在我的Android应用中,我有一个位图(例如b)和一个按钮.现在,当我单击按钮时,我要共享位图.我正在使用onClick()中的以下代码来实现这一目标:-
In my android app, I have a bitmap (say b) and a button. Now when I click on the button, I want to share the bitmap. I am making use of the below code inside my onClick() to achieve this :-
Intent intent = new Intent(Intent.ACTION_SEND); intent.setType("image/png"); intent.putExtra(Intent.EXTRA_STREAM, b); startActivity(Intent.createChooser(intent , "Share"));我期望能够处理此意图的所有应用程序的列表,但我一无所获.没有应用程序列表,android studio中也没有任何错误.我的应用程序刚刚挂了一段时间,然后退出.
I was expecting a list of all application which are able to handle this intent but I get nothing. There is no list of apps nor is there any error in android studio. My application just get hanged for sometime and then quits.
我已经检查了位图,它很好(不为null).
I have checked the bitmap and it is fine (its not null).
我要去哪里错了?
推荐答案我发现了该解决方案的2种变体.两者都涉及将位图保存到存储中,但是图像不会出现在图库中.
I found 2 variants of the solution. Both involve saving Bitmap to storage, but the image will not appear in the gallery.
保存到外部存储
- 但是到应用程序的私人文件夹.
- 对于API< = 18,它需要权限,对于较新的不需要.
在标记之前添加到AndroidManifest.xml
Add into AndroidManifest.xml before tag
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" android:maxSdkVersion="18"/>2.保存方法:
/** * Saves the image as PNG to the app's private external storage folder. * @param image Bitmap to save. * @return Uri of the saved file or null */ private Uri saveImageExternal(Bitmap image) { //TODO - Should be processed in another thread Uri uri = null; try { File file = new File(getExternalFilesDir(Environment.DIRECTORY_PICTURES), "to-share.png"); FileOutputStream stream = new FileOutputStream(file); imagepress(Bitmap.CompressFormat.PNG, 90, stream); stream.close(); uri = Uri.fromFile(file); } catch (IOException e) { Log.d(TAG, "IOException while trying to write file for sharing: " + e.getMessage()); } return uri; }3.检查存储可访问性
外部存储可能无法访问,因此您应在尝试保存之前进行检查: https ://developer.android/training/data-storage/files
/** * Checks if the external storage is writable. * @return true if storage is writable, false otherwise */ public boolean isExternalStorageWritable() { String state = Environment.getExternalStorageState(); if (Environment.MEDIA_MOUNTED.equals(state)) { return true; } return false; }第二个变种
使用FileProvider保存到cacheDir.它不需要任何权限.
Second variant
Saving to cacheDir using FileProvider. It does not require any permissions.
<manifest> ... <application> ... <provider android:name="android.support.v4.content.FileProvider" android:authorities="com.mydomain.fileprovider" android:exported="false" android:grantUriPermissions="true"> <meta-data android:name="android.support.FILE_PROVIDER_PATHS" android:resource="@xml/file_paths" /> </provider> ... </application> </manifest>2.将路径添加到res/xml/file_paths.xml
<?xml version="1.0" encoding="utf-8"?> <resources> <paths xmlns:android="schemas.android/apk/res/android"> <cache-path name="shared_images" path="images/"/> </paths> </resources>3.保存方法:
/** * Saves the image as PNG to the app's cache directory. * @param image Bitmap to save. * @return Uri of the saved file or null */ private Uri saveImage(Bitmap image) { //TODO - Should be processed in another thread File imagesFolder = new File(getCacheDir(), "images"); Uri uri = null; try { imagesFolder.mkdirs(); File file = new File(imagesFolder, "shared_image.png"); FileOutputStream stream = new FileOutputStream(file); imagepress(Bitmap.CompressFormat.PNG, 90, stream); stream.flush(); stream.close(); uri = FileProvider.getUriForFile(this, "com.mydomain.fileprovider", file); } catch (IOException e) { Log.d(TAG, "IOException while trying to write file for sharing: " + e.getMessage()); } return uri; }有关文件提供程序的更多信息- developer.android. com/reference/android/support/v4/content/FileProvider
More info about file provider - developer.android/reference/android/support/v4/content/FileProvider
压缩和保存可能很耗时,因此应该在其他线程中完成
/** * Shares the PNG image from Uri. * @param uri Uri of image to share. */ private void shareImageUri(Uri uri){ Intent intent = new Intent(android.content.Intent.ACTION_SEND); intent.putExtra(Intent.EXTRA_STREAM, uri); intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION); intent.setType("image/png"); startActivity(intent); }更多推荐
通过Android Intent共享位图
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