How to write a MAUI app to receive a file from another app?

Issue

I'm new on MAUI and I need my MAUI app receiving a json file shared from other apps on Android. I searched a lot but have no luck at all. No found guides work.

I tried a dedicated activity class, then tried moving those code into MainActivity. Neither works.

Here are what I did on my app:

In AndroidManifest.xml

  <application android:allowBackup="true" android:icon="@mipmap/appicon" android:roundIcon="@mipmap/appicon_round" android:supportsRtl="true" android:label="KitCare">
    <activity android:name="KitCare.DataFileIntentActivity" android:exported="true">
      <intent-filter>
        <action android:name="android.intent.action.SEND" />
        <category android:name="android.intent.category.DEFAULT" />
        <data android:mimeType="application/json" />
      </intent-filter>
    </activity>
  </application>

In DataFileIntentActivity.cs:

namespace KitCare
{
    [Activity(Name = "KitCare.DataFileIntentActivity", Exported = true),
    Theme = "@style/MyAppTheme" //Requested by Jessie Zhang. Theme name is the same as the main activity.
    ]
    [IntentFilter(
        new[] { Android.Content.Intent.ActionSend },
        Categories = new[] { Android.Content.Intent.CategoryDefault },
        DataMimeType = "application/json")]
    public class DataFileIntentActivity : MauiAppCompatActivity
    {
        protected override void OnCreate(Bundle? savedInstanceState)
        {
            base.OnCreate(savedInstanceState);

            //Requested by Jessie Zhang
            Platform.Init(this, savedInstanceState);
            OnNewIntent(Intent);
        }

        protected override void OnNewIntent(Intent? intent)
        {
            base.OnNewIntent(intent);

            if (Intent?.Action == Intent.ActionSend)
            {
                Stream? inputStream = null;

                var filePath = Intent?.ClipData?.GetItemAt(0);
                if (filePath?.Uri != null)
                {
                    inputStream = ContentResolver!.OpenInputStream(filePath.Uri)!;
                }
                
                if (inputStream != null)
                {
                    using (var reader = new StreamReader(inputStream))
                    {
                        var content = reader.ReadToEnd();

                        //process the content here...
                    }

                    inputStream.Close();
                    inputStream.Dispose();
                }
            }
        }
    }
}

Currently, I can see my app listed as a target when a file is selected for sharing. But after the app is selected, an empty UI with program title is shown and quit immediately.

Any ideas? Thanks a lot.

Solution

You can try to add your code to function OnCreate.

Please refer to the following code:

[Activity(Label = "FormSecondApp",  Theme = "@style/MainTheme", MainLauncher = true, Exported = true, ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation)] 
[IntentFilter
(
new[] { Android.Content.Intent.ActionView, Android.Content.Intent.ActionSend },
Categories = new[]
   {
             Android.Content.Intent.CategoryDefault
   },

DataMimeType = "application/json"
)]
public class MainActivity : MauiAppCompatActivity
{

    protected override void OnCreate(Bundle savedInstanceState)
    {
        base.OnCreate(savedInstanceState);

        if (Intent?.Action == Android.Content.Intent.ActionSend)
        {
            Stream? inputStream = null;
            var filePath = Intent?.ClipData?.GetItemAt(0);
            if (filePath?.Uri != null)
            {
                inputStream = ContentResolver!.OpenInputStream(filePath.Uri)!;
            }

            if (inputStream != null)
            {
                using (var reader = new StreamReader(inputStream))
                {
                    var content = reader.ReadToEnd();

                    //process the content here...
                }

                inputStream.Close();
                inputStream.Dispose();
            }
        }
    }
}

Answered By - Jessie Zhang -MSFT