Develop Reference

How to display remote images in ListView using BaseAdapter?

I am using the following code to display images on ListView using BaseAdapter .The code displays images from inside drawable folder. But I want to modify the code so it displays remote images from following Array:
String flags[] ={"http://www.website.com/images/usa.png","http://www.website.com/images/china.png","http://www.website.com/images/australia.png","http://www.website.com/images/portugle.png","http://www.website.com/images/norway.png","http://www.website.com/images/new_zealand.png"};
Could an expert show me what part needs to be change.Thanks in advance.
MainActivity.java:
public class MainActivity extends Activity {
ListView simpleList;
String countryList[] = {"USA", "China", "australia", "Portugle", "Norway", "NewZealand"};
int flags[] = {R.drawable.usa, R.drawable.china, R.drawable.australia, R.drawable.portugle, R.drawable.norway, R.drawable.new_zealand};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
simpleList = (ListView) findViewById(R.id.simpleListView);
CustomAdapter customAdapter = new CustomAdapter(getApplicationContext(), countryList, flags);
simpleList.setAdapter(customAdapter);
simpleList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Toast.makeText(getApplicationContext(), "Hello " + countryList[position], Toast.LENGTH_LONG).show();
}
});
}
}
CustomAdapter.java:
Public class CustomAdapter extends BaseAdapter {
Context context;
String countryList[];
int flags[];
LayoutInflater inflter;
public CustomAdapter(Context applicationContext, String[] countryList, int[] flags) {
this.context = context;
this.countryList = countryList;
this.flags = flags;
inflter = (LayoutInflater.from(applicationContext));
}
#Override
public int getCount() {
return countryList.length;
}
#Override
public Object getItem(int i) {
return null;
}
#Override
public long getItemId(int i) {
return 0;
}
#Override
public View getView(int i, View view, ViewGroup viewGroup) {
view = inflter.inflate(R.layout.activity_listview, null);
TextView country = (TextView) view.findViewById(R.id.textView);
ImageView icon = (ImageView) view.findViewById(R.id.icon);
country.setText(countryList[i]);
icon.setImageResource(flags[i]);
return view;
}
}

You need to:
1) Fetch those images in a separate thread, you can use volley, retrofit, robospice for this.
2) On the response of any of those methods from 1) you have to pass the list of values you obtained from the service to your adapter's constructor. You will need to create a POJO for the model, this structure will hold all the elements from the REST webservice.
3) It is recommended to use a viewholder for your listview's adapter, to avoid inflating the views again and again.

The easiest thing to do is use Glide or Picasso:
#Override
public View getView(int i, View view, ViewGroup viewGroup) {
view = inflter.inflate(R.layout.activity_listview, null);
TextView country = (TextView) view.findViewById(R.id.textView);
ImageView icon = (ImageView) view.findViewById(R.id.icon);
country.setText(countryList[i]);
// Assuming flags is now the list of Strings of image urls
GlideApp.with(view.getContext()).load(flags[i]).into(icon);
return view;
}

you can also use some third party library like Picasso or Glide to load images right into your adapter's get view method
Picasso.with(this).load(flags[adapter's
position]).into(imageView);
same in glide.
here is simple tutorial https://www.simplifiedcoding.net/picasso-android-tutorial-picasso-image-loader-library/

Expanding an image from a thumbnail in a GridView

So I have a simple application in which I am taking an image with the camera and then loading the images into a GridView, when I click on the GridView it must open a bigger version of that image. I cannot get the image to open bigger.
The problem is that I have no reference to that image when passing it to the Activity which makes the image bigger. Code is below.
MainActivity.java
protected static final String EXTRA_RES_ID = "POS";
private ArrayList<String> mThumbIdsSelfies = new ArrayList<String>();
if(populateArrayList())
{
GridView gridview = (GridView) findViewById(R.id.gridview);
// Create a new ImageAdapter and set it as the Adapter for this GridView
gridview.setAdapter(new ImageAdapter(this, mThumbIdsSelfies));
// Set an setOnItemClickListener on the GridView
gridview.setOnItemClickListener(new AdapterView.OnItemClickListener()
{
public void onItemClick(AdapterView<?> parent, View v,
int position, long id)
{
//Create an Intent to start the ImageViewActivity
Intent intent = new Intent(MainActivity.this, ImageViewActivity.class);
// Add the ID of the thumbnail to display as an Intent Extra
intent.putExtra(EXTRA_RES_ID, (int) id);
// Start the ImageViewActivity
startActivity(intent);
}
});
}
private boolean populateArrayList()
{
File dir = getAlbumDir();
//Bitmap myBitmap;
if (dir.isDirectory())
{
File[] files = dir.listFiles();
for (int i = 0; i < files.length; i++)
{
//myBitmap = BitmapFactory.decodeFile(files[i].toString());
mThumbIdsSelfies.add(files[i].toString());
}
}
return true;
}
ImageViewActivity.java - This is the one that makes the image bigger
public class ImageViewActivity extends Activity
{
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
// Get the Intent used to start this Activity
Intent intent = getIntent();
// Make a new ImageView
ImageView imageView = new ImageView(getApplicationContext());
// Get the ID of the image to display and set it as the image for this ImageView
imageView.setImageResource(intent.getIntExtra(MainActivity.EXTRA_RES_ID, 0));
setContentView(imageView);
}
}
ImageAdapter.java
public class ImageAdapter extends BaseAdapter
{
private static final int PADDING = 8;
private static final int WIDTH = 250;
private static final int HEIGHT = 250;
private Context mContext;
private List<String> mThumbIds;
// Store the list of image IDs
public ImageAdapter(Context c, List<String> ids)
{
mContext = c;
this.mThumbIds = ids;
}
// Return the number of items in the Adapter
#Override
public int getCount()
{
return mThumbIds.size();
}
// Return the data item at position
#Override
public Object getItem(int position)
{
return mThumbIds.get(position);
}
// Will get called to provide the ID that
// is passed to OnItemClickListener.onItemClick()
#Override
public long getItemId(int position)
{
return mThumbIds.indexOf(position);
}
// Return an ImageView for each item referenced by the Adapter
#Override
public View getView(int position, View convertView, ViewGroup parent)
{
ImageView imageView = (ImageView) convertView;
// if convertView's not recycled, initialize some attributes
if (imageView == null)
{
imageView = new ImageView(mContext);
imageView.setLayoutParams(new GridView.LayoutParams(WIDTH, HEIGHT));
imageView.setPadding(PADDING, PADDING, PADDING, PADDING);
imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
}
//imageView.setImageResource(mThumbIds.get(position));
Bitmap b = BitmapFactory.decodeFile(mThumbIds.get(position));
imageView.setImageBitmap(b);
return imageView;
}
}
So the problem with the above function is that I cannot use getItemId as it does not return a long, rather it returns a string and I have no way of getting something useful from it.
The other thing I have tried is passing the bitmap image as an extra in my bundle and reading it on the other side, still I have no luck in getting the actual image to display.

I finally figured this out, so here is what I did.
MainActivity.java - Changed the following line
intent.putExtra(EXTRA_RES_ID, mThumbIdsSelfies.get(position)/*(int) id*/);
ImageViewActivity.java
String s = intent.getStringExtra(MainActivity.EXTRA_RES_ID);
Bitmap bitmap = BitmapFactory.decodeFile(s);
imageView.setImageBitmap(bitmap);
So those changes finally helped me, all I had to do was pass a string reference to the file location of the thumbnail I just clicked on. Then in the Activity that enlarges that image, I had to get that string reference and generate a bitmap out of it and then set that bitmap to the imageView.

Assuming that mThumbIdsSelfies is an ArrayList of the image paths you can use this:
Intent intent = new Intent(MainActivity.this, ImageViewActivity.class);
intent.putExtra(EXTRA_RES_ID, mThumbIdsSelfies[position]);
startActivity(intent);
Then retrieve it in your Activity(ImageViewActivity) and use it as you do in your adapter's getView() method.

Android Imageswitcher how to set initial selection

Im using an imageswitcher and want to know how to programatically set the initial selected item in my gallery of images.
Currently on activating the image selection activity the selection always defaults to the first in the array of available images. If a user has previously selected one I would like to recall that item as the first presented image in the switcher gallery.
On selection I am sending the selection int to a 'global variable' which I could use to call when the activity is recalled.
mSwitcher = (ImageSwitcher) findViewById(R.id.switcher1);
mSwitcher.setFactory(this);
mSwitcher.setInAnimation(AnimationUtils.loadAnimation(this,
android.R.anim.fade_in));
mSwitcher.setOutAnimation(AnimationUtils.loadAnimation(this,
android.R.anim.fade_out));
Gallery g = (Gallery) findViewById(R.id.gallery1);
g.setAdapter(new ImageAdapter(this));
int texPositionVariable = 2;
mSwitcher.setImageResource(mImageIds[texPositionVariable]); // should load position 2 but doesn't
g.setOnItemSelectedListener (new AdapterView.OnItemSelectedListener() {
#Override
public void onItemSelected(AdapterView<?> parent, View v, int position, long id) {
mSwitcher.setImageResource(mImageIds[position]);
Log.d("textureselected",String.valueOf(position));
GlobalVariables.setTexture((float)position);
mView.requestRender();
}
#Override
public void onNothingSelected(
AdapterView<?> paramAnonymousAdapterView) {
}
});
public class ImageAdapter extends BaseAdapter {
public ImageAdapter(Context c) {
mContext = c;
}
public int getCount() {
return mThumbIds.length;
}
public Object getItem(int position) {
return position;
}
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
ImageView i = new ImageView(mContext);
i.setImageResource(mThumbIds[position]);
i.setAdjustViewBounds(true);
i.setLayoutParams(new Gallery.LayoutParams(200, 150));
i.setBackgroundResource(R.drawable.long1);
return i;
}
private Context mContext;
}
private Integer[] mThumbIds = {
R.drawable.textures00, R.drawable.textures01,
R.drawable.textures02, R.drawable.textures03,
R.drawable.textures04, R.drawable.textures05,
R.drawable.textures06, R.drawable.textures07};
Thanks.

You are trying set the ImageResource before Gallery's OnItemSelectedListener but By default Gallery's OnItemSelectedListener will trigger so again ImageResource to your ImageSwitcher's set to position of 0(zero). You need to set the selection to Gallery
Try this:
Replace
mSwitcher.setImageResource(mImageIds[texPositionVariable]);
with
g.setSelection(texPositionVariable);

Question Answered by using 'setSelection(int)' within the gallery.
Gallery g = (Gallery) findViewById(R.id.gallery1);
g.setAdapter(new ImageAdapter(this));
// this worked
float texSelected = GloblaVariables.getTexture();
g.setSelection((int)texSelected);
g.setOnItemSelectedListener (new AdapterView.OnItemSelectedListener() {
#Override
public void onItemSelected(AdapterView<?> parent, View v, int position, long id) {
mSwitcher.setImageResource(mImageIds[position]);
Log.d("textureselected",String.valueOf(position));
GlobalVariables.setTexture((float)position);
mView.requestRender();
}
#Override
public void onNothingSelected(
AdapterView<?> paramAnonymousAdapterView) {
}
});
Thanks

Gallery- viewing more than one picture

I have a working Gallery that shows one picture at a time and can be "swiped" to rotate through the images. I want to have the option of the user to view 2 or 3 pictures at a time by using the menu and selecting how many to show. So far Ive tried adjusting the Gallery width, and LinearLayout params and all crash the Activity. any advice would be appreciated.
I declare and initialize the Gallery here and have the onOptionsItemSelected method sekeleton.
public class SpeechAppActivity extends Activity implements OnClickListener{
//Menu Items
// Class variables
Gallery myGallery;
ImageView imageView;
MyDBAdapter db;
Item item1;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
db = new MyDBAdapter(this);
db.insertEntry(item1 = new Item("Bathtub", "Bathroom", "Typical", "Clean", "fill, wash", "Round, deep", "Bathroom", "Toilet, Bathroom", R.drawable.ic_launcher));
Log.i("item", "item: " + item1.toString());
// Bind the gallery defined in the main.xml
// Apply a new (customized) ImageAdapter to it.
myGallery = (Gallery) findViewById(R.id.myGallery);
myGallery.setAdapter(new ImageAdapter(this));
//myGallery.setLayoutParams(new Gallery.LayoutParams(250, 250));
myGallery.setOnItemSelectedListener(new OnItemSelectedListener() {
public void onItemSelected(AdapterView<?> parent, View v,
int position, long id) {
}
public void onNothingSelected(AdapterView<?> parent) {
}
});
public boolean onOptionsItemSelected(MenuItem menuItem) {
switch (menuItem.getItemId()) {
case R.id.settings:
startActivity(new Intent(this, Prefs.class));
return true;
case R.id.show1:
//myGallery.findViewById(R.id.myGallery).setLayoutParams(new Gallery.LayoutParams(500, 250));
return true;
case R.id.show2:
//myGallery.findViewById(R.id.myGallery).setLayoutParams(new Gallery.LayoutParams(500, 250));
return true;
case R.id.show3:
//myGallery.findViewById(R.id.myGallery).setLayoutParams(new Gallery.LayoutParams(500, 250));
return true;
}
return false;
}
This is the Image Adapter class for the Gallery
public class ImageAdapter extends BaseAdapter {
/** The parent context */
private Context myContext;
// Put some images to project-folder: /res/drawable/
// format: jpg, gif, png, bmp, ...
private int[] myImageIds = { R.drawable.apple, R.drawable.orange,
R.drawable.ic_launcher };
/** Simple Constructor saving the 'parent' context. */
public ImageAdapter(Context c) {
this.myContext = c;
}
// inherited abstract methods - must be implemented
// Returns count of images, and individual IDs
public int getCount() {
return this.myImageIds.length;
}
public Object getItem(int position) {
return position;
}
public long getItemId(int position) {
return position;
}
// Returns a new ImageView to be displayed,
public View getView(int position, View convertView,
ViewGroup parent) {
// Get a View to display image data
ImageView iv = new ImageView(this.myContext);
iv.setImageResource(this.myImageIds[position]);
// Image should be scaled somehow
//iv.setScaleType(ImageView.ScaleType.CENTER);
iv.setScaleType(ImageView.ScaleType.CENTER_CROP);
//iv.setScaleType(ImageView.ScaleType.CENTER_INSIDE);
//iv.setScaleType(ImageView.ScaleType.FIT_CENTER);
//iv.setScaleType(ImageView.ScaleType.FIT_XY);
//iv.setScaleType(ImageView.ScaleType.FIT_END);
//iv.setScaleType(ImageView.ScaleType.FIT_START);
// Set the Width & Height of the individual images
//get scale for finding dip of a set # of pixels
final float scale = parent.getContext().getResources().getDisplayMetrics().density;
iv.setLayoutParams(new Gallery.LayoutParams((int) (300 * scale + 0.5f), (int) (250 * scale + 0.5f)));
return iv;
}
}// ImageAdapter

In your adapter,
Use View object (witn custom view) and put ImageView inside it.
This was you can put more than one images per view.
Best results can be achieved by few layout files based on number of images and using correct one according to user selection.
Let me know if you need more specific code template.

How to create a Photo Gallery on Android?

I want to create a photo gallery on Android. I'm using Gallery and BaseAdapter to create a scrollable gallery. Now I want to add an action when an image of the gallery is shown (each image's width is the same as screen width), so I need to get its index in the image array. My question is how to get the index of the image which shows on the screen?
I want to get the index of the image as soon as it shows on the screen, not on click event.
I've tried to get current image position in getView(), but the result is strange:
I scroll to image02 but position=2 (should be 1). When I scroll back, image02's position=0 (should be 1).
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Gallery g = (Gallery) this.findViewById(R.id.Gallery);
g.setAdapter(new ImageAdapter(this));
}
public class ImageAdapter extends BaseAdapter {
private Context mContext;
private Integer[] mImageIds = {
//each image's size is 320x60
R.drawable.btm01,
R.drawable.btm02,
R.drawable.btm03
};
public ImageAdapter(Context c){
this.mContext = c;
}
#Override
public int getCount() {
// TODO Auto-generated method stub
return mImageIds.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 imageView = new ImageView(mContext);
imageView.setImageResource(mImageIds[position]);
imageView.setLayoutParams(new Gallery.LayoutParams(320,60));
return imageView;
}

Check this example.
// Reference the Gallery view
Gallery g = (Gallery) this.findViewById(R.id.Gallery);
// Set the adapter to our custom adapter (below)
g.setAdapter(new ImageAdapter(this));
// Set a item click listener, and just Toast the clicked position
g.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView parent, View v, int position, long id) {
Toast.makeText(Gallery1.this, "" + position, Toast.LENGTH_SHORT).show();
}
});