我无法在 Android 应用程序的 TextView 中设置字符串（使用 Java）

Question

I'm building a simple calculator Android app in Java that will receive 2 numbers as inputs and when the user presses one of the 4 action buttons (+, -, *, /) the exercise and it's solution will appear in the bottom of the screen inside a TextView in this format:

{num1} {action} {num2} = {solution}

I tried to declare a string and form the exercise's string in it and in the end I used "setText" to change the TextView but instead of showing the full exercise when I run the app it shows something like "androidx.appcompat.widget.AppCom".

Here is an example for the string I form when the user clicks on the + button:

exerciseStr = etNum1.toString() + " + " + etNum2.toString() + " = " + String.valueOf(Integer.valueOf(etNum1.getText().toString())+Integer.valueOf(etNum2.getText() + ""));

Does anybody know what the issue may be?

Answer 1

您应该在调用toString()之前调用getText() toString() ：

exerciseStr = etNum1.getText().toString() + " + " + etNum2.getText().toString() + " = " + String.valueOf(Integer.valueOf(etNum1.getText().toString())+Integer.valueOf(etNum2.getText() + ""));

Answer 2

改成这样。

exerciseStr = etNum1.getText().toString() + " + " + etNum2.getText().toString() + " = "  + String.valueOf(Integer.valueOf(etNum1.getText().toString())+Integer.valueOf(etNum2.getText() + ""));