安卓文本觀察器計算丟失

Question

我有三個EditText元素。我想根據前兩個edittext值進行計算以存儲在thired編輯文本字段中。

但計算總是錯誤的。每當我從secound編輯文本中清除鍵入的值時，計算不能正常工作。

public void onTextChanged(CharSequence s, int a, int b, int c) { 
      try{ 
       a=Integer.parseInt(totamt.getText().toString().trim()); 
       b=Integer.parseInt(expenses.getText().toString().trim()); 
       c=Integer.parseInt(handover_amt.getText().toString().trim()); 
       int d = Integer.parseInt(String.valueOf(a)) - Integer.parseInt(String.valueOf(b)) - Integer.parseInt(String.valueOf(c)); 
       balance_amt.setText(String.valueOf(d)); 

       int myOB = Integer.parseInt(et_overall_balance.getText().toString().trim()); 
       int OverallBalance = Integer.parseInt(String.valueOf(myOB)) - Integer.parseInt(handover_amt.getText().toString().trim()); 
       et_overall_balance.setText(String.valueOf(OverallBalance)); 
       System.out.println(OverallBalance); 

      }catch(NumberFormatException numberEx) 
      { 
       System.out.println(numberEx); 
      } 

     } 

Answer 1

使用下面的代碼

edittext2.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) { 
       if (edittext1.getText().toString().trim() != null && !edittext1.getText().toString().trim().equalsIgnoreCase("")) { 
        if (edittext2.getText().toString().trim() != null && !edittext2.getText().toString().trim().equalsIgnoreCase("")) { 
         edittext3.setText("" + (Double.parseDouble(edittext1.getText().toString().trim()) - Double.parseDouble(edittext2.getText().toString().trim()))); 
        } else { 
         Toast.makeText(activity, "Please enter value in edittext 2", Toast.LENGTH_LONG).show(); 
        } 
       } else { 
        Toast.makeText(activity, "Please enter value in edittext 1", Toast.LENGTH_LONG).show(); 
       } 
      } 
     });