Java 为什么我在尝试将图像分配给GridView时会出现此NullPointerException？
我有一个GridView，其中应用了与对象实例关联的不同图像。我使用RealPathUtil对象来处理文件路径的检索，以便解码和显示位图 当我打开将这些图像分配给网格的活动时，我的应用程序会自动崩溃，并在声明此if子句的行上显示一个NullPointerException：Java 为什么我在尝试将图像分配给GridView时会出现此NullPointerException？,java,android,kotlin,Java,Android,Kotlin,我有一个GridView，其中应用了与对象实例关联的不同图像。我使用RealPathUtil对象来处理文件路径的检索，以便解码和显示位图 当我打开将这些图像分配给网格的活动时，我的应用程序会自动崩溃，并在声明此if子句的行上显示一个NullPointerException： else if ("content".equals(uri.scheme!!, ignoreCase = true)) { // Return the remote address
else if ("content".equals(uri.scheme!!, ignoreCase = true)) {
// Return the remote address
return if (isGooglePhotosUri(uri)) uri.lastPathSegment else getDataColumn(context, uri, null, null)
}
override fun getView(position: Int, convertView: View?, parent: ViewGroup?): View {
val view: View = View.inflate(activity,R.layout.layout_adapter,null)
// Get view data from UI elements - image, name, and count
val tv_lang = view.findViewById(R.id.itemName) as TextView
val imageView = view.findViewById<ImageView>(R.id.itemImage)
val itemCount = view.findViewById(R.id.itemCount) as TextView
// Assign data to UI elements
tv_lang.text = itemList[position].itemNote
itemCount.text = itemList[position].itemCount.toString()
val itemImage = itemList[position].itemImage
// Assign each item image to corresponding grid ImageView
tempUri = Uri.parse(itemImage)
realPathUri = RealPathUtil.getRealPath(parent!!.context, tempUri).toString()
val myBitmap = BitmapFactory.decodeFile(realPathUri)
imageView.setImageBitmap(myBitmap)
return view
}
override-fun-getView（位置：Int，convertView:View？，父级：ViewGroup？）：视图{
val视图：视图=视图。充气（活动，右布局。布局适配器，空）
//从UI元素（图像、名称和计数）获取视图数据
val tv_lang=view.findviewbyd（R.id.itemName）作为文本视图
val imageView=view.findViewById（R.id.itemImage）
val itemCount=view.findviewbyd（R.id.itemCount）作为TextView
//将数据分配给UI元素
tv_lang.text=itemList[position]。itemNote
itemCount.text=itemList[position].itemCount.toString（）
val itemImage=itemList[position].itemImage
//将每个项目图像指定给相应的网格图像视图
tempUri=Uri.parse（itemImage）
realPathUri=RealPathUtil.getRealPath（parent！！.context，tempUri）.toString（）
val myBitmap=BitmapFactory.decodeFile（realPathUri）
设置图像位图（myBitmap）
返回视图
}
object RealPathUtil {
// SDK <= 11 && SDK < 19
/* Calls either getRealPathFromURIAPI11to19 or getRealPathFromURIAPI19, depending upon which API the software detects the user running the app through. */
@SuppressLint("ObsoleteSdkInt")
fun getRealPath(context: Context, fileUri: Uri): String? {
return if (Build.VERSION.SDK_INT < 19) {
getRealPathFromURIAPI11to18(context, fileUri)
} else {
getRealPathFromURIAPI19(context, fileUri)
}
}
/* Uses other methods within the RealPathUtil object to determine
* location list file path based upon the user's phone's active API (11-18). */
@SuppressLint("NewApi")
fun getRealPathFromURIAPI11to18(context: Context, contentUri: Uri): String? {
val project = arrayOf(MediaStore.Images.Media.DATA)
var result: String? = ""
val cursorLoader = CursorLoader(context, contentUri, project, null, null, null)
val cursor = cursorLoader.loadInBackground()
if (cursor != null) {
val columnIndex = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA)
cursor.moveToFirst()
result = cursor.getString(columnIndex)
cursor.close()
}
return result
}
/* Uses other methods within the RealPathUtil object to determine location list file
path based upon the user's phone's active API (19). */
@SuppressLint("NewApi")
fun getRealPathFromURIAPI19(context: Context, uri: Uri): String? {
val isKitKat = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT
// Create the DocumentProvider
if (isKitKat && DocumentsContract.isDocumentUri(context, uri)) {
// Safe cast the ExternalStorageProvider
if (isExternalStorageDocument(uri)) {
val docId = DocumentsContract.getDocumentId(uri)
val split = docId.split(":".toRegex()).dropLastWhile { it.isEmpty() }.toTypedArray()
val type = split[0]
if ("primary".equals(type, ignoreCase = true)) {
return Environment.getExternalStorageDirectory().toString() + "/" + split[1]
}
} else if (isDownloadsDocument(uri)) {
var cursor: Cursor? = null
try {
cursor = context.contentResolver.query(uri, arrayOf(MediaStore.MediaColumns.DISPLAY_NAME), null, null, null)
cursor!!.moveToNext()
val fileName = cursor.getString(0)
val path = Environment.getExternalStorageDirectory().toString() + "/Download/" + fileName
if (!TextUtils.isEmpty(path)) {
return path
}
} finally {
cursor?.close()
}
val id = DocumentsContract.getDocumentId(uri)
if (id.startsWith("raw:")) {
return id.replaceFirst("raw:".toRegex(), "")
}
val contentUri = ContentUris.withAppendedId(Uri.parse("content://downloads"), java.lang.Long.valueOf(id))
return getDataColumn(context, contentUri, null, null)
} else if (isMediaDocument(uri)) {
val docId = DocumentsContract.getDocumentId(uri)
val split = docId.split(":".toRegex()).dropLastWhile { it.isEmpty() }.toTypedArray()
val type = split[0]
var contentUri: Uri? = null
when (type) {
"image" -> contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI
"video" -> contentUri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI
"audio" -> contentUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI
}
val selection = "_id=?"
val selectionArgs = arrayOf(split[1])
return getDataColumn(context, contentUri, selection, selectionArgs)
} // Media Provider
// Downloads Provider
} else if ("content".equals(uri.scheme!!, ignoreCase = true)) {
// Return the remote address
return if (isGooglePhotosUri(uri))
uri.lastPathSegment
else
getDataColumn(context, uri, null, null) /** Collapse this if-else block into one line if any new, unexplained I/O issues arise. */
} else if ("file".equals(uri.scheme!!, ignoreCase = true)) {
return uri.path
} // File
// MediaStore
return null
}
private fun getDataColumn(context: Context, uri: Uri?, selection: String?, selectionArgs: Array<String>?): String? {
var cursor: Cursor? = null
val column = "_data"
val projection = arrayOf(column)
try {
cursor = context.contentResolver.query(uri!!, projection, selection, selectionArgs, null)
if (cursor != null && cursor.moveToFirst()) {
val index = cursor.getColumnIndexOrThrow(column)
return cursor.getString(index)
}
} finally {
cursor?.close()
}
return null
}
/* Takes the URI being analyzed and determines whether the URI authority is ExternalFileProvider or not. */
private fun isExternalStorageDocument(uri: Uri): Boolean {
return "com.android.externalstorage.documents" == uri.authority
}
/* Takes the URI being analyzed and determines whether the URI authority is DownloadsProvider or not. */
private fun isDownloadsDocument(uri: Uri): Boolean {
return "com.android.providers.downloads.documents" == uri.authority
}
/* Takes the URI being analyzed and determines whether the URI authority is MediaProvider or not. */
private fun isMediaDocument(uri: Uri): Boolean {
return "com.android.providers.media.documents" == uri.authority
}
/* Takes the URI being analyzed and determines whether the URI authority is Google Photos or not. */
private fun isGooglePhotosUri(uri: Uri): Boolean {
return "com.google.android.apps.photos.content" == uri.authority
}
}
对象RealPathUtil{
//SDK=Build.VERSION\u CODES.KITKAT
//创建文档提供者
if（isKitKat&&DocumentsContract.isDocumentUri（context，uri））{
//安全强制转换ExternalStorageProvider
if（isExternalStorageDocument（uri））{
val docId=DocumentsContract.getDocumentId（uri）
val split=docId.split（“：”.toRegex（））.dropLastWhile{it.isEmpty（）}.toTypedArray（）
val类型=拆分[0]
if（“primary”.equals（type，ignoreCase=true））{
返回Environment.getExternalStorageDirectory（）.toString（）+“/”+split[1]
}
}else if（isDownloadsDocument（uri））{
变量游标：游标？=null
试一试{
cursor=context.contentResolver.query（uri，arrayOf（MediaStore.MediaColumns.DISPLAY_NAME），null，null，null）
光标！！.moveToNext（）
val fileName=cursor.getString（0）
val path=Environment.getExternalStorageDirectory（）.toString（）+“/Download/”+文件名
如果（！TextUtils.isEmpty（路径））{
返回路径
}
}最后{
光标？.close（）
}
val id=DocumentsContract.getDocumentId（uri）
if（id.startsWith（“原始：））{
返回id.replaceFirst（“原始：”.toRegex（），“”）
}
val contentUri=ContentUris.withAppendedId（Uri.parse（“content://downloads），java.lang.Long.valueOf（id））
返回getDataColumn（上下文、contentUri、null、null）
}else if（isMediaDocument（uri））{
val docId=DocumentsContract.getDocumentId（uri）
val split=docId.split（“：”.toRegex（））.dropLastWhile{it.isEmpty（）}.toTypedArray（）
val类型=拆分[0]
var contentUri:Uri？=null
何时（输入）{
“image”->contentUri=MediaStore.Images.Media.EXTERNAL\u CONTENT\u URI
“视频”->contentUri=MediaStore.video.Media.EXTERNAL\u CONTENT\u URI
“音频”->contentUri=MediaStore.audio.Media.EXTERNAL\u CONTENT\u URI
}
val selection=“\u id=？”
val selectionArgs=arrayOf（拆分[1]）
返回getDataColumn（上下文、contentUri、选择、selectionArgs）
}//媒体提供商
//下载提供商
}else如果（“content.equals（uri.scheme！！，ignoreCase=true））{
//返回远程地址
返回if（iGoogle PhotoSuri（uri））
uri.lastPathSegment
其他的
getDataColumn（上下文、uri、null、null）/**如果出现任何新的、无法解释的I/O问题，请将此if-else块折叠成一行*/
}else如果（“file.equals（uri.scheme！！，ignoreCase=true））{
返回uri.path
}//文件
//媒体商店
返回空
}
private fun getDataColumn（上下文：上下文，uri:uri？，选择：字符串？，选择：数组？）：字符串？{
变量游标：游标？=null
val column=“\u数据”
val投影=阵列（列）
试一试{
cursor=context.contentResolver.query（uri！！，投影，选择，selectionArgs，null）
if（cursor！=null&&cursor.moveToFirst（））{
val index=cursor.getColumnIndexOrThrow（列）
返回cursor.getString（索引）
}
}最后{
C
else if ("content".equals(uri.scheme!!, ignoreCase = true)) {
else if (uri.scheme?.equals("content", ignoreCase = true) == true) {
public actual fun String?.equals(other: String?, ignoreCase: Boolean = false): Boolean {
if (this === null)
return other === null
return if (!ignoreCase) (this as java.lang.String).equals(other)
else (this as java.lang.String).equalsIgnoreCase(other)
}