默认情况下，保存到内部存储的文件对您的应用程序是私有的，而其他应用程序无法访问它们（用户也不能）。
我能够在DDMS中看到文件“/ data / data / package_name / files / in file explore，但是当我在电子邮件中使用imageUri附加上述文件URI时，我看到附件的文件是0kb。 我使用了Android的默认电子邮件API。
有人可以建议我，如何将文件附加到应用程序专用的电子邮件中？
虽然我已成功将文件保存在SD卡中并从SD卡附加文件，但这样可以正常工作。
但是如果SD卡不可用并将文件保存到内部存储器，那么我该如何将它们附加到电子邮件中。
String FILENAME = "hello_file.txt";
String string = "hello world!";FileOutputStream fos = openFileOutput(FILENAME, Context.MODE_PRIVATE);
fos.write(string.getBytes());
fos.close();
File imageFile = getFileStreamPath(FILENAME );
Uri imageUri = Uri.fromFile(imageFile);
final Intent emailIntent = new Intent(android.content.Intent.ACTION_SEND);
emailIntent.setType("*/*");
emailIntent.putExtra(android.content.Intent.EXTRA_STREAM,imageUri);
this.startActivityForResult(Intent.createChooser(emailIntent, "Send mail..."),SUB_ACTIVITY);
答案 0 :(得分：6)
当您尝试从内部存储中附加文件时，GMail会将错误写入日志：
ERROR/Gmail(...): file:// attachment paths must point to file:///mnt/sdcard.
电子邮件应用程序会显示附件，即使它实际上不存在。
至于外部存储，文档说：
每个Android兼容设备都支持可用于保存文件的共享“外部存储”。这可以是可移动存储介质（例如SD卡）或内部（不可移动）存储。
这意味着您根本不必担心设备根本没有外部存储设备。尽管如此，外部存储有时也无法使用。请参阅http://developer.android.com/guide/topics/data/data-storage.html#filesExternal
答案 1 :(得分：5)
Android: Attaching files from internal cache to Gmail
package com.stephendnicholas.gmailattach;
import java.io.File;
import java.io.FileNotFoundException;
import android.content.ContentProvider;
import android.content.ContentValues;
import android.content.UriMatcher;
import android.database.Cursor;
import android.net.Uri;
import android.os.ParcelFileDescriptor;
import android.util.Log;
public class CachedFileProvider extends ContentProvider {
private static final String CLASS_NAME = "CachedFileProvider";
// The authority is the symbolic name for the provider class
public static final String AUTHORITY = "com.stephendnicholas.gmailattach.provider";
// UriMatcher used to match against incoming requests
private UriMatcher uriMatcher;
@Override
public boolean onCreate() {
uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
// Add a URI to the matcher which will match against the form
// 'content://com.stephendnicholas.gmailattach.provider/*'
// and return 1 in the case that the incoming Uri matches this pattern
uriMatcher.addURI(AUTHORITY, "*", 1);
return true;
}
@Override
public ParcelFileDescriptor openFile(Uri uri, String mode)
throws FileNotFoundException {
String LOG_TAG = CLASS_NAME + " - openFile";
Log.v(LOG_TAG,
"Called with uri: '" + uri + "'." + uri.getLastPathSegment());
// Check incoming Uri against the matcher
switch (uriMatcher.match(uri)) {
// If it returns 1 - then it matches the Uri defined in onCreate
case 1:
// The desired file name is specified by the last segment of the
// path
// E.g.
// 'content://com.stephendnicholas.gmailattach.provider/Test.txt'
// Take this and build the path to the file
String fileLocation = getContext().getCacheDir() + File.separator
+ uri.getLastPathSegment();
// Create & return a ParcelFileDescriptor pointing to the file
// Note: I don't care what mode they ask for - they're only getting
// read only
ParcelFileDescriptor pfd = ParcelFileDescriptor.open(new File(
fileLocation), ParcelFileDescriptor.MODE_READ_ONLY);
return pfd;
// Otherwise unrecognised Uri
default:
Log.v(LOG_TAG, "Unsupported uri: '" + uri + "'.");
throw new FileNotFoundException("Unsupported uri: "
+ uri.toString());
}
}
// //////////////////////////////////////////////////////////////
// Not supported / used / required for this example
// //////////////////////////////////////////////////////////////
@Override
public int update(Uri uri, ContentValues contentvalues, String s,
String[] as) {
return 0;
}
@Override
public int delete(Uri uri, String s, String[] as) {
return 0;
}
@Override
public Uri insert(Uri uri, ContentValues contentvalues) {
return null;
}
@Override
public String getType(Uri uri) {
return null;
}
@Override
public Cursor query(Uri uri, String[] projection, String s, String[] as1,
String s1) {
return null;
}
}
<provider android:name="CachedFileProvider" android:authorities="com.stephendnicholas
public static void createCachedFile(Context context, String fileName,
String content) throws IOException {
File cacheFile = new File(context.getCacheDir() + File.separator
+ fileName);
cacheFile.createNewFile();
FileOutputStream fos = new FileOutputStream(cacheFile);
OutputStreamWriter osw = new OutputStreamWriter(fos, "UTF8");
PrintWriter pw = new PrintWriter(osw);
pw.println(content);
pw.flush();
pw.close();
}
public static Intent getSendEmailIntent(Context context, String email,
String subject, String body, String fileName) {
final Intent emailIntent = new Intent(
android.content.Intent.ACTION_SEND);
//Explicitly only use Gmail to send
emailIntent.setClassName("com.google.android.gm","com.google.android.gm.ComposeActivityGmail");
emailIntent.setType("plain/text");
//Add the recipients
emailIntent.putExtra(android.content.Intent.EXTRA_EMAIL,
new String[] { email });
emailIntent.putExtra(android.content.Intent.EXTRA_SUBJECT, subject);
emailIntent.putExtra(android.content.Intent.EXTRA_TEXT, body);
//Add the attachment by specifying a reference to our custom ContentProvider
//and the specific file of interest
emailIntent.putExtra(
Intent.EXTRA_STREAM,
Uri.parse("content://" + CachedFileProvider.AUTHORITY + "/"
+ fileName));
return emailIntent;
}
enter code here
答案 2 :(得分：4)
要共享私人文件，您需要使用ContentProvider来提供其他应用程序对您的文件的访问权限。这是一个很好的例子：Android: Attaching files from internal cache to Gmail。
此外，虽然教程提到您需要在Android清单文件中声明您的提供程序，但它没有指定它应该包含在<application>中，因此请确保在声明它在<application> </application>内时1}}。
答案 3 :(得分：3)
本准则可以帮助您了解附件：
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
buttonSend = (Button) findViewById(R.id.buttonSend);
textTo = (EditText) findViewById(R.id.editTextTo);
textSubject = (EditText) findViewById(R.id.editTextSubject);
textMessage = (EditText) findViewById(R.id.editTextMessage);
buttonSend.setOnClickListener( new OnClickListener() {
@Override
public void onClick(View v) {
String to = textTo.getText().toString();
String subject = textSubject.getText().toString();
String message = textMessage.getText().toString();
Intent i = new Intent(Intent.ACTION_SEND);
i.setType("plain/text");
File data = null;
try {
Date dateVal = new Date();
String filename = dateVal.toString();
data = File.createTempFile("Report", ".csv");
FileWriter out = (FileWriter) GenerateCsv.generateCsvFile(
data, "Name,Data1");
i.putExtra(Intent.EXTRA_STREAM, Uri.fromFile(data));
i.putExtra(Intent.EXTRA_EMAIL, new String[] { to });
i.putExtra(Intent.EXTRA_SUBJECT, subject);
i.putExtra(Intent.EXTRA_TEXT, message);
startActivity(Intent.createChooser(i, "E-mail"));
} catch (IOException e) {
e.printStackTrace();
}
}
});
}
public class GenerateCsv
{
public static FileWriter generateCsvFile(File sFileName,String fileContent)
{
FileWriter writer = null;
try {
writer = new FileWriter(sFileName);
writer.append(fileContent);
writer.flush();
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
writer.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return writer;
}
}
上述代码要求您向清单文件添加以下权限：
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"></uses-permission>
答案 4 :(得分：1)
保存文件时，请尝试使用Context.MODE_WORLD_READABLE而不是Context.MODE_PRIVATE。然后其他应用程序将有权访问该文件。
答案 5 :(得分：1)
我也遇到过使用内部文件的问题，虽然我在/data/data//files/testFileName.txt上使用了带有MODE_WORLD_READABLE的openFileInput，并使用带有额外“/”的URI.parse（见下文），通过电子邮件收到的测试仍然缺乏所需的附件。很抱歉，但没有答案，除了尝试在SD卡上使用外部文件 - 这是我的下一个实验！
代码：
File tmpFile = new File(context.getFilesDir(), mfileName);
Log.d(TAG, tmpFile.toString());
// This shows: /data/data/org.eddiem.adeveloper.flatfiletest/files/testFile.csv
//File tmpFile2 = new File(context.getFileStreamPath(mfileName), mfileName);
//Log.v(TAG, tmpFile2.toString());
// This also shows: /data/data/org.eddiem.adeveloper.flatfiletest/files/testFile.csv
//Uri uri = Uri.fromFile(new File(context.getFileStreamPath(mfileName), mfileName));
Uri uri = Uri.parse("file://" + tmpFile.toString());
//Uri uri = Uri.fromFile(new File(Environment.getExternalStorageDirectory(),
// mfileName));
Log.d(TAG, "Uri-path is: " + uri.getPath()); // or .toString()
Intent i = new Intent(android.content.Intent.ACTION_SEND);
i.setType("text/plain");
i.putExtra(Intent.EXTRA_EMAIL, new String[]{"eddie.moxey@sky.com"});
i.putExtra(Intent.EXTRA_SUBJECT, "Test Email - with Attachment");
i.putExtra(Intent.EXTRA_TEXT, "This is a test Email with an Attachment.");
i.putExtra(Intent.EXTRA_STREAM, uri);
//startActivity(Intent.createChooser(i, "Select application"));
startActivity(Intent.createChooser(i, "Send mail"));
答案 6 :(得分：0)
我遇到了同样的问题，后来为我工作。
首先发送广播以通知设备创建/安装文件。
例如：
sendBroadcast(new Intent(Intent.ACTION_MEDIA_MOUNTED,Uri.parse("file://"+storagePath)));
然后使用代码发送带附件的邮件。
Intent email = new Intent(Intent.ACTION_SEND);
email.putExtra(Intent.EXTRA_EMAIL, "Receiver Email Address" );
email.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
email.putExtra(Intent.EXTRA_SUBJECT, "Subject");
email.putExtra(Intent.EXTRA_TEXT,"Email Text");
//Mime type of the attachment (or) u can use sendIntent.setType("*/*")
//email.setType("text/plain");
email.setType("application/YourMimeType");
//Full Path to the attachment
email.putExtra(Intent.EXTRA_STREAM, Uri.parse("file://"+storagePath));
try
{
startActivity(Intent.createChooser(email, "Send Message..."));
}
catch (android.content.ActivityNotFoundException ex)
{
}