java.lang.NullPointerException when adding data to sqlite (because of RadioGroup) [duplicate]

问题

This question already has answers here:

What is a NullPointerException, and how do I fix it? (12 answers)

Closed 4 years ago.

inserting data to SQLite was working until i decided to add a RadioGroup. When running i received:

     12-29 11:52:19.948: E/AndroidRuntime(21086): java.lang.NullPointerException
12-29 11:52:19.948: E/AndroidRuntime(21086):    at com.example.appointapp.PatientFragment$1.onClick(PatientFragment.java:66)
12-29 11:52:19.948: E/AndroidRuntime(21086):    at android.view.View.performClick(View.java:4438)
12-29 11:52:19.948: E/AndroidRuntime(21086):    at android.view.View$PerformClick.run(View.java:18422)
12-29 11:52:19.948: E/AndroidRuntime(21086):    at android.os.Handler.handleCallback(Handler.java:733)
12-29 11:52:19.948: E/AndroidRuntime(21086):    at android.os.Handler.dispatchMessage(Handler.java:95)
12-29 11:52:19.948: E/AndroidRuntime(21086):    at android.os.Looper.loop(Looper.java:136)
12-29 11:52:19.948: E/AndroidRuntime(21086):    at android.app.ActivityThread.main(ActivityThread.java:5017)
12-29 11:52:19.948: E/AndroidRuntime(21086):    at java.lang.reflect.Method.invokeNative(Native Method)
12-29 11:52:19.948: E/AndroidRuntime(21086):    at java.lang.reflect.Method.invoke(Method.java:515)
12-29 11:52:19.948: E/AndroidRuntime(21086):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
12-29 11:52:19.948: E/AndroidRuntime(21086):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
12-29 11:52:19.948: E/AndroidRuntime(21086):    at dalvik.system.NativeStart.main(Native Method)

PatientFragement.java code:

package com.example.appointapp;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.Toast;

public class PatientFragment extends Fragment {
    DatabaseHelper myDB;
    EditText editName,editFamilyname,editDob,editAddress,editPhonenb,editEmail;
    Button btnSave, selectedRadioButton; 
    RadioButton radioB;
    RadioGroup radioG;
    private Patient mPatient;
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mPatient= new Patient();

    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup parent, Bundle savedInstanceState){
    View v = inflater.inflate(R.layout.fragment_patient, parent, false);
    myDB = new DatabaseHelper(getActivity());
    editName = (EditText)v.findViewById(R.id.name_text);
    editFamilyname = (EditText)v.findViewById(R.id.familyname_text);
    editDob = (EditText)v.findViewById(R.id.date_text);
    editAddress = (EditText)v.findViewById(R.id.address_text);
    editPhonenb = (EditText)v.findViewById(R.id.phone_text);
    editEmail = (EditText)v.findViewById(R.id.email_text);
    btnSave = (Button)v.findViewById(R.id.save_button);
    radioG = (RadioGroup)v.findViewById(R.id.myRadioGroup);
    int selectedId = radioG.getCheckedRadioButtonId();
    if(selectedId != -1) {    
           selectedRadioButton = (RadioButton)v.findViewById(selectedId);

        }



    AddData();

    return v;
    }


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

            boolean isInserted = myDB.insertData(editName.getText().toString() ,
                        editFamilyname.getText().toString() ,
                        editDob.getText().toString() ,
                        editAddress.getText().toString() ,
                        editPhonenb.getText().toString() , 
                        editEmail.getText().toString(),
                        selectedRadioButton.getText().toString()) ;
            if(isInserted == true)
            Toast.makeText(getActivity(), "Patient inserted", Toast.LENGTH_LONG).show();
            else 
                Toast.makeText(getActivity(), "Patient not inserted", Toast.LENGTH_LONG).show();
                                               }
                }
                                       );

    }   
}

and fragment_patient.xml code:

    <?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="54dp"
        android:orientation="horizontal" >

        <EditText
            android:id="@+id/name_text"
            android:layout_width="143dp"
            android:layout_height="wrap_content"
            android:layout_marginLeft="16dp"
            android:layout_marginRight="16dp"
            android:ems="10"
            android:hint="@string/name_text_hint" />

        <EditText
            android:id="@+id/familyname_text"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginLeft="16dp"
            android:hint="@string/familyname_text_hint" />
    </LinearLayout>

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

        <EditText
            android:id="@+id/date_text"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:ems="10"
            android:hint="@string/date_text_hint" >
        </EditText>
    </LinearLayout>

    <RadioGroup
        android:id="@+id/myRadioGroup"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/text"
        android:checkedButton="@+id/male_text" >

        <RadioButton
            android:id="@+id/female_text"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/female_text" />

        <RadioButton
            android:id="@+id/male_male_text"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/male_text" />
    </RadioGroup>

    <EditText
        android:id="@+id/address_text"
        android:layout_width="348dp"
        android:layout_height="wrap_content"
        android:ems="10"
        android:hint="@string/address_text_hint" />

    <LinearLayout
        android:layout_width="340dp"
        android:layout_height="57dp"
        android:orientation="horizontal" >

        <EditText
            android:id="@+id/phone_text"
            android:layout_width="143dp"
            android:layout_height="wrap_content"
            android:hint="@string/phone_text_hint" />

        <EditText
            android:id="@+id/email_text"
            android:layout_width="213dp"
            android:layout_height="wrap_content"
            android:hint="@string/email_text_hint" />
    </LinearLayout>

    <Button
        android:id="@+id/save_button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="right"
        android:text="@string/save_button" />

</LinearLayout>


and databasehelper.java code:

package com.example.appointapp;

import android.content.ContentValues;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class DatabaseHelper extends SQLiteOpenHelper {

    public static final String DATABASE_NAME="appo.db";
    public static final String TABLE_NAME = "patients_table";
    public static final String COL_1 = "ID";
    public static final String COL_2 = "NAME";
    public static final String COL_3 = "FAMILYNAME";
    public static final String COL_4 = "DOB";
    public static final String COL_5 = "ADDRESS";
    public static final String COL_6 = "PHONENUMBER";
    public static final String COL_7 = "EMAIL";
    public static final String COL_8 = "GENDER";

    public DatabaseHelper(Context context){
        super(context, DATABASE_NAME, null, 1);

    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL( "create table "+ TABLE_NAME + "( ID INTEGER PRIMARY KEY AUTOINCREMENT, NAME TEXT, FAMILYNAME TEXT, DOB TEXT, ADDRESS TEXT, PHONENUMBER TEXT, EMAIL TEXT, GENDER TEXT )" );

    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME);
        onCreate(db);

    }

    public boolean insertData(String name, String familyname, String dob, String address, String phonenumber, String email, String gender) {
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put(COL_2,name);
        contentValues.put(COL_3,familyname);
        contentValues.put(COL_4,dob);
        contentValues.put(COL_5,address);
        contentValues.put(COL_6,phonenumber);
        contentValues.put(COL_7,email);
        contentValues.put(COL_8,gender);
        long result = db.insert(TABLE_NAME, null , contentValues);
        if(result == -1)
            return false;
        else 
            return true;
}

}

Please help am a new programmer. Note that my application was working before trying to add the result of the RadioGroup to the database. Thank you in advance.

回答1:

You need to get the currently selected RadioButton at the time that you save data to the database. Otherwise, you will never capture the choice of the user if they make a choice different from the default.

There is no need to do anything with the currently selected RadioButton on startup:

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup parent, Bundle savedInstanceState){
    View v = inflater.inflate(R.layout.fragment_patient, parent, false);
    myDB = new DatabaseHelper(getActivity());
    editName = (EditText)v.findViewById(R.id.name_text);
    editFamilyname = (EditText)v.findViewById(R.id.familyname_text);
    editDob = (EditText)v.findViewById(R.id.date_text);
    editAddress = (EditText)v.findViewById(R.id.address_text);
    editPhonenb = (EditText)v.findViewById(R.id.phone_text);
    editEmail = (EditText)v.findViewById(R.id.email_text);
    btnSave = (Button)v.findViewById(R.id.save_button);
    radioG = (RadioGroup)v.findViewById(R.id.myRadioGroup);

    //remove from here:
    /*
    int selectedId = radioG.getCheckedRadioButtonId();
    if(selectedId != -1) {    
           selectedRadioButton = (RadioButton)v.findViewById(selectedId);
    }
    */

    AddData();

    return v;
}

Take that removed code, and move it to the OnClickListener in the AddData() method:

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

                int selectedId = radioG.getCheckedRadioButtonId();
                if(selectedId != -1) {
                    selectedRadioButton = (RadioButton)v.findViewById(selectedId);

                    boolean isInserted = myDB.insertData(editName.getText().toString() ,
                            editFamilyname.getText().toString() ,
                            editDob.getText().toString() ,
                            editAddress.getText().toString() ,
                            editPhonenb.getText().toString() ,
                            editEmail.getText().toString(),
                            selectedRadioButton.getText().toString()) ;
                    if(isInserted == true)
                        Toast.makeText(getActivity(), "Patient inserted", Toast.LENGTH_LONG).show();
                    else
                        Toast.makeText(getActivity(), "Patient not inserted", Toast.LENGTH_LONG).show();
                }

            }
        }
    );

}

来源：https://stackoverflow.com/questions/34515753/java-lang-nullpointerexception-when-adding-data-to-sqlite-because-of-radiogroup