Fatal error show error не удалось запустить компонент активности, когда я запускаю это приложение

Я пытаюсь сделать простой вывод всех записей из SQLite database в приложении для просмотра списка. Компилятор не обнаруживает никаких ошибок, но когда я запускаю приложение, он получает ошибку во время выполнения.Fatal error show error не удалось запустить компонент активности, когда я запускаю это приложение

main_Activity.java

package com.example.login_userauthentication; 

import android.os.Bundle; 
import android.app.Activity; 
import android.content.Intent; 
import android.view.Menu; 
import android.view.View; 

public class MainActivity extends Activity { 

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

    public void Register(View v) 
    { 
     startActivity(new Intent(getApplicationContext(),Reg.class)); 
    } 
    public void Login(View v) 
    { 
     startActivity(new Intent(getApplicationContext(),Login.class)); 
    } 

    public void Show_allrecord(View v) 
    { 
     startActivity(new Intent(getApplicationContext(),Show_record.class)); 
    } 
    public void update_record(View v) 
    { 
     startActivity(new Intent(getApplicationContext(),Update.class)); 
    } 

    @Override 
    public boolean onCreateOptionsMenu(Menu menu) 
    { 
     // Inflate the menu; this adds items to the action bar if it is present. 
     getMenuInflater().inflate(R.menu.main, menu); 
     return true; 
    } 
}

Show_Record.java (это главный класс, показать все userdetailed в ListView)

package com.example.login_userauthentication; 

import java.util.ArrayList; 
import java.util.List; 

import android.app.Activity; 
import android.content.Context; 
import android.os.Bundle; 
import android.widget.ListView; 

public class Show_record extends Activity 
{ 
    Show_recordAdapter showrecord_adapter; 
    ListView listview; 
    ArrayList<Student> studentlist; 
    Database helper=new Database(); 

    protected void onCreate(Bundle savedInstanceState) 
    { 
     System.out.println("show sumit"); 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.show_recordlist); 
     System.out.println("show_record activity"); 
     System.out.println("show sumit"); 
     helper=new Database(); 
     listview = (ListView) findViewById(R.id.listView1); 
     studentlist=new ArrayList<Student>(); 
     studentlist = helper.getAllrecord(); 
     System.out.println(studentlist); 
     System.out.println("show sumit"); 
     showrecord_adapter=new Show_recordAdapter(getApplicationContext(),studentlist); 
     listview.setAdapter(showrecord_adapter); 

//  listview.setAdapter(new Show_recordAdapter(this, studentlist, 
//    getLayoutInflater())); 
    } 
} 


package com.example.login_userauthentication; 

import java.util.ArrayList; 
import java.util.List; 
import java.util.zip.Inflater;

show_recordAdapter.java

Это пользовательский адаптер класс

import android.content.Context; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.ViewGroup; 
import android.widget.BaseAdapter; 
import android.widget.TextView; 

public class Show_recordAdapter extends BaseAdapter 
{ 
    Context context; 
    ArrayList<Student> empList; 
    private static LayoutInflater inflater = null; 

    public Show_recordAdapter(Context context,ArrayList<Student> empList) 
    { 
     context=this.context; 
     empList=this.empList; 
     inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
    } 

    public int getCount() { 
     // TODO Auto-generated method stub 
     return empList.size(); 
    } 

    @Override 
    public Object getItem(int position) { 
     // TODO Auto-generated method stub 
     return empList.get(position); 
    } 

    @Override 
    public long getItemId(int position) 
    { 
     // TODO Auto-generated method stub 
     return position; 
    } 

    @Override 
    public View getView(int position, View convertView, ViewGroup parent) 
    { 
     //final ViewItem item; 
     if(convertView==null) 

      convertView = inflater.inflate(R.layout.listview_iteams, null); 
     //item=new ViewItem(); 
     TextView UemailTextview=(TextView)convertView.findViewById(R.id.uemail); 
     TextView upassTextview=(TextView)convertView.findViewById(R.id.upass); 
     TextView UnameTextview=(TextView)convertView.findViewById(R.id.uname); 
     TextView UmobileTextview=(TextView)convertView.findViewById(R.id.umobile); 
//  convertView.setTag(item); 
//  } 
//  else 
//  { 
//   item=(ViewItem)convertView.getTag(); 
//  } 

     Student student=new Student(); 
     student=empList.get(position); 
     UnameTextview.setText("emailid: "+student.getEmailid()); 
     upassTextview.setText("password: "+student.getPassword()); 
     UnameTextview.setText("name: "+student.getName()); 
     UmobileTextview.setText("mobile: "+student.getMobileno()); 
     return convertView; 
    } 

// private class ViewItem 
// { 
//  TextView UemailTextview; 
//  TextView upassTextview; 
//  TextView UnameTextview; 
//  TextView UmobileTextview; 
// } 
}

Databaseclass (в котором определены все filelds из таблицы, а также определенные методы)

package com.example.login_userauthentication; 

import java.util.ArrayList; 
import java.util.List; 
import android.content.ContentValues; 
import android.content.Context; 
import android.database.Cursor; 
import android.database.sqlite.SQLiteDatabase; 
import android.provider.SyncStateContract.Helpers; 
import android.util.Log; 

public class Database 
{ 
    public static final String TABLE_NAME = "student"; 
    public static final String USER_EMAILID= "emailid"; 
    public static final String USER_PASSWORD = "password"; 
    public static final String USER_NAME = "name"; 
    public static final String USER_CONTACT = "mobileno"; 
    public static final String Tag = "jobplacement"; 

    public static Databse_helper dbhelper = null; 
    public static SQLiteDatabase db = null; 
    static Context context1 = null; 

    public static boolean addUser(Context context, String email, String password, String name,String mobile) 
    { 
     context1=context; 
     try { 
     dbhelper=new Databse_helper(context); 
     db=dbhelper.getWritableDatabase(); 
     ContentValues values=new ContentValues(); 
     values.put(Database.USER_EMAILID,email); 
     values.put(Database.USER_PASSWORD,password); 
     values.put(Database.USER_NAME,name); 
     values.put(Database.USER_CONTACT,mobile); 
     long rowid = db.insert(Database.TABLE_NAME, null, values); 
     Log.d("Users", "Inserted into TRANSACTIONS " + rowid); 
     db.close(); 
     return true; 
     } catch (Exception e) { 
      // TODO: handle exception 
     } 
     return false; 
    } 

    public static boolean userAuthentication(Context context, String uname, String password) { 

     Cursor trans = null; 
     try { 
      dbhelper=new Databse_helper(context); 
      db = dbhelper.getWritableDatabase(); 
      trans = db.rawQuery("select " + USER_PASSWORD + " from " + TABLE_NAME + " where " + USER_EMAILID 
        + " = '" + uname + "'", null); 
      if (trans.getCount() == 0) 
      { 
       Log.d("userAuthentication", "Zero record"); 
      } 

      else 
      { 
       while (trans.moveToNext()) 
       { 
        String pass = trans.getString(trans.getColumnIndex(USER_PASSWORD)); 
        if (password.equals(pass)) 
        { 
         return true; 
        } else { 
         return false; 
        } 
       } 
      } 
     } catch (Exception e) { 
      // TODO: handle exception 
     } 
     return false; 
    } 

    public ArrayList<Student> getAllProducts() 
    { 
     db = dbhelper.getWritableDatabase(); 
     List<Student> productList = new ArrayList<Student>(); 
     // Select All Query 
     String selectQuery = "SELECT * FROM " + Database.TABLE_NAME; 
     Cursor cursor = db.rawQuery(selectQuery, null); 

     // looping through all rows and adding to list 
     if (cursor.moveToFirst()) { 
      do { 
       Student st = new Student(); 
       st.setEmailid(cursor.getString(0)); 
       st.setPassword(cursor.getString(1)); 
       st.setName(cursor.getString(2)); 
       st.setMobileno(cursor.getString(3)); 
//    product.setID(Integer.parseInt(cursor.getString(0))); 
//    product.setName(cursor.getString(1)); 
//    product.setNumber(Integer.parseInt(cursor.getString(2))); 
//    product.setPieces(Integer.parseInt(cursor.getString(3))); 
//    product.setPrice(Integer.parseInt(cursor.getString(4))); 
//    product.setTotPrice(Integer.parseInt(cursor.getString(5))); 
       // Adding contact to list 
       productList.add(st); 
      } while (cursor.moveToNext()); 
     } 

     // return contact list 
     return (ArrayList<Student>) productList; 
    } 

    public static boolean updateEntry(Student st) 
    { 

     db=dbhelper.getWritableDatabase(); 
     // Define the updated row content. 
     ContentValues updatedValues = new ContentValues(); 
     // Assign values for each row. 
     updatedValues.put(USER_EMAILID, st.getEmailid()); 
     updatedValues.put(USER_NAME,st.getName()); 
     updatedValues.put(USER_CONTACT, st.getMobileno()); 

     //String where=Database.USER_EMAILID +"=+?"; 
     // String where="emailid +=?"; 
     int row_id=db.update(Database.TABLE_NAME,updatedValues, "emailid=?", new String[]{st.getEmailid()}); 
     Log.d("login", "updated record " +row_id); 
     return true; 
    } 

    public ArrayList<Student> getAllrecord() 
    { 
     dbhelper=new Databse_helper(context1); 
     db=dbhelper.getWritableDatabase(); 
     List<Student> emplist=new ArrayList<Student>(); 
     String rowquery="select * from "+TABLE_NAME; 
     Cursor cursor=db.rawQuery(rowquery, null); 
     if (cursor.moveToFirst()) 
     { 
      do 
      { Student st = new Student(); 
      st.setEmailid(cursor.getString(0)); 
      st.setPassword(cursor.getString(1)); 
      st.setName(cursor.getString(2)); 
      st.setMobileno(cursor.getString(3)); 
       // Adding Translate to list 

       Student emp1=new Student(); 
       emplist.add(st); 
      } 
      while (cursor.moveToNext()); 
     } 

     // return Translate list 
     return (ArrayList<Student>) emplist; 
    } 
}

Database_helper.java (в котором определено создание таблицы и создать базу данных)

package com.example.login_userauthentication; 

import android.content.Context; 
import android.database.sqlite.SQLiteDatabase; 
import android.database.sqlite.SQLiteOpenHelper; 
import android.util.Log; 

public class Databse_helper extends SQLiteOpenHelper 
{ 
    static final int DATABASE_VERSION = 2; 
    static final String DATABASE_NAME = "collage.db"; 
    public static final String Tag = "jobplacement"; 

    public Databse_helper(Context cxt) 
    { 
     super(cxt, DATABASE_NAME, null, DATABASE_VERSION); 
     Log.i(Tag, "DBHelper class constructer called"); 
     Log.i(Tag, "Database Created Successfully"); 
    } 

    public void onCreate(SQLiteDatabase db) 
    { 
     createTables(db); 

    } 

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

     // Create tables again 
     onCreate(db); 
    } 

    private void createTables(SQLiteDatabase database) 
    { 

     String users_table_sql = "create table " + Database.TABLE_NAME + " (" + Database.USER_EMAILID 
       + " TEXT," + Database.USER_PASSWORD + " TEXT," + Database.USER_NAME 
       + " TEXT," + Database.USER_CONTACT + " TEXT)"; 
     try { 
      database.execSQL(users_table_sql); 
      Log.d(Tag, "table created successfully"); 

    //  protected static final String player = ("CREATE TABLE " + table_player 
    //    + " (" + player_id + " INTEGER PRIMARY KEY AUTOINCREMENT, " 
    //    + player_name + " TEXT, " + player_dob + " INTEGER," + player_gender + " TEXT);"); 
    //  
    //  
    //  "CREATE TABLE " + TABLE_PRODUCTS + "(" 
    //  + KEY_ID + " INTEGER PRIMARY KEY," + KEY_NAME + " TEXT," 
    //  + KEY_NO + " TEXT," + KEY_PIECES + " TEXT,"+ KEY_PRICE + " TEXT," + KEY_TOT_PRICE + " TEXT" + ")"; 

     } catch (Exception ex) 
     { 
      Log.d("Accounts", "Error in DBHelper.onCreate() : " + ex.getMessage()); 
     } 
    } 
}

Это LogCat

12-24 05:15:26.447: I/Choreographer(1009): Skipped 64 frames! The application may be doing too much work on its main thread. 
12-24 05:15:27.797: I/Choreographer(1009): Skipped 48 frames! The application may be doing too much work on its main thread. 
12-24 05:15:43.807: I/System.out(1009): show sumit 
12-24 05:15:44.547: D/dalvikvm(1009): GC_FOR_ALLOC freed 88K, 9% free 2642K/2876K, paused 245ms, total 305ms 
12-24 05:15:44.818: I/System.out(1009): show_record activity 
12-24 05:15:44.837: I/System.out(1009): show sumit 
12-24 05:15:44.857: I/jobplacement(1009): DBHelper class constructer called 
12-24 05:15:44.857: I/jobplacement(1009): Database Created Successfully 
12-24 05:15:44.887: D/AndroidRuntime(1009): Shutting down VM 
12-24 05:15:44.887: W/dalvikvm(1009): threadid=1: thread exiting with uncaught exception (group=0x40a71930) 
12-24 05:15:45.017: E/AndroidRuntime(1009): FATAL EXCEPTION: main 
12-24 05:15:45.017: E/AndroidRuntime(1009): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.login_userauthentication/com.example.login_userauthentication.Show_record}: java.lang.NullPointerException 
12-24 05:15:45.017: E/AndroidRuntime(1009):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180) 
12-24 05:15:45.017: E/AndroidRuntime(1009):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230) 
12-24 05:15:45.017: E/AndroidRuntime(1009):  at android.app.ActivityThread.access$600(ActivityThread.java:141) 
12-24 05:15:45.017: E/AndroidRuntime(1009):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234) 
12-24 05:15:45.017: E/AndroidRuntime(1009):  at android.os.Handler.dispatchMessage(Handler.java:99) 
12-24 05:15:45.017: E/AndroidRuntime(1009):  at android.os.Looper.loop(Looper.java:137) 
12-24 05:15:45.017: E/AndroidRuntime(1009):  at android.app.ActivityThread.main(ActivityThread.java:5041) 
12-24 05:15:45.017: E/AndroidRuntime(1009):  at java.lang.reflect.Method.invokeNative(Native Method) 
12-24 05:15:45.017: E/AndroidRuntime(1009):  at java.lang.reflect.Method.invoke(Method.java:511) 
12-24 05:15:45.017: E/AndroidRuntime(1009):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 
12-24 05:15:45.017: E/AndroidRuntime(1009):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 
12-24 05:15:45.017: E/AndroidRuntime(1009):  at dalvik.system.NativeStart.main(Native Method) 
12-24 05:15:45.017: E/AndroidRuntime(1009): Caused by: java.lang.NullPointerException 
12-24 05:15:45.017: E/AndroidRuntime(1009):  at android.database.sqlite.SQLiteOpenHelper.getDatabaseLocked(SQLiteOpenHelper.java:224) 
12-24 05:15:45.017: E/AndroidRuntime(1009):  at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:164) 
12-24 05:15:45.017: E/AndroidRuntime(1009):  at com.example.login_userauthentication.Database.getAllrecord(Database.java:144) 
12-24 05:15:45.017: E/AndroidRuntime(1009):  at com.example.login_userauthentication.Show_record.onCreate(Show_record.java:32) 
12-24 05:15:45.017: E/AndroidRuntime(1009):  at android.app.Activity.performCreate(Activity.java:5104) 
12-24 05:15:45.017: E/AndroidRuntime(1009):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080) 
12-24 05:15:45.017: E/AndroidRuntime(1009):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144) 
12-24 05:15:45.017: E/AndroidRuntime(1009):  ... 11 more 
12-24 05:40:30.726: D/gralloc_goldfish(1215): Emulator without GPU emulation detected. 
12-24 05:43:35.957: D/gralloc_goldfish(1271): Emulator without GPU emulation detected.

источник

2015-12-24 Sumit Kumawat

где ваш 'logcat' ??? –

Я отредактировал logcat –

Внутри класса базы данных getAllrecord() context1 прошел null.

dbhelper = new Databse_helper(context1);//here context1 is null

Вы можете попробовать прохождение контекст к getAllrecord (Context context1) в классе Database и затем можно назвать

studentlist = helper.getAllrecord(Show_record.this);

из класса Show_record. Надеюсь, это поможет решить вашу проблему.

источник

2015-12-24 06:21:32

извините ... но это решение не работает .... PLZ дать другое решение –

Вы все еще сталкиваетесь с проблемой после передачи контекста? любезно обновите свой стек logtat с обновленным кодом. –

сэр ничего не случится.i'm мое лучшее, но ничего –

Fatal error show error не удалось запустить компонент активности, когда я запускаю это приложение

ответ

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