I've recently found a code that could solve my background service problem, but I don't understand one part of it. Could you tell me what should I write in !calledOtherActivity? This part is red in my code and the hint says: " cannot resolve symbol 'calledOtherActivity' "
Code
#Override
public void onPause() {
if(!isFinishing()){
if(!calledOtherActivity){
stopService(serviceRef);
}
}
}
let's understand the Situation
if( condition )
{
// if condition is true it goes here
}
else
{
// bah condition is false meaning !true
}
If the condition in the above statement is false, then the statements in the else block will always be executed.
If it is true it goes inside it like i commented
This condition only can be true or false
and since you have only one in the condition called calledOtherActivity it needs to carry true or false so its a boolean
private boolean calledOtherActivity;
by default its value is false
looking to your condition it is if(!calledOtherActivity) as i said to go inside this it needs to be true
! <--- this is NOT operator this inverts the value of a boolean
so if you pass calledOtherActivity with a false value because of this NOT operator the full output of the condition becomes true
Related
i have the following code:
myList.find { it.code == item.bin }.let {
// 1
} ?: run {
// 2
}
I would expect that, if item is found, I enter block 1 , otherwise block 2 ;
But instead I enter block 1 in all cases, and if nothing is found , it is null
Android studio seems aware of this, as the block 2 is grey (it is code never called), but I can't figure why
Please may someone explain why ?
null is still a value so it makes sense that the first block is run. it'd be the same as if you ran null.let { println("hey!") }.
you probably want to run let with a null check: myList.find { it.code == item.bin }?.let { ... }. this way the block will only run if there is indeed a value being returned that is not null.
You are using classic dot call operator ., this operator is not allowed on nullable types. If you want to call this operator on nullable type insert !! before operator, but if you call it on null it throws NullPointerException
You have to use Kotlins safe call operator ?., which call method when insatce is not null and when is it returns null.
?: operator is called Elvis operator and it returns first value if it is not null, else it returns second value.
So just change in your code dot operator . to safe call operator ?.:
myList.find { it.code == item.bin }.let {
// 1
} ?: run {
// 2
}
This would be the first time I post a question since I couldn't find the answer to this. Something really weird is happening with my if/else statements. My code was working perfectly for the past week, but recently it kept on telling me that a statement is always true?
My code is the following:
int checking = 1;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (checking != 1) {
speaker.setChecked(true);
} else if (checking == 1) {
speaker.setChecked(false);
}
}
This says checking == 1 is always true which makes sense, but if I switch it around to:
if (checking == 1) {
speaker.setChecked(true);
} else if (checking != 1) {
speaker.setChecked(false);
}
This says that checking != 1 is always true as well. Can someone help?
It's just a logic of editor. In first if statement, you check checking == 1 and the second if statement, you negative the statement. The editor will understand the second if statement alway true
I think you should replace else if to else. Sorry my bad English.
The reason why you are seeing this warning is:
You have set int checking = 1 and you are either checking:
if (checking != 1) which is always true
Or checking == 1 which is also always true
Due to this other else if condition will not be executed at all.
The warning will be only removed if you try to change value of checking either at runtime or using some conditions at compile time.
If your intention is just to set the speaker.setChecked() you can do following:
speaker.setChecked(checking == 1)
Note: This will not remove the warning
Try this
int checking = 1;
boolean isChecked = false;
isChecked = ((checking == 1) ? true : false)
speaker.setChecked(isChecked)
Here the Text Area is constantly changing in terms of number and I want to trigger an event when the Text Area gets a particular number example I have tried this -
public void myfunction45(Canvas Panel)
{
if (Indicator = 45) {
Panel.enabled = false;.
}
} //(indicator- www.progress).
But it does not work(it does not read it nothing happens). how do I match the condition as the number is to be specific. please give an example for explanation. Thanks in advance.
That if statement would cause you problems.
You would want:
if(Indicator == 5)
instead. At the moment you're assigning the value without checking it, this would cause a compiler error. If it's just a typo, then update your answer, slightly confusing otherwise.
With regards to checking the text value. You'd have to grab the text value, for that you need a reference to the Text area. This approach assumes that the text area has it's value set by a user. Currently you're not grabbing any text values to compare, as a result, the if statement won't know what to compare.
Here's one approach:
public void myfunction5(Canvas Panel)
{
float result;
string textValue = yourTextArea.text;
if(Single.TryParse(textValue, out result))
{
if(result == Indicator)
{
Panel.enabled = false;
}
}
}
You use TryParse to avoid any potential exceptions that would be thrown if the user entered something that wasn't a number. This method will take the value from your text area, how you get your text area is up to you, and try to parse the text value into a float. The method will return true if the parse was a success, false otherwise.
Here's the reference for the TryParse stuff:
https://msdn.microsoft.com/en-us/library/26sxas5t(v=vs.110).aspx
If you wanted to parse it to an int, then you'd be using the Int32's version of TryParse, https://msdn.microsoft.com/en-us/library/system.int32_methods(v=vs.110).aspx
I'd also recommend having a peak at the Input Field documentation: https://docs.unity3d.com/Manual/script-InputField.html
You can subscribe your method to the Input-fields On Value Changed event, your function will need to tweaked slightly though:
public void myfunction5(string text)
{
float result;
if(Single.TryParse(text, out result))
{
if(result == Indicator)
{
CachedPanel.enabled = false;
}
}
}
Don't forget to store a reference to the panel you want to disable.
Hopefully this is what you're after.
Panel is already a Canvas type, it doesn't make any sense to GetComponent<Canvas> on the same type.
Try using Panel.enabled = false;.
For the rest, we don't know how you get the Indicator reference, or how you built the UI hierarchy, so we can't assess if the problem is there.
Edit: I could I miss the single = baffles me lol. I should avoid answering questions when I'm tired.
If(bool1&&bool2)
{
//some code
} else{
//some code
}
And here what I want is that even if 1 condition return true then also to proceed to run the code but I also want to know which condition returned true
Edit
I'm using RootTools library for checking root permission
RootTools.isRootAvailable() &&RootTools.isAcessgiven()
So if
RootTools.isAcessgiven() returns false
I can tell root is not proper but if
RootTools. isAcessgiven() returns true and RootTools. isRootAvailable () returns true
I can tell him root is proper
If you just want to know which one returned true, you could just log it:
if (bool1 || bool2) {
log.i("bool1: " + bool1 ", bool2: " + bool2)
code......
}
then you need two if statements.
if(bool1) {
// code
} else if(bool2) {
// slightly different code
} else {
// final code
}
no way around it
You mean proceed to run code "//someother code" ?
if(bool1 || bool2){
// fun first code for any of bool1 or bool2 - true
// you need to check which one was true - bool1, or bool2 in other statement.
} else {
// run this if bool1 and bool2 is false
}
The one possible answer could be , Here both the if block will run .
if(bool1){
// some code
// print(in bool 1)
}
if(bool2)
{
// some code
// print(in bool 2)
}
The other answer you can do is my maintaining a another variable
boolean val1,val2;
if(val1=bool1 || val2=bool2 )
{
}
http://imgur.com/DzTRV2D
In android application i have code like below
private boolean isSpinnerNotChoose(Spinner spinner)
{
if(spinner.getSelectedItem().toString().equals(""))
{
return false;
}
return true;
}
But after many tries even if condition is completed it firstly enter on return false and later anyway debbugger goes on return true (If something stays after brackets its skipped but return true always is done. In link is image how its look after if is completed.
Anyone can answer me for that situation ?
Thanks in advance :)
Better use a boolean and return the boolean once.
The boolean is initially set to true.
It will remain true, if no match happens.
If there's a match, it will change to false.
Then the boolean will be returned (true if no match happens, false if there's a match).
No ghost responses.
I also added a trim(), to cut away the eventual trailing spaces.
Try:
private boolean isSpinnerNotChoose(Spinner spinner)
{
boolean myValue = true; // default return value
if(spinner.getSelectedItem().toString().trim().equals(""))
{
myValue = false;
}
return myValue; // return once and for all
}