Question

我正在制作相机应用程序，但是当我运行它时显示不幸的应用程序已停止。在代码中它显示没有错误但仍然无法正常工作所以帮助我。

以下代码是应用程序的主要代码，包含捕获的图像保存文件

package com.example.cam;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.hardware.Camera;
import android.hardware.Camera.PictureCallback;
import android.hardware.Camera.ShutterCallback;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.SurfaceView;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.View.OnLongClickListener;
import android.view.ViewGroup.LayoutParams;
import android.view.Window;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.FrameLayout;
import android.widget.Toast;

public class CamTestActivity extends Activity  {
    private static final String TAG = "CamTestActivity";
    Preview preview;
    Button buttonClick;
    Camera camera;
    Activity act;
    Context ctx;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        ctx = this;
        act = this;
        setContentView(R.layout.main);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
        preview = new Preview(this, (SurfaceView)findViewById(R.id.surfaceView));
        preview.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
        ((FrameLayout) findViewById(R.id.layout)).addView(preview);
        preview.setKeepScreenOn(true);

        preview.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View arg0) {
                camera.takePicture(shutterCallback, rawCallback, jpegCallback);
            }
        });

        Toast.makeText(ctx,getString(R.string.take_photo_help), Toast.LENGTH_LONG).show();

                buttonClick = (Button) findViewById(R.id.btnCapture);

                buttonClick.setOnClickListener(new OnClickListener() {
                    public void onClick(View v) {
                        preview.mCamera.takePicture(shutterCallback, rawCallback, jpegCallback);
                        camera.takePicture(shutterCallback, rawCallback, jpegCallback);
                    }
                });

                buttonClick.setOnLongClickListener(new View.OnLongClickListener(){
                    @Override
                    public boolean onLongClick(View arg0) {
                        camera.autoFocus(new Camera.AutoFocusCallback(){
                            @Override
                            public void onAutoFocus(boolean arg0, Camera arg1) {
                                camera.takePicture(shutterCallback, rawCallback, jpegCallback);
                            }
                        });
                        return true;
                    }
                });
    }

    @Override
    protected void onResume() {
        super.onResume();
        int numCams = Camera.getNumberOfCameras();
        if(numCams > 0){
            try{
                camera = Camera.open(0);
                camera.startPreview();
                preview.setCamera(camera);
            } catch (RuntimeException ex){
                Toast.makeText(ctx, getString(R.string.camera_not_found), Toast.LENGTH_LONG).show();
            }
        }
    }

    @Override
    protected void onPause() {
        if(camera != null) {
            camera.stopPreview();
            preview.setCamera(null);
            camera.release();
            camera = null;
        }
        super.onPause();
    }

    private void resetCam() {
        camera.startPreview();
        preview.setCamera(camera);
    }

    private void refreshGallery(File file) {
        Intent mediaScanIntent = new Intent( Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
        mediaScanIntent.setData(Uri.fromFile(file));
        sendBroadcast(mediaScanIntent);
    }

    ShutterCallback shutterCallback = new ShutterCallback() {
        public void onShutter() {
                         Log.d(TAG, "onShutter'd");
        }
    };

    PictureCallback rawCallback = new PictureCallback() {
        public void onPictureTaken(byte[] data, Camera camera) {
                         Log.d(TAG, "onPictureTaken - raw");
        }
    };

    PictureCallback jpegCallback = new PictureCallback() {
        public void onPictureTaken(byte[] data, Camera camera) {
            new SaveImageTask().execute(data);
            resetCam();
            Log.d(TAG, "onPictureTaken - jpeg");
        }
    };

    @SuppressLint("StaticFieldLeak")
    private class SaveImageTask extends AsyncTask<byte[], Void, Void> {

        @Override
        protected Void doInBackground(byte[]... data) {
            FileOutputStream outStream = null;

            // Write to SD Card
            try {
                File sdCard = Environment.getExternalStorageDirectory();
                File dir = new File (sdCard.getAbsolutePath() + "/camtest");
                dir.mkdirs();               

                String fileName = String.format("%d.jpg", System.currentTimeMillis());
                File outFile = new File(dir, fileName);

                outStream = new FileOutputStream(outFile);
                outStream.write(data[0]);
                outStream.flush();
                outStream.close();

                Log.d(TAG, "onPictureTaken - wrote bytes: " + data.length + " to " + outFile.getAbsolutePath());

                refreshGallery(outFile);
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
            }
            return null;
        }

    }
}

听取预览代码并在拍摄照片后包含预览

    package com.example.cam;

/*
 * @author Jose Davis Nidhin
 */

import java.io.IOException;
import java.util.List;
import android.content.Context;
import android.hardware.Camera;
import android.hardware.Camera.Size;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.ViewGroup;

class Preview extends ViewGroup implements SurfaceHolder.Callback {
    private final String TAG = "Preview";

    SurfaceView mSurfaceView;
    SurfaceHolder mHolder;
    Size mPreviewSize;
    List<Size> mSupportedPreviewSizes;
    Camera mCamera;

    Preview(Context context, SurfaceView sv) {
        super(context);

        mSurfaceView = sv;
        addView(mSurfaceView);

        mHolder = mSurfaceView.getHolder();
        mHolder.addCallback(this);
        mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    }

    public void setCamera(Camera camera) {
        mCamera = camera;
        if (mCamera != null) {
            mSupportedPreviewSizes = mCamera.getParameters().getSupportedPreviewSizes();
            requestLayout();

            // get Camera parameters
            Camera.Parameters params = mCamera.getParameters();

            List<String> focusModes = params.getSupportedFocusModes();
            if (focusModes.contains(Camera.Parameters.FOCUS_MODE_AUTO)) {
                // set the focus mode
                params.setFocusMode(Camera.Parameters.FOCUS_MODE_AUTO);
                // set Camera parameters
                mCamera.setParameters(params);
            }
        }
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        // We purposely disregard child measurements because act as a
        // wrapper to a SurfaceView that centers the camera preview instead
        // of stretching it.
        final int width = resolveSize(getSuggestedMinimumWidth(), widthMeasureSpec);
        final int height = resolveSize(getSuggestedMinimumHeight(), heightMeasureSpec);
        setMeasuredDimension(width, height);

        if (mSupportedPreviewSizes != null) {
            mPreviewSize = getOptimalPreviewSize(mSupportedPreviewSizes, width, height);
        }
    }

    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        if (changed && getChildCount() > 0) {
            final View child = getChildAt(0);

            final int width = r - l;
            final int height = b - t;

            int previewWidth = width;
            int previewHeight = height;
            if (mPreviewSize != null) {
                previewWidth = mPreviewSize.width;
                previewHeight = mPreviewSize.height;
            }

            // Center the child SurfaceView within the parent.
            if (width * previewHeight > height * previewWidth) {
                final int scaledChildWidth = previewWidth * height / previewHeight;
                child.layout((width - scaledChildWidth) / 2, 0,
                        (width + scaledChildWidth) / 2, height);
            } else {
                final int scaledChildHeight = previewHeight * width / previewWidth;
                child.layout(0, (height - scaledChildHeight) / 2,
                        width, (height + scaledChildHeight) / 2);
            }
        }
    }

    public void surfaceCreated(SurfaceHolder holder) {
        // The Surface has been created, acquire the camera and tell it where
        // to draw.
        try {
            if (mCamera != null) {
                mCamera.setPreviewDisplay(holder);
            }
        } catch (IOException exception) {
            Log.e(TAG, "IOException caused by setPreviewDisplay()", exception);
        }
    }

    public void surfaceDestroyed(SurfaceHolder holder) {
        // Surface will be destroyed when we return, so stop the preview.
        if (mCamera != null) {
            mCamera.stopPreview();
        }
    }


    private Size getOptimalPreviewSize(List<Size> sizes, int w, int h) {
        final double ASPECT_TOLERANCE = 0.1;
        double targetRatio = (double) w / h;
        if (sizes == null) return null;

        Size optimalSize = null;
        double minDiff = Double.MAX_VALUE;

        int targetHeight = h;

        // Try to find an size match aspect ratio and size
        for (Size size : sizes) {
            double ratio = (double) size.width / size.height;
            if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE) continue;
            if (Math.abs(size.height - targetHeight) < minDiff) {
                optimalSize = size;
                minDiff = Math.abs(size.height - targetHeight);
            }
        }

        // Cannot find the one match the aspect ratio, ignore the requirement
        if (optimalSize == null) {
            minDiff = Double.MAX_VALUE;
            for (Size size : sizes) {
                if (Math.abs(size.height - targetHeight) < minDiff) {
                    optimalSize = size;
                    minDiff = Math.abs(size.height - targetHeight);
                }
            }
        }
        return optimalSize;
    }

    public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
        if(mCamera != null) {
            Camera.Parameters parameters = mCamera.getParameters();
            parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height);
            requestLayout();

            mCamera.setParameters(parameters);
            mCamera.startPreview();
        }
    }

}

这是崩溃日志

I/InstantRun: starting instant run server: is main process
D/AccessibilityManager: getInstance() new sInstance = android.view.accessibility.AccessibilityManager@4ed699a, context = com.example.cam.CamTestActivity@65f12cb, userId = 0
D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
                  Process: com.example.cam, PID: 3386
                  java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.cam/com.example.cam.CamTestActivity}: android.util.AndroidRuntimeException: requestFeature() must be called before adding content
                      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2417)
                      at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2477)
                      at android.app.ActivityThread.-wrap11(ActivityThread.java)
                      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1345)
                      at android.os.Handler.dispatchMessage(Handler.java:102)
                      at android.os.Looper.loop(Looper.java:148)
                      at android.app.ActivityThread.main(ActivityThread.java:5452)
                      at java.lang.reflect.Method.invoke(Native Method)
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:762)
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:652)
                   Caused by: android.util.AndroidRuntimeException: requestFeature() must be called before adding content
                      at com.android.internal.policy.PhoneWindow.requestFeature(PhoneWindow.java:326)
                      at android.app.Activity.requestWindowFeature(Activity.java:3656)
                      at com.example.cam.CamTestActivity.onCreate(CamTestActivity.java:45)
                      at android.app.Activity.performCreate(Activity.java:6251)
                      at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1110)
                      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2370)
                      at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2477) 
                      at android.app.ActivityThread.-wrap11(ActivityThread.java) 
                      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1345) 
                      at android.os.Handler.dispatchMessage(Handler.java:102) 
                      at android.os.Looper.loop(Looper.java:148) 
                      at android.app.ActivityThread.main(ActivityThread.java:5452) 
                      at java.lang.reflect.Method.invoke(Native Method) 
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:762) 
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:652) 
I/Process: Sending signal. PID: 3386 SIG: 9
Application terminated.

现在请帮我解决问题

Answer 1

以编程方式在Android应用启动时一次启用不同的权限。

此处您只需为上面的Marshmallow设备添加CAMERA权限，在启动相机屏幕之前添加此代码

参考文献：https://www.android-examples.com/request-check-multiple-runtime-permissions-android-marshmallow/

<uses-permission android:name="android.permission.CAMERA"/>

MainActivity.java 代码：

public class MainActivity extends AppCompatActivity {

Button button;
public static final int RequestPermissionCode = 1;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    button = (Button)findViewById(R.id.button);

    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {

            if(checkPermission()){

                Toast.makeText(MainActivity.this, "All Permissions Granted Successfully", Toast.LENGTH_LONG).show();

            }
            else {

                requestPermission();
            }

        }
    });
}


private void requestPermission() {

    ActivityCompat.requestPermissions(MainActivity.this, new String[]
            {
                    CAMERA,

            }, RequestPermissionCode);

}

@Override
public void onRequestPermissionsResult(int requestCode, String permissions[], int[] grantResults) {
    switch (requestCode) {

        case RequestPermissionCode:

            if (grantResults.length > 0) {

                boolean CameraPermission = grantResults[0] == PackageManager.PERMISSION_GRANTED;


                if (CameraPermission ) {

                    Toast.makeText(MainActivity.this, "Permission Granted", Toast.LENGTH_LONG).show();
                }
                else {
                    Toast.makeText(MainActivity.this,"Permission Denied",Toast.LENGTH_LONG).show();

                }
            }

            break;
    }
}

public boolean checkPermission() {

    int FirstPermissionResult = ContextCompat.checkSelfPermission(getApplicationContext(), CAMERA);


    return FirstPermissionResult == PackageManager.PERMISSION_GRANTED ;
}

}

或者，如果您在不使用此代码的情况下手动检查，仅用于检查：转到设置 - ＆gt;应用 - ＆gt;选择你的应用程序 - ＆gt;点按权限 - ＆gt;启用相机权限。

Answer 2

在CamTestActivity中，移动第requestWindowFeature(Window.FEATURE_NO_TITLE)行，使其显示在super.onCreate(savedInstanceState)之前

相机应用程序无法启动手机

2 个答案: