问题描述
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);
image.compress(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.com/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="http://schemas.android.com/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);
image.compress(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- https://developer.android. com/reference/android/support/v4/content/FileProvider
More info about file provider - https://developer.android.com/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);
}
这篇关于通过Android Intent共享位图的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!