Sunday, August 7, 2016

Android Subscript and Superscript example

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/coordinator_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#e23e3c"
    >
    <TextView
        android:id="@+id/tv"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_margin="25dp"
        android:textSize="45sp"
        android:gravity="center"
        android:fontFamily="sans-serif-condensed"
        />
</android.support.design.widget.CoordinatorLayout>
MainActivity.java

package com.cfsuman.me.androidcodesnippets;

import android.app.Activity;
import android.content.Context;
import android.support.design.widget.CoordinatorLayout;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.SpannableStringBuilder;
import android.text.Spanned;
import android.text.method.LinkMovementMethod;
import android.text.style.RelativeSizeSpan;
import android.text.style.SubscriptSpan;
import android.text.style.SuperscriptSpan;
import android.widget.TextView;


public class MainActivity extends AppCompatActivity {
    private Context mContext;
    private Activity mActivity;

    private CoordinatorLayout mCLayout;
    private TextView mTextView;

    private String mText;
    private SpannableStringBuilder mSSBuilder;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Get the application context
        mContext = getApplicationContext();
        mActivity = MainActivity.this;

        // Get the widget reference from XML layout
        mCLayout = (CoordinatorLayout) findViewById(R.id.coordinator_layout);
        mTextView = (TextView) findViewById(R.id.tv);

        // Initialize a new String variable
        mText = "Test text to show SubscriptSpan X2 and SuperscriptSpan Y5 example.";

        // Initialize a new SpannableStringBuilder instance
        mSSBuilder = new SpannableStringBuilder(mText);

        // Initialize a new SubscriptSpan instance
        SubscriptSpan subscriptSpan = new SubscriptSpan();

        // Initialize a new SuperscriptSpan instance
        SuperscriptSpan superscriptSpan = new SuperscriptSpan();

        // Apply the SubscriptSpan
        mSSBuilder.setSpan(
                subscriptSpan, // Span to add
                mText.indexOf("2"), // Start of the span (inclusive)
                mText.indexOf("2") + String.valueOf("2").length(), // End of the span (exclusive)
                Spanned.SPAN_EXCLUSIVE_EXCLUSIVE // Do not extend the span when text add later
        );

        // Apply the SuperscriptSpan
        mSSBuilder.setSpan(
                superscriptSpan,
                mText.indexOf("5"),
                mText.indexOf("5") + String.valueOf("5").length(),
                Spanned.SPAN_EXCLUSIVE_EXCLUSIVE
        );

        // Minimize the Subscript and Superscript text size
        showSmallSizeText("2");
        showSmallSizeText("5");

        // Display the spannable text to TextView
        mTextView.setText(mSSBuilder);
    }

    // Custom method to make text size small
    protected void showSmallSizeText(String textToSmall){
        // Initialize a new RelativeSizeSpan instance
        RelativeSizeSpan relativeSizeSpan = new RelativeSizeSpan(.5f);

        // Apply the RelativeSizeSpan to display small text
        mSSBuilder.setSpan(
                relativeSizeSpan,
                mText.indexOf(textToSmall),
                mText.indexOf(textToSmall) + String.valueOf(textToSmall).length(),
                Spanned.SPAN_EXCLUSIVE_EXCLUSIVE
        );
    }
}