Develop Reference

correct use of reflection to get a Class method

I try to implement the recommendation made in item #11 of issue 111316656 that says:
You should also be able to use reflection to get access to the FloatingActionButtonImpl backing the fab, and then call setImageMatrixScale(1) on that instance.
with the following code:
FloatingActionButton fab;
...
Method method = null;
try {
method = fab.getClass().getMethod("setImageMatrixScale", null);
method.invoke(fab, 1);
} catch (NoSuchMethodException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
But the NoSuchMethodException is raised. What is the problem?

Try like here
BluetoothGatt localBluetoothGatt = gatt;
java.lang.reflect.Method localMethod = localBluetoothGatt.getClass().getMethod("refresh", new Class[0]);
if (localMethod != null) {
boolean bool = ((Boolean) localMethod.invoke(localBluetoothGatt, new Object[0])).booleanValue();
return bool;
}

With the help of Mike M. (see comments in the question), this is the JAVA version of the workaround included in the referenced issue:
fab.show(new FloatingActionButton.OnVisibilityChangedListener() {
#Override
public void onShown(FloatingActionButton fab) {
try {
Field implField = FloatingActionButton.class.getDeclaredField("impl");
implField.setAccessible(true);
Object impl = implField.get(fab);
Class cls;
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
cls = impl.getClass().getSuperclass();
} else {
cls = impl.getClass();
}
Method mthd = cls.getDeclaredMethod("setImageMatrixScale", Float.TYPE);
mthd.setAccessible(true);
mthd.invoke(impl, 1);
} catch (Exception e) {
e.printStackTrace();
}
}
});

Android Wearable.API is deprecated. What should I use instead?

I'm using the following:
GoogleApiClient mApiClient = new GoogleApiClient.Builder(this)
.addApi( Wearable.API )
...
Since Wearable.API is deprecated? What is the appropriate replacement?

I found something nice which is helpful
private class StartWearableActivityTask extends AsyncTask<Void, Void, Void> {
final String key;
public StartWearableActivityTask(String msg){
key = msg;
}
#Override
protected Void doInBackground(Void... args) {
Collection<String> nodes = getNodes();
for (String node : nodes) {
sendStartActivityMessage(node,key);
}
return null;
}
}
#WorkerThread
private Collection<String> getNodes() {
HashSet<String> results = new HashSet<>();
Task<List<Node>> nodeListTask =
Wearable.getNodeClient(getApplicationContext()).getConnectedNodes();
try {
// Block on a task and get the result synchronously (because this is on a background
// thread).
List<Node> nodes = Tasks.await(nodeListTask);
for (Node node : nodes) {
results.add(node.getId());
}
} catch (ExecutionException exception) {
Log.e(TAG, "Task failed: " + exception);
} catch (InterruptedException exception) {
Log.e(TAG, "Interrupt occurred: " + exception);
}
return results;
}
#WorkerThread
private void sendStartActivityMessage(String node,String event) {
Task<Integer> sendMessageTask =
Wearable.getMessageClient(this).sendMessage(node, event, new byte[0]);
try {
// Block on a task and get the result synchronously (because this is on a background
// thread).
Integer result = Tasks.await(sendMessageTask);
} catch (ExecutionException exception) {
Log.e(TAG, "Task failed: " + exception);
} catch (InterruptedException exception) {
Log.e(TAG, "Interrupt occurred: " + exception);
}
}

I found answer here:
https://developer.android.com/training/wearables/data-layer/migrate-to-googleapi
Migrate Wear apps to GoogleApi
Starting with version 11.8.0 of Google Play services, Wear OS apps should migrate away from the GoogleApiClient class and instead use client objects that are based on the GoogleApi class.
Use of GoogleApi makes it easier to set up asynchronous operations. For example, as described in the introduction to the Tasks API, you can obtain a Task object instead of a PendingResult object.

How can I get a list of videos available from a particular YouTube channel?

How can I get a list of videos available from a particular YouTube channel, using the API?

Basically every youtube channels has three section: Uploads, Playlist, Liked Videos. Had done some work with the playlist of a channels. Used youtube api version 3.Sharing my code:
First get the Playlists from a channel:
private void getPlayList() {
YouTube.Playlists.List playLists;
try {
playLists = youtube.playlists().list("id,status,snippet");//youtube is the Youtube object, already initialised
playLists.setChannelId(channelID);//channelID is the channel id which you want to fetch
playLists.setFields("items(id,status/privacyStatus,snippet(title,thumbnails/default/url))");
playLists.setMaxResults((long) 50);
AsynRequestClass asynRequestClass = new AsynRequestClass();
asynRequestClass.execute(playLists);
} catch (IOException e) {
e.printStackTrace();
Log.e(null, "Error occur " + e.toString());
}
}
private class AsynRequestClass extends AsyncTask<YouTube.Playlists.List, Void, PlaylistListResponse> {
#Override
protected void onPreExecute() {
super.onPreExecute();
showProgressDialogWithTitle("Loading PlayList");
}
#Override
protected PlaylistListResponse doInBackground(YouTube.Playlists.List... params) {
PlaylistListResponse playlistListResponse = null;
try {
Log.d(null, "PlayListList: " + params[0]);
playlistListResponse = params[0].execute();
Log.d(null,"PlayListResponse: "+playlistListResponse);
for (int i=0;i<playlistListResponse.getItems().size();i++){
//PlayListIdentifier,PlayListTitle,PlayListThumbnails are ArrayList<String>, already allocated and initialised
PlayListTitles.add(playlistListResponse.getItems().get(i).getSnippet().getTitle());
PlayListThumbnails.add(playlistListResponse.getItems().get(i).getSnippet().getThumbnails().getDefault().getUrl());
PlayListIdentifier.add(playlistListResponse.getItems().get(i).getId());
}
}catch (UserRecoverableAuthIOException e){
startActivityForResult(e.getIntent(),REQUEST_AUTHORIZATION);
}catch (IOException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(PlaylistListResponse playlistListResponse){
super.onPostExecute(playlistListResponse);
hideProgressDialog();
PlayListDataAdapter.notifyDataSetChanged();//PlayListDataAdapter is the data adapter
}
}
Then get the playListItem or Videos:
private void loadPlayListItem(){
YouTube.PlaylistItems.List playListItemList = null;
try {
playListItemList =youtube.playlistItems().list("id,contentDetails,snippet,status");
playListItemList.setPlaylistId(playListID);
playListItemList.setFields("items(id,status/privacyStatus,snippet(title,thumbnails/default/url),contentDetails/regionRestriction)");
playListItemList.setMaxResults((long) 50);
AsyncRequestClass asyncRequestClass = new AsyncRequestClass();
asyncRequestClass.execute(playListItemList);
} catch (IOException e) {
e.printStackTrace();
}
}
//Class for asynchronous task
private class AsyncRequestClass extends AsyncTask<YouTube.PlaylistItems.List, Void, PlaylistItemListResponse> {
#Override
protected void onPreExecute() {
super.onPreExecute();
showProgressDialogWithTitle("Loading Video");
}
#Override
protected PlaylistItemListResponse doInBackground(YouTube.PlaylistItems.List... params) {
PlaylistItemListResponse playlistItemListResponse = null;
try {
Log.d(null, "PlayListListItem: " + params[0]);
playlistItemListResponse = params[0].execute();
Log.d(null,"PlayListItemListResponse: "+playlistItemListResponse);
int size = playlistItemListResponse.getItems().size();
for (int i=0;i<size;i++){
if (!playlistItemListResponse.getItems().get(i).getStatus().getPrivacyStatus().equals("private")){
//videoListIdentifier,videoListTitle,videoListThumbnails are ArrayList<String>, already allocated and initialised
videoTitles.add(playlistItemListResponse.getItems().get(i).getSnippet().getTitle());
videoThumbnails.add(playlistItemListResponse.getItems().get(i).getSnippet().getThumbnails().getDefault().getUrl());
videoIdentifier.add(playlistItemListResponse.getItems().get(i).getContentDetails().getVideoId());
}
}
}catch (UserRecoverableAuthIOException e){
startActivityForResult(e.getIntent(),REQUEST_AUTHORIZATION);
}catch (IOException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(PlaylistItemListResponse playlistItemListResponse) {
super.onPostExecute(playlistItemListResponse);
hideProgressDialog();
videoListDataAdapter.notifyDataSetChanged();//videoListDataAdapter is the data adapter
}
}
Hadn't worked with the other two(Uploads,Liked videos), but think it can be possible in a similar manner.

Using android hidden functions to manage call states

I am a beginner in android programming.
I want to use the hidden method "getState()" of "com.android.internal.telephony.call" package to manage the state of an outgoing call such as activating, ringing, answering, rejecting and disconnecting.
But there is an error in the following code on the line indicated by "**".
Any help?
My code is :
import com.android.internal.telephony.*;
public class MainActivity extends Activity {
Class myclass;
ClassLoader cloader;
Method f;
Object o;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
cloader = this.getClass().getClassLoader();
try {
myclass = cloader.loadClass("com.android.internal.telephony.Call");
// No error generated. "Call" class will be loaded.
}
catch (Exception e)
{
System.out.println(e.toString());
}
try {
f = myclass.getMethod("getState", null);
// No error generated.Method "f" will be assigned
} catch (Exception e) {
System.out.println(e.toString());
}
Constructor constructors[] = myclass.getDeclaredConstructors();
// There is one constructor only
Constructor constructor = null;
for (int i=0; i<constructors.length;i++)
{
constructor = constructors[i];
if (constructor.getGenericParameterTypes().length == 0)
break;
}
constructor.setAccessible(true);
try {
o = constructor.newInstance(null);
//*****an exception generated here.
//*****Exception is "java.lang.instantationexception"
}
catch (Exception e) {
System.out.println(e.toString());
}
try {
f = myclass.getMethod("getState", null);
// No error
} catch (Exception e) {
System.out.println(e.toString());
}
}

Don't try to call private members like this. It will not work across Android versions and even across manufacturer customized ROMs of the same version.

Need Wrapper for API16 method in SQLite

With API16 the new WAL (Write Ahead Logging) was introduced in Androids SQLiteDatabase class. I would like to test if WAL is enabled for a SQLite database. The app runs on older Android releases too, so I need a wrapper class for these new functions in SQLiteDatabase. The functions are:
public boolean isWriteAheadLoggingEnabled()
public boolean enableWriteAheadLogging()
public void disableWriteAheadLogging ()
In the Android Developer Blog I did find an article for a wrapper class that wraps new classes. What I didn't find is a wrapper for new methods in an already existing class. How should I do that?

The constructor for SQLiteDatabase is private so your're not going to be able to extend it and add "wrappers" to the class itself. You can however just write a "helper" wrapper like so:
public class WALWrapper {
private boolean mAvailable;
private Method mIsWriteAheadLoggingEnabled;
private Method mEnableWriteAheadLogging;
private Method mDisableWriteAheadLogging;
private final SQLiteDatabase mDb;
public WALWrapper(SQLiteDatabase db) {
mDb = db;
mAvailable = false;
try {
mIsWriteAheadLoggingEnabled =
SQLiteDatabase.class.getMethod("isWriteAheadLoggingEnabled");
mEnableWriteAheadLogging =
SQLiteDatabase.class.getMethod("enableWriteAheadLogging");
mDisableWriteAheadLogging =
SQLiteDatabase.class.getMethod("disableWriteAheadLogging");
mAvailable = true;
} catch (NoSuchMethodException e) {
}
}
/**
* Returns <code>true</code> if the {#link #isWriteAheadLoggingEnabled()},
* {#link #enableWriteAheadLogging()} and {#link #disableWriteAheadLogging()}
* are available.
* #return <code>true</code> if the WALWrapper is functional, <code>false</code>
* otherwise.
*/
public boolean isWALAvailable() {
return mAvailable;
}
public boolean isWriteAheadLoggingEnabled() {
boolean result = false;
if (mIsWriteAheadLoggingEnabled != null) {
try {
result = (Boolean) mIsWriteAheadLoggingEnabled.invoke(mDb);
} catch (IllegalArgumentException e) {
} catch (IllegalAccessException e) {
} catch (InvocationTargetException e) {
}
}
return result;
}
public boolean enableWriteAheadLogging() {
boolean result = false;
if (mEnableWriteAheadLogging != null) {
try {
result = (Boolean) mEnableWriteAheadLogging.invoke(mDb);
} catch (IllegalArgumentException e) {
} catch (IllegalAccessException e) {
} catch (InvocationTargetException e) {
}
}
return result;
}
public void disableWriteAheadLogging() {
if (mDisableWriteAheadLogging != null) {
try {
mDisableWriteAheadLogging.invoke(mDb);
} catch (IllegalArgumentException e) {
} catch (IllegalAccessException e) {
} catch (InvocationTargetException e) {
}
}
}
}