docs : 갤러리 예제

[philipy355]

• manifest 권한

  <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"
          android:maxSdkVersion="32" />
  
  <uses-permission android:name="android.permission.READ_MEDIA_IMAGES" />

• Composable PermissionRequestScreen, HomeScreen

  @Composable
  fun PermissionRequestScreen(onClick: () -> Unit){
      Column(
          modifier = Modifier.fillMaxSize(),
          verticalArrangement = Arrangement.Center,
          horizontalAlignment = Alignment.CenterHorizontally
      ) {
          Text("권한이 허용되지 않았습니다")
          Button(
              onClick = onClick
          ){
              Text("권한 요청")
          }
      }
  }
  
  @OptIn(ExperimentalPagerApi::class)
  @Composable
  fun HomeScreen(photoUris: List<Uri>){
      val pagerState = rememberPagerState()
  
      Column(
          modifier = Modifier.fillMaxSize()
      ) {
          HorizontalPager(
              state = pagerState,
              count = photoUris.size,
              modifier = Modifier
                  .weight(1f)
                  .padding(16.dp)
                  .fillMaxSize()
          ) {pageIndex ->
              Card(
                  modifier = Modifier
                      .graphicsLayer {
                          val pageOffset = calculateCurrentOffsetForPage(pageIndex).absoluteValue
  
                          lerp(
                              start = 0.85f,
                              stop = 1f,
                              fraction = 1f - pageOffset.coerceIn(0f, 1f),
                          ).also { scale ->
                              scaleX = scale
                              scaleY = scale
                          }
  
                          alpha = lerp(
                              start = 0.5f,
                              stop = 1f,
                              fraction = 1f - pageOffset.coerceIn(0f, 1f),
                          )
                      }
              ) {
                  Image(
                      painter = rememberImagePainter(
                          data = photoUris[pageIndex]
                      ),
                      contentDescription = null,
                      modifier = Modifier.fillMaxSize(),
                      contentScale = ContentScale.Crop
                  )
              }
          }
          HorizontalPagerIndicator(
              pagerState = pagerState,
              modifier = Modifier
                  .align(Alignment.CenterHorizontally)
                  .padding(16.dp),
          )
      }
  }
  
  private fun lerp(start: Float, stop: Float, fraction: Float): Float =
      (1 - fraction) * start + fraction * stop

• MainActivity

  class MainActivity : ComponentActivity() {
      @RequiresApi(Build.VERSION_CODES.O)
      @OptIn(ExperimentalMaterial3Api::class, ExperimentalComposeUiApi::class)
      @SuppressLint("UnusedMaterial3ScaffoldPaddingParameter",
          "UnusedMaterialScaffoldPaddingParameter"
      )
      override fun onCreate(savedInstanceState: Bundle?) {
          super.onCreate(savedInstanceState)
  
          setContent {
              val viewModel = viewModel<MainViewModel>()
              var granted by remember { mutableStateOf(false)}
              val launcher =
                  rememberLauncherForActivityResult(ActivityResultContracts.RequestPermission()){ isGranted ->
                      granted = isGranted
                  }
  
              if(Build.VERSION.SDK_INT>= Build.VERSION_CODES.TIRAMISU) {
                  if(ContextCompat.checkSelfPermission(this@MainActivity,
                          Manifest.permission.READ_MEDIA_IMAGES,)
                      == PackageManager.PERMISSION_GRANTED){
                      granted = true
                  }
              } else{
                  if(ContextCompat.checkSelfPermission(this@MainActivity,
                          Manifest.permission.READ_EXTERNAL_STORAGE,)
                      == PackageManager.PERMISSION_GRANTED){
                      granted = true
                  }
              }
  
              if(granted){
                  //Text("권한 허용 됨")
                  viewModel.fetchPhotos()
                  HomeScreen(photoUris = viewModel.photoUris.value)
              }else{
                  PermissionRequestScreen {
                      if(Build.VERSION.SDK_INT>= Build.VERSION_CODES.TIRAMISU) {
                          launcher.launch(Manifest.permission.READ_MEDIA_IMAGES)
                      } else{
                          launcher.launch(Manifest.permission.READ_EXTERNAL_STORAGE)
                      }
                  }
              }
          }
      }
  }

• MainViewModel

  class MainViewModel(application: Application) : AndroidViewModel(application){
      private val _photoUris = mutableStateOf(emptyList<Uri>())
      val photoUris: State<List<Uri>> = _photoUris
      @RequiresApi(Build.VERSION_CODES.O)
      fun fetchALLPhotos(){
          val uris = mutableListOf<Uri>()
  
          getApplication<Application>().contentResolver.query(
              MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
              null,
              null,
              null,
              "${MediaStore.Images.ImageColumns.DATE_TAKEN} DESC"
          )?.use {cursor ->
              val idIndex = cursor.getColumnIndexOrThrow(MediaStore.Images.Media._ID)
  
              while(cursor.moveToNext()){
                  val id = cursor.getLong(idIndex)
                  val contentUri = ContentUris.withAppendedId(
                      MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
                      id,
                  )
  
                  uris.add(contentUri)
              }
          }
          _photoUris.value = uris
          Log.d("MainViewModel", "Fetched URIs: $uris")
      }
  
      @RequiresApi(Build.VERSION_CODES.O)
      fun fetchPhotos() {
          val uris = mutableListOf<Uri>()
          getApplication<Application>().contentResolver.query(
              MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
              null,
              null,
              null,
              "${MediaStore.Images.ImageColumns.DATE_TAKEN} DESC"
          )?.use { cursor ->
              val idIndex = cursor.getColumnIndexOrThrow(MediaStore.Images.Media._ID)
  
              var count = 0
              while (cursor.moveToNext() && count < 5) { // 최대 5개의 이미지만 로드
                  val id = cursor.getLong(idIndex)
                  val contentUri = ContentUris.withAppendedId(
                      MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
                      id,
                  )
  
                  uris.add(contentUri)
                  count++ // 이미지 카운트 증가
              }
          }
          _photoUris.value = uris
      }
  
  }