java - 返回数据类型不匹配

Question

我在重新指定返回数据类型时遇到问题。我有FOComp实现 callabale 的类，'FOComp' 的 call() 方法返回数据类型 List<ArrayList<Mat>>如下面“FOComp”类的代码所示。

并且方法“getResults()”返回 ArrayList<Mat> 类型的数据如下面的代码所示。目前，在运行时，当我执行代码时，我收到以下错误:

该行有多个标记

• 返回类型与 Callable<ArrayList<Mat>>.call() 不兼容
• 返回类型与 Callable<List<Mat>>.call() 不兼容

请让我知道如何修复它。

“FOComp”类:

    static class FOComp implements Callable<List<Mat>> {//should return list contains 4 mats(0,45,90,135)

    private ArrayList<Mat> gaussianMatList = null;
    private List<ArrayList<Mat>> results_4OrientAngles_List = null;

    public FOComp(ArrayList<Mat> gaussianMatList) {
        // TODO Auto-generated constructor stub
        this.gaussianMatList = gaussianMatList;
        this.results_4OrientAngles_List = new ArrayList<ArrayList<Mat>>();
    }
    public List<ArrayList<Mat>> call() throws Exception {
        // TODO Auto-generated method stub
        try {
            featOrient = new FeatOrientation(this.gaussianMatList);
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (ExecutionException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        try {
            featOrient.start();
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (ExecutionException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        this.results_4OrientAngles_List.add(featOrient.getResults());

        return results_4OrientAngles_List;
    }
}

'getResults':

public ArrayList<Mat> getResults() {
    if (this.crossAddOrientMapsList != null) {
        if (!this.crossAddOrientMapsList.isEmpty()) {

            if (this.crossAddOrientMapsList.size() == 4) {
                double[] theta = new double[4];

                theta[0] = 0;
                theta[1] = 45;
                theta[2] = 90;
                theta[3] = 135;

                for (int i = 0; i < this.crossAddOrientMapsList.size(); i++) {
                    MatFactory.writeMat(FilePathUtils.newOutputPath("FinalCrossAdd_" + theta[i]+"_degs"), this.crossAddOrientMapsList.get(i));
                    //ImageUtils.showMat(this.crossAddOrientMapsList.get(i), "OrientMap_" + theta[i] + " degs");
                }

                return this.crossAddOrientMapsList;

            } else {

                Log.WTF(TAG, "getResults", "crossAddOrientMapsList != 4 !!");
                return null;
            }

        } else {
            Log.E(TAG, "getResults", "crossAddOrientMapsList is empty.");
            return null;
        }
    } else {
        Log.E(TAG, "getResults", "crossAddOrientMapsList is null");
        return null;
    }
}

Answer 1

class FOComp implements Callable<List<Mat>>

和

public List<ArrayList<Mat>> call()

并不真正兼容...您的call()方法应该是

@Override public List<Mat> call()

此外，最好避免在方法签名中使用实现类，而是使用接口(interface)(在本例中，使用 List 而不是 ArrayList)。这也将解决您的“多个标记”之一的问题:-)

干杯，