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Higher want.



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So in this tutorial you're going to go ahead and we're going to add another functionality to this application.



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So we are going to allow the user to save the image into actually external memory.



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So here you can see that we have this button save the picture in order to do that.



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So we need a class inside our project.



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So let's actually at the top and just get the kind of view to Windows and then we can project.



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So here it is our Android you and see it is the project you I need to change it to Android.



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So here look at this little triangle here.



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If I click on it I can select Android.



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Now you can see that it is actually called the Android view.



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If I open the app folder you can see that they have the manifest Java address.



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So let's open the Java folder and let's open the first package that actually contains these two classes



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the colorful class and the main theme with the class select expect package at the top menu just a click



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on File New and then click on Dobber class.



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So for the name of the class I can actually say save image or a safe flight save flight.



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So this is the name of the class and the kind is class.



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You don't have to specify the superclass or the interface.



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This is the package visibility is public and the modifiers is none.



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So just click on OK.



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So here it is our class like puppy class.



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Safe flight.



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So now that the class is created let me double click on this tab here say find that job in order to



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make it area there.



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Now let's create a method in order to actually save the file to external storage.



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So I can say Puplick static look at this method.



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It is static.



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What does this mean.



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This means that other classes if they want to actually use this method method they don't have to create



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an object of typesafe by class.



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They just need to call this method.



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On this say five class itself.



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So that's why it is actually called static.



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So you're already familiar with that right.



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Public static.



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And now I need to specify the return type of this method.



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So the return type is going to be filed if it is going to return an object of type fight.



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So what is going to be the name of that method.



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The name of them if it is going to be safe flight.



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Right that's the name of this method and this is going to accept some actually the arguments you need



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to specify some parameters for this method.



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The first priority is going to be off type activity.



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So just they've been here activity and the name of this parameter is going to be my activity my activity



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and then he'll put a comma.



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The second parameter is going to be off the bitmap.



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Right because you want to actually save a bitmap to external storage.



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So the second parameter is going to be bitmap and the name is going to be bitmap.



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So let's here specify that these Smurfette is going to throw an exception.



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Right.



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This method is error prone and it can actually go wrong and it's going to actually cause some errors.



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So we are going to allow two other Nicolet other classes and know that the Smurfit is not actually completely



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safe.



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This method can actually for an exception.



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So other classes if they want to use this method they must actually handle these exception exceptions.



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Otherwise it's not going to work.



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OK.



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So I can say fros no exception.



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Right.



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So just open and close this method by using these curly braces and opening curly brace followed by a



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closing curly brace.



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Let's go inside the Smurfette And let's see what we are going to do next.



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So create of idea but of types 3 in here so let's specify this data type yestreen.



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So notice that this variable is actually going to be a local variable right because it is local to the



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curly braces of this method.



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So now we're going to specify the name of this value.



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Well this is going to be external external storage state.



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So if you want to actually know that whether the device has or has an external threat or not.



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OK so if you want to be sure about that.



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So I create a variable here.



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I put an assignment operator and I'm going to refer to this environment class that actually knows about



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whether the user has an external storage or not.



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So environment that gets external storage.



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State semi-hollow.



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Now let's create a variable of type fight because we want to actually save this for it to extend or



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to store it right.



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Our image which is which is actually a file.



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So let's create a file and notice that this method must return a value of a file.



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So that's why I'm creating this value in here.



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And the name of this variable is going to be my file assignment operator.



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Initially I'm going to assign the value null to this variable because this is actually a local variable



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and the value is not going to be assigned to this variable.



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By default if it was an instance variable Yes it was the default value would be null.



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But here it is actually a local variable.



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And here we must actually specify an initial value for this value but otherwise later when we want to



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use this variable it's going to actually show us some error.



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The compiler is going to actually complain that this value is not initially initialized yet.



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So initially we are going to assign the value and also you know what is the what not mean not means



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nothing.



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This valuable points to nothing.



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So now I can't say if so I'm going to refer to this valuable external storage state but I'm going to



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actually compared the value of this valuable to another value so I'm going to say equals right equals



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and I'm going to is you can see that this equals my if it needs an argument of type Object.



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Right.



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So I'm going to say equals environment that media mountains.



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What does this mean.



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This means device has an external storage and it is ready and we can use it.



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Right.



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Environment that media mounted we can use the external storage if the external of the storage media



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it does have this value then in that case we are a hundred and fifty percent sure that the device has



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an external storage and we can save our file to that storage.



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So let's go inside the curly braces of this if statement if statement and let's see what you're going



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to do next.



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But first you can see that what happens if this condition evaluates to false if what happens if the



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user actually use this device doesn't have an external storage.



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In that case you are going to have an else if an else statement.



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So here I can say else and then I can open and close this whole statement by using these curly braces.



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And here we can handle this condition.



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So here I'm going to actually follow on exception.



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I can say fro new exception new exception and inside the prentices I need to specify the message so



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I can just put two codes here and I can say this device.



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This device does not have does not have to be an external that an external storage.



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Right semicolon.



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So let's go inside this if statement here.



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Let's create another variable of type file here.



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So just typing here file the name of this variable is going to be pictures directory pictures directory



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right.



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Assignment operator.



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Now I'm going to refer to this my activity argument that I receive from the Smurfette say fight right.



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I can see my activity that my activity actually my activity that gets external storage file directory



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get external.



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Actually the file still use this method here.



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So here we are way to actually pass a value of type string here and that value is going to specify a



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directory of the pictures that we want to save into our external storage.



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So here the name is going to be the name of this folder so that you're going to see that for that.



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But for now just know that you're going to actually create a directory here or a folder in order to



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hold all of the color pictures so I can put two quotes here and here instead the quotes I need to specify



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the name of that folder.



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So it is going to be color up pictures like color.



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So here let me tell you that every time they use There's actually a princess on the Save the picture



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button let me show you the activity underlayment examined here every time the user's presses on the



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spot and save the picture here all you want a new picture to be created and I want that image to be



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saved to external storage.



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Right.



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So every time the user presses on this button a new image is going to be created on your picture is



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going to be created with these values.



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For example red green blue and that image is going to be saved to our excellent storage.



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But here we have a problem.



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We must give a unique name for each image.



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OK.



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Two images with the same name cannot be existed in the same folder.



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Right.



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So we must give each image that the user actually creates by clicking on the Save the picture button.



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We must give each image a unique name.



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So let's see how we can do that.



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Let's go to the save file class below this line of code.



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I'm going to create a variable of type date right date which is in the Java that you can package date



146

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and here the name of this variable is going to be current dates current date assignment operator new



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date semicolon.



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So when I actually create a new date object it is going to give me the current date.



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OK the current date and this object is going to be assigned presumably but right.



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Let's create another variable here.



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And this is a blank right.



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It is like is actually a little bit like integer but it's going to hold more values more larger values.



153

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So learn the name of this variable is going to be elapsed time elapsed time.



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Assignment operator and here I'm going to refer to this class system clock that actually elapsed real



155

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time semicolon.



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So let me show you the web browser here because I actually opened on you of a page here in stack overflow.



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In order to let you know about this elapsed real time effort.



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So take a look at this answer.



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Here it says here is a little bit about a concept.



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It says elapsed your time effort and elapsed through time none was perfect.



161

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So here we are using the elapsed time if it's right.



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Return that time since the system was booted.



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This is really important.



164

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Let me read it again.



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The elapsed real time effort is going to return the time since the system was booted so let me go back



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to Andrew studio.



167

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What does this mean.



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This means that every time the user wants to actually save the image so as a result the user has to



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actually create a new image right because you want to create a new flight every time to use.



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It creates a new picture by clicking on the Save the picture button that image is going to have a unique



171

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elapsed time.



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OK.



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A unique elapsed time.



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Let me show you.



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That again is going to return the time since the system was booted.



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So this elapsed time here is going to be unique.



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Every time the user clicks on that button because it's impossible to use that actually create two pictures



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with the same elapsed time.



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Right.



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Because the time has passed by that moment the user presses that button.



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So if this doesn't make sense don't worry you can actually put the discussion in the course or you can



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message me in the ME and I will do my best to answer your question.



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But for now just make sure to actually look at the end of the documentation or watch this tutorial again



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in order to understand what does this elapsed time mean.



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OK.



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Searching the internet just search for this elapsed realtime effect and then you get to get what I mean.



187

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So and we have this elapsed date elapsed time.



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Now I can't say.



189

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So let's create a variable of types 3 and in order to specify that unique filename that's unique imagining



190

00:13:00,860 --> 00:13:07,630

like strange and the name of this variable is going to be unique emerge.



191

00:13:07,960 --> 00:13:14,870

The assignment operator so here I can say I can't put two coats.



192

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I can I can put us last year plus I'm concatenating this value of another value plus current state plus



193

00:13:25,610 --> 00:13:35,770

unable to Cote's yet underline plus elapsed time plus two coats or image or image format is going to



194

00:13:35,770 --> 00:13:38,170

be actually of type P and G.



195

00:13:38,200 --> 00:13:38,590

Right.



196

00:13:38,590 --> 00:13:43,430

So I'm going to put that P and G that says semicolon.



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This is going to be the unique image name that the user can actually create.



198

00:13:48,690 --> 00:13:55,200

A bunch of times like unlimited times the user can create image a unique image names with unique names



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right in the same folder.



200

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That's the trick.



201

00:13:59,010 --> 00:14:00,420

This is really important.



202

00:14:00,450 --> 00:14:01,270

This is the trick.



203

00:14:01,290 --> 00:14:05,070

In order to create unique filenames in the same folder.



204

00:14:05,070 --> 00:14:06,890

Use it in your own projects.



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00:14:06,900 --> 00:14:09,060

So after this line of code I can say.