Android：EditText TextChangedListener上的堆栈溢出错误

Question

I get the StackOverflow error running this particular code:

litera.addTextChangedListener(new TextWatcher(){
            public void afterTextChanged(Editable s) {}
            public void beforeTextChanged(CharSequence s, int start, int count, int after){}
            public void onTextChanged(CharSequence s, int start, int before, int count){
                String ghici = litera.getText().toString();
                System.out.println(ghici);
                litera.setText("");
            }

        }); 

I commented each line at a time and I found out that the culprit is the litera.setText(""); line, the others work normally. I've used it before and it baffles me why a particularly simple instruction causes such a bad error... The rest of the error messages are about "android.view.ViewGroup.addFocusables(ViewGroup.java:637)" and others, but I doubt they are conclusive.

What am I missing?

Answer 1

如果您要从同一TextView的TextWatcher设置TextView的文本，那么您将设置一个无限循环，这将导致StackOverflowException 。

Answer 2

u have to use this way

 litera.addTextChangedListener(new TextWatcher(){
        public void afterTextChanged(Editable s) {}
        public void beforeTextChanged(CharSequence s, int start, int count, int after){}
        public void onTextChanged(CharSequence s, int start, int before, int count){
            String strEnteredVal = litera.getText().toString();
            if(!strEnteredVal.equals("")){
            System.out.println(strEnteredVal);
            litera.setText("");
            }
        }

    }); 

Answer 3

You are having this problem because you are changing the text from your onChange listener. What happens is the user changes the text, which invokes your onTextChange method, which in turn changes the text and that again invokes onTextChange listener - and so on. If you are required to change the text from the listener, then you need to somehow ignore text changes from your code and only handle the ones from the user. For example, you can try something like this:

litera.addTextChangedListener(new TextWatcher(){
        public void afterTextChanged(Editable s) {}
        public void beforeTextChanged(CharSequence s, int start, int count, int after){}
        public void onTextChanged(CharSequence s, int start, int before, int count){
            if(count > 0) {
                String ghici = litera.getText().toString();
                System.out.println(ghici);
                litera.setText("");
            }
        }
    });

this will ignore all changes where the edittext content has been erased (by your code).

Answer 4

you are calling settext method inside the onTextChanged listener. this would cause the listener to fire the onTextChanged method again and again. this is causing the stackOverflow error