android - 如何在 Android 中询问相机的运行时权限，运行时存储权限

Question

我正在开发一个通过单击按钮扫描条形码的应用程序，它在 Lollipop 版本上运行良好。当我来到 Marshmallow 时，它停止工作了。这是错误:

camerabase an error occurred while connecting to camera 0

它迫使我通过以下方式打开权限:

设置 --> 应用程序 --> 我的应用程序 --> 相机。

我的问题是如何在 Marshmallow 中或通过要求用户在运行时打开相机来自动允许我的应用程序获得相机权限。屏幕截图:

Answer 1

下面我写了一段代码，用于为相机授予运行时权限，有一个字符串数组，您可以在其中根据需要在运行时授予多个请求。

public class MainActivity extends AppCompatActivity {
    private static final int PERMISSION_REQUEST_CODE = 200;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        if (checkPermission()) {
        //main logic or main code

       // . write your main code to execute, It will execute if the permission is already given.

        } else {
            requestPermission();
        }
    }

    private boolean checkPermission() {
        if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA)
                != PackageManager.PERMISSION_GRANTED) {
            // Permission is not granted
            return false;
        }
        return true;
    }

    private void requestPermission() {

        ActivityCompat.requestPermissions(this,
                new String[]{Manifest.permission.CAMERA},
                PERMISSION_REQUEST_CODE);
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, String permissions[], int[] grantResults) {
        switch (requestCode) {
            case PERMISSION_REQUEST_CODE:
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    Toast.makeText(getApplicationContext(), "Permission Granted", Toast.LENGTH_SHORT).show();

                    // main logic
                } else {
                    Toast.makeText(getApplicationContext(), "Permission Denied", Toast.LENGTH_SHORT).show();
                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
                        if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA)
                                != PackageManager.PERMISSION_GRANTED) {
                            showMessageOKCancel("You need to allow access permissions",
                                    new DialogInterface.OnClickListener() {
                                        @Override
                                        public void onClick(DialogInterface dialog, int which) {
                                            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
                                                requestPermission();
                                            }
                                        }
                                    });
                        }
                    }
                }
                break;
        }
    }

    private void showMessageOKCancel(String message, DialogInterface.OnClickListener okListener) {
        new AlertDialog.Builder(MainActivity.this)
                .setMessage(message)
                .setPositiveButton("OK", okListener)
                .setNegativeButton("Cancel", null)
                .create()
                .show();
    }
}