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1. Top results related to how does implicit intent work in android studio

   • How does an interface in Android Studio work?

     Top Answer

     Answered Oct 17, 2019 · 2 votes

     QUESTION 1 - What is the last function doing? It looks to me that it calls the method onMessageRead() but this method doesn't contain any activity in it's definition.

     The last function is the call to the method onMessageRead() your listener implements.

     You have declared a variable with the type OnMessageReadListener, that is, it implements the method onMessageRead (String message).

     OnMessageReadListener messageReadListener;....public interface OnMessageReadListener{ public void onMessageRead(String message);}

     QUESTION 2 - What is the whole onAttach method doing? I read things like "Called when a fragment is first attached to it's context" but I don't understand this. What is the context here?

     This is somewhat confusing but it boils down to the android activity life cycle.

     The Android system, invokes some callbacks when the activity enters new states to allow developers to act on those state changes.

     In this case, the Android system calls the OnAttach method when the fragment is attached to your Activity.

     Activity activity = (Activity) context; try{ messageReadListener = (OnMessageReadListener) activity; }catch (ClassCastException e){ throw new ClassCastException(); }

     As you see, what is happending here is the developer is telling Android "when you attach my fragment to the cointainer activity, set the messageReadListener variable to the Activity itself, that must implement the OnMessageReadListener interface or a ClassCastException will be thrown".

     QUESTION 3 - I really don't get it, when this last method onMessageRead() get's called here.

     It's called on your QUESTION 1 code.

     button.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { String message = editText.getText().toString(); messageReadListener.onMessageRead(message); } });

     So, What's going on here ?

     The developer is simply using interfaces to allow that fragment to send a message to the main activity when you click a button in your fragment.

     Here you say "I got a variable that holds anything that implements the OnMessageReadListener interface".

     Then on the main Activity you implement that interface by creating the method , onMessageRead().

     When Adroid attaches the fragment to the main activity you assign that activity to your Fragment's variable messageReadListener, on the OnAttach callbak.

     And after that, you just use that variable to call, at the OnClik button event, the onMessageRead() method on the main activity.

     That allows your fragment and the main activity to comunicate untangled, that is without holding one, a reference to the other.

     EDIT: QUESTION 4 I still think that I have an error somewhere, because why wouldn't I just write this MainActivity.onMessageRead(message); immediately? And why don't I just define the onMessageRead() method directly in the MainActivity and get rids of the interface in the fragment?

     You can do that, but that would mean those classes get tangled. That is you need a reference to the MainActivity on your fragment.

     With the interface, you can use your fragment on ANY activity. You just need it to implement the interface, on any new activity to use it.

     So it is easier to reuse your code, and will be much cleaner to implement that interface on any activity you want your Fragment to be used, than to get an instance of each activity you want your Fragment to be used in, and check around what is the caller one.

     To code to interfaces is considered a good practice on Object Oriented programming.

     Check all answers on Stack Overflow

     1/5

   • How does implicit conversion work in Java?

     Top Answer

     Answered Aug 14, 2023 · 31 votes

     Explanation

     Let's take a look at your code and some modified examples:

     // Example 1byte byteValue = 2;-// Example 2byte byteValue = 4/2;// Example 3byte byteValue = 2000;// Example 4byte byteValue = 500/2;// Example 5int n1 = 4;byte byteValue = n1/2;

     Non-lossy conversion

     You will get the mentioned compile-time error for Example 3, Example 4 and Example 5.

     First of all, the simple math you have for Example 1 to 4 is executed at compile-time. So Java will compute 500 / 2 at compile-time and replace the code with basically byte byteValue = 250;.

     Valid values for bytes in Java are -128 to 127. So any value outside of that range can not just be taken as a byte but requires explicit conversion. Because of that, Example 1 and Example 2 pass.

     Lossy narrowing conversion

     To understand why the rest fails, we have to study the Java Language Specification (JLS), more specifically chapter 5.1.3. Narrowing Primitive Conversion and 5.2. Assignment Contexts.

     It says that a conversion from int to byte (if it is outside of the range of byte) is a narrowing primitive conversion and that it may lose information (for obvious reasons). It continues by explaining how the conversion is done:

     A narrowing conversion of a signed integer to an integral type T simply discards all but the n lowest order bits, where n is the number of bits used to represent type T. In addition to a possible loss of information about the magnitude of the numeric value, this may cause the sign of the resulting value to differ from the sign of the input value.

     From the second chapter, assignments with narrow conversions are allowed if the value is a constant expression.

     In addition, if the expression is a constant expression (§15.29) of type byte, short, char, or int:

     A narrowing primitive conversion may be used if the variable is of type byte, short, or char, and the value of the constant expression is representable in the type of the variable.

     Long story short, a narrowing conversion that may lose information (because the value exceeds the range) has to explicitly be announced to Java. Java will not just do it for you without you forcing it. That is done by a cast.

     So for example

     byte byteValue = (byte) (500 / 2);-

     resulting in the value -6.

     Constant expression

     Your last example is very interesting:

     int n1 = 4;byte byteValue = n1/2;-

     Although this does not exceed the range, Java still treats it as lossy narrowing conversion. Why is that the case?

     Well, Java can not ensure 100% that n1 is not changed last second before n1/2 is executed. Therefore, it would have to consider all of your code to see if maybe someone accesses n1 sneaky and changes it. Java does not do this kind of analysis at compile-time.

     So if you can tell Java that n1 stays 4 and can actually never change, then this will actually compile. In this specific case, it would be enough to make it final. So with

     final int n1 = 4;byte byteValue = n1/2;-

     it will actually compile because Java knows that n1 stays 4 and can not change anymore. Hence it can compute n1/2 at compile-time to 2 and replace the code with basically byte byteValue = 2;, which is in range.

     So you made n1 / 2 a constant expression, as explained before in 5.2. Assignment Contexts.

     You can check the details what it needs to have a constant expression in 15.29. Constant Expressions. Basically everything simple that can easily be computed in place without any method invocations or other fancy stuff.

     Check all answers on Stack Overflow

     2/5

   • how to use implicit intent in android

     Top Answer

     Answered Sep 05, 2023 · 0 votes

     I had find issue in your code. Inside Click event of button change as per below. use startActivityForResult() instead of startActivity().

     It will works.

     Check all answers on Stack Overflow

     3/5

   • Android Studio - how does setImageDrawable work?

     Top Answer

     Answered Jan 10, 2016 · 17 votes

     You need to know what is a parameter and the difference between setImageDrawable and setImageResource.

     Different methods requires different parameters. And by that I mean different types of parameters. In this case, setImageDrawable requires a parameter of type Drawable but you gave it a parameter of type int. So that's why it doesn't work.

     I don't know if you know this. All the resource ids (i.e. the R.xxx.xxx thingy) in Android are integers! So when you try to pass an integer when it actually needs a Drawable, it fails to do so, of course.

     What you need is to either

     1) Find a method that accepts an integer as a parameter. or;

     2) Use the resource id to get a Drawable object.

     For 1), you can use the setImageResource method. Just replace the word Drawable with Resource and change nothing else!

     If you prefer 2), you can use this method to get the drawable using a resource id.

     Drawable myDrawable = getResources().getDrawable(<insert your id here>);

     And then you can pass myDrawable as the parameter:

     p.setImageDrawable(myDrawable);

     Check all answers on Stack Overflow

     4/5

   • How does setOnFocusChangeListener work in Android?

     Top Answer

     Answered Aug 05, 2020 · 0 votes

     I guess it is cause the editText is never leaving the focus.

     On the GUI editor or XML, there is a property named "focusOnTouch" which editText Views have on true by default that let you get the focus for the editText, but if there is no other view with that property on true too, no view could get the focus.

     That property exists for every View, set it to true for each View you want to consider to get the focus when clicking, otherwise, the focus won't be passed to other views like your textView or button.

     Check all answers on Stack Overflow

     5/5

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2. www.geeksforgeeks.org · implicit-and-explicitImplicit and Explicit Intents in Android with Examples

   www.geeksforgeeks.org · implicit-and-explicit

   

   Aug 30, 2024 · Implicit Intent. Using implicit Intent, components can’t be specified. An action to be performed is declared by implicit intent. Then android operating system will filter out components that will respond to the action. For Example, In the above example, no component is specified, instead, an action is performed i.e. a webpage is going to be opened.

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4. developer.android.com · guide · componentsIntents and intent filters | Android Developers

   developer.android.com · guide · components

   

   Sep 20, 2024 · Example implicit intent. An implicit intent specifies an action that can invoke any app on the device able to perform the action. Using an implicit intent is useful when your app cannot perform the action, but other apps probably can and you'd like the user to pick which app to use.

5. medium.com · @TippuFisalSheriff · implicit-vsImplicit vs. Explicit Intent in Android: Understanding the ...

   medium.com · @TippuFisalSheriff · implicit-vs

   

   Jul 4, 2024 · Implicit intents do not specify the component name. Instead, they declare a general action to perform, allowing the system to find an appropriate component to handle the intent. This is...

6. www.tutlane.com · tutorial · androidAndroid Implicit Intents with Examples - Tutlane

   www.tutlane.com · tutorial · android

   

   • Android Implicit Intent Example
   • Activity_main.xml
   • Output of Android Implicit Intent Example

   Following is the complete example of implementing an implicit intent in the android application. Create a new android application using android studio and open an activity_main.xml file from \src\main\res\layout path. In case if you are not aware of creating an app in android studio check this article Android Hello World App.

   See full list on tutlane.com

   Now open the main activity file MainActivity.java from \src\main\java\com\tutlane\com.tutlane.helloworldpath and write the following code to open a new browser window on button click to load given url.

   See full list on tutlane.com

   When we run above example using android virtual device (AVD)we will get a result like as shown below When we enter the website URL and click on the button it will open a website in a new browser window in the same application. This is how we can use Android Implicit Intents in applications based on our requirements.

   See full list on tutlane.com

7. developer.android.com · training · basicsSending the user to another app | Android Developers

   developer.android.com · training · basics

   

   Jan 3, 2024 · Learn how to create an implicit intent for a particular action, and how to use it to start an activity that performs the action in another app.

8. developer.android.com · guide · componentsCommon intents | Android Developers

   developer.android.com · guide · components

   

   Sep 20, 2024 · This page describes several implicit intents that you can use to perform common actions, organized by the type of app that handles the intent. Each section also shows how you can create an intent filter to advertise your app's ability to perform the action.

9. People also ask

   What is implicit intent in Android?

   • Implicit Intent Using implicit Intent, components can’t be specified. An action to be performed is declared by implicit intent. Then android operating system will filter out components that will respond to the action. For Example, In the above example, no component is specified, instead, an action is performed i.e. a webpage is going to be opened.

   Implicit and Explicit Intents in Android with Examples

   www.geeksforgeeks.org/implicit-and-explicit-intents-in-android-with-examples/

   See all results for this question

   What is an implicit intent?

   • An implicit intent specifies an action that can invoke any app on the device able to perform the action. Using an implicit intent is useful when your app cannot perform the action, but other apps probably can and you'd like the user to pick which app to use.

   Intents and intent filters | Android Developers

   developer.android.com/guide/components/intents-filters

   See all results for this question

   What is an intent in Android?

   • Intents are a fundamental component of Android, enabling communication between different parts of an app or even between different apps. In this article, we’ll dive into the differences between implicit and explicit intents, their use cases, and provide examples to illustrate how they work. What is an Intent?

   Implicit vs. Explicit Intent in Android: Understanding the ... - Medium

   medium.com/@TippuFisalSheriff/implicit-vs-explicit-intent-in-android-understanding-the-differences-with-examples-3b99fd4cfa0a

   See all results for this question

   What is explicit intent in JavaScript?

   • Syntax: Explicit Intent Using explicit intent any other component can be specified. In other words, the targeted component is specified by explicit intent. So only the specified target component will be invoked. For Example:

   Implicit and Explicit Intents in Android with Examples

   www.geeksforgeeks.org/implicit-and-explicit-intents-in-android-with-examples/

   See all results for this question

10. stackoverflow.com · questions · 6578051What is an Intent in Android? - Stack Overflow

    stackoverflow.com · questions · 6578051

    

    Jul 5, 2011 · Implicit Android Intents is the intent where instead of defining the exact components, you define the action you want to perform. The decision to handle this action is left to the operating system. The OS decides which component is best to run for implicit intents.