ANDROID MOBLIE Taking Photos Simply

Suppose you are implementing a crowd-sourced weather service that makes a global weather map by blending together pictures of the sky taken by devices running your client app. Integrating photos is only a small part of your application. You want to take photos with minimal fuss, not reinvent the camera. Happily, most Android-powered devices already have at least one camera application installed. In this lesson, you learn how to make it take a picture for you.
If an essential function of your application is taking pictures, then restrict its visibility on Google Play to devices that have a camera. To advertise that your application depends on having a camera, put a <uses-feature> tag in your manifest file:

<manifest ... >
    <uses-feature android:name="android.hardware.camera" />
    ...
</manifest ... >

If your application uses, but does not require a camera in order to function, add android:required="false" to the tag. In doing so, Google Play will allow devices without a camera to download your application. It's then your responsibility to check for the availability of the camera at runtime by calling hasSystemFeature(PackageManager.FEATURE_CAMERA). If a camera is not available, you should then disable your camera features.
Take a Photo with the Camera App

The Android way of delegating actions to other applications is to invoke an Intent that describes what you want done. This process involves three pieces: The Intent itself, a call to start the external Activity, and some code to handle the image data when focus returns to your activity.

Here's a function that invokes an intent to capture a photo.

private void dispatchTakePictureIntent(int actionCode) {
    Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
    startActivityForResult(takePictureIntent, actionCode);
}

Congratulations: with this code, your application has gained the ability to make another camera application do its bidding! Of course, if no compatible application is ready to catch the intent, then your app will fall down like a botched stage dive. Here is a function to check whether an app can handle your intent:

public static boolean isIntentAvailable(Context context, String action) {
    final PackageManager packageManager = context.getPackageManager();
    final Intent intent = new Intent(action);
    List<ResolveInfo> list =
            packageManager.queryIntentActivities(intent, PackageManager.MATCH_DEFAULT_ONLY);
    return list.size() > 0;
}


View the Photo

If the simple feat of taking a photo is not the culmination of your app's ambition, then you probably want to get the image back from the camera application and do something with it.

The Android Camera application encodes the photo in the return Intent delivered to onActivityResult() as a small Bitmap in the extras, under the key "data". The following code retrieves this image and displays it in an ImageView.

private void handleSmallCameraPhoto(Intent intent) {
    Bundle extras = intent.getExtras();
    mImageBitmap = (Bitmap) extras.get("data");
    mImageView.setImageBitmap(mImageBitmap);
}

Note: This thumbnail image from "data" might be good for an icon, but not a lot more. Dealing with a full-sized image takes a bit more work.
Save the Photo

The Android Camera application saves a full-size photo if you give it a file to save into. You must provide a path that includes the storage volume, folder, and file name.

There is an easy way to get the path for photos, but it works only on Android 2.2 (API level 8) and later:


storageDir = new File(
    Environment.getExternalStoragePublicDirectory(
        Environment.DIRECTORY_PICTURES
    ),
    getAlbumName()
);             

For earlier API levels, you have to provide the name of the photo directory yourself.


storageDir = new File (
    Environment.getExternalStorageDirectory()
        + PICTURES_DIR
        + getAlbumName()
);

Note: The path component PICTURES_DIR is just Pictures/, the standard location for shared photos on the external/shared storage.