javascript - Adjust font size of Android WebView -

how adjust font size of android webview? following appears have no effect:

private void fontsizeplus() {     fontsize = (fontsize < font_size_max) ? fontsize + font_size_increment : fontsize;     this.changefontsize(fontsize); }  private void fontsizeminus() {     fontsize = (fontsize > font_size_min) ? fontsize - font_size_increment : fontsize;     this.changefontsize(fontsize); }  private void changefontsize(int value) {     string js = "document.getelementsbytagname('body')[0].style.webkittextsizeadjust= '" + value + "%';";     mwebview.loadurl("javascript:(function() { " + js +  " })()");   } 

where webview , constants have been initialized follows:

private final static int font_size_default = 100; private final static int font_size_min = 50; private final static int font_size_max = 150; private final static int font_size_increment = 5; private int fontsize = font_size_default;  private webview mwebview;  @override protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.index);     mwebview = (webview) findviewbyid(r.id.webview);     mwebview.getsettings().setjavascriptenabled(true);     mwebview.loadurl("file:///android_asset/index.htm"); } 

@rob's answer , comment pointed me in right direction.

first make sure font sizes relative default font size. if use absolute values following not work on elements.

then:

@override protected void oncreate(bundle savedinstancestate) {     ...     mwebview = (webview) findviewbyid(r.id.webview);     fontsize = mwebview.getsettings().getdefaultfontsize();     ... }  private void fontsizeplus() {     fontsize++;     this.changefontsize(fontsize); }  private void fontsizeminus() {     fontsize--;     this.changefontsize(fontsize); }  private void changefontsize(int value) {     mwebview.getsettings().setdefaultfontsize(value); } 

by changing value of default font size relative font sizes adjusted accordingly. gives greater control websettings.settextsize (websettings.textsize t).