在应用程序启动时启动相机

Question

我想构建一个应用程序，它可以立即运行相机、拍照，然后对照片进行处理。我使用这两种方法拍照并保存到设备：

static final int REQUEST_TAKE_PHOTO = 1;

private void dispatchTakePictureIntent() {
    Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
    // Ensure that there's a camera activity to handle the intent
    if (takePictureIntent.resolveActivity(getPackageManager()) != null) {
        // Create the File where the photo should go
        File photoFile = null;
        try {
            photoFile = createImageFile();
        } catch (IOException ex) {
            // Error occurred while creating the File
            Toast.makeText(this, "Failed to save to picture", Toast.LENGTH_LONG).show();
        }
        // Continue only if the File was successfully created
        if (photoFile != null) {
            takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT,
                    Uri.fromFile(photoFile));
            startActivityForResult(takePictureIntent, REQUEST_TAKE_PHOTO);
        }
    }
}
String mCurrentPhotoPath;

private File createImageFile() throws IOException {
    // Create an image file name
    String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
    String imageFileName = "JPEG_" + timeStamp + "_";
    File storageDir = Environment.getExternalStoragePublicDirectory(
            Environment.DIRECTORY_PICTURES);
    File image = File.createTempFile(
            imageFileName,  /* prefix */
            ".jpg",         /* suffix */
            storageDir      /* directory */
    );

    // Save a file: path for use with ACTION_VIEW intents
    mCurrentPhotoPath = "file:" + image.getAbsolutePath();
    return image;
}

这是我的 onCreate 方法：

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

我想在应用程序启动时立即启动相机。我该怎么做？

Answer 1

不要将您的方法放在 onCreate 中：如果 activity 从未被销毁，它可能不会被调用（事实上，它经常发生）。这样就可以了。

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

    dispatchTakePictureIntent();
}

更新：由于没有任何反应，我建议您按照以下步骤来调试问题：

记录方法的调用，以便了解它是否被调用：

private void dispatchTakePictureIntent() {
    Log.d("CameraApp", "dispatchTakePictureIntent was called");
    // ...
}

记录可能的问题，不忽略 "elses" 子句：

private void dispatchTakePictureIntent() {
    // ...
    if (takePictureIntent.resolveActivity(getPackageManager()) != null) {
        // ...
        if (photoFile != null) {
            // ...
        } else {
            Log.e("CameraApp", "photoFile was null");
        }
    } else {
        Log.e("CameraApp", "No activity available to call the intent");
    }
}

通过这种方式，你至少可以检测到没有任何反应的原因：

如果你永远看不到 "dispatchTakePictureIntent was called"，onResume 方法有问题，因为 dispatchTakePictureIntent 实际上从未被调用
如果其他两个日志打印在 Logcat 中，那么您的意图和代码在您的方法中有问题.

在应用程序启动时启动相机

Start camera on app startup

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