aktivitesini ComponentInfo NullPointer

Question

Ana Etkinlik

package com.project.mobileshoppingassistant.activity; 

import android.content.Intent; 
import android.content.SharedPreferences; 
import android.preference.PreferenceActivity; 
import android.preference.PreferenceManager; 
import android.support.v7.app.AppCompatActivity; 
import android.os.Bundle; 
import android.util.Log; 
import android.view.Menu; 
import android.view.MenuItem; 
import android.view.View; 
import android.widget.ImageButton; 

import com.project.mobileshoppingassistant.Environment.Constants; 
import com.project.mobileshoppingassistant.MapViewActivity; 
import com.project.mobileshoppingassistant.R; 
import com.project.mobileshoppingassistant.model.SharedPrefs; 

public class MainActivity extends AppCompatActivity implements View.OnClickListener { 

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

     ImageButton bScanProduct = (ImageButton) findViewById(R.id.bScanProduct); 
     ImageButton blocateuser = (ImageButton) findViewById(R.id.bLocateUser); 
     ImageButton bAllProducts = (ImageButton) findViewById(R.id.bAllProducts); 
     ImageButton bSaleProducts = (ImageButton) findViewById(R.id.bSaleProducts); 
     ImageButton bYourCart = (ImageButton) findViewById(R.id.bYourCart); 
     ImageButton bYourList = (ImageButton) findViewById(R.id.bYourList); 
     ImageButton bLogout = (ImageButton) findViewById(R.id.bLogout); 
     ImageButton bTransactionHistory = (ImageButton) findViewById(R.id.bTransactionHistory); 

     bScanProduct.setOnClickListener(this); 
     bAllProducts.setOnClickListener(this); 
     blocateuser.setOnClickListener(this); 
     bSaleProducts.setOnClickListener(this); 
     bYourCart.setOnClickListener(this); 
     bYourList.setOnClickListener(this); 
     bLogout.setOnClickListener(this); 
     bTransactionHistory.setOnClickListener(this); 

    } 

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

    @Override 
    public boolean onOptionsItemSelected(MenuItem item) { 
     int id = item.getItemId(); 
     if (id == R.id.action_settings) { 
      Intent i = new Intent(this, PrefsActivity.class); 
      startActivity(i); 
      return true; 
     } 

     return super.onOptionsItemSelected(item); 
    } 

    @Override 
    public void onClick(View v) { 
     switch (v.getId()) { 
      case R.id.bAllProducts: 
       Intent i1 = new Intent(this, ProductCategoryActivity.class); 
       startActivity(i1); 
       break; 

      case R.id.bLocateUser: 
       Intent i8 = new Intent(this, MapViewActivity.class); 
       startActivity(i8); 
       break; 

      case R.id.bSaleProducts: 
       Intent i2 = new Intent(this, SaleProductsActivity.class); 
       startActivity(i2); 
       break; 

      case R.id.bScanProduct: 
       Intent i3 = new Intent(this, ProductScanActivity.class); 
       startActivity(i3); 
       break; 

      case R.id.bYourCart: 
       Intent i4 = new Intent(this, CartActivity.class); 
       startActivity(i4); 
       break; 

      case R.id.bYourList: 
       Intent i5 = new Intent(this, YourListActivity.class); 
       startActivity(i5); 
       break; 

      case R.id.bTransactionHistory: 
       Intent i6 = new Intent(this, TransactionHistoryActivity.class); 
       startActivity(i6); 
       break; 

      case R.id.bLogout: 
       SharedPrefs.setUserEmailId(getApplicationContext(), null); 
       Intent i7 = new Intent(this, LoginActivity.class); 
       startActivity(i7); 
       finish(); 
       break; 
     } 
    } 
} 

MapViewActivity

package com.project.mobileshoppingassistant; 

import android.content.Context; 
import android.content.Intent; 
import android.content.SharedPreferences; 
import android.graphics.PointF; 
import android.net.wifi.ScanResult; 
import android.os.Bundle; 
import android.os.Handler; 
import android.preference.PreferenceManager; 
import android.view.Menu; 
import android.view.MenuItem; 

import org.json.JSONObject; 

import java.util.ArrayList; 
import java.util.HashMap; 
import java.util.Iterator; 
import java.util.List; 
import java.util.Timer; 
import java.util.TimerTask; 
import java.util.TreeSet; 

public class MapViewActivity extends MapActivity { 
    public final static String EXTRA_MESSAGE_FLOOR = "com.inte.indoorpositiontracker.FLOOR"; 

    private static final int MENU_ITEM_EDIT_MAP = 21; 

    public static final int SCAN_DELAY = 1000; // delay for the first scan (milliseconds) 
    public static final int SCAN_INTERVAL = 1000; // interval between scans (milliseconds) 
    public static final int MAX_SCAN_THREADS = 2; // max amount of simultaneus scans 

    private int mScanThreadCount = 0; 

    //keys to save fingerPrint to sharedPereferences--start 
    public static final String KEY_ID="fingerprint_id"; 
    public static final String KEY_MAP="fingerprint_map"; 
    public static final String KEY_POSITON_X="fingerprintX"; 
    public static final String KEY_POSITON_Y="fingerprintY"; 
    //end 

    public static final String KEY_FINGERPRINT_MADE="hasFIngerPrintBeenMade";//used to check if 
    // an average point has been calculated 

    // UI pointer to visualize user where he is on the map 
    private WifiPointView mLocationPointer; 

    // handler for callbacks to the UI thread 
    private static Handler sUpdateHandler = new Handler(); 

    // runnable to refresh map (called by the handler) 
    private Runnable mRefreshMap = new Runnable() { 
     public void run() { 
      refreshMap(); 
     } 
    }; 

    private boolean mPaused = false; // used to detect if the application is on map edit mode 

    private HashMap<String, Integer> mMeasurements; // used to calculate weighted averages of signal strengths 



    /** INSTANCE METHODS*/ 

    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     mMeasurements = new HashMap<String, Integer>(); 

     mLocationPointer = mMap.createNewWifiPointOnMap(new PointF(-1000, -1000)); 
     mLocationPointer.activate(); 

     if (PreferenceManager.getDefaultSharedPreferences(this).getBoolean(KEY_FINGERPRINT_MADE,false)) 
     { 
      mLocationPointer.setFingerprint(getSavedFingerprint()); 
     } 

     Timer timer = new Timer(); 
     timer.schedule(new TimerTask() { 

      @Override 
      public void run() { 
       if(mPaused == false) { // start scan only when this activity is active 
        mWifi.startScan(); 
       } 
      } 

     }, SCAN_DELAY, SCAN_INTERVAL); 
    } 


    @Override 
    public void onReceiveWifiScanResults(final List<ScanResult> results) { 
     IndoorPositionTracker application = (IndoorPositionTracker) getApplication(); 
     final ArrayList<Fingerprint> fingerprints = application.getFingerprintData(mSelectedMap); 

     // calculating the location might take some time in case there are a lot of fingerprints (>10000), 
     // so it's reasonable to limit scan thread count to make sure there are not too many of these threads 
     // going on at the same time 
     if(results.size() > 0 && fingerprints.size() > 0 && mScanThreadCount <= MAX_SCAN_THREADS) { 
      Thread t = new Thread() { 
       public void run() { 
        mScanThreadCount++; 

        HashMap<String, Integer> measurements = new HashMap<String, Integer>(); 
        for (ScanResult result : results) { 
         measurements.put(result.BSSID, result.level); 
        } 

        TreeSet<String> keys = new TreeSet<String>(); 
        keys.addAll(mMeasurements.keySet()); 
        keys.addAll(measurements.keySet()); 

        // calculate access point signal strengths with weighted averages 
        // (adjust to suddent big changes in received signal strengths) 
        for (String key : keys) { 
         Integer value = measurements.get(key); 
         Integer oldValue = mMeasurements.get(key); 
         if(oldValue == null) { 
          mMeasurements.put(key, value); 
         } else if(value == null) { 
          mMeasurements.remove(key); 
         } else { 
          value = (int) (oldValue * 0.4f + value * 0.6f); 
          mMeasurements.put(key, value); 
         } 
        } 


        Fingerprint f = new Fingerprint(mMeasurements); 

        // find fingerprint closest to our location (one with the smallest euclidean distance to us) 
        Fingerprint closestMatch = f.getClosestMatch(fingerprints); 

        runOnUiThread(new Runnable() { 
         public void run() { 
          PreferenceManager.getDefaultSharedPreferences(MapViewActivity.this).edit() 
            .putBoolean(KEY_FINGERPRINT_MADE,true).commit(); 
         } 
        }); 
        mLocationPointer.setFingerprint(closestMatch); // translate UI pointer to new location on screen 
        saveFingerPrint(closestMatch); 
        // need to refresh map through updateHandler since only UI thread is allowed to touch its views 
        sUpdateHandler.post(mRefreshMap); 

        mScanThreadCount--; 
       } 
      }; 
      t.start(); // start new scan thread 
     } 
    } 

    public void startMapEditActivity() { 
     Intent intent = new Intent(MapViewActivity.this, MapEditActivity.class); 
     intent.putExtra(EXTRA_MESSAGE_FLOOR, mSelectedMap); 
     startActivity(intent); // start map edit mode 
    } 

    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 
     // add menu items 
     super.onCreateOptionsMenu(menu); // items for changing map 
     menu.add(Menu.NONE, MENU_ITEM_EDIT_MAP, Menu.NONE, "Edit map"); 
     return true; 
    } 

    @Override 
    public boolean onOptionsItemSelected(MenuItem item) { 
     // Handle item selection 
     switch (item.getItemId()) { 
      case MENU_ITEM_EDIT_MAP: // start map edit mode 
       startMapEditActivity(); 
       return true; 
      default: // change map 
       return super.onOptionsItemSelected(item); 
     } 
    } 

    private void saveMap(HashMap<String,Integer> inputMap){ 
     SharedPreferences pSharedPref = getApplicationContext().getSharedPreferences 
       ("MyVariables", Context.MODE_PRIVATE); 
     if (pSharedPref != null){ 
      JSONObject jsonObject = new JSONObject(inputMap); 
      String jsonString = jsonObject.toString(); 
      SharedPreferences.Editor editor = pSharedPref.edit(); 
      editor.remove("My_map").commit(); 
      editor.putString("My_map", jsonString); 
      editor.commit(); 
     } 
    } 

    private HashMap<String,Integer> loadMap(){ 
     HashMap<String,Integer> outputMap = new HashMap<String,Integer>(); 
     SharedPreferences pSharedPref = getApplicationContext().getSharedPreferences("MyVariables", Context.MODE_PRIVATE); 
     try{ 
      if (pSharedPref != null){ 
       String jsonString = pSharedPref.getString("My_map", (new JSONObject()).toString()); 
       JSONObject jsonObject = new JSONObject(jsonString); 
       Iterator<String> keysItr = jsonObject.keys(); 
       while(keysItr.hasNext()) { 
        String key = keysItr.next(); 
        Integer value = (Integer) jsonObject.get(key); 
        outputMap.put(key, value); 
       } 
      } 
     }catch(Exception e){ 
      e.printStackTrace(); 
     } 
     return outputMap; 
    } 

    private void saveFingerPrint(Fingerprint fingerprint) 
    { 
     PreferenceManager.getDefaultSharedPreferences(this).edit() 
       .putInt(KEY_ID,fingerprint.getId()) 
       .putString(KEY_MAP,fingerprint.getMap()) 
       .putFloat(KEY_POSITON_X,fingerprint.getLocation().x) 
       .putFloat(KEY_POSITON_Y,fingerprint.getLocation().y) 
       .commit(); 
     saveMap(fingerprint.getMeasurements()); 

    } 

    private Fingerprint getSavedFingerprint() 
    { 
     SharedPreferences preferences=PreferenceManager.getDefaultSharedPreferences(this); 
     int id=preferences.getInt(KEY_ID, -1); 
     String map=preferences.getString(KEY_MAP, null); 
     Float positionX=preferences.getFloat(KEY_POSITON_X, -1); 
     Float positionY=preferences.getFloat(KEY_POSITON_Y,-1); 
     PointF pointF=new PointF(positionX,positionY); 
     Fingerprint fingerprint=new Fingerprint(id,map,pointF,loadMap()); 

     return fingerprint; 
    } 


} 

Manifest

<?xml version="1.0" encoding="utf-8"?> 
<manifest xmlns:android="http://schemas.android.com/apk/res/android" 
    package="com.project.mobileshoppingassistant"> 

    <uses-permission android:name="android.permission.CAMERA" /> 
    <uses-permission android:name="android.permission.INTERNET" /> 
    <uses-permission android:name="android.permission.READ_PHONE_STATE" /> 
    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE"></uses-permission> 
    <uses-permission android:name="android.permission.CHANGE_WIFI_STATE"></uses-permission> 

    <application 
     android:allowBackup="true" 
     android:icon="@mipmap/ic_launcher" 
     android:label="@string/app_name" 
     android:theme="@style/AppTheme"> 
     <activity 
      android:name=".activity.SplashScreenActivity" 
      android:label="@string/title_activity_splash_screen" 
      android:screenOrientation="portrait"> 
      <intent-filter> 
       <action android:name="android.intent.action.MAIN" /> 

       <category android:name="android.intent.category.LAUNCHER" /> 
      </intent-filter> 
     </activity> 
     <activity 
      android:name=".activity.ProductScanActivity" 
      android:label="@string/title_activity_barcode_scanner" 
      android:screenOrientation="portrait" /> 
     <activity 
      android:name=".activity.MainActivity" 
      android:label="@string/title_activity_main" 
      android:screenOrientation="portrait" /> 
     <activity 
      android:name=".activity.UserRegisterActivity" 
      android:label="@string/title_activity_user_register" 
      android:screenOrientation="portrait" /> 
     <activity 
      android:name=".activity.DisplayProductActivity" 
      android:label="@string/title_activity_display_product" 
      android:screenOrientation="portrait" /> 
     <activity 
      android:name=".activity.TransactionActivity" 
      android:label="@string/title_activity_transaction" 
      android:screenOrientation="portrait" /> 
     <activity 
      android:name=".activity.AllProductsActivity" 
      android:label="@string/title_activity_all_products" 
      android:screenOrientation="portrait" /> 
     <activity 
      android:name=".activity.LoginActivity" 
      android:label="@string/title_activity_login" 
      android:screenOrientation="portrait" /> 
     <activity 
      android:name=".activity.CartActivity" 
      android:label="@string/title_activity_cart" 
      android:screenOrientation="portrait" /> 
     <activity 
      android:name=".activity.OrderActivity" 
      android:label="@string/title_activity_order" 
      android:screenOrientation="portrait" /> 
     <activity 
      android:name=".activity.RegisterActivity" 
      android:label="@string/title_activity_register" 
      android:screenOrientation="portrait" /> 
     <activity 
      android:name=".activity.TransactionHistoryActivity" 
      android:label="@string/title_activity_transaction_history" 
      android:screenOrientation="portrait" /> 
     <activity 
      android:name=".activity.PrefsActivity" 
      android:label="@string/title_activity_transaction_history" 
      android:screenOrientation="portrait" /> 
     PrefsActivity 
     <activity 
      android:name=".activity.SaleProductsActivity" 
      android:label="@string/title_activity_sale_products" 
      android:screenOrientation="portrait" /> 
     <activity 
      android:name=".activity.YourListActivity" 
      android:label="@string/title_activity_your_list" 
      android:screenOrientation="portrait" /> 
     <activity 
      android:name=".activity.ProductCategoryActivity" 
      android:label="@string/title_activity_product_category" 
      android:screenOrientation="portrait" /> 

     <activity android:name=".MapEditActivity" 
      android:label="Localisation"> 
     </activity> 

     <activity android:name=".MapViewActivity" 
      android:label="Localisation"></activity> 

     <activity android:name=".MapActivity" 
      android:label="Localisation"></activity> 
    </application> 

</manifest> 

i (mapeditactivity ana itibaren) Kullanıcı bulun butonuna tıklayın

i olsun bir başlatılamıyor NullException.Can aktivitesi başlatılamıyor Birisi yardım lütfen?

Answer 1

Sen mMap başlatıldı ve orada kullanmaya değil -

mLocationPointer = mMap.createNewWifiPointOnMap(new PointF(-1000, -1000)); 

kullanmadan önce başlatın.