java - EditText addTextChangedListener 循环

Question

我有两个编辑文本，每个都有文本观察器，当第一个 edittext 文本更改时，它会更改第二个 edittext 文本，代码似乎创建了一个循环，我可以做些什么来使文本观察器只听用户输入而不是通过代码更改文本？

et1.addTextChangedListener(new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence s, int start, int count, int after) {

        }

        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {

        }

        @Override
        public void afterTextChanged(Editable s) {

            double x = Double.valueOf(et1.getText().toString());
            et2.setText(String.valueOf((x*2)));
        }
    });

    et2.addTextChangedListener(new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence s, int start, int count, int after) {

        }

        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {

        }

        @Override
        public void afterTextChanged(Editable s) {

           double x = Double.valueOf(et2.getText().toString());
            et1.setText(String.valueOf((x/2)));
        }
    });

Answer 1

您可以在 TextWatcher 上保留一个引用，以便在操作之前需要时将其删除，然后再将其放回去。

private TextWatcher tv1;
private TextWatcher tv2;

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

    final EditText et1 = (EditText) findViewById(R.id.editText);
    final EditText et2 = (EditText) findViewById(R.id.editText1);

    tv1 = new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence s, int start, int count, int after) {}

        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {}

        @Override
        public void afterTextChanged(Editable s) {
            double x = Double.valueOf(et1.getText().toString());
            et2.removeTextChangedListener(tv2); // "disable" the watcher
            et2.setText(String.valueOf((x*2)));
            et2.addTextChangedListener(tv2);    // "enable" the watcher
        }
    };

    tv2 = new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence s, int start, int count, int after) {}

        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {}

        @Override
        public void afterTextChanged(Editable s) {
            double x = Double.valueOf(et2.getText().toString());
            et1.removeTextChangedListener(tv1); // "disable" the watcher
            et1.setText(String.valueOf((x/2)));
            et1.addTextChangedListener(tv1);    // "enable" the watcher
        }
    };

    et1.addTextChangedListener(tv1);
    et2.addTextChangedListener(tv2);
}