Medium - Android/Java Interfaces like a Boss! - Callbacks pt l

OpenFileHelper.java

public class OpenFileHelper {

    private final String filePath;
    private final OpenFileHelperCallback callback;

    public OpenFileHelper(String filePath, OpenFileHelperCallback callback) {
        this.filePath = filePath;
        this.callback = callback;
        init();
    }

    private void init() {
        try {
            openFile();
        } catch (Exception error) {
            error.printStackTrace();
            callback.onFileOpenFailure(error);
        }
    }

    private void openFile() throws IOException, FileNotFoundException {
        File file = new File(filePath);
        // open file code here
        // ...
        callback.onFileOpenSuccess(file);
    }

}

OpenFileHelperCallback.java

public interface OpenFileHelperCallback {
    void onFileOpenSuccess(File file);
    void onFileOpenFailure(Throwable error);
}

Ok