英文:
I can't set a string in a TextView in an Android app (using Java)
问题
我正在用Java构建一个简单的Android计算器应用程序，它将接收2个数字作为输入，当用户按下4个操作按钮之一（+，-，*，/）时，练习及其解答将以以下格式显示在屏幕底部的TextView中：
{num1} {action} {num2} = {solution}
我尝试声明一个字符串并在其中组成练习的字符串，最后我使用“setText”来更改TextView，但是当我运行应用程序时，它显示的不是完整的练习，而是类似于“androidx.appcompat.widget.AppCom”。
这是用户单击“+”按钮时我形成的字符串示例：
exerciseStr = etNum1.toString() + " + " + etNum2.toString() + " = " + String.valueOf(Integer.valueOf(etNum1.getText().toString()) + Integer.valueOf(etNum2.getText()) + "");
有谁知道可能的问题是什么吗？
英文:
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?
答案1
得分: 1
你应该在调用 toString() 之前调用 getText()：
exerciseStr = etNum1.getText().toString() + " + " + etNum2.getText().toString() + " = " + String.valueOf(Integer.valueOf(etNum1.getText().toString()) + Integer.valueOf(etNum2.getText()) + "");
英文:
You should call getText() befor calling toString():
exerciseStr = etNum1.getText().toString() + " + " + etNum2.getText().toString() + " = " + String.valueOf(Integer.valueOf(etNum1.getText().toString())+Integer.valueOf(etNum2.getText() + ""));
答案2
得分: 0
请将其更改为以下内容。
exerciseStr = etNum1.getText().toString() + " + " + etNum2.getText().toString() + " = " + String.valueOf(Integer.valueOf(etNum1.getText().toString())+Integer.valueOf(etNum2.getText() + ""));
英文:
Change it to like this.
exerciseStr = etNum1.getText().toString() + " + " + etNum2.getText().toString() + " = " + String.valueOf(Integer.valueOf(etNum1.getText().toString())+Integer.valueOf(etNum2.getText() + ""));
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