Question

我正在构建我的计算器应用程序。除了pow方法之外，一切正常。

当我点击8 + 5，然后点击pow方法时，我得到了这些：

calculatorat E/AndroidRuntime: FATAL EXCEPTION: main
                                                                                Process: com.atlant.calculator.calculatorat, PID: 28984
                                                                                java.lang.IllegalStateException: Could not execute method for android:onClick
                                                                                    at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:293)
                                                                                    at android.view.View.performClick(View.java:4780)
                                                                                    at android.view.View$PerformClick.run(View.java:19866)
                                                                                    at android.os.Handler.handleCallback(Handler.java:739)
                                                                                    at android.os.Handler.dispatchMessage(Handler.java:95)
                                                                                    at android.os.Looper.loop(Looper.java:135)
                                                                                    at android.app.ActivityThread.main(ActivityThread.java:5257)
                                                                                    at java.lang.reflect.Method.invoke(Native Method)
                                                                                    at java.lang.reflect.Method.invoke(Method.java:372)
                                                                                    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
                                                                                    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
                                                                                 Caused by: java.lang.reflect.InvocationTargetException
                                                                                    at java.lang.reflect.Method.invoke(Native Method)
                                                                                    at java.lang.reflect.Method.invoke(Method.java:372)
                                                                                    at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
                                                                                    at android.view.View.performClick(View.java:4780) 
                                                                                    at android.view.View$PerformClick.run(View.java:19866) 
                                                                                    at android.os.Handler.handleCallback(Handler.java:739) 
                                                                                    at android.os.Handler.dispatchMessage(Handler.java:95) 
                                                                                    at android.os.Looper.loop(Looper.java:135) 
                                                                                    at android.app.ActivityThread.main(ActivityThread.java:5257) 
                                                                                    at java.lang.reflect.Method.invoke(Native Method) 
                                                                                    at java.lang.reflect.Method.invoke(Method.java:372) 
                                                                                    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903) 
                                                                                    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698) 
                                                                                 Caused by: java.lang.NumberFormatException: Invalid double: "7+7"
                                                                                    at java.lang.StringToReal.invalidReal(StringToReal.java:63)
                                                                                    at java.lang.StringToReal.initialParse(StringToReal.java:164)
                                                                                    at java.lang.StringToReal.parseDouble(StringToReal.java:282)
                                                                                    at java.lang.Double.parseDouble(Double.java:301)
                                                                                    at com.atlant.calculator.calculatorat.Calculator.getResultPow(Calculator.java:178)
                                                                                    at com.atlant.calculator.calculatorat.Calculator.onClickPow(Calculator.java:205)
                                                                                    at java.lang.reflect.Method.invoke(Native Method) 
                                                                                    at java.lang.reflect.Method.invoke(Method.java:372) 
                                                                                    at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288) 
                                                                                    at android.view.View.performClick(View.java:4780) 
                                                                                    at android.view.View$PerformClick.run(View.java:19866) 
                                                                                    at android.os.Handler.handleCallback(Handler.java:739) 
                                                                                    at android.os.Handler.dispatchMessage(Handler.java:95) 
                                                                                    at android.os.Looper.loop(Looper.java:135) 
                                                                                    at android.app.ActivityThread.main(ActivityThread.java:5257) 
                                                                                    at java.lang.reflect.Method.invoke(Native Method) 
                                                                                    at java.lang.reflect.Method.invoke(Method.java:372)

比较字符串没有问题，我知道我可以将它们与.equals进行比较！.Problem是我的第三个getResultPow案例。

我只从getResultPow中的第3个案例中得到错误（当我尝试将两个数字相加然后点击POW时）.POW在1.st和2.nd情况下正常工作（输入数字然后点击POW）。

这是我的github回购：[https://github.com/adnxy/CalculatorAt][1]

有人建议吗？

Bellow是我的onClickPow：

public void onClickPow(View v) {
    if (display == "") return;
    if (!getResultPow()) return;
    {
        _screen.setText(String.valueOf(result));
    }

}

我的getResultPow方法有三种情况：1.st和2.nd情况正常，但是当我点击第三种情况时，我会收到错误。

//1.st case ,all empty, working fine
    if (display == "" && currentOperator == "" && result == "") return false;

    //2.nd case, entered number+pow, working fine
    if (currentOperator == "" && result == "" )
    if (display != "") {
        result = String.valueOf(Double.parseDouble(display) * Double.parseDouble(display));
    }

//3rd. case, two numbers entered and pow clicked, exception
if (result == "")
if (display != "" && currentOperator != "") {
    result = String.valueOf(String.valueOf(result)+Double.parseDouble(display) * Double.parseDouble(display));
    return true;
}


  [1]: https://github.com/adnxy/CalculatorAt

Answer 1

查看第三个错误。您正在尝试将字符串转换为7+7的两倍。试着写：

Double pow = Double.parseDouble(display) * Double.parseDouble(display);
result = String.valueOf(Double.parseDouble(Double.parseDouble(result)+pow));

方法gerResultPow不在计算器中工作

1 个答案: