02
they are all about 800pixel(width) and 1100pixel(height). Does that have to be scaled down a lot to get to 150dp ? If yes, what size would improve the performance ? — Shivam Bhalla, Jul 12 '13 at 14:15
That seems be be not a trivial downscaling. While android does cache resources, I am not sure that it caches the rescaled version but more likely the original one. Now imagine that every time you scroll, multiple of these have to be rescaled once a new element scrolls into the screen. If you can, provide the resource at the size you actually need it in the app. (Here, 150dp) See: http://developer.android.com/training/multiscreen/screendensities.html — Patrick, Jul 12 '13 at 19:53

score 0 · Answer 1 · answered Jul 15 '13 at 08:14

If you have a static set of images to use, as said in a comment, you should provide different drawables for different screen densities. Also you should use nine-patch bitmaps for different screen sizes. If this isn't sufficient, carefully read here:

http://developer.android.com/training/displaying-bitmaps/index.html

Depending on the resolution of your images, to achieve the best performance you should: - resize your images so that they don't fill up all your memory and are easier to render - do the resize process in a worker thread so that the UI Thread is not blocked. - cache your resized images on disk

You can use AsyncTask to do your background work.

Android laggy performance while loading gridview of images

1 Answers1