java如何在Android的第三个EditText中获得两个EditText的减法结果？

Question

我是Android编程新手。在制作一个程序时，我正在寻找一个程序来自动填充第三个EditText中两个EditText小部件的减法结果，而不需要任何按钮。请帮我找到解决办法

Answer 1

int firstvalue=FirstText.getText.Tostring();
int secondvalue=SecondText.getText.Tostring();
int Answer=firstvalue - secondvalue;
thirdvalue.setText(Answer);

希望它能起作用。如果有什么问题，请告诉我

Answer 2

可以使用OnEditorAction侦听器方法编辑文本，并在焦点更改时执行所需操作

editText2.setOnEditorActionListener(new EditText.OnEditorActionListener() {
@Override
public boolean onEditorAction(EditText v, int actionId, KeyEvent event) {
 if (actionId == EditorInfo.IME_ACTION_DONE) {
 //do here your stuff f
  int value1=Integer.valueOf(edittext1.getText().Tostring());
  int value2=Integer.valueOf(edittext2.getText().Tostring());
  int value3=value1 - value2;
  thirdvalue.setText(String.valueOf(value3));
 return true;
 }
 return false;
} });

Answer 3

   EditText  e1=(EditText) findViewById(R.id.editText1);
   EditText  e2=(EditText) findViewById(R.id.editText2);
   EditText e3=(EditText)  findViewById(R.id.editText3);




e2.addTextChangedListener(new TextWatcher() {
public void onTextChanged(CharSequence s, int start, int before,
        int count) {
    if(!s.equals("") )
            {
   float a= Float.parseFloat(e1.getText().toString());
   float b= Float.parseFloat(e2.getText().toString());
   float c=a-b;
   e3.setText(String.valueOf(c);

           }
    }

}

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

}

public void afterTextChanged(Editable s) {

}
 });

Answer 4

当然，我想你会做所有的错误处理。但只有在两个字段都已填充时，此代码才会显示

Field1 = (EditText)findViewById(R.id.field1);
Field2 = (EditText)findViewById(R.id.field2);
Field3 = (EditText)findViewById(R.id.field3);


Field1.addTextChangedListener(new TextWatcher() {


   @Override
   public void afterTextChanged(Editable s) {}

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

   @Override    
   public void onTextChanged(CharSequence s, int start,
     int before, int count) {
      if(s.length() != 0 && Field2.getText().length() != 0)
        Field3.setText(""+(Integer.parseInt(s.toString()) - Integer.parseInt(Field2.getText().toString())));
   }
  });

Field2.addTextChangedListener(new TextWatcher() {

   @Override
   public void afterTextChanged(Editable s) {}

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

   @Override
   public void onTextChanged(CharSequence s, int start,
     int before, int count) {
      if(s.length() != 0 && Field1.getText().length() != 0)
         Field3.setText(""+( Integer.parseInt(Field1.getText().toString()) -  Integer.parseInt(s.toString())));
   }
  });