Multimedia

Building Apps with Multimedia

1 Capturing Photo

1.1 Taking Photos Simply

1.1.1 Request Camera Permission

uses-feature android:name="android.hardware.camera" android:required="true" />

1. at runtime, call hasSystemFeature(PackageManager.FEATURE_CAMERA) to check for the availablity of the camera

1.1.2 Take a Photo with the Camera App

1. new Intent
2. startActivity
3. handle the image data

static final int REQUEST_IMAGE_CAPTURE = 1;

private void dispatchTakePictureIntent() {
    Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
    if (takePictureIntent.resolveActivity(getPackageManager()) != null) {
        startActivityForResult(takePictureIntent, REQUEST_IMAGE_CAPTURE);
    }
}

1.1.3 Get the Thumbnail

1. taking photos isn’t the culmination of your app’s ambition
2. back to app from the camera
3. encode the key data as a small Bitmap in the extras of the return Intent delivered to onActivityResult()

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent intent) {
    if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == RESULT_OK) {
        Bundle extras = intent.getExtras();
        Bitmap imageBitmap = (Bitmap) extras.get("data");
        mImageView.setImageBitmap(imageBitmap);
    }
}

1.1.4 Save the Full-size Photo

1. save to the public external storage, so request permission WRITE_EXTERNAL_STORAGE
2. getExternalStoragePublicDirectory() with DIRECTORY_PICTURES argument
3. but remain private to your app only. use getExternalFilesDir(), request permission WRITE_EXTERNAL_STORAGE and maxSdkVersion="18"
4. uninstall your app, and delete the directories provided by getExternalFilesDir(), getFilesDir()

static final int REQUEST_TAKE_PHOTO = 1;
String mCurrentPhotoPath;

private void dispatchTakePictureIntent() {
    Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
    // Ensure that there's a camera activity to handle the intent
    if (takePictureIntent.resolveActivity(getPackageManager()) != null) {
        // Create the File where the photo should go
        File photoFile = null;
        try {
            photoFile = createImageFile();
        } catch (IOException ex) {
            // Error occurred while creating the File
        }
        // Continue only if the File was successfully created
        if (photoFile != null) {
            Uri photoURI = FileProvider.getUriForFile(this, "com.example.android.fileprovider",photoFile);
            takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, photoURI);
            startActivityForResult(takePictureIntent, REQUEST_TAKE_PHOTO);
        }
    }
}

private File createImageFile() throws IOException {
    // Create an image file name
    String timeStamp = new SimpleDateFormat("yyyyMMdd-HHmmss").format(new Data());
    String imageFileName = "JPEG_" + timeStamp + "_";
    File storagetDir = getExternalFilesDir(Environment.DIRECTORY_PICTURES);
    File image = File.createTempFile(
    		imageFileName,	// prefix
    		".jpg",			// suffix
    		storageDir		// directory
    };
    
    // Save a file: path for use with ACTION_VIEW intents
    mCurrentPhotoPath = image.getAbsolutePath();
    return image;
}

//AndroidManifest.xml
<provider 
	android:name="android.support.v4.content.FileProvider"
	android:authorities="com.example.android.fileprovider"
	android:exported="false"
	android:grantUriPermission="true">
	<meta-data
		android:name="android.support.FILE_PROVIDER_PATHS"
		android:resource="@xml/file_paths">
	</meta-data>
</provider>

//res/xml/file_paths.xml
<path xmlns:android="http://schemas.android.com/apk/res/android">
	<external-path name="my_images" path="Android/data/com.example.package.name/files/Pictures"/>
</path>

1.1.5 Add the Photo to a Gallery

private void galleryAddPic() {
	Intent mediaScanIntent = new Intent(Intent.ACION_MEDIA_SCANNER_SCAN_FILE);
	File f = new File(mCurrentPhotoPath);
	Uri contentUri = Uri.fromFile(f);
	mediaScanIntent.setData(contentUri);
	this.sendBroadcast(mediaScanIntent);
}

1.1.6 Decode a Scaled Image

1. full-sized images can be tricky with limited memory
2. reduce the amount of dynamic heap
3. a memory array scaled to match the size of the destination view

private void setPic() {
	//Get the dimensions of the view
	int targetW = mImageView.getWidth();
	int targetH = mImageView.getHeigth();
	
	//Get the dimensions of the bitmap
	BitmapFactory.Options bmOptions = new BitmapFactory.Options();
	bmOptions.inJustDecodeBounds = true;
	BitmapFactory.decoderFile(mCurrentPhotoPath, bmOptions);
	int photoW = bmOptions.outWidth;
	int photoH = bmOptions.outHeight;
	
	//Determine how much to scale down the image
	int scaleFactor = Math.min(photoW/targetW, photoH/targetH);
	
	//Decode the image file into a Bitmap sized to fill the view
	bmOptions.inJustDecodeBounds = false;
	bmOptions.inSampleSize = scaleFactor;
	bmOptions.inPurgable = true;
	
	Bitmap bitmap = BitmapFactory.decodeFile(mCurrentPhotoPath, bmOptions);
	mImageView.setImageBitmap(bitmap);

1.2 Recording Videos Simply

1.2.1 Request Camera Permission (as Taking Photos permission)

1.2.2 Record a Video with a Camera App

1. MediaStore.ACTION_VIDEO_CAPTURE
2. as Taking Photos startActivityForResult()

1.2.3 View the video

1. as Taking photos onActivityResult()

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent intent) {
	if (requestCode == REQUEST_VIDEO_CAPTURE && resultCode == RESULT_OK) {
		Uri videoUri = intent.getData();
		mVideoView.setVideoURI(videoUri);
	}
}

1.3 Controlling the Camera

1.3.1 Open the Camera Object

1. get an instance of Camera Object, Camera.open(id)
2. open Camera on separate thread from onCreate()
3. onResume() to facilitate code reuse and keep the flow of control simple

1.3.2 Create the Camera Preview

1. click the shutter

1.3.3 Modify Camera Settings

1.3.4 Set the Preview Orientation

1.3.5 Take a Picture

1.3.6 Restart the Preview

1.3.7 Stop the Preview and Release the Camera

2 Printing Content

1. users frequently view content solely
2. share information
3. create a snapshot of information

2.1 Printing a Photo

1. take and share photos
2. use PrintHelper

2.1.1 Print an Image

1. setScaleMode(), two options : SCALE_MODE_FIT, SCALE_MODE_FILL(default)

private void doPhotoPrint() {
	PrintHelper photoPrinter = new PrintHelper(getActivity());
	photoPrinter.setScaleMode(PrintHelper.SCALE_MODE_FIT);
	Bitmap bitmap = BitmapFactory.decodeResource(getResource(), R.drawable.droid)l
	photoPrinter.printBitmap("droids.jpg - test print", bitmap);

2.2 Printing an HTTML Document

2.2.1 Load an HTML Document

1. load the HTML resource into the Webview object
2. WebViewClient starts a print job

2.2.2 Create a Print job

2.3 Printing a Custom Document

1. how to connect to the Android print manager, create a print adapter and build content for printing