Question

请参阅下面的EDIT 1

我正在使用此类FileUtils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;
}

从设备中选择视频后，我在MainActivity内的onActivityResult中调用它：

@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);
    }


}

在我的PlayerActivity中，我得到String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);

在我的设备上进行测试时，我没有任何问题。我得到正确的路径，并且Uri.parse工作正常。但是我在我的crashlytics上看到了很多崩溃，他们说-nullpointerexception at line 59，指的是mVideoUri = Uri.parse(mStringFilePath);

有人可以告诉我我做错了什么吗？为什么它可以在我的设备上运行，而在其他一些设备上返回null？

编辑1：

我忘记在清单中添加<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />。我到了至少无法获得nullpointerexception的地步，但是我得到了以下内容-

java.io.FileNotFoundException: Not found (No such file or directory)

当我从SD卡中选择文件时，Uri不正确是什么原因？

Answer 1

崩溃可能是由于mStringFilePath = getIntent().getStringExtra("videoUri");上的null字符串引起的，因为getIntent().getStringExtras()不会在请求的Extras没有值的情况下抛出nullpointerexception异常，但也不会将数据提供给分配的变量mStringFilePath的最终结果将为null以解决此问题，请确保将uri解析的给定字符串包装在以下位置：

if（mStringFilePath！= null）{mVideoUri = Uri.parse（mStringFilePath）; }

尝试从字符串路径解析Uri时为空

1 个答案: