Fragment 中的 Android AR

Question

我一直在尝试让一些 AR(增强现实)SDK 在 Fragment 中运行。但是，我似乎无法让它工作。

我找到了一些让 Metaio(AR 框架)在 fragment 中工作的人的代码。

所以我将该代码应用到我自己的项目中，它可以正常工作，但代码没有被编程为扫描图片。我想用它扫描图片标记。

我从Metaio的示例项目中复制了一些代码来扫描图片标记，但是它不起作用。

现在它失败了(之后的调试日志没有被记录):

trackingConfigFile = AssetsManager.getAssetPath(getActivity().getApplicationContext(), "AEDApp/Assets/TrackingData_PictureMarker.xml");

---

这是我的完整代码:

package com.example.bt6_aedapp;

import android.app.Application;
import android.content.res.Configuration;
import android.hardware.Camera.CameraInfo;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import com.metaio.cloud.plugin.MetaioCloudPlugin;
import com.metaio.sdk.MetaioDebug;
import com.metaio.sdk.MetaioSurfaceView;
import com.metaio.sdk.SensorsComponentAndroid;
import com.metaio.sdk.jni.ERENDER_SYSTEM;
import com.metaio.sdk.jni.ESCREEN_ROTATION;
import com.metaio.sdk.jni.IGeometry;
import com.metaio.sdk.jni.IMetaioSDKAndroid;
import com.metaio.sdk.jni.IMetaioSDKCallback;
import com.metaio.sdk.jni.MetaioSDK;
import com.metaio.sdk.jni.TrackingValuesVector;
import com.metaio.sdk.jni.Vector3d;
import com.metaio.tools.Screen;
import com.metaio.tools.SystemInfo;
import com.metaio.tools.io.AssetsManager;

public class fragmentA extends Fragment implements MetaioSurfaceView.Callback {

    private Application mAppContext;

    private ViewGroup mRootLayout;

    String trackingConfigFile;

    private MetaioSDKCallbackHandler mCallback;

    private IGeometry mModel;

    private IMetaioSDKAndroid mMetaioSDK;

    private MetaioSurfaceView mSurfaceView;

    private static boolean mNativeLibsLoaded = false;

    private boolean mRendererInitialized;

    private SensorsComponentAndroid mSensors;

    static {
        mNativeLibsLoaded = IMetaioSDKAndroid.loadNativeLibs();
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {

        MetaioCloudPlugin.startJunaio(null, getActivity().getApplicationContext());

        super.onCreate(savedInstanceState);
        Log.d("LifeCycle", "onCreate");

        mAppContext = getActivity().getApplication();
        mMetaioSDK = null;
        mSurfaceView = null;
        mRendererInitialized = false;
        try {

            mCallback = new MetaioSDKCallbackHandler();

            if (!mNativeLibsLoaded){
                throw new Exception("Unsupported platform, failed to load the native libs");
            }

            // Create sensors component
            mSensors = new SensorsComponentAndroid(mAppContext);

            // Create Unifeye Mobile by passing Activity instance and
            // application signature
            mMetaioSDK = MetaioSDK.CreateMetaioSDKAndroid(getActivity(), getResources().getString(R.string.metaioSDKSignature));
            mMetaioSDK.registerSensorsComponent(mSensors);

        } catch (Throwable e) {
            MetaioDebug.log(Log.ERROR, "ArCameraFragment.onCreate: failed to create or intialize metaio SDK: " + e.getMessage());
            return;
        }
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        Log.d("LifeCycle", "onCreateView");
        View view = inflater.inflate(R.layout.fragment_a, container, false);
        mRootLayout = (ViewGroup)getActivity().findViewById(R.id.pager);
        return view;
    }

    @Override
    public void onStart() {
        super.onStart();
        Log.d("LifeCycle", "onStart");

        if(mMetaioSDK == null){
            return;
        }
        MetaioDebug.log("ArCameraFragment.onStart()");

        try {
            mSurfaceView = null;

            // Start camera
            startCamera();

            // Add Unifeye GL Surface view
            mSurfaceView = new MetaioSurfaceView(mAppContext);
            mSurfaceView.registerCallback(this);
            mSurfaceView.setKeepScreenOn(true);

            MetaioDebug.log("ArCameraFragment.onStart: addContentView(mMetaioSurfaceView)");
            mRootLayout.addView(mSurfaceView, new ViewGroup.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT,
                    ViewGroup.LayoutParams.WRAP_CONTENT));
            mSurfaceView.setZOrderMediaOverlay(true);

        } catch (Exception e) {
            MetaioDebug.log(Log.ERROR, "Error creating views: " + e.getMessage());
            MetaioDebug.printStackTrace(Log.ERROR, e);
        }
    }

    @Override
    public void onResume() {
        super.onResume();
        Log.d("LifeCycle", "onResume");

        // make sure to resume the OpenGL surface
        if (mSurfaceView != null) {
            mSurfaceView.onResume();
        }

        if(mMetaioSDK != null){
            mMetaioSDK.resume();
        }
    }

    @Override
    public void onPause() {
        super.onPause();

        Log.d("LifeCycle", "onPause");

        // pause the OpenGL surface
        if (mSurfaceView != null) {
            mSurfaceView.onPause();
        }

        if (mMetaioSDK != null) {
            // Disable the camera
            mMetaioSDK.pause();
        }

    }

    @Override
    public void onStop() {
        super.onStop();

        Log.d("LifeCycle", "onStop");

        if (mMetaioSDK != null) {
            // Disable the camera
            mMetaioSDK.stopCamera();
        }

        if (mSurfaceView != null) {
            mRootLayout.removeView(mSurfaceView);
        }

        System.runFinalization();
        System.gc();
    }

    @Override
    public void onDestroy() {
        super.onDestroy();

        mCallback.delete();
        mCallback = null;

        /*Log.d("LifeCycle", "onDestroy");

        try {
            mRendererInitialized = false;
        } catch (Exception e) {
            MetaioDebug.printStackTrace(Log.ERROR, e);
        }

        MetaioDebug.log("ArCameraFragment.onDestroy");

        if (mMetaioSDK != null) {
            mMetaioSDK.delete();
            mMetaioSDK = null;
        }

        MetaioDebug.log("ArCameraFragment.onDestroy releasing sensors");
        if (mSensors != null) {
            mSensors.registerCallback(null);
            mSensors.release();
            mSensors.delete();
            mSensors = null;
        }

        // Memory.unbindViews(activity.findViewById(android.R.id.content));

        System.runFinalization();
        System.gc();*/
    }

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        final ESCREEN_ROTATION rotation = Screen.getRotation(getActivity());
        mMetaioSDK.setScreenRotation(rotation);
        MetaioDebug.log("onConfigurationChanged: " + rotation);
    }

    @Override
    public void onDrawFrame() {     

        if(mMetaioSDK != null) {
            TrackingValuesVector poses = mMetaioSDK.getTrackingValues();

            if(poses.size() != 0) {
                mModel.setCoordinateSystemID(poses.get(0).getCoordinateSystemID());
            }
        }

//      Log.d("LifeCycle", "onDrawFrame");
        /* if (mRendererInitialized) {
            mMetaioSDK.render();
        } */
    }

    @Override
    public void onSurfaceCreated() {
        Log.d("LifeCycle", "onSurfaceCreated");

        try {
            if (!mRendererInitialized) {
                mMetaioSDK.initializeRenderer(mSurfaceView.getWidth(), mSurfaceView.getHeight(), Screen.getRotation(getActivity()),
                        ERENDER_SYSTEM.ERENDER_SYSTEM_OPENGL_ES_2_0);
                mRendererInitialized = true;
            } else {
                MetaioDebug.log("ArCameraFragment.onSurfaceCreated: Reloading textures...");
                mMetaioSDK.reloadTextures();
            }

            MetaioDebug.log("ArCameraFragment.onSurfaceCreated: Registering audio renderer...");
            // mMetaioSDK.registerAudioCallback(mSurfaceView.getAudioRenderer());
            mMetaioSDK.registerCallback(mCallback);

            MetaioDebug.log("ARViewActivity.onSurfaceCreated");
        } catch (Exception e) {
            MetaioDebug.log(Log.ERROR, "ArCameraFragment.onSurfaceCreated: " + e.getMessage());
        }

        mSurfaceView.queueEvent(new Runnable() {
            @Override
            public void run() {
                loadContents();
            }
        });

    }

    private void loadContents() {
        try {       
            trackingConfigFile = AssetsManager.getAssetPath(getActivity().getApplicationContext(), "AEDApp/Assets/TrackingData_PictureMarker.xml");

            boolean result = mMetaioSDK.setTrackingConfiguration(trackingConfigFile);

            Log.d("result", Boolean.toString(result));

            MetaioDebug.log("Tracking data loaded: " + result);

            String aedLogo = AssetsManager.getAssetPath(getActivity().getApplicationContext(), "AEDApp/Assets/metaioman.md2");
            Log.d("aedLogo", "aaa: " + aedLogo);
            if(aedLogo != null) {
                mModel = mMetaioSDK.createGeometry(aedLogo);

                if(mModel != null) {
                    mModel.setScale(new Vector3d(4.0f, 4.0f, 4.0f));
                }
                else {
                    MetaioDebug.log(Log.ERROR, "Error loading geometry: " + aedLogo);
                }               
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    @Override
    public void onSurfaceChanged(int width, int height) {
        Log.d("LifeCycle", "onSurfaceChanged");

        mMetaioSDK.resizeRenderer(width, height);
    }

    @Override
    public void onSurfaceDestroyed() {
        Log.d("LifeCycle", "onSurfaceDestroyed");

        MetaioDebug.log("ArCameraFragment.onSurfaceDestroyed(){");
        mSurfaceView = null;
        // mMetaioSDK.registerAudioCallback(null);
    }

    protected void startCamera() {
        final int cameraIndex = SystemInfo.getCameraIndex(CameraInfo.CAMERA_FACING_BACK);
        if (mMetaioSDK != null) {
            mMetaioSDK.startCamera(cameraIndex, 640, 480);
        }
    }

    final class MetaioSDKCallbackHandler extends IMetaioSDKCallback {
        @Override
        public void onTrackingEvent(final TrackingValuesVector trackingValues) {

            super.onTrackingEvent(trackingValues);
            if(!trackingValues.isEmpty() && trackingValues.get(0).isTrackingState()){
                Log.d("Track", "NOT EMPTY");
            }
        }
    }   
}

我真的希望有人能帮我解决这个问题，因为我想不通..:(

---

编辑

抛出的错误 (e.printStackTrace()) 是:

03-24 20:25:19.068: W/System.err(28062): java.lang.NullPointerException: null string

03-24 20:25:19.068: W/System.err(28062):    at com.metaio.sdk.jni.MetaioSDKJNI.IMetaioSDK_setTrackingConfiguration__SWIG_1(Native Method)

03-24 20:25:19.068: W/System.err(28062):    at com.metaio.sdk.jni.IMetaioSDK.setTrackingConfiguration(IMetaioSDK.java:106)

03-24 20:25:19.068: W/System.err(28062):    at com.example.bt6_aedapp.fragmentA.loadContents(fragmentA.java:278)

03-24 20:25:19.068: W/System.err(28062):    at com.example.bt6_aedapp.fragmentA.access$0(fragmentA.java:274)

03-24 20:25:19.068: W/System.err(28062):    at com.example.bt6_aedapp.fragmentA$1.run(fragmentA.java:268)

03-24 20:25:19.068: W/System.err(28062):    at android.opengl.GLSurfaceView$GLThread.guardedRun(GLSurfaceView.java:1463)

03-24 20:25:19.068: W/System.err(28062):    at android.opengl.GLSurfaceView$GLThread.run(GLSurfaceView.java:1240)

我想用它做什么:

能够“扫描”图片 ( https://encrypted-tbn2.gstatic.com/images?q=tbn:ANd9GcQFqKIurD3QMU0zVeiwEhtm1twLmTCDlnFulfCwDkxTA1_XQjIQ ) 并在应用程序中检测图像。该图像在项目的 Assets 文件夹中的应用程序中被引用，我制作了一个 xml 文件，其中它的标记被定义为 Metaio 网站上的说明。检测之后，我将做一些数据库工作，但现在我需要让检测部分正常工作。

编辑如果有人知道我如何在 Fragments 中制作另一个 AR 框架，我很想知道。

Answer 1

我对 fragment 知之甚少，但至于空字符串，我认为这是因为您还没有提取 Assets 。

在此视频中 http://youtu.be/KVtCi-WwmFU?t=30m29s它的解释。基本上你要做的就是添加这段代码

private class AssetsExtracter extends AsyncTask<Integer, Integer, Boolean>{
    @Override
    protected Boolean doInBackground(Integer... params){
        try 
        {
            AssetsManager.extractAllAssets(getApplicationContext(), BuildConfig.DEBUG);
        }catch (IOException e){
            MetaioDebug.printStackTrace(Log.ERROR, e);
            return false;
        }
        return true;
    }
}

到您的 Activity (或者在这种情况下，我猜是您的 fragment )。然后你必须添加这个类的一个字段，比如

private AssetsExtracter mTask;

在你放置的 onCreate() 方法中

mTask = new AssetsExtracter();
mTask.execute(0);

之后您的 Assets 应该可以从 AssetsManager.getAssetPath(..) 获得，并且它不应再返回空字符串。