内容提供者 DocumentProvider Uri工具类-优快云博客

本文介绍Android中使用Storage Access Framework进行文件选择与读取的方法，并详细解析如何通过不同类型的URI获取文件路径。

Activity

/**详见http://blog.youkuaiyun.com/coder_pig/article/details/47905881

Calendar Provider：日历提供者，就是针对针对日历相关事件的一个资源库，通过他提供的API，我们可以对日历，时间，会议，提醒等内容做一些增删改查！

Contacts Provider：联系人提供者，这个就不用说了，这个用得最多

Storage Access Framework(SAF)：存储访问框架，4.4以后引入的一个新玩意，为用户浏览手机中的存储内容提供了便利。

可供访问的内容不仅包括：文档，图片，视频，音频，下载，而且包含所有由特定ContentProvider（须具有约定的API）提供的内容。

不管这些内容来自于哪里，不管是哪个应用调用浏览系统文件内容的命令，系统都会用一个统一的界面让你去浏览。

其实就是一个内置的应用程序，叫做DocumentsUI，因为它的IntentFilter不带有LAUNCHER，所以我们不能在桌面上找到这个东东！

public class MainActivity extends ListActivity {

private TextView tv_info;

private static final int READ_REQUEST_CODE = 42;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

List<String> mData = new ArrayList<String>(Arrays.asList("获取一张图片的Uri及Path", "", "", "", ""));

ListAdapter mAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, mData);

tv_info = new TextView(this);// 将内容显示在TextView中

tv_info.setTextColor(Color.BLUE);

tv_info.setTextSize(TypedValue.COMPLEX_UNIT_SP, 16);

tv_info.setPadding(20, 10, 20, 10);

getListView().addFooterView(tv_info);

setListAdapter(mAdapter);

}

@Override

protected void onListItemClick(ListView l, View v, int position, long id) {

switch (position) {

case 0:

Intent intent = new Intent(Intent.ACTION_OPEN_DOCUMENT);//Field requires API level 19

intent.addCategory(Intent.CATEGORY_OPENABLE);

intent.setType("image/*");

startActivityForResult(intent, READ_REQUEST_CODE);

break;

case 1:

break;

case 2:

break;

case 3:

break;

case 4:

break;

}

@Override

protected void onActivityResult(int requestCode, int resultCode, Intent data) {

if (requestCode == READ_REQUEST_CODE && resultCode == Activity.RESULT_OK) {

if (data != null) {

Uri uri = data.getData();

Log.i("bqt", "Uri: " + uri.toString() + "\nPath: " + UriPathUtils.getPath(this, uri));

tv_info.setText("Uri: " + uri.toString() + "\nPath: " + UriPathUtils.getPath(this, uri));

// 4.4之前：Uri: content://com.android.externalstorage.documents/document/primary%3A1.png。Path: /storage/emulated/0/1.png

// 4.4之后：Uri: content://com.android.providers.media.documents/document/image%3A16025。 Path: /storage/emulated/0/very_big.jpg

}

UriPathUtils

public class UriPathUtils {

/**获取Uri对应的文件的路径。 4.4之后需增加权限 <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />*/

public static String getPath(Context context, Uri uri) {

boolean isKitKat = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT;//19

if (isKitKat && DocumentsContract.isDocumentUri(context, uri)) { // 【DocumentProvider】

if (isExternalStorageDocument(uri)) { // 【ExternalStorageProvider】

String docId = DocumentsContract.getDocumentId(uri);

String[] split = docId.split(":");

String type = split[0];

if ("primary".equalsIgnoreCase(type)) return Environment.getExternalStorageDirectory() + "/" + split[1];

} else if (isDownloadsDocument(uri)) { // 【DownloadsProvider】

String id = DocumentsContract.getDocumentId(uri);

Uri contentUri = ContentUris.withAppendedId(Uri.parse("content://downloads/public_downloads"), Long.valueOf(id));

return getDataColumn(context, contentUri, null, null);

} else if (isMediaDocument(uri)) { // 【MediaProvider】

String docId = DocumentsContract.getDocumentId(uri);

String[] split = docId.split(":");

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;

String selection = "_id=?";

String[] selectionArgs = new String[] { split[1] };

return getDataColumn(context, contentUri, selection, selectionArgs);

}

} else if ("content".equalsIgnoreCase(uri.getScheme())) { // 【MediaStore (and general)】

return getDataColumn(context, uri, null, null);

} else if ("file".equalsIgnoreCase(uri.getScheme())) { // 【File】

return uri.getPath();

}

return null;

}

/**

* Get the value of the data column for this Uri. This is useful for MediaStore Uris, and other file-based ContentProviders.

* @param context The context.

* @param uri The Uri to query.

* @param selection (Optional) Filter used in the query.

* @param selectionArgs (Optional) Selection arguments used in the query.

* @return The value of the _data column, which is typically a file path.

public static String getDataColumn(Context context, Uri uri, String selection, String[] selectionArgs) {

Cursor cursor = null;

String column = "_data";

String[] projection = { column };

try {

cursor = context.getContentResolver().query(uri, projection, selection, selectionArgs, null);

if (cursor != null && cursor.moveToFirst()) {

int column_index = cursor.getColumnIndexOrThrow(column);

return cursor.getString(column_index);

}

} finally {

if (cursor != null) cursor.close();

}

return null;

}

/**

* @param uri The Uri to check.

* @return Whether the Uri authority is ExternalStorageProvider.

public static boolean isExternalStorageDocument(Uri uri) {

return "com.android.externalstorage.documents".equals(uri.getAuthority());

}

/**

* @param uri The Uri to check.

* @return Whether the Uri authority is DownloadsProvider.

public static boolean isDownloadsDocument(Uri uri) {

return "com.android.providers.downloads.documents".equals(uri.getAuthority());

}

/**

* @param uri The Uri to check.

* @return Whether the Uri authority is MediaProvider.

public static boolean isMediaDocument(Uri uri) {

return "com.android.providers.media.documents".equals(uri.getAuthority());

}

UriUtils

public class UriUtils {

private static final int WRITE_REQUEST_CODE = 43;

/**根据uri获取文件参数*/

public static void dumpImageMetaData(Context context, Uri uri) {

Cursor cursor = context.getContentResolver().query(uri, null, null, null, null, null);

try {

if (cursor != null && cursor.moveToFirst()) {

String displayName = cursor.getString(cursor.getColumnIndex(OpenableColumns.DISPLAY_NAME));

Log.e("HeHe", "Display Name: " + displayName);

int sizeIndex = cursor.getColumnIndex(OpenableColumns.SIZE);

String size = null;

if (!cursor.isNull(sizeIndex)) {

size = cursor.getString(sizeIndex);

} else {

size = "Unknown";

}

Log.e("HeHe", "Size: " + size);

}

} finally {

cursor.close();

}

/**根据Uri获得Bitmap*/

public static Bitmap getBitmapFromUri(Context context, Uri uri) throws IOException {

ParcelFileDescriptor parcelFileDescriptor = context.getContentResolver().openFileDescriptor(uri, "r");

FileDescriptor fileDescriptor = parcelFileDescriptor.getFileDescriptor();

Bitmap image = BitmapFactory.decodeFileDescriptor(fileDescriptor);

parcelFileDescriptor.close();

return image;

}

/** 根据Uri获取输入流 */

public static String readTextFromUri(Context context, Uri uri) throws IOException {

InputStream inputStream = context.getContentResolver().openInputStream(uri);

BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));

StringBuilder stringBuilder = new StringBuilder();

String line;

while ((line = reader.readLine()) != null) {

stringBuilder.append(line);

}

inputStream.close();

reader.close();

return stringBuilder.toString();

}

/** 创建文件，可在onActivityResult()中获取被创建文件的uri */

public static void createFile(Activity context, String mimeType, String fileName) {

Intent intent = new Intent(Intent.ACTION_CREATE_DOCUMENT);

intent.addCategory(Intent.CATEGORY_OPENABLE);

intent.setType(mimeType);

intent.putExtra(Intent.EXTRA_TITLE, fileName);

context.startActivityForResult(intent, WRITE_REQUEST_CODE);

}

来自为知笔记(Wiz)

转载于:https://www.cnblogs.com/baiqiantao/p/5535837.html