Java 尝试从字符串路径解析Uri时为Null
我使用这个Java 尝试从字符串路径解析Uri时为Null,java,android,Java,Android,我使用这个FileUtils类来处理Uri: public class FileUtils { private FileUtils() { } private static final String TAG = "FileUtils"; private static final boolean DEBUG = false; private static boolean isExternalStorageDocument(Uri uri) { return &quo
FileUtils
类来处理Uri
:
public class FileUtils {
private FileUtils() {
}
private static final String TAG = "FileUtils";
private static final boolean DEBUG = false;
private static boolean isExternalStorageDocument(Uri uri) {
return "com.android.externalstorage.documents".equals(uri.getAuthority());
}
private static boolean isDownloadsDocument(Uri uri) {
return "com.android.providers.downloads.documents".equals(uri.getAuthority());
}
private static boolean isMediaDocument(Uri uri) {
return "com.android.providers.media.documents".equals(uri.getAuthority());
}
private static boolean isGooglePhotosUri(Uri uri) {
return "com.google.android.apps.photos.content".equals(uri.getAuthority());
}
private static String getDataColumn(Context context, Uri uri, String selection,
String[] selectionArgs) {
Cursor cursor = null;
final String column = "_data";
final String[] projection = {
column
};
try {
cursor = context.getContentResolver().query(uri, projection, selection, selectionArgs,
null);
if (cursor != null && cursor.moveToFirst()) {
if (DEBUG)
DatabaseUtils.dumpCursor(cursor);
final int column_index = cursor.getColumnIndexOrThrow(column);
return cursor.getString(column_index);
}
} finally {
if (cursor != null)
cursor.close();
}
return null;
}
@RequiresApi(api = Build.VERSION_CODES.KITKAT)
public static String getPath(final Context context, final Uri uri) {
if (DEBUG)
Log.d(TAG + " File -",
"Authority: " + uri.getAuthority() +
", Fragment: " + uri.getFragment() +
", Port: " + uri.getPort() +
", Query: " + uri.getQuery() +
", Scheme: " + uri.getScheme() +
", Host: " + uri.getHost() +
", Segments: " + uri.getPathSegments().toString()
);
final boolean isKitKat = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT;
// DocumentProvider
if (isKitKat && DocumentsContract.isDocumentUri(context, uri)) {
if (isExternalStorageDocument(uri)) {
final String docId = DocumentsContract.getDocumentId(uri);
final String[] split = docId.split(":");
final String type = split[0];
if ("primary".equalsIgnoreCase(type)) {
return Environment.getExternalStorageDirectory() + "/" + split[1];
}
}
// DownloadsProvider
else if (isDownloadsDocument(uri)) {
final String id = DocumentsContract.getDocumentId(uri);
final Uri contentUri = ContentUris.withAppendedId(
Uri.parse("content://downloads/public_downloads"), Long.valueOf(id));
return getDataColumn(context, contentUri, null, null);
}
// MediaProvider
else if (isMediaDocument(uri)) {
final String docId = DocumentsContract.getDocumentId(uri);
final String[] split = docId.split(":");
final String type = split[0];
Uri contentUri = null;
if ("image".equals(type)) {
contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
} else if ("video".equals(type)) {
contentUri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI;
} else if ("audio".equals(type)) {
contentUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
}
final String selection = "_id=?";
final String[] selectionArgs = new String[]{
split[1]
};
return getDataColumn(context, contentUri, selection, selectionArgs);
}
}
// MediaStore (and general)
else if ("content".equalsIgnoreCase(uri.getScheme())) {
// Return the remote address
if (isGooglePhotosUri(uri))
return uri.getLastPathSegment();
return getDataColumn(context, uri, null, null);
}
// File
else if ("file".equalsIgnoreCase(uri.getScheme())) {
return uri.getPath();
}
return null;
}
在从设备中选择视频后,我在我的main活动
中,在活动结果的内调用它:
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == SELECT_VIDEO_REQUEST && resultCode == RESULT_OK) {
if (Build.VERSION.SDK_INT >= 19) {
//Calling FileUtils class
String sourcePath = FileUtils.getPath(getApplicationContext(), data.getData());
Intent intent = new Intent();
intent.setClass(MainActivity.this, PlayerActivity.class);
intent.putExtra("videoUri", sourcePath);
startActivity(intent);
} else {
//Not relevant to the question
.......
}
}
if (requestCode == SELECT_VIDEO_REQUEST && resultCode != RESULT_OK) {
Toast.makeText(getApplicationContext(), "Failed to select video", Toast.LENGTH_LONG).show();
} else {
super.onActivityResult(requestCode, resultCode, data);
}
}
在myPlayerActivity
中,我获取字符串
,并尝试解析Uri
,如下所示:
//Getting String from Intent
mStringFilePath = getIntent().getStringExtra("videoUri");
//Parse Uri from String
mVideoUri = Uri.parse(mStringFilePath);
在我的设备上测试时,我没有任何问题。我得到了正确的路径,Uri.parse
工作正常。但是我在Crashlytics上看到很多崩溃,在第59行出现了-nullpointerexception,指的是mVideoUri=Uri.parse(mStringFilePath)代码>
我做错了什么?为什么它在我的设备上工作,而在其他一些设备上返回空值
编辑1
我忘了在我的清单中添加
。我至少没有得到一个nullpointerexception
,但我得到了以下结果-
java.io.FileNotFoundException:找不到(没有这样的文件或目录)
从SD卡中选择文件时,Uri
不正确,原因是什么?崩溃可能是由于mStringFilePath=getIntent().getStringExtra(“videoUri”)上的空字符串造成的
由于getIntent().getStringExtras()
不会引发nullpointerexception,如果请求的Extras没有值,也不会向分配的变量提供数据,mStringFilePath
的最终结果将为null以解决此问题确保uri解析的给定字符串已包装在:
如果(mStringFilePath!=null){mVideoUri=Uri.parse(mStringFilePath);}
是的,我知道,但我想知道为什么它是空的。在我的设备上,我得到了预期的路径和uri。检查它是否为空并不能解决问题。哦,我在这段代码中看到的唯一当前问题是设备上没有处理非主卷,如果您可以访问SD卡,请尝试发送附加到SD卡的文件并查看结果(isExternalStorageDocument(uri)){final String docId=DocumentsContract.getDocumentId(uri);final String[]split=docId.split(“:”);final String type=split[0];//以下是我在以下情况下仅处理主卷的意思(“primary”.equalsIgnoreCase(type)){return Environment.getExternalStorageDirectory()+“/”+split[1];}}好的,我会尝试一下,让你知道。我想你是对的,我的设备中没有SD卡,这就是为什么我没有遇到这个问题。你可以检查这个,了解如何实现SD卡存储以从uri获取路径的信息