if statement, Code not work

Question

final EditText yaz = (EditText)findViewById(R.id.editText);
    final Button bas = (Button)findViewById(R.id.button);

    yaz.setText("500");
        bas.setOnClickListener(new View.OnClickListener() {
                                        @Override
                                        public void onClick(View v) {
                                            String afd = yaz.getText().toString();
                                            if (afd == "1000") {
                                                yaz.setText("2000");
                                            }
                                        }
                                    }
    );
    }

Answer 1

In Java, you cannot check equality between Strings with the == operator. This operator checks equal references for reference types, and equal values for primitive types only. Since String is a reference type, there's no surprise this is failing.

To check equality between Strings (or Objects for that matter), use this:

str1.equals(str2);

or in your case:

afd.equals("1000");

Answer 2

Replace

if (afd == "1000")

with

if (afd.equals("1000"))

This should work.

The idea is that == checks values of entities that lie on the stack, and in Java, only primitive types and references are held on the stack. Objects lie on the heap, and to compare object state you need a runtime virtual method like equals() (and not an operator like ==).