Load images from external storage into GridView in Android using Picasso library

Activity:

public class Gallery extends ActionBarActivity {

public GridView imagegrid;
private ArrayList<String> imageUrls;
private ImagesAdapter imageAdapter;

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

private void init() {
final String[] columns= {MediaStore.Images.Media.DATA, MediaStore.Images.Media._ID};
final String orderBy= MediaStore.Images.Media.DATE_TAKEN;
Cursor imageCursor= this.getContentResolver().query(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, columns, null, null, orderBy +" DESC");
this.imageUrls=new ArrayList<String>();
for(int i=0; i< imageCursor.getCount();i++){
imageCursor.moveToPosition(i);
int dataColumnIndex =imageCursor.getColumnIndex(MediaStore.Images.Media.DATA);
imageUrls.add(imageCursor.getString(dataColumnIndex));
}
 
imagegrid = (GridView) findViewById(R.id.GalleryViewLayout);

   DisplayMetrics metrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(metrics);
int width=metrics.widthPixels;
int height=metrics.heightPixels;
float scalefactor = getResources().getDisplayMetrics().density * 100;
int number=width;
int col = (int) ((float) number / (float) scalefactor);
imagegrid.setNumColumns(col);
imageAdapter=new ImagesAdapter(this,imageUrls,width,height);
imagegrid.setAdapter(imageAdapter);

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.gallery, menu);
return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
return super.onOptionsItemSelected(item);
}
}

Xml:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"

    android:id="@+id/container"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    tools:context="com.sachinsandbhor.gallerydemo.Gallery"

    tools:ignore="MergeRootFrame" >

    <GridView

        android:id="@+id/GalleryViewLayout"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:layout_alignParentTop="true"

        android:layout_centerHorizontal="true"

        android:numColumns="3" >

    </GridView>

</RelativeLayout>

Adapter:

public class ImagesAdapter extends BaseAdapter{

ArrayList<String> mList;

    LayoutInflater mInflater;

    Context mContext;

    SparseBooleanArray mSparseBooleanArray;

    int width,height;

    

    public ImagesAdapter(Context context, ArrayList<String> imageList, int Screenwidth, int Screenheight) {

        mContext = context;

        mInflater = LayoutInflater.from(mContext);

        mSparseBooleanArray = new SparseBooleanArray();

        mList = new ArrayList<String>();

        this.mList = imageList;

        this.width=Screenwidth;

        this.height=Screenheight;

    }

    

public void initialize() {

    mList.clear();

    final String[] columns= {MediaStore.Images.Media.DATA, MediaStore.Images.Media._ID};

final String orderBy= MediaStore.Images.Media.DATE_TAKEN;

Cursor imageCursor= mContext.getContentResolver().query(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, columns, null, null, orderBy +" DESC");

this.mList=new ArrayList<String>();

for(int i=0; i< imageCursor.getCount();i++){

imageCursor.moveToPosition(i);

int dataColumnIndex =imageCursor.getColumnIndex(MediaStore.Images.Media.DATA);

mList.add(imageCursor.getString(dataColumnIndex));

System.out.println("=====> Array path => "+mList.get(i));

}

imageCursor.close();

    }

    public ArrayList<String> getCheckedItems() {

        ArrayList<String> mTempArry = new ArrayList<String>();

        for(int i=0;i<mList.size();i++) {

            if(mSparseBooleanArray.get(i)) {

                mTempArry.add(mList.get(i));

            }

        }

        return mTempArry;

    }

    @Override

    public int getCount() {

        return mList.size();

    }

    @Override

    public Object getItem(int position) {

        return null;

    }

    @Override

    public long getItemId(int position) {

        return position;

    }

@Override

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

if(convertView == null) {

    convertView = mInflater.inflate(R.layout.galleryitem, null);

    }

    ImageView imageView = (ImageView) convertView.findViewById(R.id.thumbImage);

    float scalefactor = mContext.getResources().getDisplayMetrics().density * 100;

int number=width;

int columnsSize = (int) ((float) number / (float) scalefactor);

int newWidth=width/columnsSize;

int newHeight=height/4;

    Picasso.with(mContext).load("file://"+mList.get(position)).resize(newWidth,newHeight).centerCrop()

.placeholder(R.drawable.ic_launcher)

.into(imageView);

    return convertView;

}

OnCheckedChangeListener mCheckedChangeListener = new OnCheckedChangeListener() {

@Override

public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {

// TODO Auto-generated method stub

mSparseBooleanArray.put((Integer) buttonView.getTag(), isChecked);

}

};

}

Custom xml :

<?xml version="1.0" encoding="utf-8"?>

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:id="@+id/FrameLayout1"

    android:layout_width="fill_parent"

    android:layout_height="fill_parent" >

    <ImageView

        android:id="@+id/thumbImage"

        android:layout_width="match_parent"

        android:layout_height="match_parent"

        android:layout_margin="5dp"

        android:scaleType="fitXY" />

</FrameLayout>

Add below line to AndroidManifest.xml

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

Screenshot:

Here is the sample Code