Android Studio中應用立即崩潰 - 顯示java.lang.NullPointerException

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請嘗試運行我的應用程序，但出現以下錯誤：Android Studio中應用立即崩潰 - 顯示java.lang.NullPointerException

「顯示java.lang.NullPointerException：試圖調用虛擬方法android.text.Editable機器人。「空對象引用上的」widget.EditText.getText（）'

只要我真的嘗試使用該頁面上的變量運行任何代碼，就會發生這種情況。簡單地聲明他們的ID不會造成任何錯誤，我猜是因爲他們從來沒有被調用過。

我不知道我錯了什麼。我知道我需要檢查解析，因爲NumberException可能會發生，但它甚至不會達到這一點，我不知道爲什麼。即使是基本的.getText（）也會導致崩潰。

我檢查了一個重複問題的鏈接，但我看不到我可能沒有正確初始化的位置。

protected void onCreate(Bundle savedInstanceState) 
{ 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 

    // variable declarations for reservation details 
    final EditText emailInput = (EditText) findViewById(R.id.emailInput); 
    final EditText phoneInput = (EditText) findViewById(R.id.phoneInput); 
    final EditText dateInput = (EditText) findViewById(R.id.dateInput); 
    final EditText totalAdults = (EditText) findViewById(R.id.totalAdults); 
    final EditText totalKids = (EditText) findViewById(R.id.totalKids); 

    // declare next and back buttons for all pages 
    final Button nextToDinner = (Button) findViewById(R.id.nextToDinner); 
    final Button backToReservation = (Button) findViewById(R.id.backToReservation); 
    final Button nextToProcessing = (Button) findViewById(R.id.nextToProcessing); 

    // spinner declarations 
    final Spinner countySpinner = (Spinner) findViewById(R.id.countySpinner); 
    final Spinner timeSpinner = (Spinner) findViewById(R.id.timeSpinner); 

    // variable declarations for dinner choices 
    final EditText tendiesInput = (EditText) findViewById(R.id.tendiesInput); 
    final EditText crabInput = (EditText) findViewById(R.id.crabInput); 
    final EditText saladInput = (EditText) findViewById(R.id.saladInput); 
    final EditText wingsInput = (EditText) findViewById(R.id.wingsInput); 
    final EditText soupInput = (EditText) findViewById(R.id.soupInput); 
    final EditText fishDinnerInput = (EditText) findViewById(R.id.fishDinnerInput); 
    final EditText steakDinnerInput = (EditText) findViewById(R.id.steakDinnerInput); 
    final EditText chickenDinnerInput = (EditText) findViewById(R.id.chickenDinnerInput); 
    final EditText kidsDinnerInput = (EditText) findViewById(R.id.kidsDinnerInput); 
    final TextView totalAmount = (TextView) findViewById(R.id.totalAmount); 

    // declare starter prices 
    final double chickenTendies = 10.99; 
    final double crabDip = 13.99; 
    final double salad = 5.99; 
    final double buffaloWings = 8.99; 
    final double soup = 6.99; 

    // declare dinner prices 
    final double fishDinner = 26.99; 
    final double steakDinner = 31.99; 
    final double chickenDinner = 24.99; 
    final double kidsDinner = 15.99; 

    // variable declarations for confirmation page 
    final TextView confirmEmail = (TextView) findViewById(R.id.confirmEmail); 
    final TextView confirmPhone = (TextView) findViewById(R.id.confirmPhone); 
    final TextView confirmCounty = (TextView) findViewById(R.id.confirmCounty); 
    final TextView confirmTime = (TextView) findViewById(R.id.confirmTime); 
    final TextView confirmDate = (TextView) findViewById(R.id.confirmDate); 
    final TextView confirmAdults = (TextView) findViewById(R.id.confirmAdults); 
    final TextView confirmKids = (TextView) findViewById(R.id.confirmKids); 
    final TextView confirmApps = (TextView) findViewById(R.id.confirmApps); 
    final TextView confirmDinners = (TextView) findViewById(R.id.confirmDinners); 
    final TextView confirmTotal = (TextView) findViewById(R.id.confirmTotal); 
    final TextView confirmAddress = (TextView) findViewById(R.id.confirmAddress); 

    // get user input for reservation details and store in variable(s) 
    final String storeEmail = emailInput.getText().toString(); 
    final String storePhone = phoneInput.getText().toString(); 
    final String storeDate = dateInput.getText().toString(); 
    final String storeAdults = totalAdults.getText().toString(); 
    final String storeKids = totalKids.getText().toString(); 

    // declare array adapters for county and time 
    ArrayAdapter countiesArray = new ArrayAdapter(this, android.R.layout.simple_selectable_list_item, county); 
    ArrayAdapter timeArray = new ArrayAdapter(this, android.R.layout.simple_selectable_list_item, time); 

    countySpinner.setOnItemSelectedListener(this); 
    timeSpinner.setOnItemSelectedListener(this); 

    countySpinner.setAdapter(countiesArray); 
    timeSpinner.setAdapter(timeArray); 

** these lines break the code even before a NumberException can occur** 
    // get user input for appetizers and parse to double variables for calculation 
    final double tendiesNum = Double.parseDouble(tendiesInput.getText().toString()); 
    final double crabNum = Double.parseDouble(crabInput.getText().toString()); 
    final double saladNum = Double.parseDouble(saladInput.getText().toString()); 
    final double wingsNum = Double.parseDouble(wingsInput.getText().toString()); 
    final double soupNum = Double.parseDouble(soupInput.getText().toString()); 

    // get user input for dinners and parse to double variables for calculation 
    final double fishNum = Double.parseDouble(fishDinnerInput.getText().toString()); 
    final double chickenNum = Double.parseDouble(chickenDinnerInput.getText().toString()); 
    final double steakNum = Double.parseDouble(steakDinnerInput.getText().toString()); 
    final double kidsNum = Double.parseDouble(kidsDinnerInput.getText().toString());

XML的相應頁面：

<Button 
    android:id="@+id/backToReservation" 
    android:layout_width="75dp" 
    android:layout_height="40dp" 
    android:text="BACK" 
    app:layout_constraintBottom_toBottomOf="parent" 
    android:layout_marginBottom="8dp" 
    android:layout_marginRight="293dp" 
    app:layout_constraintRight_toRightOf="parent" /> 

<Button 
    android:id="@+id/nextToProcessing" 
    android:layout_width="85dp" 
    android:layout_height="40dp" 
    android:layout_marginBottom="8dp" 
    android:layout_marginLeft="259dp" 
    android:text="CONFIRM" 
    app:layout_constraintBottom_toBottomOf="parent" 
    app:layout_constraintLeft_toLeftOf="parent" /> 

<TextView 
    android:id="@+id/starterPrice1" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="$10.99" 
    android:textSize="10sp" 
    android:textStyle="italic" 
    android:layout_marginLeft="119dp" 
    app:layout_constraintLeft_toLeftOf="parent" 
    android:layout_marginTop="0dp" 
    app:layout_constraintTop_toBottomOf="@+id/tendiesText" /> 

<TextView 
    android:id="@+id/starterPrice2" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="$13.99" 
    android:textSize="10sp" 
    android:textStyle="italic" 
    android:layout_marginLeft="119dp" 
    app:layout_constraintLeft_toLeftOf="parent" 
    android:layout_marginTop="0dp" 
    app:layout_constraintTop_toBottomOf="@+id/crabText" /> 

<TextView 
    android:id="@+id/starterPrice3" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="$5.99" 
    android:textSize="10sp" 
    android:textStyle="italic" 
    android:layout_marginLeft="124dp" 
    app:layout_constraintLeft_toLeftOf="parent" 
    android:layout_marginTop="0dp" 
    app:layout_constraintTop_toBottomOf="@+id/saladText" /> 

<TextView 
    android:id="@+id/starterPrice4" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="$8.99" 
    android:textSize="10sp" 
    android:textStyle="italic" 
    android:layout_marginLeft="124dp" 
    app:layout_constraintLeft_toLeftOf="parent" 
    android:layout_marginTop="0dp" 
    app:layout_constraintTop_toBottomOf="@+id/wingsText" /> 

<TextView 
    android:id="@+id/starterPrice5" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="$6.99" 
    android:textSize="10sp" 
    android:textStyle="italic" 
    android:layout_marginLeft="124dp" 
    app:layout_constraintLeft_toLeftOf="parent" 
    android:layout_marginTop="0dp" 
    app:layout_constraintTop_toBottomOf="@+id/soupText" /> 

<TextView 
    android:id="@+id/dinnerPrice1" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="$26.99" 
    android:textSize="10sp" 
    android:textStyle="italic" 
    android:layout_marginLeft="119dp" 
    app:layout_constraintLeft_toLeftOf="parent" 
    android:layout_marginTop="0dp" 
    app:layout_constraintTop_toBottomOf="@+id/fishDinnerText" /> 

<TextView 
    android:id="@+id/dinnerPrice2" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="$31.99" 
    android:textSize="10sp" 
    android:textStyle="italic" 
    android:layout_marginLeft="119dp" 
    app:layout_constraintLeft_toLeftOf="parent" 
    android:layout_marginTop="0dp" 
    app:layout_constraintTop_toBottomOf="@+id/steakDinnerText" /> 

<TextView 
    android:id="@+id/dinnerPrice3" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="$24.99" 
    android:textSize="10sp" 
    android:layout_marginLeft="119dp" 
    app:layout_constraintLeft_toLeftOf="parent" 
    android:layout_marginTop="0dp" 
    app:layout_constraintTop_toBottomOf="@+id/chickenDinnerText" /> 

<TextView 
    android:id="@+id/dinnerPrice4" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="$15.99" 
    android:textSize="10sp" 
    android:textStyle="italic" 
    android:layout_marginLeft="119dp" 
    app:layout_constraintLeft_toLeftOf="parent" 
    android:layout_marginTop="0dp" 
    app:layout_constraintTop_toBottomOf="@+id/kidsDinnerText" /> 

<TextView 
    android:id="@+id/totalAmount" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_marginTop="178dp" 
    android:text="Total: " 
    app:layout_constraintTop_toBottomOf="@+id/dinnerTitle" 
    android:layout_marginLeft="109dp" 
    app:layout_constraintLeft_toLeftOf="parent" /> 

<TextView 
    android:id="@+id/menuText" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="Menu" 
    android:textAlignment="center" 
    android:textSize="24sp" 
    app:layout_constraintTop_toTopOf="parent" 
    android:layout_marginTop="8dp" 
    android:layout_marginLeft="162dp" 
    app:layout_constraintLeft_toLeftOf="parent" /> 

<TextView 
    android:id="@+id/appetizerTitle" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="Appetizers" 
    android:textSize="18sp" 
    android:textStyle="bold" 
    android:layout_marginTop="2dp" 
    app:layout_constraintTop_toBottomOf="@+id/menuText" 
    android:layout_marginLeft="149dp" 
    app:layout_constraintLeft_toLeftOf="parent" /> 

<TextView 
    android:id="@+id/tendiesText" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="Chicken Tenders:" 
    android:textAlignment="textStart" 
    android:textSize="16sp" 
    android:layout_marginLeft="29dp" 
    app:layout_constraintLeft_toLeftOf="parent" 
    app:layout_constraintTop_toTopOf="@+id/tendiesInput" 
    android:layout_marginTop="0dp" /> 

<EditText 
    android:id="@+id/tendiesInput" 
    android:layout_width="100dp" 
    android:layout_height="35dp" 
    android:layout_marginLeft="100dp" 
    android:layout_marginTop="8dp" 
    android:ems="10" 
    android:inputType="number" 
    android:textAlignment="center" 
    android:textSize="12sp" 
    app:layout_constraintLeft_toRightOf="@+id/tendiesText" 
    app:layout_constraintTop_toBottomOf="@+id/appetizerTitle" /> 

<TextView 
    android:id="@+id/crabText" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="Crab Dip:" 
    android:textSize="16sp" 
    android:layout_marginLeft="85dp" 
    app:layout_constraintLeft_toLeftOf="parent" 
    app:layout_constraintTop_toTopOf="@+id/crabInput" 
    android:layout_marginTop="0dp" /> 

<EditText 
    android:id="@+id/crabInput" 
    android:layout_width="100dp" 
    android:layout_height="25dp" 
    android:ems="10" 
    android:inputType="number" 
    android:layout_marginTop="16dp" 
    app:layout_constraintTop_toBottomOf="@+id/tendiesInput" 
    app:layout_constraintLeft_toRightOf="@+id/crabText" 
    android:layout_marginLeft="100dp" /> 

<TextView 
    android:id="@+id/wingsText" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="Buffalo Wings:" 
    android:textSize="16sp" 
    android:layout_marginLeft="47dp" 
    app:layout_constraintLeft_toLeftOf="parent" 
    app:layout_constraintTop_toTopOf="@+id/wingsInput" 
    android:layout_marginTop="0dp" /> 

<EditText 
    android:id="@+id/wingsInput" 
    android:layout_width="100dp" 
    android:layout_height="25dp" 
    android:ems="10" 
    android:inputType="number" 
    android:layout_marginTop="16dp" 
    app:layout_constraintTop_toBottomOf="@+id/saladInput" 
    app:layout_constraintLeft_toRightOf="@+id/wingsText" 
    android:layout_marginLeft="100dp" /> 

<TextView 
    android:id="@+id/soupText" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="Soup Special:" 
    android:textSize="16sp" 
    android:layout_marginLeft="57dp" 
    app:layout_constraintLeft_toLeftOf="parent" 
    app:layout_constraintTop_toTopOf="@+id/soupInput" 
    android:layout_marginTop="-4dp" /> 

<EditText 
    android:id="@+id/soupInput" 
    android:layout_width="100dp" 
    android:layout_height="25dp" 
    android:ems="10" 
    android:inputType="number" 
    android:layout_marginTop="16dp" 
    app:layout_constraintTop_toBottomOf="@+id/wingsInput" 
    app:layout_constraintLeft_toRightOf="@+id/soupText" 
    android:layout_marginLeft="100dp" /> 

<TextView 
    android:id="@+id/saladText" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="Salad:" 
    android:textSize="16sp" 
    android:layout_marginLeft="107dp" 
    app:layout_constraintLeft_toLeftOf="parent" 
    app:layout_constraintTop_toTopOf="@+id/saladInput" 
    android:layout_marginTop="0dp" /> 

<EditText 
    android:id="@+id/saladInput" 
    android:layout_width="100dp" 
    android:layout_height="25dp" 
    android:ems="10" 
    android:inputType="number" 
    android:layout_marginTop="16dp" 
    app:layout_constraintTop_toBottomOf="@+id/crabInput" 
    app:layout_constraintLeft_toRightOf="@+id/saladText" 
    android:layout_marginLeft="100dp" /> 

<TextView 
    android:id="@+id/dinnerTitle" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="Dinners" 
    android:textSize="18sp" 
    android:textStyle="bold" 
    android:layout_marginTop="205dp" 
    app:layout_constraintTop_toBottomOf="@+id/appetizerTitle" 
    android:layout_marginLeft="161dp" 
    app:layout_constraintLeft_toLeftOf="parent" /> 

<TextView 
    android:id="@+id/fishDinnerText" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="Fish:" 
    android:textSize="16sp" 
    android:layout_marginLeft="116dp" 
    app:layout_constraintLeft_toLeftOf="parent" 
    app:layout_constraintTop_toTopOf="@+id/fishDinnerInput" 
    android:layout_marginTop="-8dp" /> 

<EditText 
    android:id="@+id/fishDinnerInput" 
    android:layout_width="100dp" 
    android:layout_height="25dp" 
    android:ems="10" 
    android:inputType="number" 
    android:layout_marginTop="8dp" 
    app:layout_constraintTop_toBottomOf="@+id/dinnerTitle" 
    app:layout_constraintLeft_toRightOf="@+id/fishDinnerText" 
    android:layout_marginLeft="100dp" /> 

<TextView 
    android:id="@+id/steakDinnerText" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="Steak:" 
    android:textSize="16sp" 
    android:layout_marginLeft="106dp" 
    app:layout_constraintLeft_toLeftOf="parent" 
    app:layout_constraintTop_toTopOf="@+id/steakDinnerInput" 
    android:layout_marginTop="0dp" /> 

<EditText 
    android:id="@+id/steakDinnerInput" 
    android:layout_width="100dp" 
    android:layout_height="25dp" 
    android:ems="10" 
    android:inputType="number" 
    android:layout_marginTop="16dp" 
    app:layout_constraintTop_toBottomOf="@+id/fishDinnerInput" 
    app:layout_constraintLeft_toRightOf="@+id/steakDinnerText" 
    android:layout_marginLeft="100dp" /> 

<TextView 
    android:id="@+id/chickenDinnerText" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="Chicken:" 
    android:textSize="16sp" 
    android:layout_marginLeft="90dp" 
    app:layout_constraintLeft_toLeftOf="parent" 
    app:layout_constraintTop_toTopOf="@+id/chickenDinnerInput" 
    android:layout_marginTop="0dp" /> 

<EditText 
    android:id="@+id/chickenDinnerInput" 
    android:layout_width="100dp" 
    android:layout_height="25dp" 
    android:ems="10" 
    android:inputType="number" 
    android:layout_marginTop="16dp" 
    app:layout_constraintTop_toBottomOf="@+id/steakDinnerInput" 
    app:layout_constraintLeft_toRightOf="@+id/chickenDinnerText" 
    android:layout_marginLeft="100dp" /> 

<TextView 
    android:id="@+id/kidsDinnerText" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="Kid's Choice" 
    android:textSize="16sp" 
    android:layout_marginLeft="65dp" 
    app:layout_constraintLeft_toLeftOf="parent" 
    app:layout_constraintTop_toTopOf="@+id/kidsDinnerInput" 
    android:layout_marginTop="0dp" /> 

<EditText 
    android:id="@+id/kidsDinnerInput" 
    android:layout_width="100dp" 
    android:layout_height="25dp" 
    android:ems="10" 
    android:inputType="number" 
    android:layout_marginTop="16dp" 
    app:layout_constraintTop_toBottomOf="@+id/chickenDinnerInput" 
    app:layout_constraintLeft_toRightOf="@+id/kidsDinnerText" 
    android:layout_marginLeft="100dp" />

錯誤日誌：

           java.lang.RuntimeException: Unable to start activity ComponentInfo{edu.dtcc.dinnerreservationapp/edu.dtcc.dinnerreservationapp.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.text.Editable android.widget.EditText.getText()' on a null object reference 
               at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416) 
               at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476) 
               at android.app.ActivityThread.-wrap11(ActivityThread.java) 
               at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344) 
               at android.os.Handler.dispatchMessage(Handler.java:102) 
               at android.os.Looper.loop(Looper.java:148) 
               at android.app.ActivityThread.main(ActivityThread.java:5417) 
               at java.lang.reflect.Method.invoke(Native Method) 
               at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
               at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 
               Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.text.Editable android.widget.EditText.getText()' on a null object reference 
               at edu.dtcc.dinnerreservationapp.MainActivity.onCreate(MainActivity.java:116) 
               at android.app.Activity.performCreate(Activity.java:6237) 
               at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107) 
               at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369) 
               at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)  
               at android.app.ActivityThread.-wrap11(ActivityThread.java)  
               at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)  
               at android.os.Handler.dispatchMessage(Handler.java:102)  
               at android.os.Looper.loop(Looper.java:148)  
               at android.app.ActivityThread.main(ActivityThread.java:5417)  
               at java.lang.reflect.Method.invoke(Native Method)  
               at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)  
               at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

來源

2017-10-12 MrAchilles

堆棧跟蹤將指定在哪條線上發生異常。找到該行，確定哪個「EditText」引用爲空，然後確定是否忘記了分配它，或者它是否在您通過'setContentView（）'傳遞的佈局中。 –

add'R.layout.activity_main' –

'MainActivity.onCreate（MainActivity.java:116）' - 在'MainActivity'中查找第116行，並按照上面的描述繼續。我們看不到您的線路號碼。 –

從中要獲取文本 ID編輯文本不是在代碼重新檢查正確添加您的ID分配編輯文本

來源

2017-10-12 04:17:46

Android Studio中應用立即崩潰 - 顯示java.lang.NullPointerException

回答

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