top button
Flag Notify
    Connect to us
      Site Registration

Site Registration

Android: Final vs Static

+4 votes
388 views

I was wondering if final and static variables are same. I know they are different, but what is the purpose of final? When should we use final and when to use static.

Thanks in advance.

posted Jun 22, 2016 by Akshay

Share this question
Facebook Share Button Twitter Share Button LinkedIn Share Button

1 Answer

+1 vote
 
Best answer

They are different. Static variables are not associated with the instance of class, but to the class itself. Thus only one instance of variable is available at any point of time. Whereas Final is unlike static associated with instance of class. However the final variable's value can not be changed and can only be assigned once.

answer Jun 28, 2016 by Vinod Kumar K V
Similar Questions
0 votes

Can final variables be made static in Java, please explain with example?

+4 votes

I was asked a question. If you had to build an XML structure as text, would you use StringBuffer or String? I thought String is more efficient that StringBuffer, but some of my friends say StringBuffer is more efficient than String.

I assume, that StringBuffer is a class, where as String is a base datatype and StringBuffer would have some easy (wrapper) methods for String. So, it is an add-on to string. Which should make StringBuffer heavier than String. Then how come using StringBuffer better than String?

+1 vote

My app cashes when i click submit, it doesnt verify the fields as it should.
It works the way i want to but if i click on submit without entering anything it crashes.

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Button addBtn = (Button) findViewById(R.id.addBtn);
        addBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                EditText amoutGiven = (EditText) findViewById(R.id.amountG);
                EditText manyPeople = (EditText) findViewById(R.id.mPeople);
                EditText moenyGiven = (EditText) findViewById(R.id.moneyG);
                TextView changeTxt  = (TextView) findViewById(R.id.changeTxt);
                Button nxtBtn     = (Button) findViewById(R.id.nxtBtn);
                Button tryBtn     = (Button) findViewById(R.id.tryBtn);
                android.view.inputmethod.InputMethodManager imm = (android.view.inputmethod.InputMethodManager)getSystemService(INPUT_METHOD_SERVICE);
                imm.hideSoftInputFromWindow(getCurrentFocus().getWindowToken(), 0);

                if (amoutGiven.getText().length()==0){
                    amoutGiven.setError("This field is required");
                }

                if (manyPeople.getText().length()==0){
                    manyPeople.setError("This field is required");
                }

                if (moenyGiven.getText().length()==0){
                    moenyGiven.setError("This field is required");
                }

                int num1 = Integer.parseInt(amoutGiven.getText().toString());
                int num2 = Integer.parseInt(manyPeople.getText().toString());
                int num3 = Integer.parseInt(moenyGiven.getText().toString());
                int total = num1 * num2;
                int change = num3 - total;

                changeTxt.setVisibility((changeTxt.getVisibility() == View.VISIBLE)
                        ? View.INVISIBLE : View.VISIBLE);

                if (change < 0 ){
                    changeTxt.setText("Your numbers dont add up");
                    tryBtn.setVisibility((tryBtn.getVisibility() == View.VISIBLE)
                            ? View.INVISIBLE : View.VISIBLE);
                    tryBtn.setOnClickListener(new View.OnClickListener() {
                        @Override
                        public void onClick(View v) {
                            startActivity(new Intent(MainActivity.this, MainActivity.class));

                        }
                    });

                }else {

                    changeTxt.setText( "Give Back Change oF: R" + change +"" );
                    nxtBtn.setVisibility((nxtBtn.getVisibility() == View.VISIBLE)
                            ? View.INVISIBLE : View.VISIBLE);
                    nxtBtn.setOnClickListener(new View.OnClickListener() {
                        @Override
                        public void onClick(View v) {
                            startActivity(new Intent(MainActivity.this, MainActivity.class));    
                        }
                    });    
                }    
            }
        });    
    }
}
...