Chữ ký MediaPlayer.java đã đặtDataSource() chấp nhận cả chuỗi (đường dẫn) và FD. Cả hai cuối cùng đều đi vào mã C gốc. Mặc dù một trong số này có thể hiệu quả hơn nhưng nó sẽ không đáng kể trừ khi bạn thiết lập nguồn dữ liệu của mình thường xuyên hơn một lần trong một giây.
/**
* Sets the data source (file-path or http/rtsp URL) to use. Call this after
* reset(), or before any other method (including setDataSource()) that might
* throw IllegalStateException in this class.
*
* @param path the path of the file, or the http/rtsp URL of the stream you want to play
* @throws IllegalStateException if it is called
* in an order other than the one specified above
*/
public native void setDataSource(String path) throws IOException, IllegalArgumentException, IllegalStateException;
/**
* Sets the data source (FileDescriptor) to use. It is the caller's responsibility
* to close the file descriptor. It is safe to do so as soon as this call returns.
* Call this after reset(), or before any other method (including setDataSource())
* that might throw IllegalStateException in this class.
*
* @param fd the FileDescriptor for the file you want to play
* @throws IllegalStateException if it is called
* in an order other than the one specified above
*/
public void setDataSource(FileDescriptor fd)
throws IOException, IllegalArgumentException, IllegalStateException {
// intentionally less than LONG_MAX
setDataSource(fd, 0, 0x7ffffffffffffffL);
}
/**
* Sets the data source (FileDescriptor) to use. It is the caller's responsibility
* to close the file descriptor. It is safe to do so as soon as this call returns.
* Call this after reset(), or before any other method (including setDataSource())
* that might throw IllegalStateException in this class.
*
* @param fd the FileDescriptor for the file you want to play
* @param offset the offset into the file where the data to be played starts, in bytes
* @param length the length in bytes of the data to be played
* @throws IllegalStateException if it is called
* in an order other than the one specified above
*/
public native void setDataSource(FileDescriptor fd, long offset, long length)
throws IOException, IllegalArgumentException, IllegalStateException;
'FileDescriptor' có thể sử dụng được khi phát từ nội dung từ thư mục' ContentProvider' hoặc tài sản chẳng hạn. – Jens