We Keep Coding

Referencing TextViews from Activity in Service and Vice versa

I am working on an Android app with a steadily growing Code basis; the aim of the app is to scan and process QR Codes and Barcodes on Handheld Devices for Storages (not Smartphones). It hast two Activities that contain major parts of the programmatical logic; hence, I want to store major parts of the Code that contains the Functionality for processing the Scanner input in an external Service, called Scanner Service, implement the methods there and use the methods in other Activites;
however, I have a major issue with the use of Context, getApplicationContext() and the reference of the Activity in the Service and vice versa; although I think I have referenced and initialised the Textviews from the Activity in the Service, the app keeps on crashing with the following error message:
AndroidRuntime: Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.View android.app.Activity.findViewById(int)' on a null object reference
at com.xxxx.ScanService.<clinit>(ScanService.java:16)
I know what it means, but I don´t know how I could access the View
private static TextView content = (TextView) a.findViewById(R.id.content_detail);
in such a way that I can use it in the Service and in the Activity and the app stops crashing.
Therefore, any hints or help would be very much appreciated, thank you in advance.
The MainDetailActivity:
package com.example.xxx_app;
import android.app.Activity;
import android.app.Dialog;
import android.content.Context;
import android.content.Intent;
import android.graphics.drawable.ColorDrawable;
import android.os.Bundle;
import android.util.Log;
import android.view.KeyEvent;
import android.view.Menu;
import android.view.View;
import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;
import androidx.recyclerview.widget.RecyclerView;
import android.view.MenuItem;
import android.view.Window;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.PopupMenu;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import static com.xxx.ScanService.*;
import static com.xxx.SimpleItemRecyclerViewAdapter.TAGG;
/**
* An activity representing a single Main detail screen. This
* activity is only used on narrow width devices. On tablet-size devices,
* item details are presented side-by-side with a list of items
* in a {#link MainListActivity}.
*/
public class MainDetailActivity extends AppCompatActivity implements AdapterView.OnItemSelectedListener,
PopupMenu.OnMenuItemClickListener {
Context context;
private RecyclerView recyclerView;
private RecyclerviewAdapter recyclerviewAdapter;
private RecyclerTouchListener touchListener;
private ListView listView;
public TextView textView4;
public String code;
public static final String TAG = "Barcode ist:" ;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_detail);
context = this;
//TextView headerView = findViewById(R.id.txt1);
Spinner spinner = (Spinner) findViewById(R.id.spinner);
EditText editBarcode = (EditText) findViewById(R.id.editText);
TextView content = (TextView) findViewById(R.id.content_detail);
TextView editTextNumber = findViewById(R.id.editTextNumber);
Button addBooking = findViewById(R.id.button);
Button removeBooking = findViewById(R.id.button2);
removeBooking.setEnabled(false);
spinner.setOnItemSelectedListener(this);
//String selectedItem = spinner.getSelectedItem().toString();
// Create an ArrayAdapter using the string array and a default spinner layout
ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this,
R.array.mockdata, android.R.layout.simple_spinner_item);
// Specify the layout to use when the list of choices appears
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
// Apply the adapter to the spinner
spinner.setAdapter(adapter);
String scannedCode = getIntent().getStringExtra("scannedCode");
Log.d(TAG, "scannedCode" + scannedCode);
if (scannedCode != null && (content.getText().toString().equals(""))) {
content.setText(scannedCode);
}
Button btn = findViewById(R.id.imageView4);
btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
PopupMenu popup = new PopupMenu(MainDetailActivity.this, v);
popup.setOnMenuItemClickListener(MainDetailActivity.this);
popup.inflate(R.menu.popup_menu);
popup.show();
}
});
editBarcode.setOnKeyListener(new View.OnKeyListener() {
#Override
public boolean onKey(View v, int keyCode, KeyEvent event) {
// TODO Auto-generated method stub
String code = editBarcode.getText().toString();
if (code.matches("")) //{ if(code.trim().isEmpty())
//|| editBarcode.getText().toString() > 100 )
{
Log.d(TAG, "Code ist leer");
}
if (keyCode == KeyEvent.KEYCODE_ENTER && code.length() > 0) {
editBarcode.setText("");
ScanService.checkEnteredCode(code);
return true;
}
return false;
}
});
recyclerView = findViewById(R.id.recyclerview);
recyclerviewAdapter = new RecyclerviewAdapter(this);
Intent newIntent = getIntent();
String receivedPalNo = newIntent.getStringExtra("palNo");
String receivedNo = newIntent.getStringExtra("no");
String receivedType = newIntent.getStringExtra("type");
String receivedRack = newIntent.getStringExtra("rack");
String receivedCountItems = newIntent.getStringExtra("count_items");
content.setText(receivedCountItems);
RestClient.getPaletteItems(getApplicationContext(),recyclerviewAdapter,receivedPalNo);
Log.d(TAGG,"Intent 1" + receivedPalNo);
Log.d(TAGG, "Intent 2" + receivedNo);
Log.d(TAGG, "Intent 3" + receivedType);
Log.d(TAGG,"Intent 4" + receivedRack);
Log.d(TAGG, "Intent 5" + receivedCountItems);
final ArrayList<Items> itemList = new ArrayList<>();
/*
Items[] items = new Items(12345,123456, 200, 500);
itemList.add(items);*/
recyclerviewAdapter.setItemList((ArrayList<Items>) itemList);
recyclerView.setAdapter(recyclerviewAdapter);
touchListener = new RecyclerTouchListener(this,recyclerView);
RecyclerviewAdapter finalRecyclerviewAdapter = recyclerviewAdapter;
touchListener
.setClickable(new RecyclerTouchListener.OnRowClickListener() {
#Override
public void onRowClicked(int position) {
//Toast.makeText(getApplicationContext(),itemList.get(position), Toast.LENGTH_SHORT).show();
}
#Override
public void onIndependentViewClicked(int independentViewID, int position) {
}
})
.setSwipeOptionViews(R.id.delete_task,R.id.edit_task)
.setSwipeable(R.id.rowFG, R.id.rowBG, new RecyclerTouchListener.OnSwipeOptionsClickListener() {
#Override
public void onSwipeOptionClicked(int viewID, int position) {
switch (viewID){
case R.id.delete_task:
itemList.remove(position);
finalRecyclerviewAdapter.setItemList(itemList);
break;
case R.id.edit_task:
Toast.makeText(getApplicationContext(),"Edit Not Available",Toast.LENGTH_SHORT).show();
break;
}
}
});
recyclerView.addOnItemTouchListener(touchListener);
class StableArrayAdapter extends ArrayAdapter<String> {
HashMap<String, Integer> mIdMap = new HashMap<String, Integer>();
public StableArrayAdapter(Context context, int textViewResourceId,
List<String> objects) {
super(context, textViewResourceId, objects);
for (int i = 0; i < objects.size(); ++i) {
mIdMap.put(objects.get(i), i);
}
}
#Override
public long getItemId(int position) {
String item = getItem(position);
return mIdMap.get(item);
}
#Override
public boolean hasStableIds() {
return true;
}
}
// savedInstanceState is non-null when there is fragment state
// saved from previous configurations of this activity
// (e.g. when rotating the screen from portrait to landscape).
// In this case, the fragment will automatically be re-added
// to its container so we don"t need to manually add it.
// For more information, see the Fragments API guide at:
//
// http://developer.android.com/guide/components/fragments.html
//
String text = getIntent().getStringExtra("palNo");
//headerView.setText(text);
if (receivedType != null && receivedType.equals("FE")) {
ImageView mImgView = findViewById(R.id.id_col_code);
mImgView.setBackgroundResource(R.drawable.backgroun_blue);
}
if (receivedType != null && receivedType.equals("UFE")) {
ImageView mImgView = findViewById(R.id.id_col_code);
mImgView.setBackgroundResource(R.drawable.backgroun_yellow);
}
}
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;
}
public boolean onMenuItemClick(MenuItem item) {
Toast.makeText(this, "Selected Item: " +item.getTitle(), Toast.LENGTH_SHORT).show();
switch (item.getItemId()) {
case R.id.search_item:
// do your code
return true;
case R.id.upload_item:
// do your code
return true;
case R.id.copy_item:
// do your code
return true;
/* case R.id.print_item:
// do your code
return true;*/
case R.id.share_item:
// do your code
return true;
/*case R.id.bookmark_item:
// do your code
return true;*/
default:
return false;
}
}
public void newDialog(Activity activity) {
final Dialog dialog = new Dialog(activity);
dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
dialog.setCancelable(true);
dialog.setContentView(R.layout.sortiment_layout);
dialog.getWindow().setBackgroundDrawable(new ColorDrawable(android.graphics.Color.TRANSPARENT));
Button okButton = dialog.findViewById(R.id.ok);
okButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
//Toast.makeText(getApplicationContext(),"Ok" ,Toast.LENGTH_SHORT).show();
dialog.dismiss();
}
});
Button cancelButton = dialog.findViewById(R.id.cancel);
cancelButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
//Toast.makeText(getApplicationContext(),"Abbrechen" ,Toast.LENGTH_SHORT).show();
dialog.cancel();
}
});
dialog.show();
}
public void showDialog(Activity activity) {
final Dialog dialog = new Dialog(activity);
dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
dialog.setCancelable(true);
dialog.setContentView(R.layout.newcustom_layout);
dialog.getWindow().setBackgroundDrawable(new ColorDrawable(android.graphics.Color.TRANSPARENT));
Button okButton = dialog.findViewById(R.id.ok);
okButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
//Toast.makeText(getApplicationContext(),"Ok" ,Toast.LENGTH_SHORT).show();
dialog.dismiss();
}
});
dialog.show();
}
public void onItemSelected(AdapterView<?> parent, View view,
int pos, long id) {
// An item was selected. You can retrieve the selected item using
// parent.getItemAtPosition(pos)
}
public void onNothingSelected(AdapterView<?> parent) {
// Another interface callback
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == android.R.id.home) {
// This ID represents the Home or Up button. In the case of this
// activity, the Up button is shown. For
// more details, see the Navigation pattern on Android Design:
//
// http://developer.android.com/design/patterns/navigation.html#up-vs-back
//
navigateUpTo(new Intent(this, MainListActivity.class));
return true;
}
return super.onOptionsItemSelected(item);
}
#Override
public void onResume() {
super.onResume();
recyclerView.addOnItemTouchListener(touchListener);
}
#Override
public void onPointerCaptureChanged(boolean hasCapture) {
}
}
The ScanService Class:
package com.example.xxx;
import android.app.Activity;
import android.content.Context;
import android.util.Log;
import android.widget.TextView;
public class ScanService {
private static final String TAG = "Scan Service Tag";
private static Context mContext;
private static Activity a = (MainDetailActivity)mContext;
private static TextView content = (TextView)
a.findViewById(R.id.content_detail);
private static TextView editTextNumber = (TextView)
a.findViewById(R.id.editTextNumber);
public ScanService (Context mContext) {
this.mContext = mContext;
}
public static void checkEnteredCode(String code, Activity a) {
content.setText("");
//PSP-H1-EA-F3
if
(code.matches("PSP-\\p{Upper}\\d\\p{Punct}\\p{Upper}\\" +
"p{Upper}\\p{Punct}\\p{Upper}\\p{Digit}")) {
content.setText("");
content.setText(code);
Log.d(TAG, "xxx");
}
if (code.matches("LF-[0-9]*")) {
///LF-(\d+)/gi
content.setText("");
content.setText(code);
Log.d(TAG, "xxx");
}
if (code.matches("PAL-[0-9][0-9][0-9]")) {
content.setText("");
content.setText(code);
Log.d(TAG, "xxx");
}
if (code.matches("P-[0-9][0-9][0-9]")) {
content.setText("");
content.setText(code);
Log.d(TAG, "Palette");
}
if (code.matches("[0-9][0-9][0-9][0-9].[0-9][0-9].+DB")) {
if(editTextNumber == null) {
Log.d(TAG, "xxx");
}
else {
editTextNumber.setText(code);
Log.d(TAG, "xxx");
}
Log.d(TAG, "xxx");
}
if (code.matches("[0-9A-Z]*[0-9]*")) {
//editBarcode.setText("");
//editBarcode.setText(keyCode);
Log.d(TAG, "xxx");
}
if (code.matches("\\d{13}")) {
//newDialog(MainDetailActivity.this);
//editBarcode.setText("");
//editBarcode.setText(keyCode);
if(editTextNumber == null) {
Log.d(TAG, "xxx");
}
else {
editTextNumber.setText(code);
Log.d(TAG, "xxx");
}
Log.d(TAG, "xxx");
}
else {
Log.d(TAG, "xxx");
};
//editBarcode.setText("");
//editBarcode.setText(code);
/* String code = editBarcode.getText().toString();
if (code.matches("")) //{ if(code.trim().isEmpty())
//|| editBarcode.getText().toString() > 100 )
{
Log.d(TAG, "xxx");
}
//}
checkEnteredCode(code);
//editBarcode.setText("");
return Boolean.parseBoolean(code);*/
Log.d(TAG, code);
}
public static void checkEnteredCode(String code) {
}
}

You cannot access any Views from a Service! Views belong to the Activity. This is the wrong application architecture. A Service performs background processing (file I/O, network I/O, computation, etc.). The Activity is responsible for interacting with the user (inputs, display, etc.). If your Service wants to put data on the screen, you've broken the division of responsibilities. Your Service should simply notify your Activity (or any other component that is interested) when data has changed, and the Activity can then update the View itself. You can share data between the Service and your other components in a number of ways, including: event bus, publish/subscribe, shared preferences, broadcast Intents, SQLite database, etc.

Losing state of the activity when navigating from notification to activity

I have an activity named Player Activity in which I am streaming music with the help of MediaPlayer API. Whenever my activity is created a notification is displayed which has some basic control of the music player.
So when I tap on my notification it jumps back to the Player Activity, but the state of the activity is lost.
Before tapping on notification :
After tapping on notification :
Here is the code of my notification's Pending Intent
Intent notifyIntent = new Intent(context, PlayerActivity.class);
notifyIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK | Intent.FLAG_ACTIVITY_NEW_TASK);
notifyIntent.setAction("android.intent.action.MAIN");
notifyIntent.addCategory("android.intent.category.LAUNCHER");
PendingIntent pendingIntent = PendingIntent.getActivity(context, 0, notifyIntent, PendingIntent.FLAG_UPDATE_CURRENT);
Here is the code for PlayerActivity.java :
package com.example.user.musicplayer;
import android.app.ProgressDialog;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.media.MediaMetadataRetriever;
import android.media.MediaPlayer;
import android.os.AsyncTask;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.widget.Button;
import android.widget.ImageButton;
import android.widget.SeekBar;
import android.widget.TextView;
import android.widget.Toast;
import com.squareup.picasso.Picasso;
import java.util.concurrent.TimeUnit;
import de.hdodenhof.circleimageview.CircleImageView;
public class PlayerActivity extends AppCompatActivity implements MediaPlayer.OnBufferingUpdateListener,MediaPlayer.OnCompletionListener{
private static Button btn_play_pause;
private Button btnToggleRepeat;
private Button btnStop;
private SeekBar seekBar;
private TextView textView;
public static MediaPlayer mediaPlayer;
private int mediaFileLength;
private int realtimeLength;
private String musicUrl;
private String imageUrl;
final Handler handler = new Handler();
private boolean isRepeat;
private CircleImageView musicImage;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_player);
Log.d("TAG", "onCreate");
NotificationGenerator.customBigNotification(getApplicationContext());
musicUrl = getIntent().getStringExtra("musicUrl");
imageUrl = getIntent().getStringExtra("imageUrl");
seekBar = (SeekBar)findViewById(R.id.seekbar);
seekBar.setMax(99); // 100% (0~99)
seekBar.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
if(mediaPlayer.isPlaying())
{
SeekBar seekBar = (SeekBar)v;
int playPosition = (mediaFileLength/100)*seekBar.getProgress();
mediaPlayer.seekTo(playPosition);
}
return false;
}
});
textView = (TextView)findViewById(R.id.txtTime);
btnToggleRepeat = findViewById(R.id.btnRepeat);
btnStop = findViewById(R.id.btnStop);
musicImage = findViewById(R.id.musicImgView);
Picasso.get().load(imageUrl).placeholder(R.drawable.music).error(R.drawable.music).into(musicImage);
btn_play_pause = (Button) findViewById(R.id.btnTogglePlay);
btn_play_pause.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
final ProgressDialog mDialog = new ProgressDialog(PlayerActivity.this);
AsyncTask<String,String,String> mp3Play = new AsyncTask<String, String, String>() {
#Override
protected void onPreExecute() {
mDialog.setMessage("Please wait");
mDialog.show();
}
#Override
protected String doInBackground(String... params) {
try{
mediaPlayer.setDataSource(params[0]);
mediaPlayer.prepare();
}
catch (Exception ex)
{
}
return "";
}
#Override
protected void onPostExecute(String s) {
mediaFileLength = mediaPlayer.getDuration();
realtimeLength = mediaFileLength;
if(!mediaPlayer.isPlaying())
{
playMusic();
}
else
{
pauseMusic();
}
updateSeekBar();
mDialog.dismiss();
}
};
mp3Play.execute(musicUrl); // direct link mp3 file
}
});
btnToggleRepeat.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if(isRepeat){
isRepeat = false;
mediaPlayer.setLooping(false);
btnToggleRepeat.setText("Repeat");
}
else{
isRepeat = true;
mediaPlayer.setLooping(true);
btnToggleRepeat.setText("Single");
}
}
});
btnStop.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
try {
mediaPlayer.pause();
mediaPlayer.stop();
}
catch (Exception e){
Toast.makeText(PlayerActivity.this, "Opps! sorry something bad happened", Toast.LENGTH_SHORT).show();
}
}
});
mediaPlayer = new MediaPlayer();
mediaPlayer.setOnBufferingUpdateListener(this);
mediaPlayer.setOnCompletionListener(this);
}
public void pauseMusic() {
mediaPlayer.pause();
btn_play_pause.setText("Play");
}
public void playMusic() {
mediaPlayer.start();
btn_play_pause.setText("Pause");
}
private void updateSeekBar() {
seekBar.setProgress((int)(((float)mediaPlayer.getCurrentPosition() / mediaFileLength)*100));
if(mediaPlayer.isPlaying())
{
Runnable updater = new Runnable() {
#Override
public void run() {
updateSeekBar();
realtimeLength-=1000; // declare 1 second
textView.setText(String.format("%d:%d",TimeUnit.MILLISECONDS.toMinutes(realtimeLength),
TimeUnit.MILLISECONDS.toSeconds(realtimeLength) -
TimeUnit.MILLISECONDS.toSeconds(TimeUnit.MILLISECONDS.toMinutes(realtimeLength))));
}
};
handler.postDelayed(updater,1000); // 1 second
}
}
#Override
protected void onResume() {
super.onResume();
Log.d("TAG", "onResume");
}
#Override
protected void onStart() {
super.onStart();
Log.d("TAG", "onStart");
}
#Override
public void onBufferingUpdate(MediaPlayer mp, int percent) {
seekBar.setSecondaryProgress(percent);
}
#Override
public void onCompletion(MediaPlayer mp) {
if(!mediaPlayer.isLooping())
btn_play_pause.setText("Play");
}
#Override
protected void onStop() {
super.onStop();
}
#Override
protected void onPause() {
super.onPause();
}
public static class DownloadCancelReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
Log.d("notificationPlayer","Received Cancelled Event");
}
}
}
Thanks in advance. Pardon me if the explanation is not clear, because if i might have right words to explain it, I would have googled it.

Add this to your PlayerActivity activity in manifest :
android:launchMode="singleTask"
And use these flags in the intent for pendingintent :
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
intent.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);

Android Null Object References on BluetoothAdapter.isEnabled() and startscan()

I am trying to create a BLE android app, and I've been having a lot of trouble with null pointers that I can't figure out even when using androids sample apps of android-BluetoothAdvertisements and android-BluetoothLEGatt.
This is my code:
import android.app.Activity;
import android.app.ListActivity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothManager;
import android.bluetooth.BluetoothGatt;
import android.bluetooth.BluetoothGattCallback;
import android.bluetooth.BluetoothGattCharacteristic;
import android.bluetooth.BluetoothGattDescriptor;
import android.bluetooth.BluetoothGattService;
import android.bluetooth.le.BluetoothLeScanner;
import android.bluetooth.le.ScanCallback;
import android.bluetooth.le.ScanResult;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.os.Handler;
import android.support.design.widget.NavigationView;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentTransaction;
import android.support.v7.app.AppCompatActivity;
import android.support.v4.widget.DrawerLayout;
import android.widget.Button;
import android.widget.ListAdapter;
import android.widget.TextView;
import android.widget.Toast;
import android.widget.BaseAdapter;
import android.widget.ListView;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.view.LayoutInflater;
import android.view.ViewGroup;
import android.view.View.OnClickListener;
import java.util.List;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity {
private BluetoothAdapter mBluetoothAdapter;
private LeDeviceListAdapter mLeDeviceListAdapter;
private BluetoothLeScanner mBluetoothLeScanner;
private boolean mScanning;
private ScanCallback mScanCallback;
private Handler mHandler;
private BluetoothDevice mBluetoothGatt;
private String mDeviceName;
private String mDeviceAddress;
private ScanResultAdapter mAdapter;
private BluetoothGattDescriptor mDescriptor;
private BluetoothGattCharacteristic mBluetoothCharacteristic;
private BluetoothDevice device;
private int mConnectionState = STATE_DISCONNECTED;
private BluetoothLeScanner btScanner;
private BluetoothDevice mbluetoothDevice;
Button button;
DrawerLayout dLayout;
private Button ble_scan;
private final static int REQUEST_ENABLE_BT = 1;
private static final int STATE_DISCONNECTED = 0;
private static final int STATE_CONNECTING = 1;
private static final int STATE_CONNECTED = 2;
private final String LIST_NAME = "NAME";
private final String LIST_UUID = "UUID";
public static final String EXTRAS_DEVICE_NAME = "DEVICE_NAME";
public static final String EXTRAS_DEVICE_ADDRESS = "DEVICE_ADDRESS";
public final static String ACTION_GATT_CONNECTED =
"com.example.bluetooth.le.ACTION_GATT_CONNECTED";
public final static String ACTION_GATT_DISCONNECTED =
"com.example.bluetooth.le.ACTION_GATT_DISCONNECTED";
public final static String ACTION_GATT_SERVICES_DISCOVERED =
"com.example.bluetooth.le.ACTION_GATT_SERVICES_DISCOVERED";
public final static String ACTION_DATA_AVAILABLE =
"com.example.bluetooth.le.ACTION_DATA_AVAILABLE";
public final static String EXTRA_DATA =
"com.example.bluetooth.le.EXTRA_DATA";
// Stops scanning after 5 seconds.
private static final long SCAN_PERIOD = 5000;
//On entering app protocols
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
final Intent intent = getIntent();
mDeviceName = intent.getStringExtra(EXTRAS_DEVICE_NAME);
mDeviceAddress = intent.getStringExtra(EXTRAS_DEVICE_ADDRESS);
//Set View and new Handler
setContentView(R.layout.activity_main);
mHandler = new Handler();
mAdapter = new ScanResultAdapter(this.getApplicationContext(),
LayoutInflater.from(this));
// Use this check to determine whether BLE is supported on the device. Then you can
// selectively disable BLE-related features.
if (!getPackageManager().hasSystemFeature(PackageManager.FEATURE_BLUETOOTH_LE)) {
Toast.makeText(this, R.string.ble_not_supported, Toast.LENGTH_SHORT).show();
finish();
}
//sets up variables to initialize Bluetooth Manager and our Adapter settings
BluetoothManager bluetoothManager = (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);
BluetoothAdapter mBluetoothAdapter = bluetoothManager.getAdapter();
//Initializes Navigation Drawer
setNavigationDrawer();
//Checks if Bluetooth adapter is enabled and requests to enable it
if (mBluetoothAdapter != null && !mBluetoothAdapter.isEnabled()) {
Intent enableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableIntent, REQUEST_ENABLE_BT);
}
//Initializes Scan Button
//addListenerOnButton();
//startScanning();
TextView txtView = (TextView) findViewById(R.id.ScanOut);
txtView.setText(BluetoothDevice.EXTRA_NAME);
//Initializing floating action button
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();
}
});
}
// Device scan callback.
private BluetoothAdapter.LeScanCallback mLeScanCallback =
new BluetoothAdapter.LeScanCallback() {
#Override
public void onLeScan(final BluetoothDevice device, int rssi, byte[] scanRecord) {
runOnUiThread(new Runnable() {
#Override
public void run() {
mLeDeviceListAdapter.addDevice(device);
mLeDeviceListAdapter.notifyDataSetChanged();
}
});
}
};
/**
* Custom ScanCallback object - adds to adapter on success, displays error on failure.
*/
private class SampleScanCallback extends ScanCallback {
#Override
public void onBatchScanResults(List<ScanResult> results) {
super.onBatchScanResults(results);
for (ScanResult result : results) {
mAdapter.add(result);
}
mAdapter.notifyDataSetChanged();
}
#Override
public void onScanResult(int callbackType, ScanResult result) {
super.onScanResult(callbackType, result);
mAdapter.add(result);
mAdapter.notifyDataSetChanged();
}
#Override
public void onScanFailed(int errorCode) {
super.onScanFailed(errorCode);
Toast.makeText(MainActivity.this, "Scan failed with error: " + errorCode, Toast.LENGTH_LONG)
.show();
}
}
/**
* Start scanning for BLE Advertisements (& set it up to stop after a set period of time).
*/
public void startScanning() {
if (mScanCallback == null) {
// Will stop the scanning after a set time.
mHandler.postDelayed(new Runnable() {
#Override
public void run() {
stopScanning();
}
}, SCAN_PERIOD);
// Kick off a new scan.
mScanCallback = new SampleScanCallback();
mBluetoothLeScanner.startScan(mScanCallback);
Toast.makeText(MainActivity.this, "Started Scan", Toast.LENGTH_LONG).show();
} else {
Toast.makeText(MainActivity.this, "Already Scanning", Toast.LENGTH_SHORT);
}
}
/**
* Stop scanning for BLE Advertisements.
*/
public void stopScanning() {
// Stop the scan, wipe the callback.
mBluetoothLeScanner.stopScan(mScanCallback);
mScanCallback = null;
// Even if no new results, update 'last seen' times.
mAdapter.notifyDataSetChanged();
}
/* private void scanLeDevice(final boolean enable) {
//mBluetoothLeScanner = mBluetoothAdapter.getBluetoothLeScanner();
if (enable) {
// Stops scanning after a pre-defined scan period.
mHandler.postDelayed(new Runnable() {
#Override
public void run() {
mScanning = false;
mBluetoothLeScanner.stopScan(mScanCallback);
}
}, SCAN_PERIOD);
mScanning = true;
mBluetoothLeScanner.startScan(mScanCallback);
} else {
mScanning = false;
mBluetoothLeScanner.stopScan(mScanCallback);
}
}*/
private void GattConnect() {
BluetoothGatt mBluetoothGatt = mbluetoothDevice.connectGatt(this, false, mGattCallback);
mBluetoothGatt.discoverServices();
List<BluetoothGattService> services = mBluetoothGatt.getServices();
for (BluetoothGattService service : services) {
List<BluetoothGattCharacteristic> characteristics = service.getCharacteristics();
}
}
private final BluetoothGattCallback mGattCallback = new BluetoothGattCallback() {
#Override
public void onCharacteristicChanged(BluetoothGatt gatt, final BluetoothGattCharacteristic characteristic) {
// this will get called anytime you perform a read or write characteristic operation
}
#Override
public void onConnectionStateChange(final BluetoothGatt gatt, final int status, final int newState) {
// this will get called when a device connects or disconnects
}
#Override
public void onServicesDiscovered(final BluetoothGatt gatt, final int status) {
// this will get called after the client initiates a BluetoothGatt.discoverServices() call
}
};
// Adapter for holding devices found through scanning.
private class LeDeviceListAdapter extends BaseAdapter {
private ArrayList<BluetoothDevice> mLeDevices;
private LayoutInflater mInflator;
public LeDeviceListAdapter() {
super();
mLeDevices = new ArrayList<BluetoothDevice>();
mInflator = MainActivity.this.getLayoutInflater();
}
public void addDevice(BluetoothDevice device) {
if(!mLeDevices.contains(device)) {
mLeDevices.add(device);
}
}
public BluetoothDevice getDevice(int position) {
return mLeDevices.get(position);
}
public void clear() {
mLeDevices.clear();
}
#Override
public int getCount() {
return mLeDevices.size();
}
#Override
public Object getItem(int i) {
return mLeDevices.get(i);
}
#Override
public long getItemId(int i) {
return i;
}
#Override
public View getView(int i, View view, ViewGroup viewGroup) {
ViewHolder viewHolder;
// General ListView optimization code.
if (view == null) {
view = mInflator.inflate(R.layout.listitem_device, null);
viewHolder = new ViewHolder();
viewHolder.deviceAddress = (TextView) view.findViewById(R.id.device_address);
viewHolder.deviceName = (TextView) view.findViewById(R.id.device_name);
view.setTag(viewHolder);
} else {
viewHolder = (ViewHolder) view.getTag();
}
BluetoothDevice device = mLeDevices.get(i);
final String deviceName = device.getName();
if (deviceName != null && deviceName.length() > 0)
viewHolder.deviceName.setText(deviceName);
else
viewHolder.deviceName.setText("Unknown Device");
viewHolder.deviceAddress.setText(device.getAddress());
return view;
}
}
/*
Setting up Navigational Drawer that creates other fragments
*/
private void setNavigationDrawer() {
Intent intent = null;
dLayout = (DrawerLayout) findViewById(R.id.drawer_layout); // initiate a DrawerLayout
NavigationView navView = (NavigationView) findViewById(R.id.navigation); // initiate a Navigation View
// implement setNavigationItemSelectedListener event on NavigationView
navView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(MenuItem menuItem) {
Fragment frag = null; // create a Fragment Object
int itemId = menuItem.getItemId(); // get selected menu item's id
// check selected menu item's id and replace a Fragment Accordingly
if (itemId == R.id.nav_home){
frag = new HomeFragment();
} else if (itemId == R.id.nav_alarms) {
frag = new AlarmFragment();
} else if (itemId == R.id.nav_cues) {
frag = new CueFragment();
} else if (itemId == R.id.nav_data) {
frag = new DataFragment();
} else if (itemId == R.id.nav_settings){
frag = new SettingFragment();
} else if (itemId == R.id.nav_help){
frag = new HelpFragment();
}
// display a toast message with menu item's title
Toast.makeText(getApplicationContext(), menuItem.getTitle(), Toast.LENGTH_SHORT).show();
if (frag != null) {
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.frame, frag); // replace a Fragment with Frame Layout
transaction.commit(); // commit the changes
dLayout.closeDrawers(); // close the all open Drawer Views
return true;
}
return false;
}
});
}
public void addListenerOnButton() {
button = (Button) findViewById(R.id.button1);
button.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View arg0) {
//scanLeDevice(true);
}
});
}
static class ViewHolder {
TextView deviceName;
TextView deviceAddress;
}
//What happens on resuming the app
#Override
protected void onResume() {
super.onResume();
// Ensures Bluetooth is enabled on the device. If Bluetooth is not currently enabled,
// fire an intent to display a dialog asking the user to grant permission to enable it.
if (!mBluetoothAdapter.isEnabled()) {
if (!mBluetoothAdapter.isEnabled()) {
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
}
}
// Initializes list view adapter.
mLeDeviceListAdapter = new LeDeviceListAdapter();
//setListAdapter(mLeDeviceListAdapter);
//scanLeDevice(true);
}
#Override
protected void onPause() {
super.onPause();
//scanLeDevice(false);
mLeDeviceListAdapter.clear();
}
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
// User chose not to enable Bluetooth.
if (requestCode == REQUEST_ENABLE_BT && resultCode == Activity.RESULT_CANCELED) {
finish();
return;
}
super.onActivityResult(requestCode, resultCode, data);
}
}
I am using the BluetoothLeService class from the Gatt example. Right now I am trying to get my scanning to work so I can find my BLE device to attempt to set up a Gatt connection with it.
I have tried implementing many parts of the examples, and since startLeScan() and stopLeScan() are depreciated, I am attempting to merge the BLE scanning from the bluetooth advertisements example with the BLE Gatt example. The apps examples work fine, but I get a bunch of null pointers when I try to do it myself.
On my onResume function I will get this error: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean android.bluetooth.BluetoothAdapter.isEnabled()' on a null object reference
Which is weird because I invoke the same method during onCreate without problems.
The thing that hasn't been working at all no matter how I try to invoke it is my startScanning method. I always get this error: 'java.lang.NullPointerException: Attempt to invoke virtual method void android.bluetooth.le.BluetoothLeScanner.startScan(android.bluetooth.le.ScanCallback)' on a null object reference because it seems like the startScan method never actually works. Maybe I am just doing something horribly wrong.
It's called in a fragment in the example, but I don't think that should affect it and I should be able to use it in my main activity for a base level connection for debugging if I'm not mistaken.
Does anyone have any advice on what I'm doing glaringly wrong?

Android: why my onResume() DialogInterface keeps looping non stop?

May I ask why my onResume() DialogInterface keeps looping non stop? I have reference the onResume() from this website: http://pulse7.net/android/android-delete-sms-message-from-inbox-in-android/
#Override
protected void onResume() {
super.onResume(); int i=0;
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.KITKAT) {
if(i==0) {
if (!Telephony.Sms.getDefaultSmsPackage(this).equals(myPackageName)) {
AlertDialog.Builder builder = new AlertDialog.Builder(ActivityMain_txt.this);
builder.setMessage("This app is not set as your default messaging app. Do you want to set it as default?")
.setCancelable(false)
.setTitle("Alert!")
.setNegativeButton("No", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
}
})
.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
#TargetApi(19)
public void onClick(DialogInterface dialog, int id) {
Intent intent = new Intent(Telephony.Sms.Intents.ACTION_CHANGE_DEFAULT);
intent.putExtra(Telephony.Sms.Intents.EXTRA_PACKAGE_NAME, getPackageName());
startActivity(intent);
dialog.dismiss();
}
});
builder.show();
i++;}
}
}
But when I add this part of the code, the DialogInterface for "setPositiveButton" keeps looping non-stop. I am trying to set my application to become the default message application, so I will be able to delete messages. As now it is not set to become the default application, I am unable to delete any messages successfully. Any help will be deeply appreciated. Thanks in advance.
import android.annotation.TargetApi;
import android.content.ActivityNotFoundException;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.res.Configuration;
import android.database.ContentObserver;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Build;
import android.os.Bundle;
import android.os.Handler;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.NavigationView;
import android.support.design.widget.Snackbar;
import android.support.design.widget.TabLayout;
import android.support.v4.view.ViewPager;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBar;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.SearchView;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.widget.Toast;
import android.provider.Telephony;
import com.example.apple.qs.Activity.db.Constant;
import com.example.apple.qs.Activity.db.DatabaseHandler_txt;
import com.example.apple.qs.Activity.fragment.ContactFragment;
import com.example.apple.qs.Activity.fragment.FragmentAdapter;
import com.example.apple.qs.Activity.fragment.MessageFragment;
import com.example.apple.qs.Activity.db.model.Message;
import com.example.apple.qs.Activity.db.Store.ContactStore;
import com.example.apple.qs.Activity.db.Store.MessageStore;
import java.util.ArrayList;
import com.example.apple.qs.Activity.R;
import java.util.List;
public class ActivityMain_txt extends AppCompatActivity {
private ActionBarDrawerToggle mDrawerToggle;
private Toolbar toolbar;
private DrawerLayout drawerLayout;
public static MessageFragment f_message;
private ContactFragment f_contact;
public FloatingActionButton fab;
private Toolbar searchToolbar;
private boolean isSearch = false;
private ViewPager viewPager;
private DatabaseHandler_txt db;
public ContactStore contacsStore;
public MessageStore messageStore;
public static List<Message> messageList = new ArrayList<>();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_txt);
setupDrawerLayout();
db = new DatabaseHandler_txt(getApplicationContext());
toolbar = (Toolbar) findViewById(R.id.toolbar_viewpager);
searchToolbar = (Toolbar) findViewById(R.id.toolbar_search);
fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent i = new Intent(getApplicationContext(), ActivityNewMessage_txt.class);
startActivity(i);
}
});
//initToolbar();
prepareActionBar(toolbar);
contacsStore = new ContactStore(getApplicationContext());
messageStore = new MessageStore(ActivityMain_txt.this);
messageList = messageStore.getAllconversation();
viewPager = (ViewPager) findViewById(R.id.viewpager);
if (viewPager != null) {
setupViewPager(viewPager);
}
TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(viewPager);
tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
#Override
public void onTabSelected(TabLayout.Tab tab) {
closeSearch();
viewPager.setCurrentItem(tab.getPosition());
if (tab.getPosition() == 0) {
fab.show();
} else {
fab.hide();
}
}
#Override
public void onTabUnselected(TabLayout.Tab tab) {
}
#Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
// for system bar in lollipop
Window window = this.getWindow();
if (Constant.getAPIVerison() >= 5.0) {
window.addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);
window.clearFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
window.setStatusBarColor(this.getResources().getColor(R.color.colorPrimaryDark));
}
}
private void setupViewPager(ViewPager viewPager) {
FragmentAdapter adapter = new FragmentAdapter(getSupportFragmentManager());
if (f_message == null) {
f_message = new MessageFragment();
}
if (f_contact == null) {
f_contact = new ContactFragment();
}
adapter.addFragment(f_message, "MESSAGE");
adapter.addFragment(f_contact, "CONTACT");
viewPager.setAdapter(adapter);
}
private void prepareActionBar(Toolbar toolbar) {
setSupportActionBar(toolbar);
ActionBar actionBar = getSupportActionBar();
actionBar.setDisplayHomeAsUpEnabled(true);
actionBar.setHomeButtonEnabled(true);
if (Build.VERSION.SDK_INT >= 21) {
getWindow().setStatusBarColor(getResources().getColor(isSearch ? android.R.color.darker_gray : R.color.colorPrimary));
}
if (!isSearch) {
settingDrawer();
}
}
private void settingDrawer() {
mDrawerToggle = new ActionBarDrawerToggle( this, drawerLayout, toolbar, R.string.drawer_open, R.string.drawer_close ) {
/** Called when a drawer has settled in a completely closed state. */
public void onDrawerClosed(View view) {
super.onDrawerClosed(view);
}
/** Called when a drawer has settled in a completely open state. */
public void onDrawerOpened(View drawerView) {
super.onDrawerOpened(drawerView);
}
};
// Set the drawer toggle as the DrawerListener
drawerLayout.setDrawerListener(mDrawerToggle);
}
private void setupDrawerLayout() {
drawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
NavigationView view = (NavigationView) findViewById(R.id.nav_view);
view.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(MenuItem menuItem) {
menuItem.setChecked(true);
drawerLayout.closeDrawers();
actionDrawerMenu(menuItem.getItemId());
return true;
}
});
}
private void actionDrawerMenu(int itemId) {
switch (itemId) {
case R.id.nav_notif:
Intent i = new Intent(getApplicationContext(), ActivityNotificationSettings_txt.class);
startActivity(i);
break;
case R.id.nav_rate:
Uri uri = Uri.parse("market://details?id=" + getPackageName());
Intent goToMarket = new Intent(Intent.ACTION_VIEW, uri);
try {
startActivity(goToMarket);
} catch (ActivityNotFoundException e) {
startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse("http://play.google.com/store/apps/details?id=" + getPackageName())));
}
break;
case R.id.nav_about:
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("About");
builder.setMessage(getString(R.string.about_text));
builder.setNeutralButton("OK", null);
builder.show();
break;
}
}
#Override
protected void onPostCreate(Bundle savedInstanceState) {
super.onPostCreate(savedInstanceState);
// Sync the toggle state after onRestoreInstanceState has occurred.
mDrawerToggle.syncState();
}
#Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
if (!isSearch) {
mDrawerToggle.onConfigurationChanged(newConfig);
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(isSearch ? R.menu.menu_search_toolbar_txt : R.menu.menu_main_txt, menu);
if (isSearch) {
//Toast.makeText(getApplicationContext(), "Search " + isSearch, Toast.LENGTH_SHORT).show();
final SearchView search = (SearchView) menu.findItem(R.id.action_search).getActionView();
search.setIconified(false);
if (viewPager.getCurrentItem() == 0) {
search.setQueryHint("Search message...");
} else {
search.setQueryHint("Search contact...");
}
search.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
#Override
public boolean onQueryTextSubmit(String s) {
return false;
}
#Override
public boolean onQueryTextChange(String s) {
if (viewPager.getCurrentItem() == 0) {
f_message.mAdapter.getFilter().filter(s);
} else {
f_contact.mAdapter.getFilter().filter(s);
}
return true;
}
});
search.setOnCloseListener(new SearchView.OnCloseListener() {
#Override
public boolean onClose() {
closeSearch();
return true;
}
});
}
return super.onCreateOptionsMenu(menu);
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
switch (id) {
case R.id.action_search: {
isSearch = true;
searchToolbar.setVisibility(View.VISIBLE);
prepareActionBar(searchToolbar);
supportInvalidateOptionsMenu();
return true;
}
case android.R.id.home:
closeSearch();
return true;
case R.id.action_refresh: {
if(viewPager.getCurrentItem()==0){
new RefreshMessage().execute("");
}else{
new RefreshContact().execute("");
}
}
default:
return super.onOptionsItemSelected(item);
}
}
private void closeSearch() {
if (isSearch) {
isSearch = false;
if (viewPager.getCurrentItem() == 0) {
f_message.mAdapter.getFilter().filter("");
} else {
f_contact.mAdapter.getFilter().filter("");
}
prepareActionBar(toolbar);
searchToolbar.setVisibility(View.GONE);
supportInvalidateOptionsMenu();
}
}
private ChangeObserver changeObserver;
// wil update only when there a change
private class ChangeObserver extends ContentObserver {
public ChangeObserver() {
super(new Handler());
}
#Override
public void onChange(boolean selfChange) {
try{
if(!loadRunning) {
loadRunning = true;
changeLoad = new ChangeLoad();
changeLoad.execute("");
}
}catch (Exception e){
}
}
}
private ChangeLoad changeLoad;
private boolean loadRunning = false;
private class ChangeLoad extends AsyncTask<String, String, String>{
#Override
protected String doInBackground(String... strings) {
messageStore.update();
return null;
}
#Override
protected void onPostExecute(String s) {
loadRunning = false;
messageList = messageStore.getAllconversation();
f_message.bindView();
super.onPostExecute(s);
}
}
public class RefreshMessage extends AsyncTask<String, String, String>{
#Override
protected void onPreExecute() {
f_message.onRefreshLoading();
super.onPreExecute();
}
#Override
protected String doInBackground(String... strings) {
try {
Thread.sleep(100);
messageStore = new MessageStore(ActivityMain_txt.this);
messageList = messageStore.getAllconversation();
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(String s) {
f_message.onStopRefreshLoading();
super.onPostExecute(s);
}
}
private class RefreshContact extends AsyncTask<String, String, String>{
#Override
protected void onPreExecute() {
f_contact.onRefreshLoading();
super.onPreExecute();
}
#Override
protected String doInBackground(String... strings) {
try {
Thread.sleep(10);
db.truncateDB();
contacsStore = new ContactStore(getApplicationContext());
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(String s) {
f_contact.onStopRefreshLoading();
super.onPostExecute(s);
}
}
String myPackageName= getPackageName();
#Override
protected void onResume() {
super.onResume(); int i=0;
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.KITKAT) {
if(i==0) {
if (!Telephony.Sms.getDefaultSmsPackage(this).equals(myPackageName)) {
AlertDialog.Builder builder = new AlertDialog.Builder(ActivityMain_txt.this);
builder.setMessage("This app is not set as your default messaging app. Do you want to set it as default?")
.setCancelable(false)
.setTitle("Alert!")
.setNegativeButton("No", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
}
})
.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
#TargetApi(19)
public void onClick(DialogInterface dialog, int id) {
Intent intent = new Intent(Telephony.Sms.Intents.ACTION_CHANGE_DEFAULT);
intent.putExtra(Telephony.Sms.Intents.EXTRA_PACKAGE_NAME, getPackageName());
startActivity(intent);
dialog.dismiss();
}
});
builder.show();
i++;}
}
}
}
}

You are using the variable i as a flag, but whenever you open your app the value of i will be 0 again. You should store your flag in a persistent database. Either use SQLite to set i or use any other method like create a file when the user says yes to your question and then check if the file exists or not. If you don't understand what I've told you, I can send you some code snippets.
OK, I assume you are using i as a flag to check if user has set your app as default or not, so I suggest you to use SharedPreferences to store the value of i so that later on you can check the value of i in a better manner. Add the following code in your onResume function:
sharedpreferences = getSharedPreferences(MyPREFERENCES, Context.MODE_PRIVATE);
SharedPreferences.Editor editor = sharedpreferences.edit();
Instead of i++ use:
editor.putInt(i, 1);
editor.commit();
And to check if i==0 use:
int check =sharedprferences.getInt(i);
if(check == 0) {...........}

CursorLoader does not refresh data

I'm creating application to add movie data via external web service to internal database and display list of movies as the main activity in ListFragment, another activity is responsible for search function.
ListFragment mentioned above fetches data from database using LoaderManager. Also this fragment is retained using setRetainInstance(true).
Problem that I encounter is that when I navigate to search, add something to database, and go back to ListFragment by pressing Back Button its not refreshed i.e. added movie is not displayed.
A few important things:
I'm not using ContentProvider so I manually retrieve Cursor from my data base in onCreateLoaderMethod.
I'm using support library - I hope that all imports are proper (if someone could check).
ListFragment uses custom CursorAdapter as its view.
Here is the code:
package com.mp.movieplanner;
import android.app.Activity;
import android.database.Cursor;
import android.os.Build;
import android.os.Bundle;
import android.support.v4.app.ListFragment;
import android.support.v4.app.LoaderManager;
import android.support.v4.content.CursorLoader;
import android.support.v4.content.Loader;
import android.util.Log;
import android.view.View;
import android.widget.ListView;
import com.mp.movieplanner.data.DataManager;
public class MovieListFragment extends ListFragment
implements LoaderManager.LoaderCallbacks<Cursor> {
public static String TAG = MovieListFragment.class.getSimpleName();
private OnMovieSelectedListener mCallback;
private DataManager mDataManager;
private MovieCursorAdapter mAdapter;
public interface OnMovieSelectedListener {
public void onMovieSelected(int position);
}
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
Log.i(TAG, "onAttach(Activity)");
mDataManager = ((MoviePlannerApp)activity.getApplication()).getDataManager();
try {
mCallback = (OnMovieSelectedListener) activity;
} catch (ClassCastException e) {
throw new ClassCastException(activity.toString()
+ " must implement OnMovieSelectedListener");
}
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Log.i(TAG, "onCreate(Bundle)");
final int layout = Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB ? android.R.layout.simple_list_item_activated_1
: android.R.layout.simple_list_item_1;
setRetainInstance(true);
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
Log.i(TAG, "onActivityCreated(Bundle)");
super.onActivityCreated(savedInstanceState);
mAdapter = new MovieCursorAdapter(getActivity(), null, 0);
setListAdapter(mAdapter);
getLoaderManager().initLoader(0, null, this);
}
#Override
public void onStart() {
super.onStart();
Log.i(TAG, "onStart()");
if (getFragmentManager().findFragmentById(R.id.movie_details_fragment) != null) {
getListView().setChoiceMode(ListView.CHOICE_MODE_SINGLE);
}
}
#Override
public void onResume() {
super.onResume();
Log.i(TAG, "onResume()");
}
#Override
public void onDetach() {
super.onDetach();
Log.i(TAG, "onDetach()");
mCallback = null;
}
#Override
public void onListItemClick(ListView l, View v, int position, long id) {
// Notify the parent activity of selected item
if (mCallback != null) {
mCallback.onMovieSelected(position);
// Set the item as checked to be highlighted when in two-pane layout
getListView().setItemChecked(position, true);
}
}
#Override
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
return new CursorLoader(getActivity()) {
#Override
public Cursor loadInBackground() {
return mDataManager.getMovieCursor();
}
};
}
#Override
public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
mAdapter.swapCursor(data);
}
#Override
public void onLoaderReset(Loader<Cursor> arg0) {
mAdapter.swapCursor(null);
}
#Override
public void onPause() {
Log.i(TAG, "onPause()");
super.onPause();
}
#Override
public void onStop() {
Log.i(TAG, "onStop()");
super.onStop();
}
#Override
public void onDestroy() {
super.onDestroy();
Log.i(TAG, "onDestroy()");
}
}

I would advise:
#Override
public void onResume() {
super.onResume();
Log.i(TAG, "onResume()");
getLoaderManager().restartLoader(0, null, this);
}

#Override
public void onResume() {
super.onResume();
Log.i(TAG, "onResume()");
getLoaderManager().initLoader(0, null, this);
}
try that