Codelaby's questions

When updating Android studio to the new version 3.1.1, it has told me that I should change things in the dependencies compilebecause implementationI have uploaded the compilation version to 27...

But gradle when doing build returns me the error:

Android dependency 'com.android.support.constraint:constraint-layout' has different version for the compile (1.0.2) and runtime (1.1.0) classpath. You should manually set the same version via DependencyResolution

I have reset the cache with (File -> Invalidate Caches/Restart -> Invalidate and Restart).but it still gives the error

Of all the modules that I use, only one uses constraint-layoutand I have it implementation 'com.android.support.constraint:constraint-layout:1.1.0'in principle it should be well established.

Searching by SO I have found the recommendation to use apibeforeimplementation

as follows

api 'com.android.support.constraint:constraint-layout:1.1.0'

And it has been mysteriously fixed...

My question is what is the difference in using implementationor api?

I have an app that uses google maps, in debug everything works fine, but when going to release, the map is not displayed

I have created the file google_maps.api.xmloutside of debug, that is, I have it inmain/res/values/google_maps.api.xml

in AndroidManifest.xmlit I assign it

<Aplication>
...

<meta-data
    android:name="com.google.android.geo.API_KEY"
    android:value="@string/google_maps_key" />
...
</aplication>

I see that inside google_maps.api.xmlthere is the following:

Once you have your key (it starts with "AIza"), replace the "google_maps_key" string in this file.

And if it starts AIzawhere do I get the release key?

After Android-Studioit warned me that there is too much load to the main thread.

Skipped 113 frames: the application may be doing too much work on its main thread

I have created a runnable to launch a thread with some processes:

new Thread(new Runnable() {
    @Override
    public void run() {
       UpdateUI(); //Actualiza datos de la Interfaz de usuario
    }
}

But it returns the error:

Only the original thread that created a view hierarchy can touch its views.

I've searched SO and you can launch a thread

getActivity().runOnUiThread(new Runnable() {
    @Override
    public void run() {
       //Cambiar controles
    }
});

But since I have to do a lot of checks or else a thread is executed at the same time, it returns the main thread overload. I even notice that the side menu slows down when it closes.

How do you make a thread but be able to access interface elements in order to modify their data or state?

I have an extended class of BroadcastReceiverin MainActivity.java I launch the listener

registerReceiver(
        new ConnectivityChangeReceiver(),
        new IntentFilter(
                ConnectivityManager.CONNECTIVITY_ACTION));

I find that when I exit the app it shows me the following error in the log:

E/ActivityThread: Activity com.webserveis.app.myconnection.MainActivity has leaked IntentReceiver com.webserveis.app.myconnection.ConnectivityChangeReceiver@32ad932e that was originally registered here. Are you missing a call to unregisterReceiver()? android.app.IntentReceiverLeaked: Activity com.webserveis.app.myconnection.MainActivity has leaked IntentReceiver com.webserveis.app.myconnection.ConnectivityChangeReceiver@32ad932e that was originally registered here. Are you missing a call to unregisterReceiver()?

that was originally registered here. Are you missing a call to unregisterReceiver()

In onStop()I would like to unregister the listener, but not how to implement it

I try to make a request for a resource jsonusingHttpURLConnection

I test the following code in onCreate()

   try {
        URL url = new URL("http://localhost/testrealm/api/v1/status");
        HttpURLConnection urlConnection = null;

        urlConnection = (HttpURLConnection) url.openConnection();
        InputStream in = new BufferedInputStream(urlConnection.getInputStream());

        Log.d(TAG, "get json: " + in.toString());
        urlConnection.disconnect();

    } catch (IOException e) {
        e.printStackTrace();
    }

Error in the request

java.lang.RuntimeException: Unable to start activity ComponentInfo ... android.os.NetworkOnMainThreadException

Log Error integer

06-10 14:32:21.113 E/AndroidRuntime: FATAL EXCEPTION: main
  Process: realm.test.app.testrealm, PID: 11702
  java.lang.RuntimeException: Unable to start activity ComponentInfo{realm.test.app.testrealm/realm.test.app.testrealm.MainActivity}: android.os.NetworkOnMainThreadException
      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2339)
      at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2413)
      at android.app.ActivityThread.access$800(ActivityThread.java:155)
      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1317)
      at android.os.Handler.dispatchMessage(Handler.java:102)
      at android.os.Looper.loop(Looper.java:135)
      at android.app.ActivityThread.main(ActivityThread.java:5343)
      at java.lang.reflect.Method.invoke(Native Method)
      at java.lang.reflect.Method.invoke(Method.java:372)
      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:905)
      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:700)
   Caused by: android.os.NetworkOnMainThreadException
      at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1161)
      at java.net.InetAddress.lookupHostByName(InetAddress.java:418)
      at java.net.InetAddress.getAllByNameImpl(InetAddress.java:252)
      at java.net.InetAddress.getAllByName(InetAddress.java:215)
      at com.android.okhttp.HostResolver$1.getAllByName(HostResolver.java:29)
      at com.android.okhttp.internal.http.RouteSelector.resetNextInetSocketAddress(RouteSelector.java:232)
      at com.android.okhttp.internal.http.RouteSelector.next(RouteSelector.java:124)
      at com.android.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:272)
      at com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:211)
      at com.android.okhttp.internal.http.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:382)
      at com.android.okhttp.internal.http.HttpURLConnectionImpl.getResponse(HttpURLConnectionImpl.java:332)
      at com.android.okhttp.internal.http.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:199)
      at realm.test.app.testrealm.MainActivity.onCreate(MainActivity.java:57)
      at android.app.Activity.performCreate(Activity.java:6010)
      at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1129)
      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2292)
      at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2413) 
      at android.app.ActivityThread.access$800(ActivityThread.java:155) 
      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1317) 
      at android.os.Handler.dispatchMessage(Handler.java:102) 
      at android.os.Looper.loop(Looper.java:135) 
      at android.app.ActivityThread.main(ActivityThread.java:5343) 
      at java.lang.reflect.Method.invoke(Native Method) 
      at java.lang.reflect.Method.invoke(Method.java:372) 
      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:905) 
      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:700) 

HttpURLConnection documentation

I can't find a way to do an update using Realm in Android Java .

Adding data and deleting no problem, I only have problems modifying existing data, it always jumps out to me that it primary keyalready exists and cannot be overwritten, but it is obvious that I assign it the same id in order to overlap the changes.

My RealmInfoDB object is a realm table

import io.realm.RealmObject;
import io.realm.annotations.PrimaryKey;

public class RealmInfoDB extends RealmObject {

    @PrimaryKey
    private long id;

    private long lastUpdate;

    public long getId() {
        return id;
    }

    public void setId(long id) {
        this.id = id;
    }

    public long getLastUpdate() {
        return lastUpdate;
    }

    public void setLastUpdate(long lastUpdate) {
        if (lastUpdate == 0) lastUpdate = System.currentTimeMillis();
        this.lastUpdate = lastUpdate;
    }

}

To add a new record

realm.beginTransaction();
    RealmInfoDB infoDB =  realm.createObject(RealmInfoDB.class);
    infoDB.setId(0);
    infoDB.setLastUpdate(0);
realm.commitTransaction();

To modify I use the same and that is when I get the error

realm.beginTransaction();
    RealmInfoDB infoDB =  realm.createObject(RealmInfoDB.class);
    infoDB.setId(0);
    infoDB.setLastUpdate(0);
realm.commitTransaction();

Mistake

io.realm.exceptions.RealmPrimaryKeyConstraintException: Value already exists: 0

integer error log

06-09 00:24:01.909 E/AndroidRuntime: FATAL EXCEPTION: main
   Process: realm.test.app.testrealm, PID: 1177
   java.lang.RuntimeException: Unable to start activity ComponentInfo{realm.test.app.testrealm/realm.test.app.testrealm.MainActivity}: io.realm.exceptions.RealmPrimaryKeyConstraintException: Value already exists: 0
       at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2339)
       at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2413)
       at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:4032)
       at android.app.ActivityThread.access$900(ActivityThread.java:155)
       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1323)
       at android.os.Handler.dispatchMessage(Handler.java:102)
       at android.os.Looper.loop(Looper.java:135)
       at android.app.ActivityThread.main(ActivityThread.java:5343)
       at java.lang.reflect.Method.invoke(Native Method)
       at java.lang.reflect.Method.invoke(Method.java:372)
       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:905)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:700)
    Caused by: io.realm.exceptions.RealmPrimaryKeyConstraintException: Value already exists: 0
       at io.realm.internal.Table.throwDuplicatePrimaryKeyException(Table.java:684)
       at io.realm.internal.Table.addEmptyRow(Table.java:371)
       at io.realm.Realm.createObject(Realm.java:696)
       at realm.test.app.testrealm.MainActivity.onCreate(MainActivity.java:41)
       at android.app.Activity.performCreate(Activity.java:6010)
       at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1129)
       at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2292)
       at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2413) 
       at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:4032) 
       at android.app.ActivityThread.access$900(ActivityThread.java:155) 
       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1323) 
       at android.os.Handler.dispatchMessage(Handler.java:102) 
       at android.os.Looper.loop(Looper.java:135) 
       at android.app.ActivityThread.main(ActivityThread.java:5343) 
       at java.lang.reflect.Method.invoke(Native Method) 
       at java.lang.reflect.Method.invoke(Method.java:372) 
       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:905) 
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:700) 

I need to capitalize a string in Java on Android

I normally use:

public static String ucFirst(String str) {
    if (str.isEmpty()) {
        return str;            
    } else {
        return Character.toUpperCase(str.charAt(0)) + str.substring(1); 
    }
}


String ciudad = ucFirst("barcelona") //Barcelona

Is there a function in Java or library that I don't know, to put in lowercase letters etc...?

Is there any way to detect that the app is running on Tabletor on Smartphone?

Until now I do it by detecting the width of pixeles, but I find the Samsung Galaxy S3, S4 range... that have more resolution than a tablet and it is not optimal.

I wonder if assetsand resare the same in Android, is that sometimes I find examples that make references to resources in assets and others in res, it's confusing me a bit.

I have had four updates of one of my apps modifying the AndroidManifest.xmlfor if I manage to get "application compatible with all your devices" in the tab and I am not successful in the app tab .

I have the following devices

• EEpad TF101 (ICE_CREAM_SANDWICH)
• ACER LIQUID Z200 (KITKAT)
• MOTO G (Lollipop)

Update I have downloaded an SDKmin version, removed support-screenandandroid:supportsRtl

I define the API for API 14+ devices In all of them I can install it through AndroidStudiobut in the google play tab, I get that it is not compatible with any device.

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="pro.caminsderonda.app.caminsderonda"
    android:installLocation="auto">

    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

    <application
        android:name="pro.caminsderonda.app.caminsderonda.MyApplication"
        android:allowBackup="true"
        android:fullBackupContent="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme">

        <activity
            android:name="pro.caminsderonda.app.caminsderonda.SplashActivity"
            android:configChanges="keyboardHidden|orientation|screenSize"
            android:launchMode="singleInstance"
            android:theme="@style/AppTheme.SplashTheme">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <activity
            android:name="pro.caminsderonda.app.caminsderonda.MainActivity"
            android:label="@string/app_name"
            android:theme="@style/AppTheme.NoActionBar">

            <intent-filter>
                <action android:name="android.intent.action.VIEW" />

                <category android:name="android.intent.category.DEFAULT" />
                <category android:name="android.intent.category.BROWSABLE" />

                <data
                    android:host="caminsderonda.wordpress.com"
                    android:pathPrefix="/"
                    android:scheme="https" />
            </intent-filter>
        </activity>

        <activity
            android:name="pro.caminsderonda.app.caminsderonda.DetailedActivity"
            android:theme="@style/AppTheme.NoActionBar" />
        <activity
            android:name="pro.caminsderonda.app.caminsderonda.SettingsActivity"
            android:label="@string/settings_activity_title" />
        <activity
            android:name="pro.caminsderonda.app.caminsderonda.AboutActivity"
            android:label="@string/about_title_activity"
            android:theme="@style/AppTheme.NoActionBar" />
    </application>

</manifest>

And in the app.graddle

apply plugin: 'com.android.application'

android {

    compileSdkVersion 23
    buildToolsVersion '23.0.2'
    defaultConfig {
        applicationId 'app.caminsderonda.pro'
        minSdkVersion 14
        targetSdkVersion 23
        versionCode 214
        versionName '2.1.4'
        signingConfig signingConfigs.config
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    productFlavors {
    }
}

dependencies {
   compile fileTree(dir: 'libs', include: ['*.jar'])
   testCompile 'junit:junit:4.12'
   compile 'com.android.support:appcompat-v7:23.4.0'
   compile 'com.android.support:design:23.4.0'
   compile 'com.android.support:recyclerview-v7:23.4.0'
   compile 'com.android.support:cardview-v7:23.4.0'
   compile 'eu.the4thfloor.volley:com.android.volley:2015.05.28'
   compile 'com.android.support:palette-v7:23.4.0'
   compile 'com.github.bumptech.glide:glide:3.6.1'
   compile 'com.android.support:support-v4:23.4.0'
}

Inside the console in the device compatibility section

Compatible: 10685

I have a green check for all my devices, but even so, in the playstore tab that the user sees, I get "This application is not compatible with any of your devices" I have them all associated with the same account.

It would be appreciated for those of you who have a MotoG if you can visit the app file from desktop with your associated account, so you can see if it shows you if it is compatible with your device

Leave me a comment here on how compatibility is notified to you.

UPDATE / SOLVED

I have finally found why it informs me that my devices are not compatible.

If the app is paid, as Google does not allow the same developer to buy it, that message appears.

My last test has been to take out a new one app de pago, and then put itgratis

While paid: This app is not compatible with any of your devices.

When I have made it FREE: This application is compatible with all your devices.

Thank you all, for the answers, I have marked as correct the one that has offered me the most compatible devices.

I have implemented a splashcreen by means of one activitythat inflates its layoutwith a centered image, but what I find is that if it is the first time the app is installed, during the loading/compilation a blank screen is shown, more or less 6 seconds , the second time you start the app it starts directly with the SplashScreen.

graphically like this

The first time the app is run after installation or deleting data from the configuration menu

(click open app)...............................(splashscreen)------(done)

The second time the app is opened

(click open app)(splashscreen)------(done)

My question is there any way to put a splashcreen during that Android preload period?

Manifest.xml

<activity
    android:name=".SplashActivity"
    android:configChanges="keyboardHidden|orientation|screenSize"
    android:theme="@style/AppTheme.SplashTheme">
    <intent-filter>
        <action android:name="android.intent.action.MAIN" />
        <category android:name="android.intent.category.LAUNCHER" />
    </intent-filter>
</activity>

Style AppTheme.SplashThemeof the Theme that the activity inherits

<style name="AppTheme.SplashTheme" parent="Theme.AppCompat.Light.NoActionBar">
    <item name="windowActionBar">false</item>
    <item name="windowNoTitle">true</item>
    <item name="android:windowFullscreen">true</item>
    <item name="android:windowEnterAnimation">@android:anim/fade_in</item>
</style>

Layout XML splash_screen.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/colorSplashScreen">

    <LinearLayout
        android:id="@+id/splashscreen"
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center_vertical|center_horizontal">

        <ImageView
            android:layout_width="wrap_content"
            android:contentDescription="@string/about.alt_logo"
            android:layout_height="wrap_content"
            android:src="@mipmap/ic_launcher"
            android:layout_gravity="center"/>

        <TextView android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/app_name"
            android:layout_marginTop="8dp" />

    </LinearLayout>

</LinearLayout>

SplashActivity.java

import android.content.Intent;
import android.os.Bundle;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.view.animation.AccelerateInterpolator;
import android.view.animation.AlphaAnimation;
import android.view.animation.Animation;
import android.widget.LinearLayout;

/*
config_longAnimTime   = 400
config_mediumAnimTime = 300
config_shortAnimTime  = 150
*/
public class SplashActivity extends AppCompatActivity {

    private String TAG = "SplashActivity";


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        final int SPLASH_DISPLAY_LENGTH = 1200;
        final int SPLASH_DISPLAY_OFFSET = getResources().getInteger(android.R.integer.config_shortAnimTime);;

        super.onCreate(savedInstanceState);
        setContentView(R.layout.splash_screen);

        Log.d(TAG, "onCreate() called with: " + "savedInstanceState = [" + savedInstanceState + "]");
        final Handler handler = new Handler();

        handler.postDelayed(new Runnable() {
            @Override
            public void run() {


                final LinearLayout img = (LinearLayout) SplashActivity.this.findViewById(R.id.splashscreen);

                Animation fadeOut = new AlphaAnimation(1, 0);
                fadeOut.setInterpolator(new AccelerateInterpolator());
                fadeOut.setDuration(getResources().getInteger(android.R.integer.config_longAnimTime));

                fadeOut.setAnimationListener(new Animation.AnimationListener()
                {
                    public void onAnimationEnd(Animation animation)
                    {
                        img.setVisibility(View.GONE);

                        handler.postDelayed(new Runnable() {
                            @Override
                            public void run() {
                                //Create an intent that will start the main activity.
                                Intent mainIntent = new Intent(SplashActivity.this, MainActivity.class);
                                SplashActivity.this.startActivity(mainIntent);

                                //Apply splash exit (fade out) and main entry (fade in) animation transitions.
                                overridePendingTransition(R.anim.zoom_enter, android.R.anim.fade_out);

                                //Finish splash activity so user cant go back to it.
                                SplashActivity.this.finish();

                            }
                        }, SPLASH_DISPLAY_OFFSET);

                    }
                    public void onAnimationRepeat(Animation animation) {}
                    public void onAnimationStart(Animation animation) {}
                });

                img.startAnimation(fadeOut);

                Log.d(TAG, "finish SplashScreen: " + SPLASH_DISPLAY_LENGTH);

            }
        }, SPLASH_DISPLAY_LENGTH);

    }

}

Update: The white screen is shown because it inherits from the light theme, because if I add the style of the theme, the screen is shown black.

    <item name="android:background">#FF000000</item>
    <item name="android:colorBackground">#FF000000</item>

I think the solution lies in implementing drawing the icon by loading the theme before using an xml layout, open app ---> apply theme ----> load layout in frontend.

I find that when you turn the device over or if the keyboard is hidden it Activityis reset again, going through onCreate()again.

A possible solution would be to use savedInstanceStatesaving a state variable, but it is not the best solution.

Is it possible to somehow prevent the `Activity from reloading on rotate, or other possible events that make it reset again?

Lately the applications that come out, have incorporated the fact of pressing the back button twice físico como virtualto exit the app, showing a message `Press one more time to exit.

I have the following implemented:

In MainActivitymain I declare the canExitAppglobal variable to set if it has ever been pressed.

public class MainActivity extends AppCompatActivity {
...    
private boolean canExitApp = false;
...

And in the method I onBackPressedcheck the state variable if it is a trueit exits the app if it is in it falseshows the message with a toast.

@Override
public void onBackPressed() {
    //super.onBackPressed();
    if (!canExitApp) {
        canExitApp = true;
        Toast.makeText(this, getString(R.string.app_back_pressed_exit), Toast.LENGTH_SHORT).show();

        new Handler().postDelayed(new Runnable() {

            @Override
            public void run() {
                canExitApp = false;
            }
        }, 2000);
    } else {
        super.onBackPressed();
    }
}

It would be allowing the user X seconds to press to exit again.

Right now it only works on activitys.

How can I add support for 'fragments', so that if there are none left on the stack, it detects if it wants to exit altogether?

If I use, for example, a side menu that loads fragments, I navigate between them, taking into account that if there is one in the stack, it will show it, until it reaches 0, I want the double-click to exit to work.

I am about to start an Android application, I want to release two versions, one lite and one pro .

The two versions will have shared code and depending on whether it is the pro version, it will have extra options.

More or less I have read something about what to do with flavors but I am very new to the world of Android development.

How can you know if it is the first time the app is started?

It would be interesting, in the event that the user updates the application, it is detected as new or update.

I have the url https://www.google.com/maps/@41.3825581,2.1704375,16zthat positions Barcelona on the map, but I find that the address pointer does not come out, it only centers the map.

On my device I have several map apps:

• Cytymapper
• MAPS.ME
• Google Maps
• Google Earth

The code I have to launch the Intent:

Uri uri = Uri.parse("https://www.google.com/maps/@41.3825581,2.1704375,16z");
if (URLUtil.isValidUrl(uri.toString())) {
   startActivity( new Intent(Intent.ACTION_VIEW, uri));
}

I get a ActionListto choose Mapsor Chrome, if MapsI click on the application opens maps, but it does not show me the position with an indicator, it focuses on landmark and point.

If I indicate that it opens with chrome, another appears ActionList, with the other map applications.

My doubts are:

• How do I launch a Intentspecific so that it can be opened with the Maps Apps?
• How can I display the position marker within the map?

Fixed:

To display a location with marker and label

geo:<lat>,<lon>?z=<zoom>&q=<lat>,<lon>(<label>)

To show the location of Barcelona

geo:41.3825581,2.1704375?z=16&q=41.3825581,2.1704375(Barcelona)

To show the ActionListoutput of all compatible applications to position a location

Uri uri = Uri.parse("geo:41.3825581,2.1704375?z=16&q=41.3825581,2.1704375(Barcelona)");
startActivity( new Intent(Intent.ACTION_VIEW, uri));

If you want to send the position directly to the Google Maps application

Intent intent = new Intent(android.content.Intent.ACTION_VIEW, Uri.parse("geo:41.3825581,2.1704375?z=16&q=41.3825581,2.1704375(Barcelona)"));
                intent.setClassName("com.google.android.apps.maps", "com.google.android.maps.MapsActivity");
                startActivity(intent);

How can you get when there is Internet network availability in Android Java?

I need to detect when an Android device has Internet connectivity, in order to receive or send data.

Is there some type of variable or object in Java (Android) to save GPS positions, that is, each point is made up of latitude and the other longitude?

For example, to be able to save the location of Madrid :

Latitude:  40.416775
Longitude: -3.703790

and that allows you to add multiple locations, like a list.

I have a side navigation system, by loading fragments using the property addToBackStackso that when the back button is pressed, the last fragment on the fragment control stack is retrieved with the getSupportFragmentManager().popBackStack().

The problem is that when there are no fragments left in the stack it does not exit the application and the application is displayed as if a blank fragment was loaded, it takes another backstroke to exit the application.

How can I prevent loading the blank fragment and exiting the application if there are no more fragments left on the stack?

The control code onBackPressedin MainActivity.java:

@Override
public void onBackPressed() {
    Log.d(TAG, "onBackPressed()");

    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    if (drawer.isDrawerOpen(GravityCompat.START)) {
        drawer.closeDrawer(GravityCompat.START);

        Log.d(TAG, "close Drawer");
    } else {
        if (getSupportFragmentManager().getBackStackEntryCount() > 1 ){
            getSupportFragmentManager().popBackStack();

            Log.d(TAG, "fragment Manager popBackStack()");
        } else {
            super.onBackPressed();
        }
    }
}

How can you get the ip of the device in C#? That it works in the scope of the UWP (Universal Windows Platform) known as universal applications of windows10