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Ble Broadcast receiver not displaying on listview

(DISCLAIMER: SUPER NEW TO ANDROID STUDIO) I'm creating an app to scan for ble devices and display them on the list but it seems like no devices are being discovered and being displayed on the listview. Any help is appreciated. I'm planning to update the Textview with the number of devices that are found. I haven't set up the scanfilters yet since I'm still trying to figure out the UUIDs for the tags that I'm using. I also changed the min sdk to 23 since it was giving me an error while setting the scanmode, callback, and matchmode.
MainActivity.java
package com.example.tygatraxseconddraft;
import androidx.appcompat.app.AppCompatActivity;
import android.Manifest;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.le.BluetoothLeScanner;
import android.bluetooth.le.ScanCallback;
import android.bluetooth.le.ScanFilter;
import android.bluetooth.le.ScanResult;
import android.bluetooth.le.ScanSettings;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.pm.PackageManager;
import android.os.Build;
import android.os.Bundle;
import android.os.ParcelUuid;
import android.util.Log;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.List;
import java.util.UUID;
public class MainActivity extends AppCompatActivity {
private static final String TAG = "TWESBTSCANNER";
public static final int REQUEST_ACCESS_COARSE_LOCATION = 1;
public static final int REQUEST_ENABLE_BLUETOOTH = 11;
private ListView listView;
private Button scanningBtn;
private BluetoothAdapter bluetoothAdapter;
private final ArrayList<String> mDeviceList = new ArrayList<>();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
listView = findViewById(R.id.device_list);
scanningBtn = findViewById(R.id.scanning_btn);
hasPermissions();
checkBluetoothState();
IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
registerReceiver(mReceiver, filter);
listView = findViewById(R.id.device_list);
scanningBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
BluetoothAdapter adapter = BluetoothAdapter.getDefaultAdapter();
BluetoothLeScanner scanner = adapter.getBluetoothLeScanner();
final ScanCallback scanCallback = new ScanCallback() { //studio made it not private
#Override
public void onScanResult(int callbackType, ScanResult result) {
BluetoothDevice device = result.getDevice();
// ...do whatever you want with this found device
}
#Override
public void onBatchScanResults(List<ScanResult> results) {
// Ignore for now
}
#Override
public void onScanFailed(int errorCode) {
// Ignore for now
}
};
UUID SERVICE_DATA_UUID = UUID.fromString("00005246-0000-1000-8000-00805f9b34fb");//filter for the Nordic tags
UUID[] serviceUUIDs = new UUID[]{SERVICE_DATA_UUID};
List<ScanFilter> filters = null;
if (serviceUUIDs != null) {
filters = new ArrayList<>();
for (UUID serviceUUID : serviceUUIDs) {
ScanFilter filter = new ScanFilter.Builder()
.setServiceUuid(new ParcelUuid(serviceUUID))
.build();
filters.add(filter);
}
}
ScanSettings scanSettings = new ScanSettings.Builder()
.setScanMode(ScanSettings.SCAN_MODE_LOW_POWER)
.setCallbackType(ScanSettings.CALLBACK_TYPE_ALL_MATCHES)
.setMatchMode(ScanSettings.MATCH_MODE_AGGRESSIVE)
.setNumOfMatches(ScanSettings.MATCH_NUM_ONE_ADVERTISEMENT)
.setReportDelay(0L)
.build();
if (scanner != null) {
scanner.startScan(null, scanSettings, scanCallback); // must set scan settings first
Log.d(TAG, "scan started");
} else {
Log.e(TAG, "could not get scanner object");
}
}
});
}
#Override
protected void onDestroy() {
unregisterReceiver(mReceiver);
super.onDestroy();
}
public final BroadcastReceiver mReceiver = new BroadcastReceiver() { //
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (BluetoothDevice.ACTION_FOUND.equals(action)) {
BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
mDeviceList.add(device.getName() + "\n" + device.getAddress());
Log.i("BT", device.getName() + "\n" + device.getAddress());
listView.setAdapter(new ArrayAdapter<String>(context, android.R.layout.simple_list_item_1, mDeviceList));
}
}
};
private boolean hasPermissions() { //checks and asks for location permission
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
if (getApplicationContext().checkSelfPermission(Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
requestPermissions(new String[] { Manifest.permission.ACCESS_COARSE_LOCATION }, REQUEST_ACCESS_COARSE_LOCATION);
return false;
}
}
return true;
}
//ENABLE WHEN TESTING ON PHONE
private void checkBluetoothState() {
//gets the bluetooth adapter
BluetoothAdapter bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if(bluetoothAdapter.isEnabled()){
Toast.makeText(this,"Bluetooth is enabled", Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(this, "Please turn on Bluetooth", Toast.LENGTH_SHORT).show();
Intent enableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableIntent, REQUEST_ENABLE_BLUETOOTH);
}//requests permission if bluetooth is not enabled
}
}
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.tygatraxseconddraft">
<!-- Request legacy Bluetooth permissions on older devices. -->
<uses-permission android:name="android.permission.BLUETOOTH"
android:maxSdkVersion="30" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN"
android:maxSdkVersion="30" />
<!-- Needed only if your app looks for Bluetooth devices.
You must add an attribute to this permission, or declare the
ACCESS_FINE_LOCATION permission, depending on the results when you
check location usage in your app. -->
<uses-permission android:name="android.permission.BLUETOOTH_SCAN"/>
<!-- Needed only if your app makes the device discoverable to Bluetooth
devices. -->
<uses-permission android:name="android.permission.BLUETOOTH_ADVERTISE" />
<!-- Needed only if your app communicates with already-paired Bluetooth
devices. -->
<uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION_LOCATION"/>
<!--Makes the app show up for only ble enabled devices-->
<uses-feature
android:name="android.hardware.bluetooth_le"
android:required="true"/>
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="#style/Theme.TygaTraxsecondDraft">
<activity
android:name=".MainActivity"
android:exported="true">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
Activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/white"
tools:context=".MainActivity">
<TextView
android:id="#+id/number_devices"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="50dp"
android:text="#string/number_of_devices"
android:textColor="#color/black"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.498"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<Button
android:id="#+id/scanning_btn"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="24dp"
android:layout_marginEnd="24dp"
android:layout_marginBottom="50dp"
android:text="#string/button_text"
android:textColor="#212121"
app:backgroundTint="#color/gray"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent" />
<ListView
android:id="#+id/device_list"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_marginStart="24dp"
android:layout_marginTop="24dp"
android:layout_marginEnd="24dp"
android:layout_marginBottom="24dp"
app:layout_constraintBottom_toTopOf="#+id/scanning_btn"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/number_devices" />
</androidx.constraintlayout.widget.ConstraintLayout>
In case this is needed
colors.xml
<?xml version="1.0" encoding="utf-8"?>
<resources>
<color name="purple_200">#FFBB86FC</color>
<color name="purple_500">#FF6200EE</color>
<color name="purple_700">#FF3700B3</color>
<color name="teal_200">#FF03DAC5</color>
<color name="teal_700">#FF018786</color>
<color name="black">#FF000000</color>
<color name="white">#FFFFFFFF</color>
<color name="gray">#7393B3</color>
</resources>
strings.xml
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="app_name">Tyga Trax (second draft)</string>
<string name="button_text">Scan</string>
<string name="number_of_devices">There are </string>
</resources>

New Answer
I just realised you are simply doing nothing with the found devices right now, your ScanCallback is empty. You should add something like this to see the results:
final ScanCallback scanCallback = new ScanCallback() { //studio made it not private
#Override
public void onScanResult(int callbackType, ScanResult result) {
BluetoothDevice device = result.getDevice();
Log.d(TAG, "BLE scan found Device " + device.getName() + " with MAC " + device.getAddress());
// TODO: add device to ListView
}
#Override
public void onBatchScanResults(List<ScanResult> results) {
// Ignore for now
}
#Override
public void onScanFailed(int errorCode) {
// Ignore for now
}
};
You should see the found devices in your log now
Previous Answer
You are requesting the ACCESS_COARSE_LOCATION permission but your target SDK is 31. The guide for Bluetooth permissions states
ACCESS_FINE_LOCATION is necessary because a Bluetooth scan can gather information about the location of the user. This information may come from the user's own devices, as well as Bluetooth beacons in use at locations such as shops and transit facilities.
and also
Note: If your app targets Android 9 (API level 28) or lower, you can declare the ACCESS_COARSE_LOCATION permission instead of the ACCESS_FINE_LOCATION permission.
It even states to use ACCESS_BACKGROUND_LOCATION for devices with Android 10 or above. But there are new permissions for a target SDK of 31 (Android 12) as stated in this document.
<manifest>
<!-- Request legacy Bluetooth permissions on older devices. -->
<uses-permission android:name="android.permission.BLUETOOTH"
android:maxSdkVersion="30" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN"
android:maxSdkVersion="30" />
<!-- Needed only if your app looks for Bluetooth devices.
You must add an attribute to this permission, or declare the
ACCESS_FINE_LOCATION permission, depending on the results when you
check location usage in your app. -->
<uses-permission android:name="android.permission.BLUETOOTH_SCAN" />
<!-- Needed only if your app makes the device discoverable to Bluetooth
devices. -->
<uses-permission android:name="android.permission.BLUETOOTH_ADVERTISE" />
<!-- Needed only if your app communicates with already-paired Bluetooth
devices. -->
<uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />
...
</manifest>
As you can see the legacy Bluetooth permissions like BLUETOOTH are added as well, but have the option android:maxSdkVersion="30" set to only work up to Android 11.

Android Internet Connectivity Listener Problem

I would like to put a Network Detector in an Android application, to inform a Screen immediately the Network state even if that state is changing. I have study similar questions in:
Android: Internet connectivity change listener
So my Java code in Main Activity is:
package com.example.netdetector;
import androidx.annotation.RequiresApi;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Context;
import android.net.ConnectivityManager;
import android.net.Network;
import android.net.NetworkCapabilities;
import android.net.NetworkInfo;
import android.net.NetworkRequest;
import android.os.Build;
import android.os.Bundle;
import android.view.View;
import android.widget.*;
public class MainActivity extends AppCompatActivity {
private TextView Screen;
#RequiresApi(api = Build.VERSION_CODES.M)
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Screen = (TextView) findViewById(R.id.Screen);
Screen.setText("Start!");
ConnectivityManager.NetworkCallback networkCallback = new ConnectivityManager.NetworkCallback() {
#Override
public void onAvailable(Network network) {
// network available
Screen.setText("Net On!");
}
#Override
public void onLost(Network network) {
// network unavailable
Screen.setText("Net Off!");
}
};
ConnectivityManager connectivityManager =
(ConnectivityManager) this.getSystemService(Context.CONNECTIVITY_SERVICE);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
connectivityManager.registerDefaultNetworkCallback(networkCallback);
} else {
NetworkRequest request = new NetworkRequest.Builder()
.addCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET).build();
connectivityManager.registerNetworkCallback(request, networkCallback);
}
}
}
The AndroidManifest.xml is:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.netdetector">
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.INTERNET" />
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="#style/Theme.NetDetector">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
The Layout activity_main.xml is:
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<TextView
android:id="#+id/Screen"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center"
android:text="Hello World!"
android:textSize="25sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.222" />
</androidx.constraintlayout.widget.ConstraintLayout>
There are some issues:
Starting the App with the Network Off, the Screen displays "Start!" instead of "Net Off!"
Starting the App with the Network On, the Screen displays "Net On" that is fine
On changing Internet state while the app is running the Screen displays the right text for a few moments and the app closes immediately.
How can I fix 1 and 3? What went wrong?
Thanks
Nickolas

Application stopped on device(no terminal errors) - doesn't show ListView

I try to make a simple ListView in Android.
activity_labas.xml:
<TextView
android:id="#+id/message"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="#dimen/activity_horizontal_margin"
android:layout_marginStart="#dimen/activity_horizontal_margin"
android:layout_marginTop="#dimen/activity_vertical_margin"
android:text="#string/title_home"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="#+id/text1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="#string/title_home2"/>
<android.support.design.widget.BottomNavigationView
android:id="#+id/navigation"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginEnd="0dp"
android:layout_marginStart="0dp"
android:background="?android:attr/windowBackground"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:menu="#menu/navigation" />
</android.support.constraint.ConstraintLayout>
labas.java:
package com.labas.holiday.labas;
import android.content.Intent;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.design.widget.BottomNavigationView;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.MenuItem;
import android.widget.ListView;
import android.widget.TextView;
public class labas extends AppCompatActivity {
private TextView mTextMessage;
private TextView mTextMessage2;
private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
= new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
switch (item.getItemId()) {
case R.id.navigation_home:
mTextMessage.setText(R.string.title_home);
return true;
case R.id.navigation_dashboard:
mTextMessage.setText(R.string.title_dashboard);
mTextMessage2.setText(R.string.title_dashboard2);
return true;
case R.id.navigation_notifications:
mTextMessage.setText(R.string.title_notifications);
return true;
}
return false;
}
};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_labas);
mTextMessage2 = (TextView) findViewById(R.id.message);
mTextMessage = (TextView) findViewById(R.id.message);
Log.i("myTag2", "STARTINGBOOTOM");
Intent myIntent = new Intent(labas.this, ListViewLoader.class);
//myIntent.putExtra("key", value); //Optional parameters
labas.this.startActivity(myIntent);
//setContentView(R.layout);
BottomNavigationView navigation = (BottomNavigationView) findViewById(R.id.navigation);
navigation.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener);
}
}
ListViewLoader
package com.labas.holiday.labas;
import android.app.ListActivity;
import android.app.LoaderManager;
import android.content.CursorLoader;
import android.content.Loader;
import android.database.Cursor;
import android.os.Bundle;
import android.provider.ContactsContract;
import android.support.constraint.ConstraintLayout;
import android.util.Log;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ListView;
import android.widget.ProgressBar;
import android.widget.SimpleCursorAdapter;
public class ListViewLoader extends ListActivity
implements LoaderManager.LoaderCallbacks<Cursor> {
// This is the Adapter being used to display the list's data
SimpleCursorAdapter mAdapter;
// These are the Contacts rows that we will retrieve
static final String[] PROJECTION = new String[] {ContactsContract.Data._ID,
ContactsContract.Data.DISPLAY_NAME};
// This is the select criteria
static final String SELECTION = "((" +
ContactsContract.Data.DISPLAY_NAME + " NOTNULL) AND (" +
ContactsContract.Data.DISPLAY_NAME + " != '' ))";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Log.i("myTag", "STAAAAAAAAAAAAAAAAAARRRRRRRRRRRRRRRRRTTTTTTTT");
// Create a progress bar to display while the list loads
ProgressBar progressBar = new ProgressBar(this);
progressBar.setLayoutParams(new ConstraintLayout.LayoutParams(ConstraintLayout.LayoutParams.WRAP_CONTENT,
ConstraintLayout.LayoutParams.WRAP_CONTENT));
progressBar.setIndeterminate(true);
getListView().setEmptyView(progressBar);
// Must add the progress bar to the root of the layout
ViewGroup root = (ViewGroup) findViewById(android.R.id.content);
root.addView(progressBar);
// For the cursor adapter, specify which columns go into which views
String[] fromColumns = {ContactsContract.Data.DISPLAY_NAME};
int[] toViews = {android.R.id.text1}; // The TextView in simple_list_item_1
// Create an empty adapter we will use to display the loaded data.
// We pass null for the cursor, then update it in onLoadFinished()
mAdapter = new SimpleCursorAdapter(this,
android.R.layout.simple_list_item_1, null,
fromColumns, toViews, 0);
setListAdapter(mAdapter);
// Prepare the loader. Either re-connect with an existing one,
// or start a new one.
getLoaderManager().initLoader(0, null, this);
}
#Override
public Loader<Cursor> onCreateLoader(int i, Bundle bundle) {
return new CursorLoader(this, ContactsContract.Data.CONTENT_URI,
PROJECTION, SELECTION, null, null);
}
#Override
public void onLoadFinished(Loader<Cursor> loader, Cursor cursor) {
mAdapter.swapCursor(cursor);
}
#Override
public void onLoaderReset(Loader<Cursor> loader) {
mAdapter.swapCursor(null);
}
}
AndroidManifest:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.labas.holiday.labas">
<uses-permission android:name="android.permission.READ_CONTACTS" />
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="#style/AppTheme">
<activity
android:name=".labas"
android:label="#string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name="ListViewLoader" android:label="#string/title_activity_test"/>
<activity android:name="Testing" android:label="#string/title_activity_test"/>
</application>
</manifest>
The result should be a List of the contacts in the application.
At the moment the code throws no errors in the IDE, but stops at loading the application on the device. In the debugging mode it crashes at "return new CursorLoader(this, ContactsContract.Data.CONTENT_URI,PROJECTION, SELECTION, null, null);".
I saw no Nullpointers (I wouldn't bet on it^^).

one of the reasons your cursor is not retrieving data is because you are missing runtime permission on your code, you need to ask for permissions on runtime along with adding in manifest.
something like:
private static final int INITIAL_REQUEST_NUMBER=1337;
private static final String[] INITIAL_PERMESSION={android.Manifest.permission.READ_CONTACTS};
ActivityCompat.requestPermissions(this, INITIAL_PERMESSION, INITIAL_REQUEST_NUMBER);
for more details: https://developer.android.com/training/permissions/requesting.html
you need to make sure that users granted you permissions before running the cursor loader, so requesting permission on activity before running the loader is the best so that if users deny permissions (during first run) you cancel running the loader.
users can revoke permissions even if granted during first run, so good practice to check permissions are still granted each time before running your loader, if revoked you cancel the loader.
hope permission is the only issue you need to consider.

Android - Admob test ads not appearing in app

I want to integrate Google Mobile Ads into my app, but when I debug it, whenever using my own device, or using an emulator, no ads appear.
I am using the code from Google's developer page: https://developers.google.com/mobile-ads-sdk/docs/admob/fundamentals
When looking at logcat, I find that my app is not requesting any ads, and Admob is reporting no requests.
What am I missing?
Here is my code
AndroidManifest
<application android:icon="#drawable/ic_launcher">
<meta-data android:name="com.google.android.gms.version"
android:value="#integer/google_play_services_version"/>
android:label="#string/app_name" >
<activity
android:name=".MainActivity"
android:label="#string/app_name"
android:screenOrientation="portrait"
android:configChanges="keyboard|keyboardHidden|orientation|screenSize">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name="com.google.android.gms.ads.AdActivity"
android:configChanges="keyboard|keyboardHidden|orientation|screenLayout|uiMode|screenSize|smallestScreenSize"/>
</application>
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
</manifest>
layout - main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/adBanner"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
xmlns:ads="http://schemas.android.com/apk/lib/com.google.ads">
<com.google.ads.AdView android:id="#+id/ad"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
ads:adUnitId="-omitted-"
ads:adSize="BANNER" />
</LinearLayout>
AdBanner.java (the class with Google's example test code)
package com.google.android.gms.ads.banner;
import com.google.android.gms.ads.AdRequest;
import com.google.android.gms.ads.AdSize;
import com.google.android.gms.ads.AdView;
import -omitted-
import android.os.Bundle;
import android.widget.LinearLayout;
import -omitted-
public class AdBanner extends MainActivity{
/**
* A simple {#link Activity} that embeds an AdView.
*/
/** The view to show the ad. */
private AdView adView;
/* Your ad unit id. Replace with your actual ad unit id. */
private static final String AD_UNIT_ID = "-omitted-";
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// Create an ad.
adView = new AdView(this);
adView.setAdSize(AdSize.BANNER);
adView.setAdUnitId(AD_UNIT_ID);
// Add the AdView to the view hierarchy. The view will have no size
// until the ad is loaded.
LinearLayout layout = (LinearLayout) findViewById(R.id.adBanner);
layout.addView(adView);
// Create an ad request. Check logcat output for the hashed device ID to
// get test ads on a physical device.
AdRequest adRequest = new AdRequest.Builder()
.addTestDevice(AdRequest.DEVICE_ID_EMULATOR)
.addTestDevice("-omitted-")
.build();
// Start loading the ad in the background.
adView.loadAd(adRequest);
}
#Override
public void onResume() {
super.onResume();
if (adView != null) {
adView.resume();
}
}
#Override
public void onPause() {
if (adView != null) {
adView.pause();
}
super.onPause();
}
/** Called before the activity is destroyed. */
#Override
public void onDestroy() {
// Destroy the AdView.
if (adView != null) {
adView.destroy();
}
super.onDestroy();
}
}

I have seen something strange in your code:
In your AdBanner.java you use this:
import com.google.android.gms.ads.AdView;
but in your layout you use:
<com.google.ads.AdView
which corresponds to old Admob, but seems you may want to use com.google.android.gms.ads.AdView in your layout instead

I think you must check the android logs to see if any errors or warnings are given for your admob. For example: I was not able to see the ads too and when i check the logs i found the "not enough space" warning for my advertisement. I was using the size "SMART_BANNER" that uses the width as 360dp (you can check the sizes here). So i changed my AdView's width to exact 360dp to solve my problem and it is now working: Stil
I hope this information helps. Just check the logs and also console.
In addition, my adView:
<com.google.android.gms.ads.AdView
xmlns:ads="http://schemas.android.com/apk/res-auto"
android:id="#+id/adView"
android:layout_width="360dp"
android:layout_height="wrap_content"
ads:adSize="SMART_BANNER"
ads:adUnitId="#string/banner_ad_unit_id" />
Best regards.

how to access downloads folder in android?

I am new android, i'm making an app in which one can download files to downloads folder (using Download Manager). I can see pictures if i go to downloads folder in emulator. So if i want to show a slideshow of downloaded files how can i get the access to that folder? Secondly how to add progress bar to this code:--
import java.util.Arrays;
import android.app.Activity;
import android.app.DownloadManager;
import android.app.DownloadManager.Query;
import android.app.DownloadManager.Request;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.widget.ImageView;
public class Download_managerActivity extends Activity {
private long quueue_for_url;
private DownloadManager dm;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
BroadcastReceiver receiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (DownloadManager.ACTION_DOWNLOAD_COMPLETE.equals(action)) {
long downloadId = intent.getLongExtra(
DownloadManager.EXTRA_DOWNLOAD_ID, 0);
Query query = new Query();
query.setFilterById(quueue_for_url);
Cursor c = dm.query(query);
if (c.moveToFirst()) {
int columnIndex = c
.getColumnIndex(DownloadManager.COLUMN_STATUS);
if (DownloadManager.STATUS_SUCCESSFUL == c
.getInt(columnIndex)) {
ImageView view = (ImageView) findViewById(R.id.imageView1);
String uri_String_abcd = c
.getString(c
.getColumnIndex(DownloadManager.COLUMN_LOCAL_URI));
view.setImageURI(Uri.parse(uri_String_abcd));
}
}
}
}
};
registerReceiver(receiver, new IntentFilter(
DownloadManager.ACTION_DOWNLOAD_COMPLETE));
}
public void onClick(View view) {
dm = (DownloadManager) getSystemService(DOWNLOAD_SERVICE);
Request request_for_url = new Request(
Uri.parse("http://fc03.deviantart.net/fs14/i/2007/086/9/1/Steve_Jobs_portrait_by_tumb.jpg"));
Request request_for_url1 = new Request(
Uri.parse("http://2.bp.blogspot.com/_q7Rxg4wqDyc/S5ZRVLxVYuI/AAAAAAAAAvU/fQAUZ2XFcp8/s400/katrina-kaif.jpg"));
Request request_for_url2 = new Request(
Uri.parse("http://www.buzzreactor.com/sites/default/files/Bill-Gates1.jpg"));
quueue_for_url = dm.enqueue(request_for_url);
quueue_for_url = dm.enqueue(request_for_url1);
quueue_for_url = dm.enqueue(request_for_url2);
}
public void showDownload(View view) {
Intent i = new Intent();
//try more options to show downloading , retrieving and complete
i.setAction(DownloadManager.ACTION_VIEW_DOWNLOADS);
startActivity(i);
}
}
I want to add a button which performs the function of taking the pictures from downloads folder and then display like a slideshow.
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="cmpe235.lab1"
android:versionCode="1"
android:versionName="1.0">
<uses-sdk android:minSdkVersion="9" />
<uses-permission android:name="android.permission.INTERNET"></uses-permission>
<application android:icon="#drawable/icon" android:label="#string/app_name">
<activity android:name=".Download_managerActivity"
android:label="#string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
main.xml:-
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<Button android:text="Start Download" android:id="#+id/button1"
android:layout_width="wrap_content" android:layout_height="wrap_content"
android:layout_gravity="center_vertical|center_horizontal|center" android:textColor="#0000A0"
android:typeface="serif" android:onClick="onClick"></Button>
<Button android:text="View Downloads" android:id="#+id/button2"
android:layout_width="wrap_content" android:layout_height="wrap_content"
android:layout_gravity="center_vertical|center_horizontal|center" android:textColor="#0000A0"
android:typeface="serif" android:onClick="showDownload"></Button>
<ImageView android:layout_height="wrap_content" android:id="#+id/imageView1"
android:src="#drawable/icon" android:layout_width="wrap_content"></ImageView>
</LinearLayout>

For your first question try
Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS);
(available since API 8)
To access individual files in this directory use either File.list() or File.listFiles().
Seems that reporting download progress is only possible in notification, see here.

Updated
getExternalStoragePublicDirectory() is deprecated.
To get the download folder from a Fragment,
val downloadFolder = requireContext().getExternalFilesDir(Environment.DIRECTORY_DOWNLOADS)
From an Activity,
val downloadFolder = getExternalFilesDir(Environment.DIRECTORY_DOWNLOADS)
downloadFolder.listFiles() will list the Files.
downloadFolder?.path will give you the String path of the download folder.
Update:
The Direct filesystem access to storage has become limited in recent versions of Android.
context.getExternalFilesDir(Environment.DIRECTORY_DOWNLOADS) gives you the directory /emulated/0/Android/data/{package}/files/Download. If you want to have the public downloads folder, look into the Storage Access Framework of Android documentation.

You need to set this permission in your manifest.xml file
android.permission.WRITE_EXTERNAL_STORAGE

If you are using Marshmallow, you have to either:
Request permissions at runtime (the user will get to allow or deny the request) or:
The user must go into Settings -> Apps -> {Your App} -> Permissions and
grant storage access.
This is because in Marshmallow, Google completely revamped how permissions work.

If you're using a shell, the filepath to the Download (no "s") folder is
/storage/emulated/0/Download

You should add next permission:
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
And then here is usages in code:
val externalFilesDir = context.getExternalFilesDir(DIRECTORY_DOWNLOADS)