Android 不幸的是，应用程序已经停止，允许后的权限允许或拒绝它的工作，但在一开始我得到弹出窗口，我的应用程序已经停止

我正在尝试请求相机许可，但每当我运行我的项目时，我的应用程序都会先停止弹出，然后显示“允许”或“拒绝”选项。如果我单击“不再显示”选项，它将不允许我按“允许”。若我允许我的应用程序运行它，那个么它就存在了，我必须再次打开应用程序。但问题将消失，我的应用程序将在下一次尝试中完美运行。。这是航海日志

07-26 18:41:56.080 3003-3003/com.example.android.camerapermission E/AndroidRuntime:FATAL EXCEPTION:main 进程：com.example.android.camerapermission，PID:3003 java.lang.RuntimeException:无法启动活动组件信息{com.example.android.camerapermission/com.example.android.camerapermission.MainActivity}:java.lang.RuntimeException:无法连接到相机服务 在android.app.ActivityThread.performLaunchActivity（ActivityThread.java:2416）上 位于android.app.ActivityThread.handleLaunchActivity（ActivityThread.java:2476） 位于android.app.ActivityThread.-wrap11（ActivityThread.java） 在android.app.ActivityThread$H.handleMessage（ActivityThread.java:1344）上 位于android.os.Handler.dispatchMessage（Handler.java:102） 位于android.os.Looper.loop（Looper.java:148） 位于android.app.ActivityThread.main（ActivityThread.java:5417） 位于java.lang.reflect.Method.invoke（本机方法） 在com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run上（ZygoteInit.java:726） 位于com.android.internal.os.ZygoteInit.main（ZygoteInit.java:616） 原因：java.lang.RuntimeException:无法连接到相机服务 在android.hardware.Camera.（Camera.java:495） 打开（Camera.java:356） 位于com.example.android.camerapermission.MainActivity.onCreate（MainActivity.java:52） 位于android.app.Activity.performCreate（Activity.java:6237） 位于android.app.Instrumentation.callActivityOnCreate（Instrumentation.java:1107） 在android.app.ActivityThread.performLaunchActivity（ActivityThread.java:2369）上 位于android.app.ActivityThread.handleLaunchActivity（ActivityThread.java:2476） 位于android.app.ActivityThread.-wrap11（ActivityThread.java） 在android.app.ActivityThread$H.handleMessage（ActivityThread.java:1344）上 位于android.os.Handler.dispatchMessage（Handler.java:102） 位于android.os.Looper.loop（Looper.java:148） 位于android.app.ActivityThread.main（ActivityThread.java:5417） 位于java.lang.reflect.Method.invoke（本机方法） 在com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run上（ZygoteInit.java:726） 位于com.android.internal.os.ZygoteInit.main（ZygoteInit.java:616）

这是我的MainActivity.java

 package com.example.android.camerapermission;

import android.Manifest;
import android.content.DialogInterface;

import android.content.pm.PackageManager;
import android.hardware.Camera;

import android.os.Build;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.test.mock.MockPackageManager;
import android.util.Log;
import android.view.View;
import android.widget.ImageButton;
import android.widget.Toast;

import com.nispok.snackbar.Snackbar;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;


public class MainActivity extends AppCompatActivity {
    private static final int REQUEST_CAMERA = 0;


    ImageButton imageButton;
    Camera camera;
    Camera.Parameters parameters;
    boolean isflash = false;
    boolean isOn = false;


    public static final String TAG = "MainActivity";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        imageButton = (ImageButton) findViewById(R.id.imageButton);

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            if (checkSelfPermission(Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
                requestPermissions(new String[] {Manifest.permission.CAMERA}, 0);
            }
        }
        if (getApplicationContext().getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA_FLASH))
            ;

        {
            camera = Camera.open();
            parameters = camera.getParameters();
            isflash = true;

        }


        imageButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {


                if (isflash) {

                    if (!isOn) {
                        imageButton.setImageResource(R.drawable.on);
                        parameters.setFlashMode(Camera.Parameters.FLASH_MODE_TORCH);
                        camera.setParameters(parameters);
                        camera.startPreview();
                        isOn = true;

                    } else {
                        imageButton.setImageResource(R.drawable.off);
                        parameters.setFlashMode(Camera.Parameters.FLASH_MODE_OFF);
                        camera.setParameters(parameters);
                        camera.stopPreview();
                        isOn = false;
                    }


                } else {
                    AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
                    builder.setTitle("Error.....");
                    builder.setMessage("Flashlight is not available on this device...");
                    builder.setPositiveButton("Ok", new DialogInterface.OnClickListener() {
                        @Override
                        public void onClick(DialogInterface dialog, int which) {

                            dialog.dismiss();
                            finish();
                        }
                    });

                    AlertDialog alertDialog = builder.create();
                    alertDialog.show();
                }

            }
        });


    }

    public void showCamera(View view) {

        Log.i(TAG, "Show that camera button is clicked. Checking permission.");
        /**
         * Include camera permission and
         * check if camera is available in phone or not
         */
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.CAMERA)
                != PackageManager.PERMISSION_GRANTED) {
            // Camera permission is not granted yet
            requestCameraPermission();
        } else {
            //Camera is available, show the camera preview

            Log.i(TAG, "CAMERA permission has granted, displaying camera preview");
            showCameraPreview();
        }

    }

    /**
     * Request the Camera Permission again in the case of user mistakenly denied permission.
     * Create a SnackBar that will prompt the user to grant the permission, otherwise it is requested direcly.
     */

    private void requestCameraPermission() {
        Log.i(TAG, " Camera permission is still not granted. Requesting permission.");

        //Start (camera_permission_request)
        if (ActivityCompat.shouldShowRequestPermissionRationale(this,
                Manifest.permission.CAMERA)) {
            // show an additional request to the user if the permission was not granted earlier.


        } else {
            //Camera permission has not been granted yet. Request directly.
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CAMERA}, REQUEST_CAMERA);
        }
        // END (camera_permission_request)
    }


    private void showCameraPreview() {
        getSupportFragmentManager().beginTransaction()
                .replace(R.id.sample_content_fragment, CameraPreviewFragment.newInstance())
                .commit();
    }


    /**
     * Receiving permission after granted
     */

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

        if (requestCode == REQUEST_CAMERA) {
            //Begin request (permission_result)
            //Recieved permission result for the camera permission.
            Log.i(TAG, "Request for Camera permission is received. ");

            //Check if the only required permission has been granted
            if (grantResults.length == 1 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                //Camera permission is safely granted, now you can preview.
                Log.i(TAG, "Camera permission has succesfully granted, preview is being displayed");


            } else {
                Log.i(TAG, "CAMERA permission is not granted.");

                // Finish(permission_result)
            }

            super.onRequestPermissionsResult(requestCode, permissions, grantResults);

        }

    }

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

        parameters = camera.getParameters();
        parameters.setFlashMode(Camera.Parameters.FLASH_MODE_OFF);
        camera.setParameters(parameters);
        camera.stopPreview();
        isflash = false;

        if (camera != null) {
            camera.release();
            camera = null;
        }
    }
}

---

注意：已在Manifest.xml中设置相机权限

您需要在try catch中包含摄像头打开呼叫

try {
        c = Camera.open(); // attempt to get a Camera instance
    }
    catch (Exception e){
        // Camera is not available (in use or does not exist)
    }

从Android开发者网站

Caution: Always check for exceptions when using Camera.open(). Failing to check for exceptions if the camera is in use or does not exist will cause your application to be shut down by the system.

---

让我们将其分解，这是您的代码：

1.  if (getApplicationContext().getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA_FLASH))
2.      ;
3.  {
        camera = Camera.open();
        parameters = camera.getParameters();
        isflash = true;
    }

事情就是这样

1.  // If the system has a camera flash
2.  // Do nothing. The condition terminates here.
3.  // Open camera in any case.

---

要解决此问题，请删除第2行中的分号，以后请注意分号。

是。我在7.1.2版本的手机上测试这个，在emulator的6.0版本中测试。同样的问题。我想你必须申请读写外部存储权限才能使用相机。因为在拍摄后，当相机将图像存储时，您必须获得写入权限。本例还使用了写入权限（不是运行时，而是manifiest）-我删除了它，但问题仍然存在。您检查权限，但无论权限检查的结果如何，都尝试打开相机。还有一个