Develop Reference

Splash screen at the beginning of app

I need some help. I have a problem with my app. I want to put a splash screen at the beginning. I have done it before. I have made the code, the layout, and all works perfectly in a new project! When I put the code I run it on my phone and the layout in my application, the application runs perfectly without any errors. But when I open it on my phone, it stops and it doesn't open it!!! Can you suggest something??
my android manifest.xml:
android:name=".activities.SplashScreenActivity"
android:label="#string/splash">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>

Assuming you want to launch Main activity from your SplashScreenActivity.
In your SplashScreenActivity's onCreate():
Intent intent = new Intent(SplashScreenActivity.this, MainActivity.class);
startActivity(intent);
finish();
The first 2 lines launch Main activity through an Intent, and the 3rd line kills SplashScreenActivity so you cannot go back to it from MainActivity.

public class SplashScreenActivity extends AppCompatActivity {
private int SLEEP_TIMER = 3;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.activity_splash_screen);
View imageView = findViewById(R.id.imageView);
Animation animation = AnimationUtils.loadAnimation(getApplicationContext(),R.anim.fade);
imageView.startAnimation(animation);
getSupportActionBar().hide();
LogoLauncher logoLauncher = new LogoLauncher();
logoLauncher.start();
}
private class LogoLauncher extends Thread {
public void run() {
try {
sleep(1000 * SLEEP_TIMER);
} catch (InterruptedException e) {
e.printStackTrace();
}
Intent intent = new Intent(SplashScreenActivity.this,LoginActivity.class);
startActivity(intent);
SplashScreenActivity.this.finish();
}
}

Android getIntent() not returning expected Intent when launched from history

I have a problem with Activity lifecycle and NFC:
I have a MainActivity with the AndroidManifest.xml entry:
<activity
android:name=".ui.main.MainActivity"
android:finishOnTaskLaunch="true"
android:launchMode="singleTask"
android:theme="#style/AppTheme.NoActionBar">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
<intent-filter>
<action android:name="android.nfc.action.NDEF_DISCOVERED" />
<category android:name="android.intent.category.DEFAULT" />
<data android:mimeType="application/androidbeam" />
</intent-filter>
<intent-filter>
<action android:name="android.nfc.action.NDEF_DISCOVERED" />
<category android:name="android.intent.category.DEFAULT" />
<data android:mimeType="application/nfctag" />
</intent-filter>
<meta-data
android:name="android.nfc.action.TECH_DISCOVERED"
android:resource="#xml/nfc_tech_filter" />
</activity>
where launchMode="singleTask" is used for NFC to prevent multiple MainActivity instances.
In MainActivity I have the following code:
public class MainActivity extends BaseActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Timber.d("onCreate");
setContentView(R.layout.activity_main);
handleIntent(getIntent());
}
#Override
protected void onNewIntent(Intent intent) {
Timber.d("OnNewIntent");
handleIntent(intent);
}
private void handleIntent(Intent intent){
String action = intent.getAction();
String intent_type = intent.getType();
Timber.d("Intent action:" + action + "\n " + "Intent type:" + intent_type);
if (NfcAdapter.ACTION_TECH_DISCOVERED.equals(action) || NfcAdapter.ACTION_NDEF_DISCOVERED.equals(action)) {
// Handle data from intent.getParcelableExtra()
Timber.d("onNFCDataReaded");
}
// and implementing creating of activity here
}
#Override
protected void onResume() {
super.onResume();
Timber.d("onResume");
enableNFCDispatch();
}
#Override
protected void onPause() {
Timber.d("onPause");
super.onPause();
disableNFCDispatch();
}
#Override
protected void onDestroy() {
super.onDestroy();
Timber.d("OnDestroy");
}
#Override
public void onBackPressed() {
super.onBackPressed();
Timber.d("OnBackPressed");
}
}
Everything works as expected, except for one use case:
When I am opening the application first with Android Beam or an NFC tag, onCreate() is called and it passes getIntent() to handleIntent() with the data received from another phone or an NFC tag. This works fine.
But after that, when I
click onBackPressed button inside MainActivity (i.e. exiting the application), and
then hold the Home button and in the overview screen select my application,
my application is opened again and onCreate() is called again. However, getIntent() returns the old intent with same data (intent.getAction(), intent.getParcelableExtra()) as I got with Android Beam or NFC tag!
I don't understand why! I expect to receive a new intent; the same as if the app is created when I click the application icon.
Can somebody help me with this?
Here is my MainActivity lifecycle:
MainActivity: onCreate
MainActivity: handleIntent
MainActivity: Intent action: android.nfc.action.NDEF_DISCOVERED
Intent type: application/androidbeam
MainActivity: onNFCDataReaded
MainActivity: OnResume
MainActivity: OnBackPressed
MainActivity: onPause
MainActivity: OnDestroy
//After that, I am holding Home Button and selecting my application from
//OverViewScreen, and getting next Log:
MainActivity: onCreate
MainActivity: handleIntent
MainActivity: Intent action:android.nfc.action.NDEF_DISCOVERED
Intent type:application/androidbeam
- // I do not expect it here !!!!!
MainActivity: onNFCDataReaded
MainActivity: OnResume

This is expected behavior. When you bring your activity to the background and later open the activity again from history (long-press home key), Android will recreate the previous activity stack and the activity will be launched with the same parameters as it was opened before. I.e. if it was launched with intent NDEF_DISCOVERED, it will, again, receive that intent.
However, you can easily detect if the activity was launched with the original intent or if it was launched from history. In the latter case, Android adds the flag FLAG_ACTIVITY_LAUNCHED_FROM_HISTORY to the intent. Consequently, you can test for this flag in your handleIntent() method:
if ((intent.getFlags() & Intent.FLAG_ACTIVITY_LAUNCHED_FROM_HISTORY) == 0) {
if (NfcAdapter.ACTION_NDEF_DISCOVERED.equals(intent.getAction()) ||
NfcAdapter.ACTION_TECH_DISCOVERED.equals(intent.getAction())) {
...
}
}

Launch login activity instead of MainActivity if app is on its first run

I need my app to check if it's running for first time or not. If it's the first time, then it should launch LoginActivity instead of MainActivity. And if it's not the first run, it should display MainActivity as usual.
I used SharedPreference value to check if it's available, then app decides its not running it's first run.
This is what I've tried so far
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Set default values into settings
PreferenceManager.setDefaultValues(this, R.xml.preferences, false);
// Check if the app is running on its first run
SharedPreferences fRun = getPreferences(MODE_PRIVATE);
if(fRun.getBoolean("firstrun", true)){
SharedPreferences.Editor editX=fRun.edit();
editX.putBoolean("firstrun", false);
editX.apply();
// Login activity stuff here
// Goto login screen
Intent loginIntent=new Intent(getApplicationContext(),LoginActivity.class);
startActivity(loginIntent);
//finish();
} else {
setContentView(R.layout.activity_main);
}
}
}
My problem is, when I run my app, it suddenly crashes and displays message Unfortunately, the app has stopped.
Why does the app crash? Is it because code in my LoginActivity have errors or do I need to first load MainActivity then call LoginActivity?

You can use LoginActivity as LAUNCHER activty and check whether the user is logged in. If yes, start MainActivity.
The AndroidManifest.xml:
<activity
android:name=".LoginActivity"
android:label="#string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
<category android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>
<activity android:name=".MainActivity"/>
And the LoginActivity:
public class LoginActivity extends ActionBarActivity {
private static final String LOGIN_KEY = "LOGIN_KEY";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
SharedPreferences pref = getPreferences(Context.MODE_PRIVATE);
if (pref.getBoolean(LOGIN_KEY, false)) {
//has login
startActivity(new Intent(this, MainActivity.class));
//must finish this activity (the login activity will not be shown when click back in main activity)
finish();
}
else {
// Mark login
pref.edit().putBoolean(LOGIN_KEY, true).apply();
// Do something
}
}
}
The MainActivity:
public class MainActivity extends ActionBarActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Do something
}
}

<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="#style/AppTheme"
tools:ignore="GoogleAppIndexingWarning">
<activity android:name=".Activity.MainActivity" />
<activity android:name=".Activity.SignupActivity" />
<activity android:name=".Activity.SigninActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>

You need to rearrange your Activity classes a bit I think. It's very simple to decide if your application has run first time or not and launch some Activity based on this decision. I would like to suggest the following architecture.
You can set a LauncherActivity to decide whether you need to start LoginActivity or MainActivity like this:
public class LauncherActivity extends Activity {
private boolean firstLaunch = false;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Intent i;
SharedPreferences pref = getSharedPreferences(Constants.ApplicationTag, MODE_PRIVATE);
firstLaunch = pref.getBoolean(Constants.FIRST_LAUNCH, true);
if (firstLaunch) {
i = new Intent(LauncherActivity.this, LoginActivity.class);
startActivity(i);
} else {
i = new Intent(LauncherActivity.this, MainActivity.class);
startActivity(i);
}
finish();
}
}
You have another problem I need to sort out is calling setContentView inside an else statement which is erroneous. You need to put setContentView just after the super.onCreate(savedInstanceState); in any of your Activity.
When you're putting it inside an else statement, the content view may not be set which will cause an application crash.
So remove the checking for first run from MainActivity and move that portion to LauncherActivity which will solve the problem.
The AndroidManifest.xml of the LauncherActivity may look like this
<activity
android:name=".Activities.LauncherActivity"
android:label="#string/app_name"
android:theme="#style/AppTheme.NoActionBar">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>

How to put the a picture before the app starts?

I'm trying to put a picture in my app but not really sure how.
Do I need a new activity for it? If so, how that activity will understand when to stop and go to the real program?
To clarify what I'm trying to do: When you open any app probably I think that they will have what I'm talking about. For example, the Youtube app when opened there will be a screen showing a the logo of Youtube before it opens the real app. I think this screen takes about 3 to 5 seconds.

Use splash activity as it was sais below. Here's example:
public class SplashActivity extends Activity {
private static String TAG = SplashActivity.class.getName();
private static long SLEEP_TIME = 2; // Time in seconds to show the picture
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.requestWindowFeature(Window.FEATURE_NO_TITLE); // Removes title bar
this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN); // Removes notification bar
setContentView(R.layout.splash_screen); //your layout with the picture
// Start timer and launch main activity
IntentLauncher launcher = new IntentLauncher();
launcher.start();
}
private class IntentLauncher extends Thread {
#Override
/**
* Sleep for some time and than start new activity.
*/
public void run() {
try {
// Sleeping
Thread.sleep(SLEEP_TIME*1000);
} catch (Exception e) {
Log.e(TAG, e.getMessage());
}
// Start main activity
Intent intent = new Intent(SplashActivity.this, MainActivity.class);
SplashActivity.this.startActivity(intent);
SplashActivity.this.finish();
}
}}
And don't forget to add to the manifest
<activity
android:name=".SplashActivity"
android:screenOrientation="portrait">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>

It called Splash Screen
You should to create new activity which has a timer. After 1-2 seconds it launches your main activity.
How to implement Splash Screen in android

First time shown Activity solution

I need to show one SecondActivity only once and only on first launch of the application. I implemented it like this (see below), but I don't really like a solution because I need to inflate layout on onResume() because if I do not I have an empty Activity when I click back hardware button being on SecondActivity.
public class TestActivity extends Activity {
public static final String PREFS_NAME = "MyPrefsFile";
public static final String FIRST_RUN = "FirstRun";
SharedPreferences sharedPreferences;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
sharedPreferences = getSharedPreferences(PREFS_NAME, 0);
if (sharedPreferences.getBoolean(FIRST_RUN, false)) {
setContentView(R.layout.main);
} else {
Intent i = new Intent(this, Second.class);
startActivity(i);
}
}
#Override
protected void onResume() {
super.onResume();
setContentView(R.layout.main);
}
}
In Second Activity I just put flag FirstRun to true.

In the first Activity call finish() after you make the call to startActivity(i)
Like this...
if (sharedPreferences.getBoolean(FIRST_RUN, false)) {
setContentView(R.layout.main);
} else {
Intent i = new Intent(this, Second.class);
startActivity(i);
finish();
}
You can then remove setContentView(...) from onResume().

The bestWay i can think is having Init activity that don't have any layout and just decides what activity to run first

If all you want is to prevent the user to go back to the activity, add the "noHistory" flag in your manifest file, like this:
<activity android:name=".SecondActivity" android:noHistory="true">
If this is your "splash screen" activity, and only needs to be shown on app start, do this:
<activity android:name=".SecondActivity" android:noHistory="true">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>