/**
* Copyright (c) 2010, The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.content;
import android.content.res.AssetFileDescriptor;
import android.graphics.Bitmap;
import android.net.Uri;
import android.os.Parcel;
import android.os.Parcelable;
import android.text.TextUtils;
import android.util.Log;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
/**
* Representation of a clipped data on the clipboard.
*
* <p>ClippedData is a complex type containing one or Item instances,
* each of which can hold one or more representations of an item of data.
* For display to the user, it also has a label and iconic representation.</p>
*
* <p>A ClipData contains a {@link ClipDescription}, which describes
* important meta-data about the clip. In particular, its
* {@link ClipDescription#getMimeType(int) getDescription().getMimeType(int)}
* must return correct MIME type(s) describing the data in the clip. For help
* in correctly constructing a clip with the correct MIME type, use
* {@link #newPlainText(CharSequence, CharSequence)},
* {@link #newUri(ContentResolver, CharSequence, Uri)}, and
* {@link #newIntent(CharSequence, Intent)}.
*
* <p>Each Item instance can be one of three main classes of data: a simple
* CharSequence of text, a single Intent object, or a Uri. See {@link Item}
* for more details.
*
* <div class="special reference">
* <h3>Developer Guides</h3>
* <p>For more information about using the clipboard framework, read the
* <a href="{@docRoot}guide/topics/clipboard/copy-paste.html">Copy and Paste</a>
* developer guide.</p>
* </div>
*
* <a name="ImplementingPaste"></a>
* <h3>Implementing Paste or Drop</h3>
*
* <p>To implement a paste or drop of a ClippedData object into an application,
* the application must correctly interpret the data for its use. If the {@link Item}
* it contains is simple text or an Intent, there is little to be done: text
* can only be interpreted as text, and an Intent will typically be used for
* creating shortcuts (such as placing icons on the home screen) or other
* actions.
*
* <p>If all you want is the textual representation of the clipped data, you
* can use the convenience method {@link Item#coerceToText Item.coerceToText}.
* In this case there is generally no need to worry about the MIME types
* reported by {@link ClipDescription#getMimeType(int) getDescription().getMimeType(int)},
* since any clip item an always be converted to a string.
*
* <p>More complicated exchanges will be done through URIs, in particular
* "content:" URIs. A content URI allows the recipient of a ClippedData item
* to interact closely with the ContentProvider holding the data in order to
* negotiate the transfer of that data. The clip must also be filled in with
* the available MIME types; {@link #newUri(ContentResolver, CharSequence, Uri)}
* will take care of correctly doing this.
*
* <p>For example, here is the paste function of a simple NotePad application.
* When retrieving the data from the clipboard, it can do either two things:
* if the clipboard contains a URI reference to an existing note, it copies
* the entire structure of the note into a new note; otherwise, it simply
* coerces the clip into text and uses that as the new note's contents.
*
* {@sample development/samples/NotePad/src/com/example/android/notepad/NoteEditor.java
* paste}
*
* <p>In many cases an application can paste various types of streams of data. For
* example, an e-mail application may want to allow the user to paste an image
* or other binary data as an attachment. This is accomplished through the
* ContentResolver {@link ContentResolver#getStreamTypes(Uri, String)} and
* {@link ContentResolver#openTypedAssetFileDescriptor(Uri, String, android.os.Bundle)}
* methods. These allow a client to discover the type(s) of data that a particular
* content URI can make available as a stream and retrieve the stream of data.
*
* <p>For example, the implementation of {@link Item#coerceToText Item.coerceToText}
* itself uses this to try to retrieve a URI clip as a stream of text:
*
* {@sample frameworks/base/core/java/android/content/ClipData.java coerceToText}
*
* <a name="ImplementingCopy"></a>
* <h3>Implementing Copy or Drag</h3>
*
* <p>To be the source of a clip, the application must construct a ClippedData
* object that any recipient can interpret best for their context. If the clip
* is to contain a simple text, Intent, or URI, this is easy: an {@link Item}
* containing the appropriate data type can be constructed and used.
*
* <p>More complicated data types require the implementation of support in
* a ContentProvider for describing and generating the data for the recipient.
* A common scenario is one where an application places on the clipboard the
* content: URI of an object that the user has copied, with the data at that
* URI consisting of a complicated structure that only other applications with
* direct knowledge of the structure can use.
*
* <p>For applications that do not have intrinsic knowledge of the data structure,
* the content provider holding it can make the data available as an arbitrary
* number of types of data streams. This is done by implementing the
* ContentProvider {@link ContentProvider#getStreamTypes(Uri, String)} and
* {@link ContentProvider#openTypedAssetFile(Uri, String, android.os.Bundle)}
* methods.
*
* <p>Going back to our simple NotePad application, this is the implementation
* it may have to convert a single note URI (consisting of a title and the note
* text) into a stream of plain text data.
*
* {@sample development/samples/NotePad/src/com/example/android/notepad/NotePadProvider.java
* stream}
*
* <p>The copy operation in our NotePad application is now just a simple matter
* of making a clip containing the URI of the note being copied:
*
* {@sample development/samples/NotePad/src/com/example/android/notepad/NotesList.java
* copy}
*
* <p>Note if a paste operation needs this clip as text (for example to paste
* into an editor), then {@link Item#coerceToText(Context)} will ask the content
* provider for the clip URI as text and successfully paste the entire note.
*/
public class ClipData implements Parcelable {
static final String[] MIMETYPES_TEXT_PLAIN = new String[] {
ClipDescription.MIMETYPE_TEXT_PLAIN };
static final String[] MIMETYPES_TEXT_URILIST = new String[] {
ClipDescription.MIMETYPE_TEXT_URILIST };
static final String[] MIMETYPES_TEXT_INTENT = new String[] {
ClipDescription.MIMETYPE_TEXT_INTENT };
final ClipDescription mClipDescription;
final Bitmap mIcon;
final ArrayList<Item> mItems = new ArrayList<Item>();
/**
* Description of a single item in a ClippedData.
*
* <p>The types than an individual item can currently contain are:</p>
*
* <ul>
* <li> Text: a basic string of text. This is actually a CharSequence,
* so it can be formatted text supported by corresponding Android built-in
* style spans. (Custom application spans are not supported and will be
* stripped when transporting through the clipboard.)
* <li> Intent: an arbitrary Intent object. A typical use is the shortcut
* to create when pasting a clipped item on to the home screen.
* <li> Uri: a URI reference. This may be any URI (such as an http: URI
* representing a bookmark), however it is often a content: URI. Using
* content provider references as clips like this allows an application to
* share complex or large clips through the standard content provider
* facilities.
* </ul>
*/
public static class Item {
final CharSequence mText;
final Intent mIntent;
final Uri mUri;
/**
* Create an Item consisting of a single block of (possibly styled) text.
*/
public Item(CharSequence text) {
mText = text;
mIntent = null;
mUri = null;
}
/**
* Create an Item consisting of an arbitrary Intent.
*/
public Item(Intent intent) {
mText = null;
mIntent = intent;
mUri = null;
}
/**
* Create an Item consisting of an arbitrary URI.
*/
public Item(Uri uri) {
mText = null;
mIntent = null;
mUri = uri;
}
/**
* Create a complex Item, containing multiple representations of
* text, intent, and/or URI.
*/
public Item(CharSequence text, Intent intent, Uri uri) {
mText = text;
mIntent = intent;
mUri = uri;
}
/**
* Retrieve the raw text contained in this Item.
*/
public CharSequence getText() {
return mText;
}
/**
* Retrieve the raw Intent contained in this Item.
*/
public Intent getIntent() {
return mIntent;
}
/**
* Retrieve the raw URI contained in this Item.
*/
public Uri getUri() {
return mUri;
}
/**
* Turn this item into text, regardless of the type of data it
* actually contains.
*
* <p>The algorithm for deciding what text to return is:
* <ul>
* <li> If {@link #getText} is non-null, return that.
* <li> If {@link #getUri} is non-null, try to retrieve its data
* as a text stream from its content provider. If this succeeds, copy
* the text into a String and return it. If it is not a content: URI or
* the content provider does not supply a text representation, return
* the raw URI as a string.
* <li> If {@link #getIntent} is non-null, convert that to an intent:
* URI and returnit.
* <li> Otherwise, return an empty string.
* </ul>
*
* @param context The caller's Context, from which its ContentResolver
* and other things can be retrieved.
* @return Returns the item's textual representation.
*/
//BEGIN_INCLUDE(coerceToText)
public CharSequence coerceToText(Context context) {
// If this Item has an explicit textual value, simply return that.
if (mText != null) {
return mText;
}
// If this Item has a URI value, try using that.
if (mUri != null) {
// First see if the URI can be opened as a plain text stream
// (of any sub-type). If so, this is the best textual
// representation for it.
FileInputStream stream = null;
try {
// Ask for a stream of the desired type.
AssetFileDescriptor descr = context.getContentResolver()
.openTypedAssetFileDescriptor(mUri, "text/*", null);
stream = descr.createInputStream();
InputStreamReader reader = new InputStreamReader(stream, "UTF-8");
// Got it... copy the stream into a local string and return it.
StringBuilder builder = new StringBuilder(128);
char[] buffer = new char[8192];
int len;
while ((len=reader.read(buffer)) > 0) {
builder.append(buffer, 0, len);
}
return builder.toString();
} catch (FileNotFoundException e) {
// Unable to open content URI as text... not really an
// error, just something to ignore.
} catch (IOException e) {
// Something bad has happened.
Log.w("ClippedData", "Failure loading text", e);
return e.toString();
} finally {
if (stream != null) {
try {
stream.close();
} catch (IOException e) {
}
}
}
// If we couldn't open the URI as a stream, then the URI itself
// probably serves fairly well as a textual representation.
return mUri.toString();
}
// Finally, if all we have is an Intent, then we can just turn that
// into text. Not the most user-friendly thing, but it's something.
if (mIntent != null) {
return mIntent.toUri(Intent.URI_INTENT_SCHEME);
}
// Shouldn't get here, but just in case...
return "";
}
//END_INCLUDE(coerceToText)
}
/**
* Create a new clip.
*
* @param label Label to show to the user describing this clip.
* @param mimeTypes An array of MIME types this data is available as.
* @param item The contents of the first item in the clip.
*/
public ClipData(CharSequence label, String[] mimeTypes, Item item) {
mClipDescription = new ClipDescription(label, mimeTypes);
if (item == null) {
throw new NullPointerException("item is null");
}
mIcon = null;
mItems.add(item);
}
/**
* Create a new clip.
*
* @param description The ClipDescription describing the clip contents.
* @param item The contents of the first item in the clip.
*/
public ClipData(ClipDescription description, Item item) {
mClipDescription = description;
if (item == null) {
throw new NullPointerException("item is null");
}
mIcon = null;
mItems.add(item);
}
/**
* Create a new ClipData holding data of the type
* {@link ClipDescription#MIMETYPE_TEXT_PLAIN}.
*
* @param label User-visible label for the clip data.
* @param text The actual text in the clip.
* @return Returns a new ClipData containing the specified data.
*/
static public ClipData newPlainText(CharSequence label, CharSequence text) {
Item item = new Item(text);
return new ClipData(label, MIMETYPES_TEXT_PLAIN, item);
}
/**
* Create a new ClipData holding an Intent with MIME type
* {@link ClipDescription#MIMETYPE_TEXT_INTENT}.
*
* @param label User-visible label for the clip data.
* @param intent The actual Intent in the clip.
* @return Returns a new ClipData containing the specified data.
*/
static public ClipData newIntent(CharSequence label, Intent intent) {
Item item = new Item(intent);
return new ClipData(label, MIMETYPES_TEXT_INTENT, item);
}
/**
* Create a new ClipData holding a URI. If the URI is a content: URI,
* this will query the content provider for the MIME type of its data and
* use that as the MIME type. Otherwise, it will use the MIME type
* {@link ClipDescription#MIMETYPE_TEXT_URILIST}.
*
* @param resolver ContentResolver used to get information about the URI.
* @param label User-visible label for the clip data.
* @param uri The URI in the clip.
* @return Returns a new ClipData containing the specified data.
*/
static public ClipData newUri(ContentResolver resolver, CharSequence label,
Uri uri) {
Item item = new Item(uri);
String[] mimeTypes = null;
if ("content".equals(uri.getScheme())) {
String realType = resolver.getType(uri);
mimeTypes = resolver.getStreamTypes(uri, "*/*");
if (mimeTypes == null) {
if (realType != null) {
mimeTypes = new String[] { realType, ClipDescription.MIMETYPE_TEXT_URILIST };
}
} else {
String[] tmp = new String[mimeTypes.length + (realType != null ? 2 : 1)];
int i = 0;
if (realType != null) {
tmp[0] = realType;
i++;
}
System.arraycopy(mimeTypes, 0, tmp, i, mimeTypes.length);
tmp[i + mimeTypes.length] = ClipDescription.MIMETYPE_TEXT_URILIST;
mimeTypes = tmp;
}
}
if (mimeTypes == null) {
mimeTypes = MIMETYPES_TEXT_URILIST;
}
return new ClipData(label, mimeTypes, item);
}
/**
* Create a new ClipData holding an URI with MIME type
* {@link ClipDescription#MIMETYPE_TEXT_URILIST}.
* Unlike {@link #newUri(ContentResolver, CharSequence, Uri)}, nothing
* is inferred about the URI -- if it is a content: URI holding a bitmap,
* the reported type will still be uri-list. Use this with care!
*
* @param label User-visible label for the clip data.
* @param uri The URI in the clip.
* @return Returns a new ClipData containing the specified data.
*/
static public ClipData newRawUri(CharSequence label, Uri uri) {
Item item = new Item(uri);
return new ClipData(label, MIMETYPES_TEXT_URILIST, item);
}
/**
* Return the {@link ClipDescription} associated with this data, describing
* what it contains.
*/
public ClipDescription getDescription() {
return mClipDescription;
}
/**
* Add a new Item to the overall ClipData container.
*/
public void addItem(Item item) {
if (item == null) {
throw new NullPointerException("item is null");
}
mItems.add(item);
}
/** @hide */
public Bitmap getIcon() {
return mIcon;
}
/**
* Return the number of items in the clip data.
*/
public int getItemCount() {
return mItems.size();
}
/**
* Return a single item inside of the clip data. The index can range
* from 0 to {@link #getItemCount()}-1.
*/
public Item getItemAt(int index) {
return mItems.get(index);
}
@Override
public int describeContents() {
return 0;
}
@Override
public void writeToParcel(Parcel dest, int flags) {
mClipDescription.writeToParcel(dest, flags);
if (mIcon != null) {
dest.writeInt(1);
mIcon.writeToParcel(dest, flags);
} else {
dest.writeInt(0);
}
final int N = mItems.size();
dest.writeInt(N);
for (int i=0; i<N; i++) {
Item item = mItems.get(i);
TextUtils.writeToParcel(item.mText, dest, flags);
if (item.mIntent != null) {
dest.writeInt(1);
item.mIntent.writeToParcel(dest, flags);
} else {
dest.writeInt(0);
}
if (item.mUri != null) {
dest.writeInt(1);
item.mUri.writeToParcel(dest, flags);
} else {
dest.writeInt(0);
}
}
}
ClipData(Parcel in) {
mClipDescription = new ClipDescription(in);
if (in.readInt() != 0) {
mIcon = Bitmap.CREATOR.createFromParcel(in);
} else {
mIcon = null;
}
final int N = in.readInt();
for (int i=0; i<N; i++) {
CharSequence text = TextUtils.CHAR_SEQUENCE_CREATOR.createFromParcel(in);
Intent intent = in.readInt() != 0 ? Intent.CREATOR.createFromParcel(in) : null;
Uri uri = in.readInt() != 0 ? Uri.CREATOR.createFromParcel(in) : null;
mItems.add(new Item(text, intent, uri));
}
}
public static final Parcelable.Creator<ClipData> CREATOR =
new Parcelable.Creator<ClipData>() {
public ClipData createFromParcel(Parcel source) {
return new ClipData(source);
}
public ClipData[] newArray(int size) {
return new ClipData[size];
}
};
}