在AndroidManifest.xml中添加权限声明，并在代码中进行权限请求。示例代码如下所示：

1. 在AndroidManifest.xml中添加以下权限声明：

2. 在代码中请求相机权限：

private static final int REQUEST_CAMERA_PERMISSION = 200;

private void requestCameraPermission() { if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.CAMERA)) { new AlertDialog.Builder(this) .setTitle("Permission needed") .setMessage("This permission is needed because of the use of the camera") .setPositiveButton("ok", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { ActivityCompat.requestPermissions(MainActivity.this, new String[]{Manifest.permission.CAMERA}, REQUEST_CAMERA_PERMISSION); } }) .setNegativeButton("cancel", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { dialog.dismiss(); } }) .create().show();

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

}

3. 在回调中处理权限请求结果：

@Override public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) { if (requestCode == REQUEST_CAMERA_PERMISSION) { if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) { // permission was granted } else { // permission denied } } }