本地文件读取是开发中常用的功能,这里介绍一个使用系统本地的文件管理器去选择需要的文件。代码如下:
1. Activity 定义的返回接收函数和点击触发函数:
- @Override
- protected void onActivityResult(int requestCode, int resultCode, Intent data) {
- super.onActivityResult(requestCode, resultCode, data);
- Log.e(TAG,"onActivityResult:" + "requestCode " + requestCode + " resultCode " + resultCode);
- switch (requestCode){
- case REQUEST_FILE_CHOOSE:
- if(resultCode == Activity.RESULT_OK){
- /* 使用系统的文件选择器*/
- try {
- Uri uri = data.getData();//得到uri,后面就是将uri转化成file的过程。
- String path = FileChooseUtil.getPath(this,uri);
- Log.e(TAG,"getPath:" + path);
- if(!isBookDuplicate(path)) {
- File file = new File(path);
- Book book = getFileInfo(file);
- book_list.add(book);
- updateConfigFile();
- updateBookListView();
- Toast.makeText(this, "你已成功导入一本新书了!", Toast.LENGTH_SHORT).show();
- }else {
- Toast.makeText(this, "这个书你已经在看了!", Toast.LENGTH_SHORT).show();
- }
- } catch (Exception e) {
- Toast.makeText(this, "这个书看不了!"+ e.getMessage(), Toast.LENGTH_SHORT).show();
- }
- }
- break;
- default
- break;
- }
- }
- button_add.setOnClickListener(new View.OnClickListener() {
- @Override
- public void onClick(View v) {
- /* 使用系统的文件选择器 */
- Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
- intent.setType("text/plain");//设置类型
- intent.addCategory(Intent.CATEGORY_OPENABLE);
- startActivityForResult(intent, REQUEST_FILE_CHOOSE);
- }
- });
2. 新建一个FileChooseUtil来处理不同sdk版本下的文件路径获取:
- import android.annotation.SuppressLint;
- import android.content.ContentUris;
- import android.content.Context;
- import android.database.Cursor;
- import android.net.Uri;
- import android.os.Build;
- import android.os.Environment;
- import android.provider.DocumentsContract;
- import android.provider.MediaStore;
- @SuppressLint("NewApi")
- public class FileChooseUtil {
- /**
- * Get a file path from a Uri. This will get the the path for Storage Access
- * Framework Documents, as well as the _data field for the MediaStore and
- * other file-based ContentProviders.
- *
- * @param context The context.
- * @param uri The Uri to query.
- */
- public static String getPath(final Context context, final Uri uri) {
- final boolean isKitKat = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT;
- // DocumentProvider
- if (isKitKat && DocumentsContract.isDocumentUri(context, uri)) {
- // ExternalStorageProvider
- 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];
- }
- // TODO handle non-primary volumes
- }
- // 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 getDataColumn(context, uri, null, null);
- }
- // File
- else if ("file".equalsIgnoreCase(uri.getScheme())) {
- 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;
- final String column = "_data";
- final String[] projection = {
- column
- };
- try {
- cursor = context.getContentResolver().query(uri, projection, selection, selectionArgs,
- null);
- if (cursor != null && cursor.moveToFirst()) {
- final 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());
- }
- }
以上就可以进行简单的文件选择
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