Develop Reference

How to create a progressDialog onload of imageView?

I would like to load a large/complex svg image file into my imageView. Loading the svg takes time to load on my HTC Desire S and Lenovo a60. About 5 Second and 10 seconds respectively.
Right now my app becomes unresponsive for about 5 seconds until the imageView is fully loaded
I load the image using this simple code..
svg = SVGParser.getSVGFromResource(getResources(), R.raw.gf);
mImageView.setImageDrawable(svg.createPictureDrawable());
I was looking something like (webView)
webView.setWebViewClient(new WebViewClientEx(MainActivity.this, DEBUG) {
#Override
public void onPageFinished(final WebView view, String url) {
...........
.............}
});
which I used in my previous project...
Finally my questions:
1.) What is the best approach to make the app look responsive?
I was planning to use asynctask but don't know how to use it... Is it applicable here?
2.) Is there listener after the image is fully loaded?
My approach here is to show the progressDialog by the time I load the imageView and hide it after the imageView has fully loaded.
another other suggestions which you think is better to use for showing/hiding progressDialog ? Thanks!

Use an async task here. (a Loader would work aswell but async task is a bit easier to explain.)
private class LoadSVGTask extends AsyncTask<Integer, Void, Drawable> {
protected Drawable doInBackground(Integer... res) {
mProgressBar.setVisibility(View.Visible);
svg = SVGParser.getSVGFromResource(getResources(),res);
Drawable d = svg.createPictureDrawable();
return d;
}
// gets executed in main thread
protected void onPostExecute(Drawable result) {
mProgressBar.setVisibility(View.Gone);
mImageView.setImageDrawable(result);
}
}
Launch the Task with:
new LoaderSVGTask().execute(R.raw.gf, null, null);
see: http://developer.android.com/reference/android/os/AsyncTask.html

Just refer AsyncTask in that
protected void onPreExecute (){
progressDialog.show(......);
}
protected abstract Result doInBackground (Params... params){
//load your image from here
}
protected void onPostExecute (Result result){
progressDialog.dismiss();
}

Delay between One Activity to Another Activity

I develop one application in Android. Which contains so many data (String) and images. string data are come from database and images comes from /res folder.
In My Application First Activity shows categories of books. Then i select any one of them then jump to the next activity which display all books images and brief description of selected category these all data are coming from database with Query operation and fill custom list view with ArrayAdapter. These is working and display all the things which i want.
but the problem is that when i click on category from one activity it takes more than 1 minute time to display second activity (Detail Information of Selected Category). So, Here user is stuck. It is bad for my application.
So is there any way to solve these or any Idea to display Activity Loading Process between One Activity to Second Activity ?
Thanks in Advance.
Please Help Me to solve these.

use AsyncTask as
public class My_Game_Task extends AsyncTask<String, Void, Void> {
#Override
protected void onPreExecute() {
//put a preloder
super.onPreExecute();
}
#Override
protected Void doInBackground(String... arg0) {
// TODO Auto-generated method stub
find data from database
return null;
}
#Override
protected void onPostExecute(Void result) {
dismiss preloader
set adapter here
super.onPostExecute(result);
}
}
call on
oncreate as new My_Game_Task().execute();
this will immediately show the next activity and will show a preloader

First of all where are you testing the app.. if its on emulator then check it on actual device you would get a idea how much delay takes place actually.!
I had similar problem it takes minutes on emulator but runs amazingly on actual device.It takes just 1 second to display..

Try this one it will make a delay of one second before going to execute any other operations,
try {
Thread.sleep(1000);
} catch (InterruptedException e)
{
e.printStackTrace();
}

Android: How to solve slow response after clicking TabWidget

I have four Tab at the top of my apps
The content of the fourth tab is that it will get data from sql server and then display in listview
since the amount of data retrieved is quite big, it takes 2-3 sec
The problem is that:
After I click the fourth tab, it has no response, then after 2-3sec, it displays the content
As I know it is loading the data from database, I will not continue to click
However, when users click it and no response, he may click and click and click
How to show something to user so that they know it is loading data??

You should use a CrusorLoader. This will display a loading circle while still making the UI active. Note that even if you're using lower versions of the android API, you can still access the CursorLoader class via the Android Support Package. For more information on loaders, checkout

new SomeTask(0).execute(); // write this line in your 4th tab onCreate()
/** Inner class for implementing progress bar before fetching data **/
private class SomeTask extends AsyncTask<Void, Void, Integer>
{
private ProgressDialog Dialog = new ProgressDialog(yourActivityClass.this);
#Override
protected void onPreExecute()
{
Dialog.setMessage("loading...");
Dialog.show();
}
#Override
protected Integer doInBackground(Void... params)
{
//Task for doing something
// get data from sql server and then display in listview
return 0;
}
#Override
protected void onPostExecute(Integer result)
{
if(result==0)
{
//do some thing if your list completed
}
// after completed finished the progressbar
Dialog.dismiss();
}
}

When a long-running process is started, you'll want to indicate that something is happening so the user knows to wait. You want a progress dialog.
Here is an example:
http://www.androidpeople.com/android-progress-dialog-example

How to load images from server properly?

I have a code below, this code works perfectly fine when you are trying to load one or two images. However, the problem is, when you have a lot of images in one Activity, all images must load first before you can get in. My question is, what is the best way to handle this images? I want the images to load one by one and not simultaneously. I want it to load just like the ListView made by Fedor "http://stackoverflow.com/questions/541966/android-how-do-i-do-a-lazy-load-of-images-in-listview" (Note: I'm not using a ListView, I just want my images to load like that). Please help me, I would really appreciate it a lot. Thanks in advance!
class ImageDownlaodThread extends Thread {
ImageDownloadMessageHandler imageDownloadMessageHandler;
String imageUrl;
#Override
public void run() {
Drawable drawable = LoadImageFromWebOperations(imageUrl);
Message message = imageDownloadMessageHandler.obtainMessage(1, drawable);
System.out.println("Message sent");
}
}
class ImageDownloadMessageHandler extends Handler {
View imageTextView;
}
#Override
public void handleMessage(Message message) {
progressBar.setVisibility(View.GONE);
imageTextView.setVisibility(View.VISIBLE);
}
}
Drawable LoadImageFromWebOperations(String url) {
Drawable d = null;
InputStream is = null;
try {
} catch (IOException e) {
e.printStackTrace();
}
return d;
}

Would this tutorial help [TUT] ImageView with Loading Spinner:
http://www.anddev.org/novice-tutorials-f8/imageview-with-loading-spinner-t49439.html
It basically show's a spinner until the image has loaded from the remote site :-)
You could strip the code to show a blank space / whatever you want till it loads.
If you don't want anything to happen till it all loads, you could have a count of how many images there are and then increment this each time an image has loaded.

IMO, AsyncTask is the easiest way to do this; in fact, it was basically built for this sort of task.
There's really too much to discuss in a StackOverflow answer. Just see Painless Threading to get started.

Display the rotating progress before display the data

I'm displaying some data by using SQLite. When I click on one button data come from database. It takes some time. At that time the screen is black. At that time I want to display the rotating spinner before the data dispay. Any ideas?

Android provides a ProgressDialog for accomplishing what you want.

First i would like to suggest to have a look at AsyncTask page, so that you will come to know about the AsyncTask exactly.
Now, Implement AsyncTask as given below:
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
new performBackgroundTask().execute();
}
private class performBackgroundTask extends AsyncTask <Void, Void, Void>
{
private ProgressDialog Dialog = new ProgressDialog(main.this);
protected void onPreExecute()
{
Dialog.setMessage(getString("Please wait..."));
Dialog.show();
}
protected void onPostExecute(Void unused)
{
Dialog.dismiss();
// displaying all the fetched data
}
#Override
protected Void doInBackground(Void... params)
{
// implement long-running task here i.e. select query/fetch data from table
// fetch data from SQLite table/database
return null;
}
}
Enjoy !!!

You should not execute long running tasks in UI thread as this blocks the UI redraw and makes app look unresponsive.
Use AsyncTask to execute long running tasks in background, while still updating the screen.

You can look at the standard music picker as one example of how to do this:
https://android.googlesource.com/platform/packages/apps/Music/+/master/src/com/android/music/MusicPicker.java
In addition to the whole "queries must be done off the main UI thread," this shows an indeterminant progress while first loading its data, fading to the list once the data is available. The function to start the query is here:
https://android.googlesource.com/platform/packages/apps/Music/+/master/src/com/android/music/MusicPicker.java#581
And to do the switch is here:
https://android.googlesource.com/platform/packages/apps/Music/+/master/src/com/android/music/MusicPicker.java#569
The layout has the list view put in a frame layout with another container holding the progress indicator and label. The visibility of these is changed to control whether the list or progress indicator are shown:
https://android.googlesource.com/platform/packages/apps/Music/+/master/res/layout/music_picker.xml