为此使用TextWatcher。设置它的EditText用户类型：

myEditText1.addTextChangedListener(new TextWatcher() {

@Override

public void afterTextChanged(Editable s) {

String value = s.toString();

// Perform computations using this string

// For example: parse the value to an Integer and use this value

// Set the computed value to the other EditText

myEditText2.setText(computedValue);

}

@Override

public void beforeTextChanged(CharSequence s, int start, int count, int after) {

}

@Override

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

}

});

编辑1：

检查空字符串""：

myEditText1.addTextChangedListener(new TextWatcher() {

@Override

public void afterTextChanged(Editable s) {

String value = s.toString();

if (value.equals("")) {

myEditText1.setText("0");

// You may not need this line, because "myEditText1.setText("0")" will

// trigger this method again and go to else block, where, if your code is set up

// correctly, myEditText2 will get the value 0. So, try without the next line

// and if it doesn't work, put it back.

myEditText2.setText("0");

} else {

// Perform computations using this string

// For example: parse the value to an Integer and use this value

// Set the computed value to the other EditText

myEditText2.setText(computedValue);

}

}

@Override

public void beforeTextChanged(CharSequence s, int start, int count, int after) {

}

@Override

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

}

});