日食+；Linux+；OpenCV+；Android--java.lang.RuntimeException

当我试图使用opencv4android改变android摄像头（Linux操作系统）的分辨率时，我遇到了这个问题

java.lang.RuntimeException: Unable to start activity ComponentInfo{org.opencv.samples.tutorial2/org.opencv.samples.tutorial2.Tutorial2Activity}: java.lang.NullPointerException

活动源代码为：

package org.opencv.samples.tutorial2;

import org.opencv.android.BaseLoaderCallback;
import org.opencv.android.CameraBridgeViewBase.CvCameraViewFrame;
import org.opencv.android.LoaderCallbackInterface;
import org.opencv.android.OpenCVLoader;
import org.opencv.core.CvType;
import org.opencv.core.Mat;
import org.opencv.android.CameraBridgeViewBase;
import org.opencv.android.CameraBridgeViewBase.CvCameraViewListener2;


import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.WindowManager;

public class Tutorial2Activity extends Activity implements CvCameraViewListener2 {
    private static final String    TAG = "OCVSample::Activity";

    private Mat                   mRgba;
    private Mat                    mIntermediateMat;


    private CameraBridgeViewBase mOpenCvCameraView;
    private Tutorial2View mOpenCvCameraView1;

    private BaseLoaderCallback  mLoaderCallback = new BaseLoaderCallback(this) {
        @Override
        public void onManagerConnected(int status) {
            switch (status) {
                case LoaderCallbackInterface.SUCCESS:
                {
                    Log.i(TAG, "OpenCV loaded successfully");

                    // Load native library after(!) OpenCV initialization
                    System.loadLibrary("mixed_sample"); 
                    mOpenCvCameraView.enableView();

                } break;
                default:
                {
                    super.onManagerConnected(status);
                } break;
            }
        }
    };

    public Tutorial2Activity() {
        Log.i(TAG, "Instantiated new " + this.getClass());
    }

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        Log.i(TAG, "called onCreate");
        super.onCreate(savedInstanceState);
        getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);


        setContentView(R.layout.tutorial2_surface_view);



        mOpenCvCameraView = (CameraBridgeViewBase) findViewById(R.id.tutorial2_activity_surface_view);
        //mOpenCvCameraView.setMaxFrameSize(1920, 1080);
        mOpenCvCameraView.setCvCameraViewListener(this);
        mOpenCvCameraView1.setResolution(1920, 1080);



    }



    @Override
    public void onPause()
    {
        super.onPause();
        if (mOpenCvCameraView != null)
            mOpenCvCameraView.disableView();
    }

    @Override
    public void onResume()
    {
        super.onResume();
        OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_2_4_3, this, mLoaderCallback);
    }

    public void onDestroy() {
        super.onDestroy();
        if (mOpenCvCameraView != null)
            mOpenCvCameraView.disableView();
    }

    public void onCameraViewStarted(int width, int height) {
        mRgba = new Mat(height, width, CvType.CV_8UC4);
        mIntermediateMat = new Mat(height, width, CvType.CV_8UC4);
    }

    public void onCameraViewStopped() {
        mRgba.release();
        mIntermediateMat.release();
    }

    public Mat onCameraFrame(CvCameraViewFrame inputFrame) {

            mRgba = inputFrame.rgba();
        return mRgba;
    }
}

# This file is automatically generated by Android Tools.
# Do not modify this file -- YOUR CHANGES WILL BE ERASED!
#
# This file must be checked in Version Control Systems.
#
# To customize properties used by the Ant build system edit
# "ant.properties", and override values to adapt the script to your
# project structure.
#
# To enable ProGuard to shrink and obfuscate your code, uncomment this (available properties: sdk.dir, user.home):
#proguard.config=${sdk.dir}/tools/proguard/proguard-android.txt:proguard-project.txt

android.library.reference.1=../../sdk/java
# Project target.
target=android-19

04-18 22:30:47.422: E/AndroidRuntime(12540): FATAL EXCEPTION: main
04-18 22:30:47.422: E/AndroidRuntime(12540): Process: org.opencv.samples.tutorial2, PID: 12540
04-18 22:30:47.422: E/AndroidRuntime(12540): java.lang.RuntimeException: Unable to start activity ComponentInfo{org.opencv.samples.tutorial2/org.opencv.samples.tutorial2.Tutorial2Activity}: java.lang.NullPointerException
04-18 22:30:47.422: E/AndroidRuntime(12540):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2202)
04-18 22:30:47.422: E/AndroidRuntime(12540):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2252)
04-18 22:30:47.422: E/AndroidRuntime(12540):    at android.app.ActivityThread.access$800(ActivityThread.java:139)
04-18 22:30:47.422: E/AndroidRuntime(12540):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1200)
04-18 22:30:47.422: E/AndroidRuntime(12540):    at android.os.Handler.dispatchMessage(Handler.java:102)
04-18 22:30:47.422: E/AndroidRuntime(12540):    at android.os.Looper.loop(Looper.java:136)
04-18 22:30:47.422: E/AndroidRuntime(12540):    at android.app.ActivityThread.main(ActivityThread.java:5103)
04-18 22:30:47.422: E/AndroidRuntime(12540):    at java.lang.reflect.Method.invokeNative(Native Method)
04-18 22:30:47.422: E/AndroidRuntime(12540):    at java.lang.reflect.Method.invoke(Method.java:515)
04-18 22:30:47.422: E/AndroidRuntime(12540):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:790)
04-18 22:30:47.422: E/AndroidRuntime(12540):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:606)
04-18 22:30:47.422: E/AndroidRuntime(12540):    at dalvik.system.NativeStart.main(Native Method)
04-18 22:30:47.422: E/AndroidRuntime(12540): Caused by: java.lang.NullPointerException
04-18 22:30:47.422: E/AndroidRuntime(12540):    at org.opencv.samples.tutorial2.Tutorial2Activity.onCreate(Tutorial2Activity.java:68)
04-18 22:30:47.422: E/AndroidRuntime(12540):    at android.app.Activity.performCreate(Activity.java:5275)
04-18 22:30:47.422: E/AndroidRuntime(12540):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
04-18 22:30:47.422: E/AndroidRuntime(12540):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2166)
04-18 22:30:47.422: E/AndroidRuntime(12540):    ... 11 more

AndroidManifest.xml

<manifest package="org.opencv.samples.tutorial2" android:versionCode="21" android:versionName="2.1"><application android:label="@string/app_name" android:icon="@drawable/icon" android:theme="@android:style/Theme.NoTitleBar.Fullscreen"><activity android:name="Tutorial2Activity" android:label="@string/app_name" android:screenOrientation="landscape" android:configChanges="keyboardHidden|orientation"><intent-filter><action android:name="android.intent.action.MAIN"/><category android:name="android.intent.category.LAUNCHER"/></intent-filter></activity></application><supports-screens android:resizeable="true" android:smallScreens="true" android:normalScreens="true" android:largeScreens="true" android:anyDensity="true"/><uses-sdk android:minSdkVersion="8"/><uses-permission android:name="android.permission.CAMERA"/><uses-feature android:name="android.hardware.camera" android:required="false"/><uses-feature android:name="android.hardware.camera.autofocus" android:required="false"/><uses-feature android:name="android.hardware.camera.front" android:required="false"/><uses-feature android:name="android.hardware.camera.front.autofocus" android:required="false"/></manifest>

问题是：

package org.opencv.samples.tutorial2;

import org.opencv.android.BaseLoaderCallback;
import org.opencv.android.CameraBridgeViewBase.CvCameraViewFrame;
import org.opencv.android.LoaderCallbackInterface;
import org.opencv.android.OpenCVLoader;
import org.opencv.core.CvType;
import org.opencv.core.Mat;
import org.opencv.android.CameraBridgeViewBase;
import org.opencv.android.CameraBridgeViewBase.CvCameraViewListener2;


import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.WindowManager;

public class Tutorial2Activity extends Activity implements CvCameraViewListener2 {
    private static final String    TAG = "OCVSample::Activity";

    private Mat                   mRgba;
    private Mat                    mIntermediateMat;


    private CameraBridgeViewBase mOpenCvCameraView;
    private Tutorial2View mOpenCvCameraView1;

    private BaseLoaderCallback  mLoaderCallback = new BaseLoaderCallback(this) {
        @Override
        public void onManagerConnected(int status) {
            switch (status) {
                case LoaderCallbackInterface.SUCCESS:
                {
                    Log.i(TAG, "OpenCV loaded successfully");

                    // Load native library after(!) OpenCV initialization
                    System.loadLibrary("mixed_sample"); 
                    mOpenCvCameraView.enableView();

                } break;
                default:
                {
                    super.onManagerConnected(status);
                } break;
            }
        }
    };

    public Tutorial2Activity() {
        Log.i(TAG, "Instantiated new " + this.getClass());
    }

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        Log.i(TAG, "called onCreate");
        super.onCreate(savedInstanceState);
        getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);


        setContentView(R.layout.tutorial2_surface_view);



        mOpenCvCameraView = (CameraBridgeViewBase) findViewById(R.id.tutorial2_activity_surface_view);
        //mOpenCvCameraView.setMaxFrameSize(1920, 1080);
        mOpenCvCameraView.setCvCameraViewListener(this);
        mOpenCvCameraView1.setResolution(1920, 1080);



    }



    @Override
    public void onPause()
    {
        super.onPause();
        if (mOpenCvCameraView != null)
            mOpenCvCameraView.disableView();
    }

    @Override
    public void onResume()
    {
        super.onResume();
        OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_2_4_3, this, mLoaderCallback);
    }

    public void onDestroy() {
        super.onDestroy();
        if (mOpenCvCameraView != null)
            mOpenCvCameraView.disableView();
    }

    public void onCameraViewStarted(int width, int height) {
        mRgba = new Mat(height, width, CvType.CV_8UC4);
        mIntermediateMat = new Mat(height, width, CvType.CV_8UC4);
    }

    public void onCameraViewStopped() {
        mRgba.release();
        mIntermediateMat.release();
    }

    public Mat onCameraFrame(CvCameraViewFrame inputFrame) {

            mRgba = inputFrame.rgba();
        return mRgba;
    }
}

# This file is automatically generated by Android Tools.
# Do not modify this file -- YOUR CHANGES WILL BE ERASED!
#
# This file must be checked in Version Control Systems.
#
# To customize properties used by the Ant build system edit
# "ant.properties", and override values to adapt the script to your
# project structure.
#
# To enable ProGuard to shrink and obfuscate your code, uncomment this (available properties: sdk.dir, user.home):
#proguard.config=${sdk.dir}/tools/proguard/proguard-android.txt:proguard-project.txt

android.library.reference.1=../../sdk/java
# Project target.
target=android-19

04-18 22:30:47.422: E/AndroidRuntime(12540): FATAL EXCEPTION: main
04-18 22:30:47.422: E/AndroidRuntime(12540): Process: org.opencv.samples.tutorial2, PID: 12540
04-18 22:30:47.422: E/AndroidRuntime(12540): java.lang.RuntimeException: Unable to start activity ComponentInfo{org.opencv.samples.tutorial2/org.opencv.samples.tutorial2.Tutorial2Activity}: java.lang.NullPointerException
04-18 22:30:47.422: E/AndroidRuntime(12540):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2202)
04-18 22:30:47.422: E/AndroidRuntime(12540):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2252)
04-18 22:30:47.422: E/AndroidRuntime(12540):    at android.app.ActivityThread.access$800(ActivityThread.java:139)
04-18 22:30:47.422: E/AndroidRuntime(12540):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1200)
04-18 22:30:47.422: E/AndroidRuntime(12540):    at android.os.Handler.dispatchMessage(Handler.java:102)
04-18 22:30:47.422: E/AndroidRuntime(12540):    at android.os.Looper.loop(Looper.java:136)
04-18 22:30:47.422: E/AndroidRuntime(12540):    at android.app.ActivityThread.main(ActivityThread.java:5103)
04-18 22:30:47.422: E/AndroidRuntime(12540):    at java.lang.reflect.Method.invokeNative(Native Method)
04-18 22:30:47.422: E/AndroidRuntime(12540):    at java.lang.reflect.Method.invoke(Method.java:515)
04-18 22:30:47.422: E/AndroidRuntime(12540):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:790)
04-18 22:30:47.422: E/AndroidRuntime(12540):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:606)
04-18 22:30:47.422: E/AndroidRuntime(12540):    at dalvik.system.NativeStart.main(Native Method)
04-18 22:30:47.422: E/AndroidRuntime(12540): Caused by: java.lang.NullPointerException
04-18 22:30:47.422: E/AndroidRuntime(12540):    at org.opencv.samples.tutorial2.Tutorial2Activity.onCreate(Tutorial2Activity.java:68)
04-18 22:30:47.422: E/AndroidRuntime(12540):    at android.app.Activity.performCreate(Activity.java:5275)
04-18 22:30:47.422: E/AndroidRuntime(12540):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
04-18 22:30:47.422: E/AndroidRuntime(12540):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2166)
04-18 22:30:47.422: E/AndroidRuntime(12540):    ... 11 more

请提供一些帮助。谢谢。

排印第68行：

mOpenCvCameraView1.setResolution(1920, 1080);

应该是：

mOpenCvCameraView.setResolution(1920, 1080);

---

@谢谢你的回复。在我的例子中，我定义了两个私有类（请参考活动源代码第18行和第19行），一个是camera和opencv库（它没有.setResolution），另一个是我在OpenCv4Android教程3（mOpenCvCameraView1.setResolution）的基础上添加的，它有.setResolution函数，像这样

public void setResolution（int Height，int weight）{disconnectCamera（）；mMaxHeight=Height；mMaxWidth=weight；connectCamera（getWidth（），getHeight（））；}

很抱歉没有看到它，那么在这种情况下，您必须实例化

mOpenCvCameraView1

，或者在mOpenCvCameraView1.setResolution是：

public void setResolution的地方检索它（int-Height，int-weight）{disconnectCamera（）；mMaxHeight=Height；mMaxWidth=weight；connectCamera（getWidth（），getHeight（））；}