Android HashTag Detection Sample

This post about how to detect hashtag text and linkfy.

like Instagram, twitter ,  google+ and facebook tags.

Check the below example.

Screen Shot

Source Code

package com.vj.hashtags;

import java.util.ArrayList;

import java.util.regex.Pattern;

import com.vj.hashtags.R;

import android.app.Activity;

import android.os.Bundle;

import android.text.util.Linkify;

import android.view.Menu;

import android.view.View;

import android.view.ViewGroup;

import android.view.View.OnClickListener;

import android.widget.ArrayAdapter;

import android.widget.Button;

import android.widget.EditText;

import android.widget.ListView;

import android.widget.TextView;

public class MainActivity extends Activity {

//public static variable for demo purpose

//we'll use this ArrayList in other activity

public static ArrayList<String> tagList=new ArrayList<String>();

private ArrayAdapter<String> adapter;

private ListView tagListView;

private EditText tagEditText;

private Button addButton;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

//initialize variables

tagListView = (ListView)findViewById(R.id.tagListView);

tagEditText = (EditText)findViewById(R.id.tagEditText);

addButton = (Button)findViewById(R.id.addButton);

//Extend an ArrayAdapter so that we can make 

//our TextView HashTag compatible 

adapter = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,

tagList){

@Override

public View getView(int position, View convertView, ViewGroup parent) {

TextView hashView;

if (convertView == null) {

hashView = new TextView(MainActivity.this);

} else 

hashView = (TextView) convertView;

//Get the message from list and set as text

String message = tagList.get(position);

hashView.setText(message);

//Pattern to find if there's a hash tag in the message

//i.e. any word starting with a # and containing letter or numbers or _

Pattern tagMatcher = Pattern.compile("[#]+[A-Za-z0-9-_]+\\b");

//Scheme for Linkify, when a word matched tagMatcher pattern,

//that word is appended to this URL and used as content URI

        String newActivityURL = "content://com.vj.hashtags.tagdetailsactivity/";

       

        //Attach Linkify to TextView

        Linkify.addLinks(hashView, tagMatcher, newActivityURL);

return hashView;

}

};

//assign custom adapter to messages listview

tagListView.setAdapter(adapter);

//Add text from EditText to our messages list on button click

addButton.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View arg0) {

String message = tagEditText.getText().toString();

if(message.trim()!="")

{

tagList.add(0,"#"+message);

adapter.notifyDataSetChanged();

tagEditText.setText("");

}

}

});

}

@Override

public boolean onCreateOptionsMenu(Menu menu) {

// Inflate the menu; this adds items to the action bar if it is present.

getMenuInflater().inflate(R.menu.main, menu);

return true;

}

}

Tag details Activity

package com.vj.hashtags;

import android.app.Activity;

import android.net.Uri;

import android.os.Bundle;

import android.widget.TextView;

public class TagDetailsActivity extends Activity {

TextView selectedTag;

@Override

    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

       

        selectedTag = new TextView(this);

        //Get the content URI

        Uri uri = getIntent().getData();

        //strip off hashtag from the URI

        String tag=uri.toString().split("/")[3];

        

        selectedTag.setText("Selected hash tag :" +tag);

        

        setContentView(selectedTag);

}

}

Manifest file

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

    package="com.vj.hashtags"

    android:versionCode="1"

    android:versionName="1.0" >

    <uses-sdk

        android:minSdkVersion="8"

        android:targetSdkVersion="17" />

    <application

        android:allowBackup="true"

        android:icon="@drawable/ic_launcher"

        android:label="@string/app_name"

        android:theme="@style/AppTheme" >

<provider

            android:name="com.vj.hashtags.TagProvider"

            android:authorities="com.vj.hashtags.tagdetailsactivity" />

        <activity

            android:name="com.vj.hashtags.MainActivity"

            android:label="@string/app_name" >

            <intent-filter>

                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />

            </intent-filter>

        </activity>

        <activity android:name="com.vj.hashtags.TagDetailsActivity"

            android:label = "@string/app_name">

            <intent-filter >

            <action android:name="android.intent.action.VIEW" />

                <category android:name="android.intent.category.DEFAULT" />

                <data android:mimeType="vnd.android.cursor.item/vnd.cc.tag" />

               </intent-filter> 

        </activity>

    </application>

</manifest>

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