এই উত্তরের ভিত্তিতে আমি আমার নিজের লোডারটি লিখি।
লোডিং প্রভাব এবং উপস্থিতি প্রভাব সহ:
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup;
import android.view.animation.AlphaAnimation;
import android.view.animation.Animation;
import android.widget.FrameLayout;
import android.widget.ImageView;
import android.widget.ProgressBar;
import java.io.InputStream;
/**
* Created by Sergey Shustikov (pandarium.shustikov@gmail.com) at 2015.
*/
public class DownloadImageTask extends AsyncTask<String, Void, Bitmap>
{
public static final int ANIMATION_DURATION = 250;
private final ImageView mDestination, mFakeForError;
private final String mUrl;
private final ProgressBar mProgressBar;
private Animation.AnimationListener mOutAnimationListener = new Animation.AnimationListener()
{
@Override
public void onAnimationStart(Animation animation)
{
}
@Override
public void onAnimationEnd(Animation animation)
{
mProgressBar.setVisibility(View.GONE);
}
@Override
public void onAnimationRepeat(Animation animation)
{
}
};
private Animation.AnimationListener mInAnimationListener = new Animation.AnimationListener()
{
@Override
public void onAnimationStart(Animation animation)
{
if (isBitmapSet)
mDestination.setVisibility(View.VISIBLE);
else
mFakeForError.setVisibility(View.VISIBLE);
}
@Override
public void onAnimationEnd(Animation animation)
{
}
@Override
public void onAnimationRepeat(Animation animation)
{
}
};
private boolean isBitmapSet;
public DownloadImageTask(Context context, ImageView destination, String url)
{
mDestination = destination;
mUrl = url;
ViewGroup parent = (ViewGroup) destination.getParent();
mFakeForError = new ImageView(context);
destination.setVisibility(View.GONE);
FrameLayout layout = new FrameLayout(context);
mProgressBar = new ProgressBar(context);
FrameLayout.LayoutParams params = new FrameLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
params.gravity = Gravity.CENTER;
mProgressBar.setLayoutParams(params);
FrameLayout.LayoutParams copy = new FrameLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
copy.gravity = Gravity.CENTER;
copy.width = dpToPx(48);
copy.height = dpToPx(48);
mFakeForError.setLayoutParams(copy);
mFakeForError.setVisibility(View.GONE);
mFakeForError.setImageResource(android.R.drawable.ic_menu_close_clear_cancel);
layout.addView(mProgressBar);
layout.addView(mFakeForError);
mProgressBar.setIndeterminate(true);
parent.addView(layout, new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT));
}
protected Bitmap doInBackground(String... urls)
{
String urlDisplay = mUrl;
Bitmap bitmap = null;
try {
InputStream in = new java.net.URL(urlDisplay).openStream();
bitmap = BitmapFactory.decodeStream(in);
} catch (Exception e) {
Log.e("Error", e.getMessage());
e.printStackTrace();
}
return bitmap;
}
protected void onPostExecute(Bitmap result)
{
AlphaAnimation in = new AlphaAnimation(0f, 1f);
AlphaAnimation out = new AlphaAnimation(1f, 0f);
in.setDuration(ANIMATION_DURATION * 2);
out.setDuration(ANIMATION_DURATION);
out.setAnimationListener(mOutAnimationListener);
in.setAnimationListener(mInAnimationListener);
in.setStartOffset(ANIMATION_DURATION);
if (result != null) {
mDestination.setImageBitmap(result);
isBitmapSet = true;
mDestination.startAnimation(in);
} else {
mFakeForError.startAnimation(in);
}
mProgressBar.startAnimation(out);
}
public int dpToPx(int dp) {
DisplayMetrics displayMetrics = mDestination.getContext().getResources().getDisplayMetrics();
int px = Math.round(dp * (displayMetrics.xdpi / DisplayMetrics.DENSITY_DEFAULT));
return px;
}
}
অনুমতি যোগ করুন
<uses-permission android:name="android.permission.INTERNET"/>
এবং কার্যকর:
new DownloadImageTask(context, imageViewToLoad, urlToImage).execute();