I was online looking at some android coding examples and i came across a method that had a return expression by itself,and i was wondering if someone could explain what that means.
Here is the code sample:
if(tempText.getText().length() ==0){
Toast.makeText(this, "Please enter a valid number", Toast.LENGTH_LONG).show();
return;
}
This is the If condition which checks for the length of the text which is "0" or not. If its "0" then it will show the Toast message and will return from or exit from the if loop an no further execution will processed.
using if condition you are checking for the length of text, if it is 0 then you are showing Toast
Using a return Keyword within a class, with a method
A method returning nothing
public void Void_Method()
{
<statements>
return;
}
A method returning a String
public String String_Method()
{
String s = "its Ridiculous to do such kind of work, people here are just aim less";
return s;
}
A method returning an Int value
public int Int_Method()
{
int i = 5;
return(i);
}
I hope this will help you understand the use of return keyword, and as name suggest - The return keyword is always used with a method only to specify that the method is going to return something.
Related
I want to searching two words ("error" , "correct") Simultaneously inside webView.
I use below code for API <16
int number_match_error=web.findAll("error");
int number_match_ok=DeleteAccount.web.findAll("correct");
if(number_match_error!=0)
Toast.makeText(base_context, "error", Toast.LENGTH_LONG).show();
else if(number_match_ok!=0)
Toast.makeText(base_context, "correct", Toast.LENGTH_LONG).show();
This code works properly.
method findAll() returns a value.
I am using the return value, to separate
but for API>16
I Should use findAllAsync()
This function returns an empty value
So I do not know how search for the two words separately, inside Web View?
web.findAllAsync("error");
web.findAllAsync("correct");
web.setFindListener(new FindListener() {
#Override
public void onFindResultReceived(int activeMatchOrdinal, int numberOfMatches, boolean isDoneCounting) {
// how found numberofMathes is for word "error" or "correct"?
});
}
Scenario: when the focus is lost from an EditText, I'm checking if it contains null (in the first if block).
If so, then I'll show a Toast.
In the else-if block I'm checking if the EditText doesn't contain letters.
Then I'll show a toast, but when I run the application, the Toast is shown even on a correct input.
I.e.: If I enter any letter the Toast should not be shown, it should be shown only when a null or digit/special symbol is entered.
Here is the code
et1.setOnFocusChangeListener(new View.OnFocusChangeListener() {
#Override
public void onFocusChange(View v, boolean hasFocus) {
// TODO Auto-generated method stub
if(!hasFocus)
{
a = et1.getText().toString();
if (a.equals(""))
{
Toast.makeText(getApplicationContext(), "Your entry is incorrect!!", Toast.LENGTH_LONG).show();
}
else if (!a.contains("[a-z]")||!a.contains("[A-Z]")) {
Toast.makeText(getApplicationContext(), "Your entry is incorrect!!", Toast.LENGTH_LONG).show();
}
else
{
}
Please help
The '==' operator only compares references. To compare string values you must use the equals() method.
Instead of
if (a == "")
use
if (a.equals(""))
See: What is the difference between == vs equals() in Java?
It's not working because:
if (a == "")
won't work in Java
Use
if (a.equals(""))
instead
Also, String.contains doesn't use regular expressions, but CharacterSequences.
So, unless your string doesn't contain the exact character sequences "[a-z]" or "[A-Z]" (and only one of these 2 strings), you'll never get a match.
See: http://developer.android.com/reference/java/lang/String.html#contains(java.lang.CharSequence)
The problem is:
if (a == "")
Strings can't be compared like this. Instead, check for size equal to 0, or against a specific string with the equals() method.
Hopefully a simple answer but I'm a little baffled. I'm expecting the code to go down the first if section below, but it always goes to the else.
When I get to line on a breakpoint >> if (url2!=null && !url2.isEmpty())
In the expressions window:
url2 IS "???/wp-content/uploads/2011/01/toonieJune10_091-640x334.jpg"
url2!=null IS true
!url2.isEmpty() IS true
However when debugging it always seems to hit the else, even though both conditions are true. I'm suspecting something is out of sync with my built code somehow as the step through debugging seems to give me inconsistencies.
I've tried cleaning the code and making some changes in the class and recompiling etc.
Help is much appreciated! Thanks!
public String getImageBannerUrl()
{
if (getPhotoFile1()!=null) return getPhotoFile1().getUrl();
String url2 = getRemoteImageUrl();
if (url2!=null && !url2.isEmpty())
{
return url2;
}
else
{
//Otherwise get default image based on category
return getImageCategoryUrl();
}
}
Try somthing like..
public String getImageBannerUrl()
{
if ((!getPhotoFile1().isEmpty()) && (!getPhotoFile1().matches(" "))) return getPhotoFile1().getUrl();
String url2 = getRemoteImageUrl();
if ((!url2.isEmpty()) && (!url2.matches(" ")))
{
return url2;
}
else
{
//Otherwise get default image based on category
return getImageCategoryUrl();
}
}
Note : here getPhotoFile1() must be returning String value..
I am trying to create a random (50/50) chance of a case A or case B happen in android and I need it to be as simple and as resource efficient as possible. I've looked through stackoverflow but all I find for random boolean is in C++?
Would appreciate if someone could give me a suggestion as to how to do this, whether with boolean or with strings/integers (since I was told that booleans is a primitive).
I tried the following
public static boolean getRandomBoolean() {
return Math.random() < 0.5; }
boolean atrg = getRandomBoolean();
if (atrg = true)
{ Toast.makeText(cxt, "TRUE", Toast.LENGTH_SHORT).show(); }
else if (atrg = false)
{ Toast.makeText(cxt, "FALSE", Toast.LENGTH_SHORT).show(); }
But in nearly every case, I tested (>20x), its TRUE?. This is likely a stupid question but is getRandomBoolean a boolean or an int/double? Sorry, I'm very new to android, as you probably guessed.
Your random generator is fine, but your toast displaying the result is not.
The problem is in the if-statement where you use a single equals sign (=) which is an assignment. The result of this assignment will be true and thus it will never show the "FALSE" toast.
Try this instead.
boolean atrg = getRandomBoolean();
if (atrg) {
Toast.makeText(cxt, "TRUE", Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(cxt, "FALSE", Toast.LENGTH_SHORT).show();
}
This is not how you check boolean in if. = is the assignment operator and == is used for comparison. You should check like:
if(atrg == true)
or in case of boolean it is simply:
if(atrg)
Your statement:
if(atrg = true)
assigns atrg with true and you never get a false case.
Just use Math.random(), it will return a value between 0 and 1.. Example below:
public static boolean getRandomBoolean() {
return Math.random() < 0.5;
}
public static void main(String[] args) {
System.out.println(getRandomBoolean());
}
i need a favor.. i'm confused to put these codes to check whether the edittext is empty or not:
String input = editText.getText().toString();
if(input == null || input.trim().equals("")){
Toast.makeText(context, "Sorry you did't type anything"), Toast.LENGTH_SHORT).show();
}
where must i write these codes? is it between these codes?
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.menuawal);
...
...
...
JmlAhliWarisAnakLK = (EditText) findViewById(R.id.JmlAhliWarisAnakLK);
JmlAhliWarisAnakPR = (EditText)findViewById(R.id.JmlAhliWarisAnakPR);
or in this function after double sisa=0;??
public void cc() {
int JmlWarisAnakPR = Integer.parseInt(JmlAhliWarisAnakPR.getText().toString());
int JmlWarisAnakLK = Integer.parseInt(JmlAhliWarisAnakLK.getText().toString());
int JmlHarta = Integer.parseInt(JmlHartaPeninggalan.getText().toString());
double HasilSuami = 0;
double HasilIstri = 0;
double HasilAnakLK = 0;
double HasilAnakPR = 0;
double sisa = 0;
}
please correct me if i'm wrong.. :D
you are on the right track
After you set the layout using setContentView you need to add your EditText's which you are doing fine as follows.
JmlAhliWarisAnakLK = (EditText)findViewById(R.id.JmlAhliWarisAnakLK);
JmlAhliWarisAnakPR = (EditText)findViewById(R.id.JmlAhliWarisAnakPR);
You then need to store the value you get from the EditText's in some variable,
int JmlWarisAnakPR = Integer.parseInt(JmlAhliWarisAnakPR.getText().toString());
....
....
After you have stored your values you can then call some method that validates your input on click of a button(if you have):
public void validateinput()
{
if(input == null || input.trim().equals(""))
{
Toast.makeText(context, "Sorry you did't type anything"), Toast.LENGTH_SHORT).show();
}
}
According to me, you should put the check on some event, like if its login screen, then on click of submit button. or other wise on focus change it main instantly provide user with the toast that he left the field empty. or if other case, please provide more information for your query. thanks.
That depends on when you want to validate the editText..You propably have some button which "submits" the EditText so call this code in after onClick event gets fired on the button..
Put the input validation code when you have to navigate away from the current activity, either to go to another activity or to save the input details. That's the least annoying place to shove an error message onto the user.
Another approach is to validate when the focus leaves the EditText. But in this case the error notification should be more subtle (and therefore less annoying) like changing the EditText's background to lightred.
Ur questions does not seem to be clear. Are u asking where do u need to put the validation for empty edittext? If this is ur question then the general case would be to validate during any events such as BUTTON CLICK. Set the onClickListener for ur button and inside ur onclick perform the validation.
String input = editText.getText().toString();
if(input == null || input.trim().equals("")){
Toast.makeText(context, "Sorry you did't type anything"), Toast.LENGTH_SHORT).show();
}
Your above code is pretty much correct. You Must need to add above code whenever you want to take input from these edittext, Or whenever you want to save these value. make a function which will return true if edit text is empty so u can ask user to enter values
public boolean isETEmpty(){
String input = editText.getText().toString();
if(input == null || input.trim().equals("")){
Toast.makeText(context, "Sorry you did't type anything"), Toast.LENGTH_SHORT).show();
return true;
}
return false; // if not empty
}
call this function Whenever u want to use values from ET, if this function return true, you must let user enter values. Such as on Button Click to save etc