[解決済み] android - getSystemService メソッドの問題を解決できない。

質問

Android Studio IDEで、getSystemServiceメソッドが解決できないと言われ続けています。私が読んだ限りでは、私のクラスがアクティビティを含んでいないことに起因しているようです。getSystemServiceの問題についての関連トピックを読んでいましたが、一致する解決策は全く見つかりませんでした。

私のコードを上に配置します。

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Rect;
import android.hardware.Camera;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

private Camera mCamera;
private CameraView mCameraView;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
}


@Override
protected void onResume(){
    super.onResume();

    try{
        mCamera = Camera.open(1);
        mCameraView = new CameraView(this, mCamera);
        setContentView(mCameraView);
    } catch (Exception e){
        finish();
    }
}

@Override
protected void onPause(){
    if(mCamera != null){
        mCamera.release();
        mCamera = null;
    }
    super.onPause();


   }

}

上のクラスの太字は、私が理解しようとしているものです

import android.content.Context;
import android.hardware.Camera;
import android.hardware.Camera.Parameters;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.Surface;
import android.view.Display;
import android.view.WindowManager;
import java.io.IOException;
import android.app.Activity;
import java.util.List;


public class CameraView extends SurfaceView implements SurfaceHolder.Callback{


private Camera mCamera;
private View mView;
private WindowManager display;


public CameraView(Context context, Camera mCamera) {
    super(context);

    this.mCamera = mCamera;
    mCamera.setDisplayOrientation(90);

    SurfaceHolder holder = getHolder();
    holder.addCallback(this);
    holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);

}


@Override
public void surfaceCreated(SurfaceHolder holder) {
    try{
        mCamera.setPreviewDisplay(holder);
        mCamera.startPreview();
    } catch (IOException e) {
        Log.e("cameraPreview", "The failure of the camera settings");
    }
}


@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
    Camera.Parameters params = mCamera.getParameters();
    List<Camera.Size> sizes = params.getSupportedPreviewSizes();
    Camera.Size optionalSize = getOptimalPreviewSize(sizes, width, height);
    params.setPreviewSize(optionalSize.width, optionalSize.height);
    mCamera.setParameters(params);

    boolean isPreviewRunning = true;

    if (isPreviewRunning)
    {
        mCamera.stopPreview();
    }

    Parameters parameters = mCamera.getParameters();
    Display display = ((WindowManager) getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();  

    if(display.getRotation() == Surface.ROTATION_0)
    {
        parameters.setPreviewSize(height, width);
        mCamera.setDisplayOrientation(90);
    }

    if(display.getRotation() == Surface.ROTATION_90)
    {
        parameters.setPreviewSize(width, height);
    }

    if(display.getRotation() == Surface.ROTATION_180)
    {
        parameters.setPreviewSize(height, width);
    }

    if(display.getRotation() == Surface.ROTATION_270)
    {
        parameters.setPreviewSize(width, height);
        mCamera.setDisplayOrientation(180);
    }

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

public void previewCamera()
{
    try
    {
        mCamera.setPreviewDisplay();
        mCamera.startPreview();
        boolean isPreviewRunning = true;
    }
    catch(Exception e)
    {
        Log.d(APP_CLASS, "Cannot start preview", e);
    }
}

@Override
public void surfaceDestroyed(SurfaceHolder holder) {
    mCamera.release();
    mCamera = null;
}

private Camera.Size getOptimalPreviewSize(List<Camera.Size> sizes, int w, int h) {

    final double ASPECT_TOLERANCE = 0.1;
    double targetRatio=(double)h / w;

    if (sizes == null) return null;

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

    int targetHeight = h;

    for (Camera.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);
        }
    }

    if (optimalSize == null) {
        minDiff = Double.MAX_VALUE;
        for (Camera.Size size : sizes) {
            if (Math.abs(size.height - targetHeight) < minDiff) {
                optimalSize = size;
                minDiff = Math.abs(size.height - targetHeight);
            }
        }
    }
    return optimalSize;


  }



}

この問題を回避するためには、どのようにすればよいか教えていただけないでしょうか。

ありがとうございます。

解決方法は？

を呼び出す必要があります。 getSystemService の上で Context で動作しないのはそのためです。 CameraView . すでに渡してあるコンテキストをフィールドとして保存し、その上で getSystemService を呼び出すことができます。以下の修正したコードをご覧ください。

import android.content.Context;
import android.hardware.Camera;
import android.hardware.Camera.Parameters;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.Surface;
import android.view.Display;
import android.view.WindowManager;
import java.io.IOException;
import android.app.Activity;
import java.util.List;


public class CameraView extends SurfaceView implements SurfaceHolder.Callback{


private Camera mCamera;
private View mView;
private WindowManager display;
private Context mContext;


public CameraView(Context context, Camera mCamera) {
    super(context);

    mContext = context;

    this.mCamera = mCamera;
    mCamera.setDisplayOrientation(90);

    SurfaceHolder holder = getHolder();
    holder.addCallback(this);
    holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);

}


@Override
public void surfaceCreated(SurfaceHolder holder) {
    try{
        mCamera.setPreviewDisplay(holder);
        mCamera.startPreview();
    } catch (IOException e) {
        Log.e("cameraPreview", "The failure of the camera settings");
    }
}


@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
    Camera.Parameters params = mCamera.getParameters();
    List<Camera.Size> sizes = params.getSupportedPreviewSizes();
    Camera.Size optionalSize = getOptimalPreviewSize(sizes, width, height);
    params.setPreviewSize(optionalSize.width, optionalSize.height);
    mCamera.setParameters(params);

    boolean isPreviewRunning = true;

    if (isPreviewRunning)
    {
        mCamera.stopPreview();
    }

    Parameters parameters = mCamera.getParameters();
    Display display = ((WindowManager) mContext.getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();  

    if(display.getRotation() == Surface.ROTATION_0)
    {
        parameters.setPreviewSize(height, width);
        mCamera.setDisplayOrientation(90);
    }

    if(display.getRotation() == Surface.ROTATION_90)
    {
        parameters.setPreviewSize(width, height);
    }

    if(display.getRotation() == Surface.ROTATION_180)
    {
        parameters.setPreviewSize(height, width);
    }

    if(display.getRotation() == Surface.ROTATION_270)
    {
        parameters.setPreviewSize(width, height);
        mCamera.setDisplayOrientation(180);
    }

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

public void previewCamera()
{
    try
    {
        mCamera.setPreviewDisplay();
        mCamera.startPreview();
        boolean isPreviewRunning = true;
    }
    catch(Exception e)
    {
        Log.d(APP_CLASS, "Cannot start preview", e);
    }
}

@Override
public void surfaceDestroyed(SurfaceHolder holder) {
    mCamera.release();
    mCamera = null;
}

private Camera.Size getOptimalPreviewSize(List<Camera.Size> sizes, int w, int h) {

    final double ASPECT_TOLERANCE = 0.1;
    double targetRatio=(double)h / w;

    if (sizes == null) return null;

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

    int targetHeight = h;

    for (Camera.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);
        }
    }

    if (optimalSize == null) {
        minDiff = Double.MAX_VALUE;
        for (Camera.Size size : sizes) {
            if (Math.abs(size.height - targetHeight) < minDiff) {
                optimalSize = size;
                minDiff = Math.abs(size.height - targetHeight);
            }
        }
    }
    return optimalSize;


  }