Android CheckBox空指針

-2

我有用於條件語句複選框的代碼。Android CheckBox空指針

CheckBox Cb_Ar,Cb_Db,Cb_Hb; 
    Cb_Ar = (CheckBox) findViewById(R.id.check1); 
    Cb_Db = (CheckBox) findViewById(R.id.check2); 
    Cb_Hb = (CheckBox) findViewById(R.id.check3); 
    String toPass=""; 


    if(Cb_Ar.isChecked()){ 
     toPass = "Arthritis"; 
    }

這是給一個零指示字例外

logcat的：

Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean android.widget.CheckBox.isChecked()' on a null object reference

活動其中使用複選框，這整個活動它是用於包com.example.jello.letscook ;

import android.app.AlertDialog; 
import android.content.DialogInterface; 
import android.database.Cursor; 
import android.database.DatabaseUtils; 
import android.os.Bundle; 
import android.provider.ContactsContract; 
import android.support.design.widget.FloatingActionButton; 
import android.support.design.widget.Snackbar; 
import android.support.v7.app.AppCompatActivity; 
import android.support.v7.widget.Toolbar; 
import android.util.Log; 
import android.view.View; 
import android.widget.CheckBox; 
import android.widget.EditText; 
import android.widget.ListView; 
import android.widget.SimpleCursorAdapter; 
import android.widget.Spinner; 
import android.widget.TextView; 
import android.widget.Toast; 

import java.util.List; 

public class showmenu extends AppCompatActivity { 
    DatabaseHelper myDb; 
    Spinner mainIng; 
    EditText sub1,sub2,sub3,sub4,sub5,sub6; 
    CheckBox Cb_Ar,Cb_Db,Cb_Hb; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_showmenu); 
    myDb = new DatabaseHelper(this); 

    mainIng = (Spinner) findViewById(R.id.spinner); 
    sub1 = (EditText) findViewById(R.id.sub1); 
    sub2 = (EditText) findViewById(R.id.sub2); 
    sub3 = (EditText) findViewById(R.id.sub3); 
    sub4 = (EditText) findViewById(R.id.sub4); 
    sub5 = (EditText) findViewById(R.id.sub5); 
    sub6 = (EditText) findViewById(R.id.sub6); 
    Cb_Ar = (CheckBox) findViewById(R.id.check1); 
    Cb_Db = (CheckBox) findViewById(R.id.check2); 
    Cb_Hb = (CheckBox) findViewById(R.id.check3); 
    showList(); 


        // myDb.insertHB(true); 
        // myDb.inert_Arth(true); 
         //myDb.inert_Dia(true); 






    FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab); 
    fab.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View view) { 
      Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG) 
        .setAction("Action", null).show(); 
     } 
    }); 
} 

public void showList() { 
    String toPass=""; 

    if(Cb_Ar.isChecked()){ 
     toPass = "Arthritis"; 
    } 


    Cursor cursor = myDb.getData(toPass); 
    String[] fromField = new String[] {DatabaseHelper.RECIPE_NAME}; 
    int[] toView = new int[] {R.id.textViewMenuSuggest}; 
    SimpleCursorAdapter myCursorAdapter; 
    myCursorAdapter = new SimpleCursorAdapter(this,R.layout.menushow,cursor,fromField,toView,0); 
    ListView myList = (ListView) findViewById(R.id.selectView); 
    myList.setAdapter(myCursorAdapter); 

} 
}

XML代碼中的複選框是：

<?xml version="1.0" encoding="utf-8"?> 
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:tools="http://schemas.android.com/tools" 
    xmlns:app="http://schemas.android.com/apk/res-auto" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin" 
    android:paddingRight="@dimen/activity_horizontal_margin" 
    android:paddingBottom="15dp" 
    android:paddingTop="16dp" 
    android:background="#3A539B" 
    app:layout_behavior="@string/appbar_scrolling_view_behavior" 
    tools:showIn="@layout/activity_starting_screen" tools:context=".StartingScreen"> 


    <LinearLayout 
     android:orientation="horizontal" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" 
     android:background="#EEEEEE"> 

     <LinearLayout 
      android:orientation="vertical" 
      android:layout_width="match_parent" 
      android:layout_height="match_parent" 
      android:background="#3A539B"> 

      <TextView 
       android:layout_marginTop="35dp" 
       android:layout_width="wrap_content" 
       android:layout_height="wrap_content" 
       android:textAppearance="?android:attr/textAppearanceLarge" 
       android:text="Main Ingredient" 
       android:id="@+id/textView2" /> 


      <Spinner 
       android:layout_width="fill_parent" 
       android:layout_height="wrap_content" 
       android:layout_marginTop="15dp" 
       android:spinnerMode="dialog" 
       android:id="@+id/spinner" /> 


      <RelativeLayout 
       android:orientation="horizontal" 
       android:layout_width="match_parent" 
       android:layout_height="wrap_content" 
       android:id="@+id/relLayout"> 

       <TextView 
        android:layout_marginTop="15dp" 
        android:layout_width="wrap_content" 
        android:layout_height="wrap_content" 
        android:textAppearance="?android:attr/textAppearanceLarge" 
        android:text="Sub Ingredients" 
        android:id="@+id/textView3" /> 

       <Button 
        android:layout_width="40dp" 
        android:layout_height="30dp" 
        android:layout_marginTop="10dp" 
        android:layout_gravity="center" 
        android:textAlignment="center" 
        android:text="+" 
        android:textSize="25dp" 
        android:background="#2ECC71" 
        android:layout_alignParentRight="true" 
        android:id="@+id/addText" /> 
      </RelativeLayout> 

      <LinearLayout 
       android:layout_marginTop="10dp" 
       android:orientation="vertical" 
       android:layout_width="fill_parent" 
       android:layout_height="wrap_content" 
       android:layout_gravity="center" > 

       <LinearLayout 
        android:orientation="horizontal" 
        android:id="@+id/mLayout" 
        android:layout_width="match_parent" 
        android:layout_height="match_parent" 
        android:focusableInTouchMode="true"> 


        <LinearLayout 
         android:orientation="vertical" 
         android:layout_width="fill_parent" 
         android:layout_height="match_parent"> 

         <EditText 
          android:layout_width="match_parent" 
          android:layout_height="wrap_content" 
          android:hint="Sub Ingredient 1" 
          android:textStyle="italic" 
          android:textColorHint="#95A5A6" 
          android:id="@+id/sub1" /> 

         <EditText 
          android:layout_width="match_parent" 
          android:layout_height="wrap_content" 
          android:visibility="gone" 
          android:hint="Sub Ingredient 2" 
          android:textStyle="italic" 
          android:textColorHint="#95A5A6" 
          android:id="@+id/sub2" /> 

         <EditText 
          android:layout_width="match_parent" 
          android:layout_height="wrap_content" 
          android:visibility="gone" 
          android:hint="Sub Ingredient 3" 
          android:textStyle="italic" 
          android:textColorHint="#95A5A6" 
          android:id="@+id/sub3" /> 

         <EditText 
          android:layout_width="match_parent" 
          android:layout_height="wrap_content" 
          android:visibility="gone" 
          android:hint="Sub Ingredient 4" 
          android:textStyle="italic" 
          android:textColorHint="#95A5A6" 
          android:id="@+id/sub4" /> 

         <EditText 
          android:layout_width="match_parent" 
          android:layout_height="wrap_content" 
          android:visibility="gone" 
          android:hint="Sub Ingredient 5" 
          android:textStyle="italic" 
          android:textColorHint="#95A5A6" 
          android:id="@+id/sub5" /> 

         <EditText 
          android:layout_width="match_parent" 
          android:layout_height="wrap_content" 
          android:visibility="gone" 
          android:hint="Sub Ingredient 6" 
          android:textStyle="italic" 
          android:textColorHint="#95A5A6" 
          android:id="@+id/sub6" /> 
        </LinearLayout> 

       </LinearLayout> 

       <TextView 
        android:layout_marginTop="50dp" 
        android:layout_width="wrap_content" 
        android:layout_height="wrap_content" 
        android:textAppearance="?android:attr/textAppearanceLarge" 
        android:text="Health Condition" 
        android:id="@+id/textView" /> 

       <LinearLayout 
        android:layout_weight="1" 
        android:orientation="horizontal" 
        android:layout_width="match_parent" 
        android:layout_height="match_parent"> 

        <LinearLayout 
         android:orientation="horizontal" 
         android:layout_width="fill_parent" 
         android:layout_height="match_parent"> 

         <CheckBox 
          android:layout_width="100dp" 
          android:layout_height="wrap_content" 
          android:text="Arthritis" 
          android:textSize="15dp" 
          android:id="@+id/check1" 
          android:checked="false" /> 

         <CheckBox 
          android:layout_width="100dp" 
          android:layout_height="wrap_content" 
          android:text="Diabetic" 
          android:textSize="15dp" 
          android:id="@+id/check2" /> 

         <CheckBox 
          android:layout_width="wrap_content" 
          android:layout_height="wrap_content" 
          android:text="Highblood" 
          android:textSize="15dp" 
          android:id="@+id/check3" /> 
        </LinearLayout> 

       </LinearLayout> 

       <Button 
        android:layout_marginTop="80dp" 
        android:gravity="center" 
        android:layout_width="fill_parent" 
        android:onClick="nextScreen" 
        android:layout_height="match_parent" 
        android:background="#2ECC71" 
        android:layout_gravity="bottom" 
        android:text="Lets Cook!" 
        android:id="@+id/button" /> 

      </LinearLayout> 

      </LinearLayout> 

     </LinearLayout> 


    </ScrollView>

來源

2016-03-07 Jellolicious

張貼您stacktrace –

什麼是先生？ – Jellolicious

發佈您的logcat，其中包含您的錯誤的詳細信息。 –

有每一件事情沒關係，就像

CheckBox Cb_Ar,Cb_Db,Cb_Hb; 
    Cb_Ar = (CheckBox) view.findViewById(R.id.check1); 
    Cb_Db = (CheckBox) view.findViewById(R.id.check2); 
    Cb_Hb = (CheckBox) view.findViewById(R.id.check3); 
    String toPass=""; 


    if(Cb_Ar.isChecked()){ 
     toPass = "Arthritis"; 
    }

如果您正在使用片段和任何對話框，然後

使用

Cb_Ar = (CheckBox) dialog.findViewById(R.id.check1); 
    Cb_Db = (CheckBox) dialog.findViewById(R.id.check2); 
    Cb_Hb = (CheckBox) dialog.findViewById(R.id.check3);

它工作正常我

來源

2016-03-07 15:02:55

view.findViewById在我身上的錯誤。它錯誤的觀點。 – Jellolicious

這個錯誤是正常的，你不使用片段使用view.findViewById ....這是一個錯誤的答案... –

它是多麼可悲。你認爲我的錯誤先生是什麼？ – Jellolicious

Android CheckBox空指針

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