序列化和Java的反序列android.graphics.Bitmap [英] Serializing and De-Serializing android.graphics.Bitmap in Java
问题描述
我已经开始工作的我的第一个Android应用程序，并有一个处理带有多个图层的图像的应用的基础。我能够出口一台版本的项目文件为PNG，但我希望能够保存进行后期编辑（包括适用于某些层的任何选项，如基于文本层）的分层图像。
不管怎样，我已确保需要被写入到文件中的类是可序列化，但遇到了一个位所造成的事实，android.graphics.Bitmap不是可序列化道路块。下面code基本输出位图作为一个PNG至ByteArray，应该读回作为的readObject的一部分。然而，当code同时运行 - 我可以验证所读取的'imageByteArrayLength'变量是相同被输出 - 但'位图图象总是空
任何帮助将是很大的AP preciated。感谢您的阅读。
私人字符串名称;
私人诠释宽度;
私人诠释高度;
私人位图sourceImage;
私人帆布sourceCanvas;
私人位图currentImage;
私人帆布currentCanvas;
私人油漆currentPaint;
私人无效的writeObject（ObjectOutputStream的了）抛出IOException异常{
out.writeObject（职称）;
out.writeInt（宽）;
out.writeInt（高度）;
ByteArrayOutputStream流=新ByteArrayOutputStream（）;
currentImage.com preSS（Bitmap.Com pressFormat.PNG，100，流）;
byte []的imageByteArray = stream.toByteArray（）;
INT长度= imageByteArray.length;
out.writeInt（长）;
out.write（imageByteArray）;
}
私人无效的readObject（ObjectInputStream中的）抛出IOException异常，ClassNotFoundException异常{
this.title =（字符串）in.readObject（）;
this.width = in.readInt（）;
this.height = in.readInt（）;
INT imageByteArrayLength = in.readInt（）;
byte []的imageByteArray =新的字节[imageByteArrayLength]
in.read（imageByteArray，0，imageByteArrayLength）;
BitmapFactory.Options选择=新BitmapFactory.Options（）;
opt.in preferredConfig = Bitmap.Config.ARGB_8888;
位图图像= BitmapFactory.de codeByteArray（imageByteArray，0，imageByteArrayLength，OPT）;
sourceImage = Bitmap.createBitmap（宽度，高度，Bitmap.Config.ARGB_8888）;
currentImage = Bitmap.createBitmap（宽度，高度，Bitmap.Config.ARGB_8888）;
sourceCanvas =新的Canvas（sourceImage）;
currentCanvas =新的Canvas（currentImage）;
currentPaint =新的油漆（Paint.ANTI_ALIAS_FLAG）;
如果（图像！= NULL）{
sourceCanvas.drawBitmap（图像，0，0，currentPaint）;
}
}
过了一段时间，但我已经找到了干净的解决这个问题。我公司生产的自定义对象（BitmapDataObject）即实现Serializable接口，并有一个byte []从原来的位图存储PNG数据。用这种方法，数据被正确地存储在用ObjectOutputStream / ObjectInputStream的 - 这有效地允许一个序列化，并通过存储它作为在自定义对象一个字节[]一个PNG反序列化Bitmap对象。下面的code解析我的查询。
私人字符串名称;
私人诠释sourceWidth，currentWidth;
私人诠释sourceHeight，currentHeight;
私人位图sourceImage;
私人帆布sourceCanvas;
私人位图currentImage;
私人帆布currentCanvas;
私人油漆currentPaint;
保护类BitmapDataObject实现Serializable {
私有静态最后长的serialVersionUID = 111696345129311948L;
公共字节[] imageByteArray;
}
/ **包含了序列化 - 写这层到输出流。 * /
私人无效的writeObject（ObjectOutputStream的了）抛出IOException异常{
out.writeObject（职称）;
out.writeInt（currentWidth）;
out.writeInt（currentHeight）;
ByteArrayOutputStream流=新ByteArrayOutputStream（）;
currentImage.com preSS（Bitmap.Com pressFormat.PNG，100，流）;
BitmapDataObject bitmapDataObject =新BitmapDataObject（）;
bitmapDataObject.imageByteArray = stream.toByteArray（）;
out.writeObject（bitmapDataObject）;
}
/ **包含了序列化 - 读取所提供的输入流这个对象。 * /
私人无效的readObject（ObjectInputStream中的）抛出IOException异常，ClassNotFoundException异常{
标题=（字符串）in.readObject（）;
sourceWidth = currentWidth = in.readInt（）;
sourceHeight = currentHeight = in.readInt（）;
BitmapDataObject bitmapDataObject =（BitmapDataObject）in.readObject（）;
位图图像= BitmapFactory.de codeByteArray（bitmapDataObject.imageByteArray，0，bitmapDataObject.imageByteArray.length）;
sourceImage = Bitmap.createBitmap（sourceWidth，sourceHeight，Bitmap.Config.ARGB_8888）;
currentImage = Bitmap.createBitmap（sourceWidth，sourceHeight，Bitmap.Config.ARGB_8888）;
sourceCanvas =新的Canvas（sourceImage）;
currentCanvas =新的Canvas（currentImage）;
currentPaint =新的油漆（Paint.ANTI_ALIAS_FLAG）;
thumbnailPaint =新的油漆（Paint.ANTI_ALIAS_FLAG）;
thumbnailPaint.setARGB（255，200，200，200）;
thumbnailPaint.setStyle（Paint.Style.FILL）;
}
I have started work on an my first android application and have the basis of an application that handles an image with multiple layers. I am able to export a flat version of the project file as a PNG but I would like to be able to save the layered image for later editing (including any options applied to certain layers, such as text based layers).
Anyway, I have ensured that the classes that need to be written to a file are 'Serializable' but have run into a bit of a road block caused by the fact that android.graphics.Bitmap isn't serializable. The following code essentially outputs the Bitmap as a PNG into a ByteArray and should read it back in as part of 'readObject'. However, when the code runs - I can verify that the 'imageByteArrayLength' variable that is read in is the same as that which is output - but the 'Bitmap image' is always null.
Any help would be greatly appreciated. Thanks for reading.
private String title;
private int width;
private int height;
private Bitmap sourceImage;
private Canvas sourceCanvas;
private Bitmap currentImage;
private Canvas currentCanvas;
private Paint currentPaint;
private void writeObject(ObjectOutputStream out) throws IOException{
out.writeObject(title);
out.writeInt(width);
out.writeInt(height);
ByteArrayOutputStream stream = new ByteArrayOutputStream();
currentImage.compress(Bitmap.CompressFormat.PNG, 100, stream);
byte[] imageByteArray = stream.toByteArray();
int length = imageByteArray.length;
out.writeInt(length);
out.write(imageByteArray);
}
private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException{
this.title = (String)in.readObject();
this.width = in.readInt();
this.height = in.readInt();
int imageByteArrayLength = in.readInt();
byte[] imageByteArray = new byte[imageByteArrayLength];
in.read(imageByteArray, 0, imageByteArrayLength);
BitmapFactory.Options opt = new BitmapFactory.Options();
opt.inPreferredConfig = Bitmap.Config.ARGB_8888;
Bitmap image = BitmapFactory.decodeByteArray(imageByteArray, 0, imageByteArrayLength, opt);
sourceImage = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
currentImage = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
sourceCanvas = new Canvas(sourceImage);
currentCanvas = new Canvas(currentImage);
currentPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
if ( image != null ) {
sourceCanvas.drawBitmap(image, 0, 0, currentPaint);
}
}
It took a while, but I have found a clean solution to this problem. I produced a custom object (BitmapDataObject) that implements Serializable and has a byte[] to store the PNG data from the original Bitmap. Using this, the data is stored correctly in the ObjectOutputStream / ObjectInputStream - which effectively allows one to Serialize and Deserialize a Bitmap object by storing it as a PNG in a byte[] in a custom object. The code below resolves my query.
private String title;
private int sourceWidth, currentWidth;
private int sourceHeight, currentHeight;
private Bitmap sourceImage;
private Canvas sourceCanvas;
private Bitmap currentImage;
private Canvas currentCanvas;
private Paint currentPaint;
protected class BitmapDataObject implements Serializable {
private static final long serialVersionUID = 111696345129311948L;
public byte[] imageByteArray;
}
/** Included for serialization - write this layer to the output stream. */
private void writeObject(ObjectOutputStream out) throws IOException{
out.writeObject(title);
out.writeInt(currentWidth);
out.writeInt(currentHeight);
ByteArrayOutputStream stream = new ByteArrayOutputStream();
currentImage.compress(Bitmap.CompressFormat.PNG, 100, stream);
BitmapDataObject bitmapDataObject = new BitmapDataObject();
bitmapDataObject.imageByteArray = stream.toByteArray();
out.writeObject(bitmapDataObject);
}
/** Included for serialization - read this object from the supplied input stream. */
private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException{
title = (String)in.readObject();
sourceWidth = currentWidth = in.readInt();
sourceHeight = currentHeight = in.readInt();
BitmapDataObject bitmapDataObject = (BitmapDataObject)in.readObject();
Bitmap image = BitmapFactory.decodeByteArray(bitmapDataObject.imageByteArray, 0, bitmapDataObject.imageByteArray.length);
sourceImage = Bitmap.createBitmap(sourceWidth, sourceHeight, Bitmap.Config.ARGB_8888);
currentImage = Bitmap.createBitmap(sourceWidth, sourceHeight, Bitmap.Config.ARGB_8888);
sourceCanvas = new Canvas(sourceImage);
currentCanvas = new Canvas(currentImage);
currentPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
thumbnailPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
thumbnailPaint.setARGB(255, 200, 200, 200);
thumbnailPaint.setStyle(Paint.Style.FILL);
}
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