Develop Reference

How to display Splash Screen in android

I want to display splash screen in android app. But I want to execute onCreate() method of MainActivity behind the splash screen. because i am doing huge work in this method. Anyone can tel me how to do that.

Basically you want to do some work in background while user is shown some splash screen, right ? What you need is an Async Task or a Loader kind of thing.
Step 1: Display the splash screen.
Step 2: Start an Async task and do all your heavy processing in the doInBackground method of Async Task
Step 3: Update the UI using the onPostExecute method of Async Task. In this method, first close the timer to splash screen. Then send the intent to start another screen with the data of the heavy processed result of Async task. Display it on UI thread.
Only Showing Splash screen is very simple. This code creates a splash screen of 3 seconds and then sends an Intent to another activity.
public class SplashScreenActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_splash_screen);
CountDownTimer cdt1 = new CountDownTimer(3000, 1000) {
Boolean checkInternetConnection = false;
#Override
public void onTick(long l) {
}
#Override
public void onFinish() {
//Send Intent here
Intent i = new Intent(getApplicationContext(),
anotherActivity.class);
startActivity(i);
}
}.start();
}
PS- Dont forget to make the activity with this code as launcher activity from manifest file.

You can try this for Splash Screen...
public class SplashScreen extends Activity {
//Further Needed Declarations
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_splash);
/**
* Showing splashscreen while making network calls to download necessary
* data before launching the app Will use AsyncTask to make http call
*/
new PrefetchData().execute();
}
}

This is exactly the same way you wanted it.
create file in drawable
<item
android:drawable="#color/gray"/>
<item>
<bitmap
android:gravity="center"
android:src="#mipmap/ic_launcher"/>
</item>
</layer-list>
Styles.xml
<resources>
<!-- Base application theme. -->
<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
<!-- Customize your theme here. -->
</style>
<style name="SplashTheme" parent="Theme.AppCompat.NoActionBar">
<item name="android:windowBackground">#drawable/background_splash</item>
</style>
</resources>
Activity:
public class SplashActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Intent intent = new Intent(this, MainActivity.class);
startActivity(intent);
finish();
}
}

You can add this in your onCreate Method
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
// going to next activity
Intent i=new Intent(SplashScreenActivity.this,MainActivity.class);
startActivity(i);
finish();
}
},time);
And initialize your time value in milliseconds as yo want...
private static int time=5000;
for more detail download full code from this link...
https://github.com/Mr-Perfectt/Splash-Screen

Android app without a layout

I'm a totally noob on Android, is there a way to execute an app without a layout? The process would be like: Click app icon -> run some code (Without prompting any window) -> display toast.

The trick is to open a transparent activity, show the toast and finish the activity, which makes it look like only the toast is displayed because the activity which opened was transparent.
To do this you can do.
public class MainActivity extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Toast.makeText(this, messageToBeDisplayed, Toast.LENGTH_SHORT).show();
// finish the activity as soon as it opened.
this.finish();
}
}
Also you need to give a transparent theme to your activity by specifying it in AndroidManifest.xml, For which you can use NoDisplayeTheme provided by Android like this.
<activity android:name="TransparentActivity"
android:theme="#android:style/Theme.NoDisplay">
</activity>

Yes you can by adding:
android:theme="#android:style/Theme.NoDisplay"
in your activity in Android manifest.
Check this answer for more details.

Use this:
public class MainActivity extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Toast.makeText(this, "", Toast.LENGTH_SHORT).show();
this.finish();
}
}
and in manifest file add: android:theme="#android:style/Theme.NoDisplay"

Why won't dismissDialog, removeDialog, or dialog.dismiss work in onDestroy or onPause?

I can't for the life of me figure out how to manage dialogs without using configChanges to specify that you want to manually handle orientation changes.
So lets say you have this AndroidManifest:
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.testandroid"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="15" />
<application
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="#string/title_activity_main" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
Take this MainActivity.java:
package com.example.testandroid;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.AlertDialog.Builder;
import android.app.Dialog;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.View;
public class MainActivity extends Activity {
private final static String TAG = "MainActivity";
Dialog mDialog = null;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Log.d(TAG, "onCreate");
setContentView(R.layout.activity_main);
}
public void doShowDialog(View b) {
Log.d(TAG, "doShowDialog");
showDialog(1);
}
private void tryDismiss() {
Log.d(TAG, "tryDismiss");
try {
dismissDialog(1);
removeDialog(1);
mDialog.dismiss();
} catch(IllegalArgumentException ex) {
Log.e(TAG, ex.getMessage());
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
#Override
protected void onPause() {
tryDismiss();
super.onPause();
Log.d(TAG, "onPause");
}
#Override
protected Dialog onCreateDialog(int dialog) {
Builder b = new AlertDialog.Builder(this);
b.setTitle("Hello").setMessage("Waiting..");
mDialog = b.create();
return mDialog;
}
}
and this layout (main.xml)
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Open Dialog"
android:onClick="doShowDialog"
/>
</LinearLayout>
It doesn't seem to matter if you call from onDestroy or onPause, the dialog shows back up after the orientation switches. But why? I told it to go away. If call removeDialog/dismissDialog it does nothing when called before the orientation changes. I can't figure out for the life of me why this is. The only way to get rid of this that I know of is to handle the orientation change yourself by using
android:configChanges="keyboardHidden|orientation"
I know the new way of working is to use the FragmentDialog stuff which I have not upgraded to yet and am not ready to rewrite my whole app for that. Just seems strange that this doesn't work.
This is just an example of a real world problem I'm having in my app where the user can request some data be pulled from a remote server (to update a spinner's data), and if they switch orientation the loading dialog will never go away and there seems to be no fix for this besides handling the orientation change with the android:configChanges option. Which I can do but it seems ridiculous to me to have to do that.
-- Update --
Removed the button to dismiss the dialog as it's not necessary and you can't click it anyways since the dialog is on top.
To reproduce just start the app, click the button that opens the dialog, and then rotate your phone.

Your dialog is saved in onSaveInstanceState, so you might try dismissing it before it's launched:
#Override
protected void onSaveInstanceState(Bundle state)
{
tryDismiss();
super.onSaveInstanceState(state);
}
Also I don't really understand why do you use Activity's onCreateDialog to manage dialogs. The reason it was designed was to handle orientation changes automatically. If you want to handle it manually, why don't you just use dialog's functions? Instead of using showDialog(id) and onCreateDialog(id) just launch it directly, it won't reappear after rotating the screen.
Builder b = new AlertDialog.Builder(this);
b.setTitle("Hello").setMessage("Waiting..");
Dialog mDialog = b.create();
mDialog.show(); // <-----

Sebastian got it but I'd like to explain a bit more about the situation and my findings on dialogs since it can be quite confusing:
As sebastian put it, you must call dismissDialog/removeDialog from
onSaveInstanceState if you want the dialog gone before the rotation.
While you can create a dialog from onCreate, if you don't dismiss it before the orientation
change you won't be able to dismiss in the onCreate method when the activity restarts. You must call dismissDialog from onPostCreate
Calling dismissDialog didn't work in onRestoreInstanceState after orientation change as well. I tried both before and after calling super.onRestoreInstanceState and neither worked (thought it would since dimissing happens in onSaveInstanceState)
Even more important than this is that I learned if you are doing some Asynchronous task, such as an HTTP call and you have an inner class which contains a callback function which will run when the task is complete, you need to be aware that that inner class method will contain a reference to the original instance of the outer Activity class if the screen is rotated. This was not at all obvious to me as and I wasn't actually using AsyncTask as many others have had issues with (I was using an asynchronous http library).
Taking a small example similar to my real code:
public class MyActivity extends Activity {
private static MyActivity sThis;
#Override
public void onCreate(Bundle state) {
super.onCreate(state);
sThis = this;
doAsyncWork();
}
#Override
public void onDestroy() {
super.onDestroy();
sThis = null;
}
private void doAsyncWork() {
showDialog(LOADING_DIALOG);
ExampleAsyncWorker.work(new AsyncWorkerCallback() {
#Override
public void onWorkComplete() {
dismissDialog(LOADING_DIALOG); //doesn't work if orientation change happened.
}
});
}
}
The above code, through the CategoryManager, connects to an external server, downloads a list of categories, and once it is complete calls onCategoriesObtained and then onFetchComplete (also there are some error handling callback function removed for brevity). If an orientation change happens between the fetchCategories call and onFetchComplete then the call to dismissDialog in onFetchComplete will never work. The reason is that this inner class has an implicit reference to the original instance of the Activity class which was created before the orientation change. Thus, when you call dismissDialog you are calling it on the original instance not the new one, which will cause the dismissDialog to fail with the message: "no dialog with id 1 was ever shown via Activity#showDialog". I did figure out a way around this but its a bit of hack:
In your Activity class, include a static reference to the this reference and set it in onCreate, and null it in onDestroy, and use that reference from your inner class like so:
public class MyActivity extends Activity {
private static MyActivity sThis;
#Override
public void onCreate(Bundle state) {
super.onCreate(state);
sThis = this;
doAsyncWork();
}
#Override
public void onDestroy() {
super.onDestroy();
sThis = null;
}
private void doAsyncWork() {
showDialog(LOADING_DIALOG);
ExampleAsyncWorker.work(new AsyncWorkerCallback() {
#Override
public void onWorkComplete() {
sThis.dismissDialog(LOADING_DIALOG);
}
});
}
}
Note that I'm not sure this is a great practice but it worked for me. I know there can be problems with inner classes in activities that refer to the outer class (leaking the context) so there may be better ways of solving this problem.

AFAIK , This window leaked can be handled in two ways.
#Override
public void onDestroy(){
super.onDestroy();
if ( Dialog!=null && Dialog.isShowing() ){
Dialog.dismiss();
}
}
Or
if(getActivity()!= null && !getActivity().isFinishing()){
Dialog.show();
}
Here Dailog is your progress /alert dailog

for creating your app without the savedinstace you can use super.onCreate(null);

Nothing happens when I configure RoboGuice

I am new to RoboGuice and I am trying to set up my activity to use DI. However, nothing happens when I attempt to use it. I only get a blank black window with no content and no logging in my Activity.onCreate() method after I call "super.onCreate(savedInstanceState);"
See these 2 snippets of code:
public class ClikClokActivity extends RoboActivity{
#Inject
private TileAdapter tileAdapter;
#Inject
private GameLogicService gameLogicService;
#Inject
private GridOperationQueue gridOperationQueue;
private GridView gridView;
#Inject
private Handler handler;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
Log.v(this.getClass().toString(), "Entering onCreate");
super.onCreate(savedInstanceState);
Log.v(this.getClass().toString(), "Never logs this with RoboGuice");
setContentView(R.layout.main);
gridView = (GridView) findViewById(R.id.gridview);
gridView.setNumColumns(Constants.GRID_WIDTH);
gridView.setAdapter(tileAdapter);
Log.v(this.getClass().toString(), "GridView initialized");
gridOperationQueue.start();
Log.v(this.getClass().toString(), "Completed onCreate");
}
and
public class ClikClokApplication extends RoboApplication{
#Override
protected void addApplicationModules(List<Module> modules) {
modules.add(new ClikClokModule());
}
}
and
public class ClikClokModule extends AbstractAndroidModule {
#Override
protected void configure() {
}
}
and
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.clikclok"
android:versionCode="1"
android:versionName="1.0">
<application android:name="com.clikclok.ClikClokApplication" android:icon="#drawable/icon" android:label="#string/app_name">
<activity android:name=".ClikClokActivity"
android:label="#string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
If you look at the above code, I never get the second logging. However, if I was to extend from Activity instead and remove the android:name="com.clikclok.ClikClokApplication" attribute from my manifest then I do get the second logging (albeit fails with NullPointers as there is no initialization performed).
So what may be happening in super.onCreate(savedInstanceState); that is causing my application not to work?
Thanks
Update from the above:
I've spent quite a bit of time investigating this and using Eclipse's debugger can now see where my code seems to hang within RoboGuice.
The following code is from the InjectorImpl class:
public void injectMembers(Object instance) {
// Reaches here but...
MembersInjector membersInjector = getMembersInjector(instance.getClass());
// ....this comment is never reached
membersInjector.injectMembers(instance);
}
So I dug into the Guice 3.0 code using my debugger and into the FailableCache class:
public V get(K key, Errors errors) throws ErrorsException {
// Reaches here....
Object resultOrError = delegate.get(key);
// ...but not here
if (resultOrError instanceof Errors) {
errors.merge((Errors) resultOrError);
throw errors.toException();
} else {
#SuppressWarnings("unchecked") // create returned a non-error result, so this is safe
V result = (V) resultOrError;
return result;
}
}
How could this be that it just hangs while retrieving a key from a map? I'm not familiar enough with the code and it is quite confusing to troubleshoot.
Any advice is appreciated.

Try to add some bindings in your configure method.
You can also try to inject your grid view like this
#InjectView(R.id.gridview)
GridView gridView;
I hope this will help you.
Regards.

This was caused by me attempting to inject my Activity class into a service class.
So I was attempting to #Inject an instance of "ClikClokActivity" instead of "Activity".
Once I removed this injection attempt, everything worked fine. Not sure if this exposes some other issue with RoboGuice or Guice itself.

How do I avoid a black screen before startup?

I created a loadpage with a background and a progress bar and when it finishes loading, it starts the main class but the loading screen is not showing up. It is just a black screen while it loads and then the main screen. I put all the work in the onResume and I also tried onStart with no luck
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.loadpage);
//get rid of title bar
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
setRequestedOrientation(1);
}
#Override
public void onResume() {
super.onResume();
words = WordList.sharedWordList(this);
if(generatedLevels==null)
{
generatedLevels = new ArrayList<PuzzleMZLen>();
}
if(!p.isAlive())
{
p.start();
}
Intent i = new Intent(getApplicationContext(), Main.class);
startActivity(i);
}
thanks in advance

You have to use AsyncTask for this kind of work.Your layout is populated after the completion of the loading.So you are watching black screen.
Use onPreExecute of AsyncTask class to show the progress bar. And write loading code in the doInBackground method.

Definitely use AsyncTask for this. I had the same thing going for my app, and here's my code:
private class getAllData extends AsyncTask<Context, Void, Cursor> {
protected void onPreExecute () {
dialog = ProgressDialog.show(Directory.this, "",
"Loading. Please wait...", true);
}
#Override
protected Cursor doInBackground(Context... params) {
DirectoryTransaction.doDepts();
return null;
}
protected void onPostExecute(Cursor c) {
for(int i = 0 ; i < DeptResults.length ; i++){
deptsAdapter.add(DeptResults[i][0]);
}
dialog.dismiss();
}
}
onPreExecute method loads a ProgressDialog that just shows "Loading. Please wait...". doInBackground does what was making my app load (in my case grabbing and parsing text from a server) and then onPostExecute is filling a spinner then dismissing the ProgressDialog. You'll want some thing different for a progress BAR, but the AsyncTask will be very similar. Call it in onCreate with new getAllData.execute(this);

There is a good way how to create a good splash activity.
To prevent ANR you should move all data loading outside of UI thread as it was mentioned at other answers. Please use AsyncTask or any other kind of multi-threading for that.
However to remove annoying black screen which shows for few moments on some slow devices you need to do next steps:
Create bg_splash drawable. It will be shown instead of black background just in time activity shows to user. For example it can be brand logo on brand color background.
Create a splash screen theme and put it into /res/values/themes.xml:
<?xml version="1.0" encoding="utf-8"?>
<resources>
<style name="MyApp.Splash" parent="#style/Theme.Sherlock.Light.NoActionBar">
<item name="android:windowBackground">#drawable/bg_splash</item>
</style>
</resources>
Don't forget assign created theme to splash activity by updating AndroidManifest.xml:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.myapp"
android:versionCode="1"
android:versionName="1" >
...
<application>
<activity
android:name=".SplashActivity"
android:theme="#style/MyApp.Splash" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
<activity>
...
</application>
</manifest>