Most voted "android" questions
Android is an operating system for mobile devices developed by Google and the Open Handset Alliance. Use this tag to reference questions related to programming for Android and be relevant only to this operating system. Use the [android-subject] tag instead of [subject] alone.
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156
votes7
answers20768
viewsHow to protect source code?
I am thinking of making an application to sell, I would like to know how to protect my source code to keep my software safe. I saw the Java bytecodes, stored in the file .class are easily converted…
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35
votes2
answers6387
viewsWhat is Android NDK?
From what I understand Android NDK is focused on development with c or c++, despite supporting Java through JNI (Java Native Interface), but I would like to understand some things: When we compile…
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30
votes3
answers1450
viewsRemote control of an Android is technically possible?
Today I saw the following video: https://www.youtube.com/watch?v=9J7GpVQCfms Shows a bracelet that projects the screen of an Android phone paired on the user’s arm. This then can manipulate the cell…
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29
votes3
answers13164
viewsWhat are the default sizes of android images?
I’m creating my first app on the Android platform and as far as I know one of the negatives of this platform is that existing devices on the market have different screen sizes. I created a project…
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29
votes1
answer10807
viewsWhen and how to implement Parcelable vs Serializable?
After a long time using the Serializable implementation in my classes on the Java platform (Android), I discovered Parcelable, but I was in doubt regarding the following questions below: 1. When to…
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28
votes2
answers1891
viewsHow to design a basic socket client application
First of all I apologise for the long text, and for the various points raised. I thought it best to cast everyone on a question just because they are interrelated and because I think anyone with…
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27
votes1
answer1896
viewsWhat’s the difference between "@id" and "@+id"?
When creating a component, we use @+id/nome to identify him. For example: <TextView android:id="@+id/tv_fornecedor" android:layout_width="match_parent" android:layout_height="match_parent"…
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25
votes3
answers1989
viewsHow do I know if the first digit of a string is a number?
I have a form where I need to validate the taxpayer number. If you start with PT or if it is a number without an acronym I validated by the Portuguese finance algorithm, otherwise I do not validate.…
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24
votes3
answers36150
viewsHow to use Mysql on Android
After some searches, I saw that the only database that Android can use is Sqlite, It is correct this information? Because I have an application that connects to an online database (Mysql) and would…
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24
votes2
answers17995
viewsWhat is a context on Android?
What is a context on Android? What’s the difference between getContext(), getApplicationContext(), getBaseContext()? Has some relationship with getActivity?…
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23
votes3
answers627
viewsOptimize Java method using the Scopes concept
Well some time ago, when I took some classes J2ME to Mobile (almost deceased ), where I was presented to a concept of scope hitherto unknown by me, that would be: { // cria um novo escopo } Where…
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22
votes1
answer68862
viewsHow to generate a . apk file in Android Studio?
If it is already generated in which folder it is located?
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22
votes1
answer311
viewsClick on Loginbutton facebook on android using Xamarin with Facebooksdk nothing happens
I’m using Xamarin to try to log in with facebook, I already generated the Hash and appid. ( Apparently correct, because previously the app returned me an msg saying that the HASH was invalid ).…
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21
votes2
answers22046
viewsWhat is the difference between px, dp, Dip and sp?
What’s the difference between px, dp, dip and sp on Android?
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21
votes8
answers7407
viewsWhat better way to work offline and synchronize data with server?
I am working on a project where it will be necessary for users to register offline and then submit their registration to the server as soon as the internet connection is available. My problem is…
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21
votes3
answers5317
viewsWhy use get and set in Java?
I learned in college a while back that you should always use getters and setters for access of values in an object and I heard that it is for security reasons. So I ended up always using and seeing…
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21
votes1
answer6034
viewsWhat is the storage limit for Sqlite?
A new demand for the application of the company where I work, I need to store more than 100k of records in different tables, I’m worried if the Sqlite will withstand such demand, my question is:…
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20
votes1
answer15905
viewsHow to rescue the GPS location in coordinates, from all users of the application?
Explanation/Scenario: I am developing an application that must redeem in real time the location of users of the same, and these users aware of this, will also, access the location of other users, in…
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20
votes1
answer10213
viewsWhat is the Firebase?
I haven’t touched with Android in a while and I haven’t had a chance to mess with Firebase. However, it is often mentioned in SOPT questions. After all, what is Firebase? It is a set of…
android firebase firebase-cloud-messaging firebase-cloud-functions firebase-databaseasked 6 years ago Piovezan 15,850 -
19
votes1
answer3428
viewsCommunication between Android and USB devices
I’m developing an application for Android that communicates with a USB device, a printer, an Arduino or another Android device. Is it possible to read and write on the Android USB port? How should I…
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19
votes1
answer361
viewsCheck if a screen screenshot has been taken
The Snapchat has a feature that is to notify the user every time someone, any other user, takes a screenshot of their stories. At first I thought about the hypothesis of checking if the user pressed…
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18
votes2
answers389
viewsAndroid app for tablets only
I developed an android app using Android Studio, in the archives xml of the screens I used the layout of Nexus 10 because my application is only for tablets. After I moved the app up to the Google…
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17
votes3
answers506
viewsHow to instantiate a Gridview or a Listview for the same Activity?
In my app I am presenting a list of items. I would like in certain situations to be presented with a ListView and others like GridView. Situations are: Smartphone(Portrait) - ListView…
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17
votes1
answer2508
viewsHow to develop two versions of the same application, one free and the other paid?
I’m starting the development of an application for Android using Android Studio, I intend to make it available in two versions, one paid, with more features, and one free, more basic. I thought…
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16
votes9
answers17662
viewsError: R cannot be resolved
I am creating an Android project and am facing the following error in my IDE. package br.com.app; import android.R; public class MinhaApp extends Activity { @Override public void onCreate (Bundle…
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16
votes6
answers14835
viewsAndroid app development: what are the tools and language to start a project?
I would like to venture into creating apps for Android. At first I would make one just for own use. What tools would I need to build my development environment? My application would use database,…
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16
votes1
answer1089
viewsWhy is the "@" symbol being translated to "¿" when sent via SMS from an Android 2.3 device?
I’m developing an application for Android that sends commands to a remote device via SMS. The commands used are all common text messages, and some of them are started with the prefix A@@. To test…
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15
votes3
answers1353
viewsArchitecture for a JSF Application with Android APP
I am in the planning part of a web application that I will develop for a Client. It will be Cruds and some report, nothing too complicated. At the moment I’m designing an architecture so that this…
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15
votes2
answers2984
viewsGoogle Play private app
There is the possibility to do the upload of an app for Google Play and it is only available for a list of users of my interest? As happens on youtube that can only see that video who has permission…
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15
votes1
answer693
viewsHow to discover the mobile operator of Android?
I’m developing an app on Eclipse and I want it to work only on devices of a particular carrier. Any idea how to check the operator?
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15
votes0
answers312
viewsCardview does not display JSON information
Guys I’m trying to set some information in a Cardview, where these are obtained from a JSON, however, it does not display, the information search this ok, it returns the values normally but does not…
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15
votes2
answers13776
viewsWhat’s the difference between Apache Cordova and Ionic?
I have some questions regarding Apache Cordova and Ionic. Both, to me, seem the same thing with the same purpose, allow the creation of hybrid applications for mobile devices. See that in the ionic…
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15
votes2
answers3894
viewsError message: "java.lang.Illegalstateexception: package not installed?"
Situation I’m getting this kind of mistake in mine logcat and I don’t know exactly what it could be. Although this error is not compromising the operation of the application (as far as it is…
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14
votes1
answer13158
viewsDeveloping Android apps using Python
Is it possible to create Android apps with the Python language? If yes, how does it work?
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14
votes1
answer542
viewsIs Android an OS or a stack software?
The definitions given by Google for Android "Android is an open-source software stack for a wide range of mobile Devices and a corresponding open-source project led by Google." and by American…
androidasked 9 years, 12 months ago Geison Santos 4,428 -
14
votes1
answer2918
viewsHow to translate Android app?
I created the values-es folder, with the strings.xml file with items in the array string. However when I put the translation into Spanish on my cell phone, I open the application and nothing…
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14
votes2
answers13123
viewsIdentify if set of coordinates is within a radius on Android
I want to delimit a radius from a central coordinate (the red marker in the figure) and, from a set of coordinates (the green markers), check that these are within the area bounded by this radius.…
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13
votes3
answers514
viewsJava / Android: how to view Stacktrace log
How can I display the whole exception error code (Fullstacktrace) in Android Log? try { //CODE }catch (Exception e){ Log.e(TAG,e.getStackTrace()); }…
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13
votes2
answers1894
viewsHow to align strings to use in a listview?
In my Android project I need to create a table with a listview but the data always comes misaligned. I place each record of my database in a position of a string array to use it in listview. The…
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13
votes3
answers6699
viewsConversion of JSON string to Java object
I am trying to convert a JSON string into a Java object used by Gson. This is the json I get from the webservice: {"concurso": { "numero":1499, "data_sorteio":"01\/06\/2013",…
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13
votes3
answers711
viewsExtend classes with private constructor
Because I can’t extend classes with private builder? Consindo the classes To: public class A { private A(){} public static void limao(){} } and B: public class B extends A { private B(){} public…
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13
votes1
answer796
viewsHow to treat exception in a Webview?
I wanted to know how to treat exceptions in my Webview, because sometimes the site ta off, and the page does not load, and sometimes even crashes the application. I tried a try catch no load, but…
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13
votes2
answers4510
viewsWhat is the difference between Activity, Fragmentactivity and Fragment?
What are the differences in functioning, performance etc. in inheriting from each of the classes in controllers views (XML) on Android?
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13
votes2
answers756
viewsDisplay player in Android notifications area
I created an app that transmits a Streaming radio, but if I "minimize" the application it continues playing. So I’d like to know how I can get you to open a box at notification list android, type…
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13
votes2
answers3271
viewsWhat is the difference between Listview and Recyclerview?
What difference between ListView and RecyclerView on Android? From which Api to RecyclerView is available? It is valid to use the RecyclerView and not the ListView?…
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13
votes1
answer1010
viewsAndroid Studio does not open new project (stay transpatente)
when I installed and tried to open for the first time, it worked perfectly, however, when I tried to open again later, when I click on "Start a new Android Studio project", the window opens, but is…
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12
votes2
answers235
viewsHow to avoid an Illegalstateexception: The content of the Adapter has changed but Listview Did not receive a notification?
I have a Activity that displays a ListView, to which a Adapter "backed by" a ArrayList global. If I add an element to that ArrayList, ideal is to do it in the main thread and immediately call…
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12
votes3
answers4720
viewsImplement HTTP POST and GET Requests on Android
How do I send information via get to an Android url, passing parameters? And how do I return data like JSON from my PHP?
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12
votes2
answers1942
viewsHow to insert EMOJI - SMARTFONES into Mysql database with PHP?
Well, since the question is very self-explanatory I will only reinforce the question. I have an APP chat system, which through the HTML, command to PHP with Ajax, but if the usurer tries to insert…
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12
votes3
answers16185
viewsCalculate difference between dates
I need to calculate the difference between the registration date and the current date, if it is greater than 6 months, return boolean. I am registering at the bank the registration date as follows:…