From Zero to App (with a Camera)

Guest poster, Michael Gangolf, has been using Titanium since 2010, been a Titan since 2017 and Android lover since the beginning. You can follow him at @michaelgangolf or on Github at https://github.com/m1ga. This blog is part of a “From Zero to App” series. You can find the first one about Maps here

Use the camera

Another must have feature in an app is to access the camera and take pictures or videos. In this short tutorial, we will create a small app that adds a ‘take a picture’ button.

Project setup

We will start with an empty Alloy project.

appc new

Permissions

For security reasons, both Android and iOS need to ask the user in order to access the camera. For iOS, you need to add a key to the tiapp.xml:

<ios>
    <plist>
        <dict>
            <key>NSCameraUsageDescription</key>
            <string>To take a picture we want to use the camera</string>

            <!-- needed for video -->
            <key>NSCameraUsageDescription</key>
            <string>For Video recording we want to use the microphone</string>
        </div>
    </plist>
</ios>

and for Android this needs to be added to the manifest:

<android xmlns:android="https://schemas.android.com/apk/res/android">
    <manifest>
        <uses-permission android:name="android.permission.CAMERA"/>

        <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
        <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
    </manifest>
</android>

Then, inside the app itself, we need to ask for permission again which the users has to accept or decline.

Titanium has built-in functions to request these permissions. Since it might be handy to use this in other apps too, we need to create an external library and include the code there, so we can use this file in other apps as well. To do this, you have to create a lib folder at /app/lib/ and inside this folder, create a new file called helper.js.

There we add our getPermissions() script:

exports.getPermissions = function(opt) {
//
}

The code for Android and iOS is a bit different, so we need to check for the platform and ask for the specific platform permission.

exports.getPermissions = function(opt) {
    if (OS_ANDROID) {
        // Android part
        var permissions = ['android.permission.CAMERA', 'android.permission.READ_EXTERNAL_STORAGE'];
        var hasPermission = Ti.Android.hasPermission(permissions);

        // check if the permissions are already allowed
        if (hasPermission) {
            // run callback
            opt();
            return;
        }
        // no permission - request it
        Ti.Android.requestPermissions(permissions, function(e) {
            if (e.successs) {
                // run callback
                opt();
            } else {
                // ask again
                exports.getPermissions(opt);
            }
        });
    } else {
        // iOS part
        var map = {};
        map[Ti.Media.CAMERA_AUTHORIZATION_AUTHORIZED] = 'CAMERA_AUTHORIZATION_AUTHORIZED';
        map[Ti.Media.CAMERA_AUTHORIZATION_DENIED] = 'CAMERA_AUTHORIZATION_DENIED';
        map[Ti.Media.CAMERA_AUTHORIZATION_RESTRICTED] = 'CAMERA_AUTHORIZATION_RESTRICTED';
        map[Ti.Media.CAMERA_AUTHORIZATION_NOT_DETERMINED] = 'CAMERA_AUTHORIZATION_NOT_DETERMINED';

        var cameraAuthorization = Ti.Media.cameraAuthorization;
        if (cameraAuthorization === Ti.Media.CAMERA_AUTHORIZATION_RESTRICTED) {
            return;
        } else if (cameraAuthorization === Ti.Media.CAMERA_AUTHORIZATION_DENIED) {
            return;
        }
        Ti.Media.requestCameraPermissions(function(e) {
            if (e.success) {
                // run callback
                opt();
            } else {
                // ask again
                exports.getPermissions(opt);
            }
        });
    }
}

Say cheese

Now that we can ask for the permission, it is time to open the camera! We add a simple button to our view and add a click event to it, so we can open the camera.

<Alloy>
    <Window>
        <Button id="btn_record" title="Take a picture" />
    </Window>
</Alloy>
function onClickRecord(e) {}

$.btn_record.addEventListener("click",onClickRecord);
$.index.open();

All we need to do now is call our getPermissions() helper script. And, once we have the correct permission we can open the camera. To use the lib/helper.js, we need to require() it:

var helper = require("/helper");

Then, we can use all export functions in our code:

helper.getPermissions(function(){});

The last part is opening the camera:

Ti.Media.showCamera({});

So the whole code will look like this:

var helper = require("/helper");

function onClickRecord(e) {
    helper.getPermissions(function(){
        // permission granted

        // open the camera
        Ti.Media.showCamera({})
    });
}

$.btn_record.addEventListener("click",onClickRecord);
$.index.open();

If you click the button now, it will ask you for camera and storage permission the first time and then open the camera.

The showCamera() method has some properties you can set to change some options and to get the image. For a full list check out: https://docs.appcelerator.com/platform/latest/#!/api/CameraOptionsType

The most common option is the success callback. This will be called after the images was taken and you can get the actual image to show it in your app or store it.

Ti.Media.showCamera({
    success: function(e) {
        // display image information:
        console.log(e.media);
        // $.imageView.image = e.media; // to put it into an imageview
    }
})

You can also add a custom overlay to the camera with overlay. When you set an overlay, it won’t run the normal camera as an intent, but it will create a custom camera view for you. You have to take care of the actions/buttons (Ti.Media.takePicture(),Ti.Media.hideCamera(),…) yourself! overlay accepts a view as a parameter.

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