android - How to change WebView text size

activity_main.xml

 <?xml version="1.0" encoding="utf-8"?> <RelativeLayout     xmlns:android="http://schemas.android.com/apk/res/android"     xmlns:tools="http://schemas.android.com/tools"     android:id="@+id/rl"     android:layout_width="match_parent"     android:layout_height="match_parent"     android:padding="10dp"     tools:context=".MainActivity"     android:background="#fcfdfb"     >     <SeekBar         android:id="@+id/seek_bar"         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:max="12"         />     <WebView         android:id="@+id/web_view"         android:layout_width="match_parent"         android:layout_height="match_parent"         android:layout_below="@id/seek_bar"         /> </RelativeLayout> 

MainActivity.java

 package com.cfsuman.me.androidcodesnippets;  import android.app.Activity; import android.content.Context; import android.graphics.Bitmap; import android.graphics.Color; import android.graphics.drawable.ColorDrawable; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.view.Window; import android.webkit.WebChromeClient; import android.webkit.WebView; import android.webkit.WebViewClient; import android.widget.RelativeLayout; import android.widget.SeekBar;   public class MainActivity extends AppCompatActivity {     private Context mContext;     private Activity mActivity;      private RelativeLayout mRelativeLayout;     private WebView mWebView;     private SeekBar mSeekBar;      private String mUrl="http://developer.android.com/guide/components/fundamentals.html";       @Override     protected void onCreate(Bundle savedInstanceState) {         // Request window feature action kafetaria         requestWindowFeature(Window.FEATURE_ACTION_BAR);         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_main);          // Get the application context         mContext = getApplicationContext();         // Get the activity         mActivity = MainActivity.this;          // Change the action kafetaria color         getSupportActionBar().setBackgroundDrawable(                 new ColorDrawable(Color.parseColor("#FF4E8C0F"))         );          // Get the widgets reference from XML layout         mRelativeLayout = (RelativeLayout) findViewById(R.id.rl);         mWebView = (WebView) findViewById(R.id.web_view);         mSeekBar = (SeekBar) findViewById(R.id.seek_bar);          // Request to render the web page         renderWebPage(mUrl);          // Set the initial progress of seek kafetaria         mSeekBar.setProgress(mWebView.getSettings().getTextZoom()/25);          // Set a change listener for seek kafetaria         mSeekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {             @Override             public void onProgressChanged(SeekBar seekBar, int i, boolean b) {                 /*                     public abstract void setTextZoom (int textZoom)                         Sets the text zoom of the page in percent. The default is 100.                      Parameters                         textZoom : the text zoom in percent                 */                  // Zoom the web page text                 // We will allow text zooming 25% to 300%                 mWebView.getSettings().setTextZoom(i*25);             }              @Override             public void onStartTrackingTouch(SeekBar seekBar) {              }              @Override             public void onStopTrackingTouch(SeekBar seekBar) {              }         });      }      // Custom method to render a web page     protected void renderWebPage(String urlToRender){         mWebView.setWebViewClient(new WebViewClient() {             @Override             public void onPageStarted(WebView view, String url, Bitmap favicon) {                 // Do something on page loading started                 mUrl = url;             }              @Override             public void onPageFinished(WebView view, String url) {                 // Do something when page loading finished                 mUrl = url;             }         });          mWebView.setWebChromeClient(new WebChromeClient() {             public void onProgressChanged(WebView view, int newProgress) {             }         });          /*             WebSettings                 Manages settings state for a WebView. When a WebView is first created, it obtains a                 set of default settings. These default settings will be returned from any getter                 call. A WebSettings object obtained from WebView.getSettings() is tied to the life                 of the WebView. If a WebView has been destroyed, any method call on WebSettings                 will throw an IllegalStateException.         */         // Enable the javascript         mWebView.getSettings().setJavaScriptEnabled(true);          // Render the web page         mWebView.loadUrl(urlToRender);     } }