QIviPlayQueue Class

Provides a play queue for the QIviMediaPlayer More...

Header: #include <QIviPlayQueue>
qmake: QT += ivimedia
Instantiated By: PlayQueue
Inherits: QAbstractListModel

Public Types

enum LoadingType { FetchMore, DataChanged }
enum Roles { NameRole, TypeRole, ItemRole }

Properties

  • 1 property inherited from QObject

Public Functions

~QIviPlayQueue()
T at(int i) const
int chunkSize() const
int currentIndex() const
int fetchMoreThreshold() const
QVariant get(int i) const
void insert(int index, const QVariant &variant)
QIviPlayQueue::LoadingType loadingType() const
void move(int cur_index, int new_index)
void remove(int index)
void setChunkSize(int chunkSize)
void setCurrentIndex(int currentIndex)
void setFetchMoreThreshold(int fetchMoreThreshold)
void setLoadingType(QIviPlayQueue::LoadingType loadingType)

Reimplemented Public Functions

virtual bool canFetchMore(const QModelIndex &parent) const override
virtual QVariant data(const QModelIndex &index, int role) const override
virtual void fetchMore(const QModelIndex &parent) override
virtual QHash<int, QByteArray> roleNames() const override
virtual int rowCount(const QModelIndex &parent = QModelIndex()) const override

Signals

void chunkSizeChanged(int chunkSize)
void countChanged()
void currentIndexChanged(int currentIndex)
void fetchMoreThresholdChanged(int fetchMoreThreshold)
void fetchMoreThresholdReached() const
void loadingTypeChanged(QIviPlayQueue::LoadingType loadingType)

Protected Functions

QIviPlayQueue(QIviMediaPlayer *parent = nullptr)

Additional Inherited Members

Detailed Description

Provides a play queue for the QIviMediaPlayer

The QIviPlayQueue is a model which is used by the QIviMediaPlayer to control the play order of QIviPlayableItems.

It provides mechanisms for adding new items and managing the existing ones by removing or moving them around.

The QIviPlayQueue can't be instantiated by its own and can only be retrieved through the QIviMediaPlayer.

The following roles are available in this model:

Role nameTypeDescription
namestringThe name of the playable item. E.g. The track name or the name of the web-stream.
typestringThe type of the playable item. E.g. "track" or "web-stream"
itemQIviPlayableItemThe playable item instance. This can be used to access type specific properties like the artist.

Member Type Documentation

enum QIviPlayQueue::LoadingType

ConstantValueDescription
QIviPlayQueue::FetchMore0This is the default and can be used if you don't know the final size of the list (e.g. a infinite list). The list will detect that it is near the end (fetchMoreThreshold) and then fetch the next chunk of data using canFetchMore and fetchMore. The drawback of this method is that, because the final size of the data is not known, you can't display a dynamic scroll-bar indicator which is resized depending on the content of the list. The other problem could be fast scrolling, as the data might not come in-time and scrolling stops. This can be tweaked by the fetchMoreThreshold property.
QIviPlayQueue::DataChanged1For this loading type you need to know how many items are in the list, as dummy items are created and the user can already start scrolling even though the data is not yet ready to be displayed. Similar to FetchMore the data is also loaded in chunks. You can safely use a scroll indicator here. The delegate needs to support this approach, as it doesn't have a content when it's first created.

enum QIviPlayQueue::Roles

ConstantValueDescription
QIviPlayQueue::NameRoleQt::DisplayRoleThe name of the playable item. E.g. The track name or the name of the web-stream.
QIviPlayQueue::TypeRoleQt::UserRoleThe type of the playable item. E.g. "track" or "web-stream"
QIviPlayQueue::ItemRole?The playable item instance. This can be used to access type specific properties like the artist.

Property Documentation

chunkSize : int

Holds the number of rows which are requested from the backend interface.

This property can be used to fine tune the loading performance.

Bigger chunks means less calls to the backend and to a potential IPC underneath, but more data to be transferred and probably longer waiting time until the request was finished.

Access functions:

int chunkSize() const
void setChunkSize(int chunkSize)

Notifier signal:

void chunkSizeChanged(int chunkSize)

count : const int

Holds the current number of rows in this model.

Access functions:

virtual int rowCount(const QModelIndex &parent = QModelIndex()) const override

Notifier signal:

void countChanged()

currentIndex : int

Holds the index of the currently active track.

Use the get() method to retrieve more information about the active track.

Access functions:

int currentIndex() const
void setCurrentIndex(int currentIndex)

Notifier signal:

void currentIndexChanged(int currentIndex)

fetchMoreThreshold : int

Holds the row delta to the end before the next chunk is loaded

This property can be used to fine tune the loading performance. When the threshold is reached the next chunk of rows are requested from the backend. How many rows are fetched can be defined by using the chunkSize property.

The threshold defines the number of rows before the cached rows ends.

Note: This property is only used when loadingType is set to FetchMore.

Access functions:

int fetchMoreThreshold() const
void setFetchMoreThreshold(int fetchMoreThreshold)

Notifier signal:

void fetchMoreThresholdChanged(int fetchMoreThreshold)

loadingType : QIviPlayQueue::LoadingType

Holds the currently used loading type used for loading the data.

Note: When changing this property the content will be reset.

Access functions:

QIviPlayQueue::LoadingType loadingType() const
void setLoadingType(QIviPlayQueue::LoadingType loadingType)

Notifier signal:

void loadingTypeChanged(QIviPlayQueue::LoadingType loadingType)

Member Function Documentation

[protected] QIviPlayQueue::QIviPlayQueue(QIviMediaPlayer *parent = nullptr)

Creates a play queue for the QIviMediaPlayer instance parent.

QIviPlayQueue::~QIviPlayQueue()

Destroys the instance of QIviPlayQueue.

T QIviPlayQueue::at(int i) const

Returns the item at index i converted to the template type T.

[override virtual] bool QIviPlayQueue::canFetchMore(const QModelIndex &parent) const

Reimplemented from QAbstractItemModel::canFetchMore().

[override virtual] QVariant QIviPlayQueue::data(const QModelIndex &index, int role) const

Reimplemented from QAbstractItemModel::data().

[override virtual] void QIviPlayQueue::fetchMore(const QModelIndex &parent)

Reimplemented from QAbstractItemModel::fetchMore().

[signal] void QIviPlayQueue::fetchMoreThresholdReached() const

This signal is emitted whenever the fetchMoreThreshold is reached and new data is requested from the backend.

QVariant QIviPlayQueue::get(int i) const

Returns the item at index i.

This function is intended to be used from QML. For C++ please use the at() instead.

void QIviPlayQueue::insert(int index, const QVariant &variant)

Insert the variant at the position index.

If the backend doesn't accept the provided item, this operation will end in a no op.

void QIviPlayQueue::move(int cur_index, int new_index)

Moves the item at position cur_index to the new position new_index the play queue.

void QIviPlayQueue::remove(int index)

Removes the item at position index from the play queue.

[override virtual] QHash<int, QByteArray> QIviPlayQueue::roleNames() const

Reimplemented from QAbstractItemModel::roleNames().

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