java - Android 测验应用程序崩溃

Question

我正在开发一个简单的测验应用程序，但我认为代码有问题。如果文本字段留空，当我单击提交按钮时，它会崩溃。这是我的代码。

public class Quiz extends Activity
{

Button submit;
EditText e1,e2,e3,e4,e5;
int ctr;
String msg = "", msg1 = "";

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_quiz);
    submit=(Button)findViewById(R.id.button1);
    e1=(EditText)findViewById(R.id.editText1);
    e2=(EditText)findViewById(R.id.editText2);
    e3=(EditText)findViewById(R.id.editText3);
    e4=(EditText)findViewById(R.id.editText4);
    e5=(EditText)findViewById(R.id.editText5);
    submit.setOnClickListener(new View.OnClickListener() {

          @Override
          public void onClick(View arg0){
              String ans1 = String.valueOf(e1.getText());
              int ans11 = Integer.parseInt(ans1);
              String ans2 = String.valueOf(e2.getText());
              int ans22 = Integer.parseInt(ans2);
              String ans3 = String.valueOf(e3.getText());
              int ans33 = Integer.parseInt(ans3);
              String ans4 = String.valueOf(e4.getText());
              int ans44 = Integer.parseInt(ans4);
              String ans5 = String.valueOf(e5.getText());
              int ans55 = Integer.parseInt(ans5);

              if(e1.getText().toString().equals("")||e2.getText().toString().equals("")||e3.getText().toString().equals("")||e4.getText().toString().equals("")||e5.getText().toString().equals("")){
                    msg1 = "Text fields cannot be empty.";
                     Toast.makeText(Quiz.this, msg1, Toast.LENGTH_LONG).show();  
                  }

              else{
              if(ans11==4){
                  ctr++;
              }
              if(ans22==3){
                  ctr++;
              }
              if(ans33==1){
                  ctr++;
              }
              if(ans44==2){
                  ctr++;
              }
              if(ans55==5){
                  ctr++;
              }
              msg = "Your score is " + ctr;
                 Toast.makeText(Quiz.this, msg, Toast.LENGTH_LONG).show();
              }


          }
      });
}

logcat 说:

10-06 21:47:35.888: E/AndroidRuntime(1759): FATAL EXCEPTION: main
10-06 21:47:35.888: E/AndroidRuntime(1759): java.lang.NumberFormatException: unable to parse '' as integer
10-06 21:47:35.888: E/AndroidRuntime(1759):     at java.lang.Integer.parseInt(Integer.java:362)
10-06 21:47:35.888: E/AndroidRuntime(1759):     at java.lang.Integer.parseInt(Integer.java:332)
10-06 21:47:35.888: E/AndroidRuntime(1759):     at com.example.capslock.Quiz$1.onClick(Quiz.java:39)
10-06 21:47:35.888: E/AndroidRuntime(1759):     at android.view.View.performClick(View.java:2485)
10-06 21:47:35.888: E/AndroidRuntime(1759):     at android.view.View$PerformClick.run(View.java:9080)
10-06 21:47:35.888: E/AndroidRuntime(1759):     at android.os.Handler.handleCallback(Handler.java:587)
10-06 21:47:35.888: E/AndroidRuntime(1759):     at android.os.Handler.dispatchMessage(Handler.java:92)
10-06 21:47:35.888: E/AndroidRuntime(1759):     at android.os.Looper.loop(Looper.java:130)
10-06 21:47:35.888: E/AndroidRuntime(1759):     at android.app.ActivityThread.main(ActivityThread.java:3683)
10-06 21:47:35.888: E/AndroidRuntime(1759):     at java.lang.reflect.Method.invokeNative(Native Method)
10-06 21:47:35.888: E/AndroidRuntime(1759):     at java.lang.reflect.Method.invoke(Method.java:507)
10-06 21:47:35.888: E/AndroidRuntime(1759):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
10-06 21:47:35.888: E/AndroidRuntime(1759):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
10-06 21:47:35.888: E/AndroidRuntime(1759):     at dalvik.system.NativeStart.main(Native Method)

Answer 1

尝试使用

从 editText 获取字符串

editText.getText().toString();

如果你想将一个字符串与另一个字符串进行比较，请执行以下操作:

if(ans1.equals("4")){...}

如果你想从 EditText 得到一个整数，试试这个

int a11 = 0;
try {
  a11 = Integer.parseInt(editText.getText().toString());
}catch(NumberFormatException e){   }

因此，当您的 EditText 中没有字符串或垃圾字符串时，您不会收到异常

我是对的，你试图从“”解析一个整数:-D