[移动开发]近段时间的学习碎片整理（13）

1、一个很好用的权限框架

 implementation "com.github.permissions-dispatcher:permissionsdispatcher:4.9.1"
 kapt "com.github.permissions-dispatcher:permissionsdispatcher-processor:4.9.1"

@OnNeverAskAgain(
        Manifest.permission.READ_EXTERNAL_STORAGE,
        Manifest.permission.WRITE_EXTERNAL_STORAGE
    )
    fun onOpenAlbumNeverAskAgain() {
        AlertDialog.Builder(this)
            .setCancelable(true)
            .setTitle(getString(R.string.tip))
            .setMessage(getString(R.string.close_write_read_permission_tip))
            .setNegativeButton(getString(R.string.cancel)) { _, _ ->

            }
            .setPositiveButton(getString(R.string.go_setting)) { _, _ ->
                PermissionUtils.startSystemIntent(this)
            }
            .create()
            .show()
    }

2、使用手机自带的相机拍照并获得结果（参考Android:调用系统相机实现拍照+裁切（兼容 7.0，11.0） - 简书）

@NeedsPermission(
        Manifest.permission.CAMERA,
        Manifest.permission.WRITE_EXTERNAL_STORAGE,
        Manifest.permission.READ_EXTERNAL_STORAGE
    )
    fun takePhotos() {
        imageFile = createImageFile()
        imageFile?.let {
            val intent = Intent(MediaStore.ACTION_IMAGE_CAPTURE)
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {  //如果是7.0以上，使用FileProvider，否则会报错
                intent.flags = Intent.FLAG_GRANT_READ_URI_PERMISSION
                imgUri = FileProvider.getUriForFile(this, AUTHORITY, it)
                intent.putExtra(MediaStore.EXTRA_OUTPUT, imgUri) //设置拍照后图片保存的位置
            } else {
                intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(it)) //设置拍照后图片保存的位置
            }
            intent.putExtra("outputFormat", Bitmap.CompressFormat.JPEG.toString()) //设置图片保存的格式
            intent.resolveActivity(packageManager)?.let {
                activityResultLauncher.launch(intent) //调起系统相机
            }
        }
    }

  private var imageFile: File? = null
    private var imgUri: Uri? = null
    private val AUTHORITY = "com.transportation.camera.fileProvider" //FileProvider的签名(后面会介绍)
private val activityResultLauncher: ActivityResultLauncher<Intent> =
        registerForActivityResult(ActivityResultContracts.StartActivityForResult()) {
 if (it.resultCode == Activity.RESULT_OK) {
                imgUri?.let {
                    i1 ->
                    val timeStamp = SimpleDateFormat("yyyyMMdd_HHmmss").format(Date())
                    val savePath = "${getCacheFilePath(this)}/IMG_$timeStamp.jpg"
                    launch(Dispatchers.IO, {
                        val bitmap = getImage(FileUtil.getFilePathByUri(this@UploadActivity, i1))
                        Timber.d("savePath = $savePath")
                        bitmap?.let { b ->
                            saveBitmap(b, savePath)
                        }
                        withContext(Dispatchers.Main) {
                            imageUri.add(0, savePath)
                            uploadImageAdapter.notifyDataSetChanged()
                            if (imageUri.size > 1) {
                                binding.ivFinish.visibility = View.VISIBLE
                            }
                        }

                    }, { it2 ->
                        it2.printStackTrace()})

//                    imageUri.add(0 ,i1.toString())
                }
            }
}
  private fun saveBitmap(bitmap: Bitmap, path: String) {
        try {
            val file = File(path)
            if (!file.exists()) {
                file.getParentFile().mkdirs()
                file.createNewFile()
                val fos = FileOutputStream(file);
                bitmap.compress(Bitmap.CompressFormat.JPEG, 100, fos)
                fos.flush()
                fos.close()
            }
        }catch (e: IOException) {
            e.printStackTrace()
            return;
        }
    }

    //根据路径获取用户选择的图片
    private fun getImage(imgPath: String): Bitmap? {
        val options = BitmapFactory.Options()
        options.inSampleSize = 2 //直接设置它的压缩率，表示1/2
        var b: Bitmap? = null
        try {
            val a = BitmapFactory.decodeFile(imgPath, options)
            val matrix = Matrix()
            a?.let {
                b = Bitmap.createBitmap(it, 0, 0, it.width, it.height, matrix, true)
            }
        } catch (e: Exception) {
            e.printStackTrace()
        }
        return b
    }