1.分享bitmap:

java:

//将mipmap中图片转换成Uri
                Uri imgUri = Uri.parse(MediaStore.Images.Media.insertImage(getContentResolver(), bitmapByUrl, null,null));

                Intent shareIntent = new Intent();
                shareIntent.setAction(Intent.ACTION_SEND);
//其中imgUri为图片的标识符
                shareIntent.putExtra(Intent.EXTRA_STREAM, imgUri);
                shareIntent.setType("image/*");
//切记需要使用Intent.createChooser，否则会出现别样的应用选择框，您可以试试
                shareIntent = Intent.createChooser(shareIntent, "Here is the title of Select box");
                startActivity(shareIntent);

AndroidManifest.xml的application中添加

<!--分享
        //注意和上面FileProvider方法中声明的authorities保持一致
        -->
        <provider
            android:name="androidx.core.content.FileProvider"
            android:authorities="com.yongdaimi.android.fileprovider1"
        android:exported="false"
        android:grantUriPermissions="true">
        <meta-data
            android:name="android.support.FILE_PROVIDER_PATHS"
            android:resource="@xml/file_paths_share_img" />

xml：新建一个xml，写file_paths_share_img

<?xml version="1.0" encoding="utf-8"?>
<resource xmlns:android="http://schemas.android.com/apk/res/android">
    <external-path
        name="images"
        path="DCIM/IMAGE" />
</resource>