Develop Reference

I want every http url request in the device from any source to pass through my android app

I am developing an application in which I have to first examine the URL and then allow or disallow the HTTP request. So I wanted to know how can we do this in the Android Studio i.e. to examine every URL HTTP request in the device to pass through my android app so that I can analyze it.

Have a look at Android VpnService (added in API 14.)
There is also a Guide on it.
It probably also would not hurt to look at current opensource VPN projects for android: https://github.com/schwabe/ics-openvpn

Read all the messages in inbox

I am new to react-native.I am trying to build a simple android application that reads all the messages from the inbox and display it in a listview. In android,i can read all the messages using URI.
How can i read all the messages in a similar way using react-native?
Thanks in advance

In React native,you want to read sms from android phone:
react-native-get-sms-android
This module that supports interaction with the Messaging API on Android
The package allows you to:
• get messages
• send messages
• delete messages
Refer this for this module integration:react-native-get-sms-android
Make sure that you need specific permissions to read SMS for android.
For checking permissions in android,use PermissionsAndroid API.It provides access to Android M's new permissions model.For more details check this docs
react-native-android-sms-listener
To listen for the new messages in your app use this library.This library allows you to listen for incoming SMS messages.
Refer this for this module integration:react-native-android-sms-listener

Remember that everything that you did in Android, you can still do it in react Native, writing a Native Module, and here is a well explained example of how to do that https://facebook.github.io/react-native/docs/native-modules-android
Or I saw that there is this external library https://github.com/briankabiro/react-native-get-sms-android, that you might try.

how to make email app in Android?

today I'm working with network in Android.I want to get mail from Gmail/Yahoo account and show them in textbox.Can anyone teach me how to fetch mail content ? I need a point to do it.

You can use javamail – android jar files to get and send email from android. From following you can also find a example to send email using android. This work is based on the opensourced version of JavaMail and activation (JAF) available in the glassfish repository, and some parts of Apache. You can find these files to download from this link https://code.google.com/p/javamail-android/downloads/list.
For Receiving email you can use following link. this link will be helpful for you http://www.javatpoint.com/example-of-receiving-email-using-java-mail-api

Android-facebook Message

I would like to know is there any way to send a message to a friend in facebook from an android app.(Not wall post).Googled a lot about this topic but didn't get any proper solution.Guide me to some reference or blog

I am not sure about native application but you can do it from HTML5 application using javascript:-
https://developers.facebook.com/docs/reference/dialogs/send/
If no other solution place the script in an html file and load the same from the native app

Android MMS Example

I tried to follow this answer about sending MMS through code.
However, I stopped when he start talking about BroadCastRecivers and Android git and not providing the code. I really get lost with this. It was very straight at the beginning but it becomes so complicated after that.
Can any one explain the missing code in that answer or provide it if it is exist ?
Thanks a lot

To those who might be interested:
MMS Functionality is a bit unreliable, not well-documented feature in Android. So, the existed solutions will not work always. You can't depend on them, yet.

In order to send MMS on Android, you can alternatively use a commercial MMS SDK instead of using the internal stack.
There's one from Winwap here that let's you send and receive MMS messages with simple functions, like the send-example from their docs:
1. Initialize the API by calling the mmss_init function
2. Connect to the HTTP Proxy or WAP Gateway using the mmss_connect function
3. Create MMS message of type SEND_REQUEST_TYPE by calling mms_message_create function
4. Add MMS headers using mms_set_header_str, mms_set_header_encstr or mms_set_header_long functions. Mandatory headers TRANSACTION_ID, FROM and CONTENT_TYPE shall be set. Also at least one of the headers TO, CC or BCC shall be set. Other headers suitable for this type of message are optional
5. Add content to MMS Message by the help of mms_add_content function
6. Call the mmss_send_message function
7. Destroy MMS message using mms_message_destroy function
8. Disconnect from the HTTP Proxy or WAP Gateway using the mmss_disconnect function
9. Finalize the API by calling the mmss_fini function
The downside is, it's a commercial product not available for free.

I do not have experience in this type of problem but maybe this will help you out a bit:
Intent sendIntent = new Intent(Intent.ACTION_SEND);
sendIntent.putExtra("sms_body", "some text");
String url = "\\sdcard\\potrait.PNG";
sendIntent.putExtra(Intent.EXTRA_STREAM, Uri.parse(url));
sendIntent.setType("image/png");
startActivity(sendIntent);
This is a copy from here.
This is another example.