Question

我正在尝试从json文件中读取内容，以便通过处理创建视觉图像。到目前为止，我的代码是：

ldconfig

stoke []是一个浮点数组，它将控制笔触的颜色。我解析的json文件是

public void generateShape(JSONObject file) {
    //convert file to json object
    JSONArray shapes = (JSONArray) file.get("shapes");
    for (Object o : shapes) {
        JSONObject json_shape = (JSONObject)o;
        //getting shape id and function so we know which shapes to create
        id = ((Number) json_shape.get("id")).intValue();
        func = ((Number) json_shape.get("func")).intValue();
        animate = ((Number) json_shape.get("animate")).intValue();
        stroke_weight = ((Number) json_shape.get("stroke_weight")).floatValue();

        JSONArray strokes = (JSONArray) json_shape.get("stroke");
        Iterator<Float> iterator = strokes.iterator();
        index = 0;
        while(iterator.hasNext())
        {
            stroke[index] = ((Number)iterator.next()).floatValue();
            index++;

        }

我在一行中得到错误：

{
   "shapes": [
{
  "id":0,
  "func":1,
  "stroke":[143,50,200],
  "stroke_weight": 70,
  "animate": 1,
  "jelly_func": 5,
  "points":[268,330,400,333,74,210,90,300]

  }

  ]
}

我正在使用json.simple库，而我所看到的所有解决方案都是针对org.json库的

我可以对笔触数组中的值进行硬编码，但我想尝试迭代。有任何提示/指导吗？

完整堆栈跟踪为

     stroke[index] = ((Number)iterator.next()).floatValue();

其中草图是：

java.lang.NullPointerException
at ImageLoader.generateShape(ImageLoader.java:35)
at Sketch.setup(Sketch.java:48)
at processing.core.PApplet.handleDraw(PApplet.java:2404)
at processing.awt.PSurfaceAWT$12.callDraw(PSurfaceAWT.java:1557)
at processing.core.PSurfaceNone$AnimationThread.run(PSurfaceNone.java:313)

eta：好的，因此删除导致异常的行，并检查是否甚至读取了我的json值，我可以在将它们打印到控制台时确认所解析的值是正确的。我现在需要将它们放在一个数组中

Answer 1

我仍然认为您没有正确初始化数组...您可以尝试这段代码，看看它是否有效吗？

public void generateShape(JSONObject file) {
    // convert file to json object
    JSONArray shapes = (JSONArray) file.get("shapes");
    for (Object o : shapes) {
        JSONObject json_shape = (JSONObject) o;
        // getting shape id and function so we know which shapes to create
        int id = ((Number) json_shape.get("id")).intValue();
        int func = ((Number) json_shape.get("func")).intValue();
        int animate = ((Number) json_shape.get("animate")).intValue();
        float stroke_weight = ((Number) json_shape.get("stroke_weight")).floatValue();

        JSONArray strokes = (JSONArray) json_shape.get("stroke");
        Iterator<Float> iterator = strokes.iterator();
        int index = 0;
        float[] stroke = new float[strokes.size()];
        while (iterator.hasNext()) {
            stroke[index] = ((Number) iterator.next()).floatValue();
            index++;

        }
    }
}

尝试从JSON文件读取时不断获取java.lang.NullPointerException

1 个答案: