Android Archives • Page 3 of 5 • Catzie.net Blog

Add “options menu” to an AppCompatActivity (Android App Development)

Adding an “options menu” to an Android app’s Activity is quite simple.

This is an example of what an Android options menu looks like. Look at the icon that looks like 3 dots vertically stacked.

My dev environment status as of writing this

Android Studio version: v. 2.1
OS: Mac OS X El Capitan v. 10.11
My Android app build status:

compileSdkVersion: 24
buildToolsVersion: 24.0.2
minSdkVersion: 16
targetSdkVersion: 24

Add “options menu” to an Android AppCompatActivity

#1 Create menu layout file

Create res/menu/main.xml, creating the menu folder if not yet existing.

Add the following to res/menu/main.xml:

<?xml version=”1.0″ encoding=”utf-8″?>
<menu xmlns:android=”http://schemas.android.com/apk/res/android”>
    <item android:id=”@+id/about”
        android:title=”About” />
    <item android:id=”@+id/help”
        android:title=”Help” />
</menu>

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<?xml version=“1.0” encoding=“utf-8”?>

<item android:id=“@+id/about”

android:title=“About” />

<item android:id=“@+id/help”

android:title=“Help” />

</menu>

#2 Enable menu by adding MenuInflater to the Activity

Add the following overriding method to your AppCompatActivity:

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.main, menu);
        return true;
    }

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@Override

public boolean onCreateOptionsMenu(Menu menu) {

MenuInflater inflater = getMenuInflater();

inflater.inflate(R.menu.main, menu);

return true;

}

#3 Add listener for selected options menu item

Again, add the following overriding method to your AppCompatActivity. Replace the Toasts with whatever you need to do upon menu item selection:

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case R.id.about:
                Toast.makeText(MainActivity.this, “Selected options menu item: About”, Toast.LENGTH_SHORT).show();
                return true;
            case R.id.help:
                Toast.makeText(MainActivity.this, “Selected options menu item: Help”, Toast.LENGTH_SHORT).show();
                return true;
            default:
                return super.onOptionsItemSelected(item);
        }
    }

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@Override

public boolean onOptionsItemSelected(MenuItem item) {

switch (item.getItemId()) {

case R.id.about:

Toast.makeText(MainActivity.this, “Selected options menu item: About”, Toast.LENGTH_SHORT).show();

return true;

case R.id.help:

Toast.makeText(MainActivity.this, “Selected options menu item: Help”, Toast.LENGTH_SHORT).show();

return true;

default:

return super.onOptionsItemSelected(item);

}

That’s it! Your Android Activity should now have an options menu on the actionbar

My resources for adding my options menu to Activity

Adding the App Bar
Android SDK: Implement an Options Menu

October 17, 2016

Java: method to convert degrees into directions (16-wind compass rose)

I’m working on a weather app for Android. The data for wind direction that I get from the weather API is in form of degrees (0 to 360). I want to display wind direction in a user-friendly format such as N (North), NNE (North-northeast), NE (Northeast), ENE (East-Northeast), E (East), ESE (East-Southeast), SE (Southeast), SSE (South-Southeast), S (South), SSW (South-Southwest), SW (Southwest), WSW (West-Southwest), W (West), WNW (West-Northwest), NW (Northwest), and NNW (North-Northwest). I think this is more user-friendly, at least when compared to degrees format.

16-wind compass rose
The eight half-winds are the points obtained by bisecting the angles between the principal winds. The half-winds are north-northeast (NNE), east-northeast (ENE), east-southeast (ESE), south-southeast (SSE), south-southwest (SSW), west-southwest (WSW), west-northwest (WNW) and north-northwest (NNW). Notice that the name is constructed simply by combining the names of the principal winds to either side, with the cardinal wind coming first, the ordinal wind second. The eight principal winds and the eight half-winds together yield a 16-wind compass rose, with each compass point at a 22 1⁄2° angle from the next.

Points of the Compass

And here is the Java method that I prepared so I can convert direction data from degrees into directions (16-wind compass rose):

public String convertDegreeToCardinalDirection(int directionInDegrees){
    String cardinalDirection = null;
    if( (directionInDegrees >= 348.75) && (directionInDegrees <= 360) ||
        (directionInDegrees >= 0) && (directionInDegrees <= 11.25)    ){
        cardinalDirection = “N”;
    } else if( (directionInDegrees >= 11.25 ) && (directionInDegrees <= 33.75)){
        cardinalDirection = “NNE”;
    } else if( (directionInDegrees >= 33.75 ) &&(directionInDegrees <= 56.25)){
        cardinalDirection = “NE”;
    } else if( (directionInDegrees >= 56.25 ) && (directionInDegrees <= 78.75)){
        cardinalDirection = “ENE”;
    } else if( (directionInDegrees >= 78.75 ) && (directionInDegrees <= 101.25) ){
        cardinalDirection = “E”;
    } else if( (directionInDegrees >= 101.25) && (directionInDegrees <= 123.75) ){
        cardinalDirection = “ESE”;
    } else if( (directionInDegrees >= 123.75) && (directionInDegrees <= 146.25) ){
        cardinalDirection = “SE”;
    } else if( (directionInDegrees >= 146.25) && (directionInDegrees <= 168.75) ){
        cardinalDirection = “SSE”;
    } else if( (directionInDegrees >= 168.75) && (directionInDegrees <= 191.25) ){
        cardinalDirection = “S”;
    } else if( (directionInDegrees >= 191.25) && (directionInDegrees <= 213.75) ){
        cardinalDirection = “SSW”;
    } else if( (directionInDegrees >= 213.75) && (directionInDegrees <= 236.25) ){
        cardinalDirection = “SW”;
    } else if( (directionInDegrees >= 236.25) && (directionInDegrees <= 258.75) ){
        cardinalDirection = “WSW”;
    } else if( (directionInDegrees >= 258.75) && (directionInDegrees <= 281.25) ){
        cardinalDirection = “W”;
    } else if( (directionInDegrees >= 281.25) && (directionInDegrees <= 303.75) ){
        cardinalDirection = “WNW”;
    } else if( (directionInDegrees >= 303.75) && (directionInDegrees <= 326.25) ){
        cardinalDirection = “NW”;
    } else if( (directionInDegrees >= 326.25) && (directionInDegrees <= 348.75) ){
        cardinalDirection = “NNW”;
    } else {
        cardinalDirection = “?”;
    }

    return cardinalDirection;
}

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public String convertDegreeToCardinalDirection(int directionInDegrees){

String cardinalDirection = null;

if( (directionInDegrees >= 348.75) && (directionInDegrees <= 360) ||

(directionInDegrees >= 0) && (directionInDegrees <= 11.25) ){

cardinalDirection = “N”;

} else if( (directionInDegrees >= 11.25 ) && (directionInDegrees <= 33.75)){

cardinalDirection = “NNE”;

} else if( (directionInDegrees >= 33.75 ) &&(directionInDegrees <= 56.25)){

cardinalDirection = “NE”;

} else if( (directionInDegrees >= 56.25 ) && (directionInDegrees <= 78.75)){

cardinalDirection = “ENE”;

} else if( (directionInDegrees >= 78.75 ) && (directionInDegrees <= 101.25) ){

cardinalDirection = “E”;

} else if( (directionInDegrees >= 101.25) && (directionInDegrees <= 123.75) ){

cardinalDirection = “ESE”;

} else if( (directionInDegrees >= 123.75) && (directionInDegrees <= 146.25) ){

cardinalDirection = “SE”;

} else if( (directionInDegrees >= 146.25) && (directionInDegrees <= 168.75) ){

cardinalDirection = “SSE”;

} else if( (directionInDegrees >= 168.75) && (directionInDegrees <= 191.25) ){

cardinalDirection = “S”;

} else if( (directionInDegrees >= 191.25) && (directionInDegrees <= 213.75) ){

cardinalDirection = “SSW”;

} else if( (directionInDegrees >= 213.75) && (directionInDegrees <= 236.25) ){

cardinalDirection = “SW”;

} else if( (directionInDegrees >= 236.25) && (directionInDegrees <= 258.75) ){

cardinalDirection = “WSW”;

} else if( (directionInDegrees >= 258.75) && (directionInDegrees <= 281.25) ){

cardinalDirection = “W”;

} else if( (directionInDegrees >= 281.25) && (directionInDegrees <= 303.75) ){

cardinalDirection = “WNW”;

} else if( (directionInDegrees >= 303.75) && (directionInDegrees <= 326.25) ){

cardinalDirection = “NW”;

} else if( (directionInDegrees >= 326.25) && (directionInDegrees <= 348.75) ){

cardinalDirection = “NNW”;

} else {

cardinalDirection = “?”;

}

return cardinalDirection;

}

September 23, 2016

Android Maps: Get current location coordinates with Google API Client Builder

To get your current location via Google Map in an Android app, this was how we do it:

@Override
public void onMapReady(GoogleMap googleMap) {
    Location location = googleMap.getMyLocation();
}

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@Override

public void onMapReady(GoogleMap googleMap) {

Location location = googleMap.getMyLocation();

}

Stop. Don’t use that! The method GoogleMap.getMyLocation() is deprecated. Instead, we need to use FusedLocationApi and the callback onLocationChanged().

Here’s an example code that works for me ( consider copying the contents of onResume() into onStart() ):

public class MainActivity extends FragmentActivity
        implements OnMapReadyCallback,
        GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener,
        LocationListener {

    private GoogleMap map;
    private LocationRequest mLocationRequest;
    private GoogleApiClient mGoogleApiClient;
    private Location mLastLocation;
    private Marker marker;

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

    }

    @Override
    protected void onResume() {
        super.onResume();

        if (mGoogleApiClient == null || !mGoogleApiClient.isConnected()){

            buildGoogleApiClient();
            mGoogleApiClient.connect();

        }

        if (map == null) {
            MapFragment mapFragment = (MapFragment) getFragmentManager()
                    .findFragmentById(R.id.map);

            mapFragment.getMapAsync(this);
        }
    }

    @Override
    public void onMapReady(GoogleMap retMap) {

        map = retMap;

        setUpMap();

    }

    public void setUpMap(){

        map.setMapType(GoogleMap.MAP_TYPE_HYBRID);
        map.setMyLocationEnabled(true);
    }

    @Override
    protected void onPause(){
        super.onPause();
        if (mGoogleApiClient != null) {
            LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);
        }
    }

    protected synchronized void buildGoogleApiClient() {
        Toast.makeText(this, “buildGoogleApiClient”, Toast.LENGTH_SHORT).show();
        mGoogleApiClient = new GoogleApiClient.Builder(this)
                .addConnectionCallbacks(this)
                .addOnConnectionFailedListener(this)
                .addApi(LocationServices.API)
                .build();
    }

    @Override
    public void onConnected(Bundle bundle) {
        Toast.makeText(this,”onConnected”, Toast.LENGTH_SHORT).show();

        mLocationRequest = new LocationRequest();
        mLocationRequest.setInterval(1000);
        mLocationRequest.setFastestInterval(1000);
        mLocationRequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);

        //mLocationRequest.setSmallestDisplacement(0.1F);

        LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);
    }

    @Override
    public void onConnectionSuspended(int i) {

    }

    @Override
    public void onConnectionFailed(ConnectionResult connectionResult) {

    }

    @Override
    public void onLocationChanged(Location location) {
        mLastLocation = location;

        //remove previous current location Marker
        if (marker != null){
            marker.remove();
        }

        double dLatitude = mLastLocation.getLatitude();
        double dLongitude = mLastLocation.getLongitude();
        marker = map.addMarker(new MarkerOptions().position(new LatLng(dLatitude, dLongitude))
                .title(“My Location”).icon(BitmapDescriptorFactory
                        .defaultMarker(BitmapDescriptorFactory.HUE_RED)));
        map.moveCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(dLatitude, dLongitude), 8));

    }

}

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public class MainActivity extends FragmentActivity

implements OnMapReadyCallback,

GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener,

LocationListener {

private GoogleMap map;

private LocationRequest mLocationRequest;

private GoogleApiClient mGoogleApiClient;

private Location mLastLocation;

private Marker marker;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

}

@Override

protected void onResume() {

super.onResume();

if (mGoogleApiClient == null || !mGoogleApiClient.isConnected()){

buildGoogleApiClient();

mGoogleApiClient.connect();

}

if (map == null) {

MapFragment mapFragment = (MapFragment) getFragmentManager()

.findFragmentById(R.id.map);

mapFragment.getMapAsync(this);

}

@Override

public void onMapReady(GoogleMap retMap) {

map = retMap;

setUpMap();

}

public void setUpMap(){

map.setMapType(GoogleMap.MAP_TYPE_HYBRID);

map.setMyLocationEnabled(true);

}

@Override

protected void onPause(){

super.onPause();

if (mGoogleApiClient != null) {

LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);

}

protected synchronized void buildGoogleApiClient() {

Toast.makeText(this, “buildGoogleApiClient”, Toast.LENGTH_SHORT).show();

mGoogleApiClient = new GoogleApiClient.Builder(this)

.addConnectionCallbacks(this)

.addOnConnectionFailedListener(this)

.addApi(LocationServices.API)

.build();

}

@Override

public void onConnected(Bundle bundle) {

Toast.makeText(this,“onConnected”, Toast.LENGTH_SHORT).show();

mLocationRequest = new LocationRequest();

mLocationRequest.setInterval(1000);

mLocationRequest.setFastestInterval(1000);

mLocationRequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);

//mLocationRequest.setSmallestDisplacement(0.1F);

LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);

}

@Override

public void onConnectionSuspended(int i) {

}

@Override

public void onConnectionFailed(ConnectionResult connectionResult) {

}

@Override

public void onLocationChanged(Location location) {

mLastLocation = location;

//remove previous current location Marker

if (marker != null){

marker.remove();

}

double dLatitude = mLastLocation.getLatitude();

double dLongitude = mLastLocation.getLongitude();

marker = map.addMarker(new MarkerOptions().position(new LatLng(dLatitude, dLongitude))

.title(“My Location”).icon(BitmapDescriptorFactory

.defaultMarker(BitmapDescriptorFactory.HUE_RED)));

map.moveCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(dLatitude, dLongitude), 8));

}

Code source: How to get current location of device on google maps api v2, getMyLocation() method is deprecated

June 10, 2016

Android Studio and the 64K methods limit (DEX error)

Hi! I’ll share a few tips with you on how to find out the number of methods that your Android app has. I’m gonna show you a few tools such as APK file methods counter, and an Android plugin that will show you the number of methods each imported class or dependency has. These will help you figure out if you’re nearing the 64K methods limit, and determine which classes/dependencies must be causing it.

First off, try this online drag-and-drop tool that will show you the total method count as well as breakdown based on the APK file you’ll use: APK Method Count

Now, let’s install the plugin. After installation, you should be able to see method counts on your app/build.gradle file.

Install plugin to check for unused dependencies: Jonnyzzz Dependencies. I used version 1.0.10. To do this, in [Windows] go to File -> Plugins, or in [Mac] go to Android Studio -> Preferences. Press “Browse Repositories” then find and install Jonnyzzz Dependencies. Restart Android Studio.

To use, from the menu, select Tools -> Unused Module Dependencies -> Analyse All Modules

You’ll be prompted for an option to remove all unused dependencies. I could not do that because I had a team mate who might use some of those in the list, so I manually deleted libraries that I’m sure we no longer need.

Sync Gradle, Clean, or even Rebuild… and run your app again.

I must admit that this DEX file error is a nightmare to me. xD I used to only code my Android app in a Windows 7 computer, which was very slow. Then some office friends decided to lend me a higher-specs Mac Mini that nobody’s using. It’s helping a lot, but the app I’m working on in Windows is getting 64K methods limit in Mac. I had the exact same copy of my Android Studio project in both Windows and Mac computers, but only the one in Mac was getting 64K methods limit error. 😆

Now I’m thinking of the small differences in my Windows’ and Mac’s config for Android Studio…

Could it be because ‘com.google.gms:google-services:2.0.0-alpha9’ and Android Studio v.2.1 in Mac, while my Windows 7 had ‘com.google.gms:google-services:2.0.0-alpha6’ and Android Studio v.1.4?

From what I understand in the Methods Count pages for Google Services 2.0.0 Alpha 6 and Alpha 9, Alpha 6 has more methods than Alpha 9.

My Android Studio v.1.4 in Windows using Alpha 6 (more methods) but the app runs without problem, while Android Studio 2.1 in Mac using Alpha 9 (less methods) triggers the 64K methods limit. 😆

I don’t want to keep thinking about this right now because I have pending tasks to do. 😆 But it’s nice to know roughly what we can do next time I get this dreaded 64K methods limit error.

May 17, 2016

Android ImageView has unwanted padding: layout troubleshooting

If you use ImageView in your android app layout and you get that unwanted padding around the image, here’s an Android XML attribute that helped me solved the layout issue:

<ImageView
  (…)
  android:adjustViewBounds=”true” />

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<ImageView

(...)

android:adjustViewBounds=“true” />

Add android:adjustViewBounds="true" attribute to your ImageView XML tag and you’ll probably see the unwanted padding go away.

According to the ImageView docs:

android:adjustViewBounds

Set this to true if you want the ImageView to adjust its bounds to preserve the aspect ratio of its drawable.

You might also want to check the related Java method: setAdjustViewBounds(boolean)

January 19, 2016

Android app dev: image sizes for variety of screen sizes

As a mobile app developer, we need to consider various screen sizes for a wide range of Android devices.

Here’s a quick note of recommended image sizes for Android app icons:

36×36 for low-density (LDPI)
48×48 for medium-density (MDPI)
72×72 for high-density (HDPI)
96×96 for extra high-density (XHDPI)
180×180 for extra extra high-density (XXHDPI)
192×192 for extra extra extra highv-density (XXXHDPI)

Image Scaling

Source: Units and measurements – Layout – Google design guidelines

Images can be scaled to look the same across different screen resolutions by using these ratios:

Screen resolution	dpi	Pixel ratio	Image size (pixels)
xxxhdpi	640	4.0	400 x 400
xxhdpi	480	3.0	300 x 300
xhdpi	320	2.0	200 x 200
hdpi	240	1.5	150 x 150
mdpi	160	1.0	100 x 100

For our reference. 🙂

You may read more about Supporting Multiple Devices.

I also want to share MakeAppIcon. Use that online tool to quickly generate resized images for various Android screen sizes for you.

January 18, 2016

Android: 2-dimensional List String (List of List)

For a web developer who used mostly PHP and JavaScript for several years, plunging into Java can be challenging especially when it comes to data types.

PHP and JavaScript are loosely typed languages, while Java is strict about types.

I was told that in Android, List<String> is very commonly used, even more than arrays. And now I’ve come to the point when I need to use a 2-dimensional List<String>.

Here’s a sample code:

        List<List<String>> listOfList = new ArrayList<List<String>>();
        List<String> x = new ArrayList<String>();
        x.add(“Hello”);
        x.add(“world!”);
        listOfList.add(x);

        List<String> y = new ArrayList<String>();
        y.add(“1”);
        y.add(“4”);
        y.add(“3”);

        listOfList.add(y);

        for(List<String> ls : listOfList) {
            System.out.println(Arrays.deepToString(ls.toArray()));
        }

        Log.d(“serialized”, listOfList.toString());

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List<List<String>> listOfList = new ArrayList<List<String>>();

List<String> x = new ArrayList<String>();

x.add(“Hello”);

x.add(“world!”);

listOfList.add(x);

List<String> y = new ArrayList<String>();

y.add(“1”);

y.add(“4”);

y.add(“3”);

listOfList.add(y);

for(List<String> ls : listOfList) {

System.out.println(Arrays.deepToString(ls.toArray()));

}

Log.d(“serialized”, listOfList.toString());

Output of System.outprintln(Arrays.deepToString(ls.toArray())); is this:

I/System.out: [Hello, world!]
I/System.out: [1, 4, 3]

1 2	I/System.out: [Hello, world!] I/System.out: [1, 4, 3]

The output of Log.d("serialized", listOfList.toString()); is this:

D/serialized: [[Hello, world!], [1, 4, 3]]

1	D/serialized: [[Hello, world!], [1, 4, 3]]

December 14, 2015

Android confirm dialog box with OK and Cancel button

This will probably be one of the Android code snippets that I will need to go back to from time to time.

I’m sharing the codes we need to show an Android confirm dialog to prompt the user to click “yes” or “no”, or in my case, “OK” or “Cancel”.

The following code for Android confirm dialog is in my MainActivity.java file:

(more…)

November 25, 2015

Android Studio dark theme (change into Darcula theme)

You might feel more comfortable with a dark theme in Android Studio, but the default theme is light in color.

I’m one of the developers who always code in dark screens since it’s less tiring to the eyes.

If you’re like me who prefers dark themes while coding, then I’ll show you how to change into a dark theme called Darcula in Android Studio here. (more…)

November 17, 2015

How to change app name in Android Studio

I’m trying to learn how to build a simple app in Android just to satisfy my curiosity. This will also be a very handy skill because I use Android phones often, and there are times that the apps I download from Google Play Store lack features that I need.

This will be a very simple guide on how to change app name in Android Studio, something that most beginners in Android development probably want to know.

It is assumed in this guide that you have prior knowledge in coding.

The app name that I’m referring to is the one that says “My Application”, as marked on the image below:

To change that, go to your Project and find the app folder. Under app, find AndroidManifest.xml and edit android:label="My Application", replacing “My Application” with the name you’d like to use.

Refer to the image below:

Your changed app name should be reflected in the live preview now, if you have it activated. If you don’t have live preview yet, check this out: Where is Android Studio layout preview?

Updates…

How to rename project folders of Android Studio

You may also want to change the name of your Android app’s folder. Check this folder, it’s probably where your Android project folder is located — C:\Users\catkeng\AndroidStudioProjects\

How to rename package in Android Studio

Right-click on your package name in the Project tree. It’s probably under app->java. Then choose “Refactor”, then choose “Rename”. Take note that you’ll see “Rename package” and “Rename folders” button here — you might need to go back to this screen later to click “Rename folders”. For now, click the “Rename package” button. Type the new name that you want to use, then click “Refactor”. If that hasn’t changed all package name instances for you, follow the same steps until you can click “Rename folders” button too. That should do it!

November 9, 2015

Tag: Android

My dev environment status as of writing this

Add “options menu” to an Android AppCompatActivity

#1 Create menu layout file

#2 Enable menu by adding MenuInflater to the Activity

#3 Add listener for selected options menu item

My resources for adding my options menu to Activity

Image Scaling

How to rename project folders of Android Studio

How to rename package in Android Studio