Question

我在Android工作室创建了一个包含4个问题的简短测验。一个问题有RadioButtons，第二个有CheckBoxes，第三个有常规按钮，第四个/第五个是EditText。每当我在运行它之后按任何按钮时，应用程序崩溃，并且日志中会显示一个大错误。

活动主要：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        style="@style/Background"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:paddingBottom="@dimen/activity_vertical_margin"
        android:paddingLeft="@dimen/activity_horizontal_margin"
        android:paddingRight="@dimen/activity_horizontal_margin"
        android:paddingTop="@dimen/activity_vertical_margin"
        tools:context="com.example.hende.germanquiz.MainActivity">


        <TextView
            android:id="@+id/Header_text_view"
            style="@style/Header"
            android:text="@string/header_text" />

        <TextView
            android:id="@+id/question_one"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:paddingTop="16dp"
            android:text="@string/questionOne" />


        <RadioGroup
            android:id="@+id/radio_group"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content">

            <RadioButton
                android:id="@+id/radio1"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="10dp"
                android:checked="true"
                android:onClick="Bitte schön"
                android:text="@string/wrong1_answer" />

            <RadioButton
                android:id="@+id/radio2"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="10dp"
                android:onClick="Ich heiße"
                android:text="@string/correct_answer" />

            <RadioButton
                android:id="@+id/radio3"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="10dp"
                android:onClick="Sprechen sie Deutsch?"
                android:text="@string/wrong2_answer" />

            <TextView
                android:id="@+id/question_two"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:paddingTop="16dp"
                android:text="@string/questionTwo"
                android:textColor="#B71C1C" />

            <CheckBox
                android:id="@+id/checkbox1"
                style="@style/Buttons"
                android:onClick="rechnung1"
                android:text="@string/correct2_answer" />

            <CheckBox
                android:id="@+id/checkbox2"
                style="@style/Buttons"
                android:onClick="rechnung2"
                android:text="@string/correct3_answer" />

            <CheckBox
                android:id="@+id/checkbox3"
                style="@style/Buttons"
                android:onClick="Vogel"
                android:text="Hast du einen Vogel?" />

            <TextView
                android:id="@+id/question_three_text_view"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:paddingTop="16dp"
                android:text="@string/question_three" />

            <TextView
                android:id="@+id/question_threea_text_view"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="@string/question_threea" />


            <Button
                android:id="@+id/button2"
                style="@style/RegularButton"
                android:text="@string/wrong4_answer"
                android:onClick="button2"/>

            <Button
                android:id="@+id/button3"
                style="@style/RegularButton"
                android:text="@string/wrong5_answer"
                android:onClick="button3"/>
            <Button
                android:id="@+id/button1"
                style="@style/RegularButton"
                android:text="@string/correct4_answer"
                android:onClick="button1"/>



            <TextView
                android:id="@+id/aurora_text_view"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="@string/questionFour"
                android:layout_marginTop="10dp" />

            <EditText
                android:id="@+id/edit_text_view"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"/>
            <TextView
                android:id="@+id/_text_view"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="@string/questionFive"
                android:layout_marginTop="10dp"/>

            <EditText
                android:id="@+id/edit2_text_view"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content" />

            <Button
                android:id="@+id/submit_button"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="@string/submit_button"
                android:onClick="calculateScore"/>

            <TextView
                android:id="@+id/score_text_view"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content" />

        </RadioGroup>
    </LinearLayout>
</ScrollView>

MainActivity：

public class MainActivity extends AppCompatActivity {
    int score = 0;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
    public void questionOne(){
        RadioButton radio2 =(RadioButton)findViewById(R.id.radio2);


        if (radio2.isSelected()) {
            score = score + 1;
    }}

     public void questionTwo(){
         CheckBox checkbox1 =(CheckBox) findViewById(R.id.checkbox1);
         CheckBox checkbox2=(CheckBox) findViewById(R.id.checkbox2);

         if(checkbox1.isChecked() &&checkbox2 .isChecked()){
             score = score + 1;
         }

}
  public void questionThree(){
      Button button1 = (Button)findViewById(R.id.button1);
      Button button2 = (Button)findViewById(R.id.button2);
      Button button3 = (Button)findViewById(R.id.button3);
       if (button1.isSelected()) {
           score= score + 1;
       }
}



    public void questionFour(){
        EditText edit_text_view =(EditText) findViewById(R.id.edit_text_view);
        if (edit_text_view.getText().toString().contains("Nordlicht") || edit_text_view.getText().toString().contains("Nordlicht")) {
            score = score + 1;

    }
}

public void questionFive(){
EditText edit2_text_view=(EditText)findViewById(R.id.edit2_text_view);
    if (edit2_text_view.getText().toString().contains("On October 10th at 10:10, 10 tame goats pull 10 centners of sugar to the zoo")|| edit2_text_view.getText().toString().contains("On October 10th at 10:10, 10 tame goats pull 10 centners of sugar to the zoo")) {
         score = score + 1;

}
}public void calculateScore(View view){
  display (score);
    questionOne ();
    questionTwo ();
 questionThree();
    questionFour ();
    questionFive ();




}
    private void display(int number) {
        TextView score_text_view = (TextView) findViewById(
                R.id.score_text_view);
        score_text_view.setText("" + number);
    }}

记录错误：

08-27 13:07:50.408 3344-3344/com.example.hende.germanquiz E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.hende.germanquiz, PID: 3344
java.lang.IllegalStateException: Could not find method rechnung2(View) in a parent or ancestor Context for 
android:onClick attribute defined on view class android.support.v7.widget.AppCompatCheckBox with id 'checkbox2'
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.resolveMethod(AppCompatViewInflater.java:327)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:284)
at android.view.View.performClick(View.java:5609)
at android.widget.CompoundButton.performClick(CompoundButton.java:122)
at android.view.View$PerformClick.run(View.java:22259)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6077)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
08-27 12:49:22.499 32531-416/com.example.hende.germanquiz E/InstantRun:
Failed to update existing theme for activity com.example.hende.germanquiz.MainActivity@587f4d8
java.lang.NoSuchFieldException: No field mTheme in class Landroid/content/res/Resources$Theme; 
(declaration of 'android.content.res.Resources$Theme' appears in /system/framework/framework.jar)
at java.lang.Class.getDeclaredField(Native Method)
at com.android.tools.fd.runtime.MonkeyPatcher.monkeyPatchExistingResources(MonkeyPatcher.java:374)
at com.android.tools.fd.runtime.Server.restart(Server.java:523)
at com.android.tools.fd.runtime.Server.access$600(Server.java:61)
at com.android.tools.fd.runtime.Server$SocketServerReplyThread.handle(Server.java:318)
at com.android.tools.fd.runtime.Server$SocketServerReplyThread.run(Server.java:190)
at com.android.tools.fd.runtime.Server$SocketServerThread.run(Server.java:158)
at java.lang.Thread.run
08-27 12:49:43.382 32531-32531/com.example.hende.germanquiz E/SpannableStringBuilder: SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length
08-27 12:49:43.590 32531-32531/com.example.hende.germanquiz E/SpannableStringBuilder: SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length

Answer 1

在xml中定义属性onClick。这意味着当你点击那个按钮时，android会调用在＆＃34; onClick＆＃34;中命名的方法。属性。由于您没有在MainActivity中定义这些方法，因此会出现运行时错误

Answer 2

这里有很多问题。第一个似乎是因为你已经宣布了一个名为＆＃34; rechnung2＆＃34;在Checkbox的onClick属性上，但您从未实现过它。在出现第二个错误时，您使用的是与默认主题不同的主题，并且可能会在链中的某处产生冲突。跟踪中的最后一个错误可能是因为您要将分数附加到显示方法

中的空白处

Answer 3

onClick XML属性调用方法，您必须在MainActivity中使用该方法。此外，您必须遵循以下规则：

The method you declare in the android:onClick attribute must have a 
specific signature. Specifically, the method must:

Be public
Return void
Define a View as its only parameter (this will be the View that was clicked)

Answer 4

在Activity中，没有名为rechnung2的方法

你的logcat说：

java.lang.IllegalStateException: Could not find method rechnung2(View) in a parent or ancestor Context for android:onClick attribute defined on view class android.support.v7.widget.AppCompatCheckBox with id 'checkbox2'

建议：请检查您的xml并找到所有android:onclick个元素，然后检查Activity，Activity您必须拥有的方法。

Android Studio如果您的Activity中没有这种方法，Node会发出警告：

按下按钮时应用程序崩溃

4 个答案: