Android照相机

本篇文章内容来自：
https://blog.csdn.net/u011277123/article/details/52677581

目录

1. 直接调取相机拍照，获取到缩略图
2. 调取相机拍照，保存全尺寸照片

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1.直接调取相机拍照，获取到缩略图

直接调取相机拍照，无需任何权限，但是只能获取到缩略图

第一步 声明照相机权限
照相机为危险权限

    @OnClick(R.id.btn_camera)
    public void onViewClicked() {
        if (ContextCompat.checkSelfPermission(CameraActivity.this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
            //没有授权，则申请授权
            //ActivityCompat.requestPermissions() 参数一：context 参数二：申请的权限名数组 参数三：请求码，要求唯一值
            ActivityCompat.requestPermissions(CameraActivity.this, new String[]{Manifest.permission.CAMERA}, PERMISSION_TAKE_CAMERA);
        } else {
            takePhoto();
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        switch (requestCode) {
            case PERMISSION_TAKE_CAMERA:
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    takePhoto();
                } else {
                    Toast.makeText(CameraActivity.this, "you denied", Toast.LENGTH_SHORT).show();
                }
                break;
        }
    }

第二步 调用照相机 获取缩略图

    private void takePhoto() {
        Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        if (intent.resolveActivity(getPackageManager()) != null) {//判断是否有相机应用
            startActivityForResult(intent, REQ_CAMERA);
        }
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        switch (requestCode) {
            case REQ_CAMERA:
                if (resultCode != Activity.RESULT_OK) return;
                Bundle extras = data.getExtras();
                Bitmap imageBitmap = (Bitmap) extras.get("data");
                ivShow.setImageBitmap(imageBitmap);
                break;
        }
    }

2. 调取相机拍照，保存全尺寸照片

第一步 声明照相机权限+存储权限

    @OnClick({R.id.btn_camera_full})
    public void onViewClicked(View view) {
        switch (view.getId()) {
            case R.id.btn_camera_full:
                List permissionList = new ArrayList<>();
                if (ContextCompat.checkSelfPermission(CameraActivity.this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
                    permissionList.add(Manifest.permission.READ_PHONE_STATE);
                }
                if (ContextCompat.checkSelfPermission(CameraActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
                    permissionList.add(Manifest.permission.WRITE_EXTERNAL_STORAGE);
                }
                if (!permissionList.isEmpty()) {
                    String[] permissions = permissionList.toArray(new String[permissionList.size()]);
                    ActivityCompat.requestPermissions(CameraActivity.this, permissions, PERMISSION_TAKE_CAMERA_FULL);
                } else {
                    takeFullPhoto();
                }
                break;
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        switch (requestCode) {
            case PERMISSION_TAKE_CAMERA_FULL:
                if (grantResults.length > 0) {
                    for (int result : grantResults) {
                        if (result != PackageManager.PERMISSION_GRANTED) {
                            Toast.makeText(CameraActivity.this, "you denied some", Toast.LENGTH_SHORT).show();
                            return;
                        }
                    }
                    takeFullPhoto();
                } else {
                    Toast.makeText(CameraActivity.this, "发生未知错误", Toast.LENGTH_SHORT).show();
                }
        }
    }

第二步 调用照相机 获取全尺寸图片
要点：Android N 以上要使用FileProvider

 private void takeFullPhoto() {
        Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        if (intent.resolveActivity(getPackageManager()) != null) {//判断是否有相机应用
            photoFile = null;
            try {
                photoFile = FileUtil.createImageFile(CameraActivity.this);
            } catch (IOException e) {
                e.printStackTrace();
            }
            if (photoFile != null) {
                //判断是否是AndroidN以及更高的版本
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
                    Uri photoURI = FileProvider.getUriForFile(CameraActivity.this, "com.example.android.fileprovider", photoFile);
                    intent.putExtra(MediaStore.EXTRA_OUTPUT, photoURI);
                } else {
                    Uri uri = Uri.fromFile(photoFile);
                    intent.putExtra(MediaStore.EXTRA_OUTPUT, uri);
                }
                startActivityForResult(intent, REQUEST_TAKE_PHOTO_FULL);
            }
        }
    }

public class FileUtil {
    public static File createImageFile(Context context) throws IOException {
        // Create an image file name
        String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss", Locale.CHINA).format(new Date());
        String imageFileName = "JPEG_" + timeStamp + "_";
        //.getExternalFilesDir()方法可以获取到 SDCard/Android/data/你的应用的包名/files/ 目录，一般放一些长时间保存的数据
        File storageDir = context.getExternalFilesDir(Environment.DIRECTORY_PICTURES);
        //创建临时文件,文件前缀不能少于三个字符,后缀如果为空默认未".tmp"
        File image = File.createTempFile(
                imageFileName,  /* 前缀 */
                ".jpg",         /* 后缀 */
                storageDir      /* 文件夹 */
        );
        return image;
    }
}

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        switch (requestCode) {
            case REQUEST_TAKE_PHOTO_FULL:
                if (resultCode != Activity.RESULT_OK) return;
                ivShow.setImageBitmap(BitmapFactory.decodeFile(photoFile.getAbsolutePath()));
                break;
        }
    }

部分手机可能出现不显示照片的bug
解决办法来自
BitmapFactory解码图片不显示（项目中的 bug)
将显示图片的ivShow.setImageBitmap(BitmapFactory.decodeFile(photoFile.getAbsolutePath()));
改为：

                BitmapFactory.Options opts = new BitmapFactory.Options();
                opts.inSampleSize = 4;
                Bitmap bitmap = BitmapFactory.decodeFile(photoFile.getAbsolutePath(), opts);

                ivShow.setImageBitmap(bitmap);