如何序列化 android.graphics.Path 的对象 [英] how to serialize an object of android.graphics.Path

问题描述

我正在尝试将 Android.graphics.Path 的对象存储在内部设备内存中.有谁知道如何序列化一个 android.graphics.Path 对象?而且，还有其他方法可以存储 Path 对象吗?谢谢.

I'm trying to store objects of Android.graphics.Path in internal device memory. Does anyone know how to serialize a android.graphics.Path object? And also, is there any other way of storing a Path object? Thanks.

推荐答案

我这样做的方法是从原始 Path 类中识别出我需要的方法，然后简单地覆盖这些方法，如下所示:

The way I did it is to identify the methods that I needed from the original Path class and then simply override those methods as follows:

public class CustomPath extends Path implements Serializable {

private static final long serialVersionUID = -5974912367682897467L;

private ArrayList<PathAction> actions = new ArrayList<CustomPath.PathAction>();

private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException{
    in.defaultReadObject();
    drawThisPath();
}

@Override
public void moveTo(float x, float y) {
    actions.add(new ActionMove(x, y));
    super.moveTo(x, y);
}

@Override
public void lineTo(float x, float y){
    actions.add(new ActionLine(x, y));
    super.lineTo(x, y);
}

private void drawThisPath(){
    for(PathAction p : actions){
        if(p.getType().equals(PathActionType.MOVE_TO)){
            super.moveTo(p.getX(), p.getY());
        } else if(p.getType().equals(PathActionType.LINE_TO)){
            super.lineTo(p.getX(), p.getY());
        }
    }
}

public interface PathAction {
    public enum PathActionType {LINE_TO,MOVE_TO};
    public PathActionType getType();
    public float getX();
    public float getY();
}

public class ActionMove implements PathAction, Serializable{
    private static final long serialVersionUID = -7198142191254133295L;

    private float x,y;

    public ActionMove(float x, float y){
        this.x = x;
        this.y = y;
    }

    @Override
    public PathActionType getType() {
        return PathActionType.MOVE_TO;
    }

    @Override
    public float getX() {
        return x;
    }

    @Override
    public float getY() {
        return y;
    }

}

public class ActionLine implements PathAction, Serializable{
    private static final long serialVersionUID = 8307137961494172589L;

    private float x,y;

    public ActionLine(float x, float y){
        this.x = x;
        this.y = y;
    }

    @Override
    public PathActionType getType() {
        return PathActionType.LINE_TO;
    }

    @Override
    public float getX() {
        return x;
    }

    @Override
    public float getY() {
        return y;
    }

}
}

在我的示例中，我需要moveTo"和lineTo"，因此在这种情况下，我只需将绘图信息保存在列表中.此列表包含 Path 所需的绘图信息(我称之为操作")，以便将绘图恢复为对象序列化之前的样子.然后，当我反序列化 CustomPath 类型的对象时，我确保让 默认序列化协议调用drawThisPath"，所以路径被重绘.

In my example I need "moveTo" and "lineTo", so in this case I simply hold the drawing information in a list. This list contains the drawing information (what I call "action") needed by Path in order to restore the drawing as it looked like before the object was serialized. Then when I deserialize my objects of type CustomPath i make sure to let the default serialization protocol call "drawThisPath", so the path is redrawn.

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