Question

我正在创建一个应用程序，我有三个editText和一个Button。我正在做的是在EditText中获取一些输入，进行计算并按下按钮进入另一个活动。

我的问题是当我没有输入任何值并按下按钮时应用程序崩溃这是我的代码 -

     btn.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View v) {

            Double x  = Double.parseDouble(editText1.getText().toString());

            try{

            if(x == null || x.equals("")){

                Toast.makeText(getApplicationContext(), "Insert All The Fields", Toast.LENGTH_LONG).show();
                  return;
            }else{

            }
            }
                catch(Exception e){
                    Toast.makeText(getApplicationContext(), "Insert All The Fields", Toast.LENGTH_LONG).show();
                }

            Double y  = Double.parseDouble(editText2.getText().toString());

            try{

                if(y == null || y.equals("")){

                    Toast.makeText(getApplicationContext(), "Insert All The Fields", Toast.LENGTH_LONG).show();
                      return;
                }else{

                }
                }
                    catch(Exception e){
                        Toast.makeText(getApplicationContext(), "Insert All The Fields", Toast.LENGTH_LONG).show();
                    }


            Double z  = Double.parseDouble(editText3.getText().toString());

            try{

                if(z == null || z.equals("")){

                    Toast.makeText(getApplicationContext(), "Insert All The Fields", Toast.LENGTH_LONG).show();
                      return;
                }else{

                }
                }
                    catch(Exception e){
                        Toast.makeText(getApplicationContext(), "Insert All The Fields", Toast.LENGTH_LONG).show();
                    }

            i = x+y+z;

            Intent intent = new Intent(getApplicationContext(),SecondActivity.class);
            intent.putExtra("key", +i);
            startActivity(intent);

这是Logcat

01-04 05:43:20.342: E/AndroidRuntime(1814): FATAL EXCEPTION: main
01-04 05:43:20.342: E/AndroidRuntime(1814): Process: com.example.calculatorpd, PID: 1814
01-04 05:43:20.342: E/AndroidRuntime(1814): java.lang.NumberFormatException: Invalid double: ""
01-04 05:43:20.342: E/AndroidRuntime(1814):     at java.lang.StringToReal.invalidReal(StringToReal.java:63)
01-04 05:43:20.342: E/AndroidRuntime(1814):     at java.lang.StringToReal.parseDouble(StringToReal.java:248)
01-04 05:43:20.342: E/AndroidRuntime(1814):     at java.lang.Double.parseDouble(Double.java:295)
01-04 05:43:20.342: E/AndroidRuntime(1814):     at com.example.calculatorpd.MainActivity$1.onClick(MainActivity.java:76)
01-04 05:43:20.342: E/AndroidRuntime(1814):     at android.view.View.performClick(View.java:4438)
01-04 05:43:20.342: E/AndroidRuntime(1814):     at android.view.View$PerformClick.run(View.java:18422)
01-04 05:43:20.342: E/AndroidRuntime(1814):     at android.os.Handler.handleCallback(Handler.java:733)
01-04 05:43:20.342: E/AndroidRuntime(1814):     at android.os.Handler.dispatchMessage(Handler.java:95)
01-04 05:43:20.342: E/AndroidRuntime(1814):     at android.os.Looper.loop(Looper.java:136)
01-04 05:43:20.342: E/AndroidRuntime(1814):     at android.app.ActivityThread.main(ActivityThread.java:5017)
01-04 05:43:20.342: E/AndroidRuntime(1814):     at java.lang.reflect.Method.invokeNative(Native Method)
01-04 05:43:20.342: E/AndroidRuntime(1814):     at java.lang.reflect.Method.invoke(Method.java:515)
01-04 05:43:20.342: E/AndroidRuntime(1814):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
01-04 05:43:20.342: E/AndroidRuntime(1814):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
01-04 05:43:20.342: E/AndroidRuntime(1814):     at dalvik.system.NativeStart.main(Native Method)

Answer 1

问题是你正在解析一些null的文本。因此，在进行导致异常的解析double之前，首先检查文本本身。

     btn.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View v) {

           Double x, y,z;

            try
            {
             String a = editText1.getText().toString();

             if(a == null || a.equals(""))
             {
                 x = 0;
                 Toast.makeText(getApplicationContext(), 
                 "Insert All The Fields", Toast.LENGTH_LONG).show();
                  return;
            }
            else
            {
              x  = Double.parseDouble(a);
            }
            }
                catch(Exception e){
                    Toast.makeText(getApplicationContext(), 
                    "Insert All The Fields", Toast.LENGTH_LONG).show();
                }



            try{

                 String b = editText2.getText().toString();

               if(b == null || b.equals(""))
             {
                    y = 0;
                    Toast.makeText(getApplicationContext(), 
                    "Insert All The Fields", Toast.LENGTH_LONG).show();
                      return;
                }else{
                 y  = Double.parseDouble(editText2.getText().toString());
                }
                }
                    catch(Exception e){
                        Toast.makeText(getApplicationContext(), 
                        "Insert All The Fields", Toast.LENGTH_LONG).show();
                    }




            try{
                 String c = editText3.getText().toString();

               if(c == null || c.equals(""))
             {

                    z = 0;
                    Toast.makeText(getApplicationContext(), 
                    "Insert All The Fields", Toast.LENGTH_LONG).show();
                      return;
                }else{
                   z  = Double.parseDouble(editText3.getText().toString());
                }
                }
                    catch(Exception e){
                        Toast.makeText(getApplicationContext(), 
                        "Insert All The Fields", Toast.LENGTH_LONG).show();
                    }

            i = x +y+z;
            Intent intent = new Intent(getApplicationContext(),SecondActivity.class);
            intent.putExtra("key", +i);
            startActivity(intent);

Answer 2

在使用此行之前

Double x  = Double.parseDouble(editText1.getText().toString());

您需要检查该字符串是否代表数字。

    if(editText1.getText().toString() == null || editText1.getText().toString().equals("")){

        Toast.makeText(getApplicationContext(), 
        "Insert All The Fields", Toast.LENGTH_LONG).show();
          return;
     }else{
             Double x  = Double.parseDouble(editText1.getText().toString());
     }

您需要添加更多测试以验证除了数字

之外的其他内容

单击按钮上的应用程序崩溃

2 个答案: