Android: Html TextView - is it possible?

I'm interested in creating a custom android component that extends textview and shows the text inside of it as formatted. this is the code I wrote:

/** * TODO */

import android.content.Context;
import android.graphics.Canvas;
import android.text.Html;
import android.util.AttributeSet;
import android.widget.TextView;

public class HtmlTextView extends TextView {

    private static final String tag = "HtmlTextView";

    public HtmlTextView(Context context, AttributeSet attrs,
            int defStyle) {
        super(context, attrs, defStyle);
    }

    public HtmlTextView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public HtmlTextView(Context context) {
        super(context);
    }

    /*
     * (non-Javadoc)
     * 
     * @see android.widget.TextView#onDraw(android.graphics.Canvas)
     */
    @Override
    protected void onDraw(Canvas canvas) {


                setText(Html.fromHtml((String) getText()));


        super.onDraw(canvas);
    }

}

and in the test layout xml I have the following:

<com.package.ui.tools.HtmlTextView 
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:text="@string/elad"
  android:textSize="28dip"
  android:padding="10dip"
  android:gravity="center"/>

The string defined in strings.xml is:

<!-- testing -->
<string name="elad">elad <b> elad </b> elad</string>

This doesnt work, but the weird this is that I get the following exception thrown in eclipse:

java.lang.NoClassDefFoundError: org/ccil/cowan/tagsoup/Parser
at android.text.Html.fromHtml(Html.java:125)
at android.text.Html.fromHtml(Html.java:102)
at com.package.ui.tools.HtmlTextView.onDraw(HtmlTextView.java:39)
at android.view.View.draw(View.java:6740)
at android.view.ViewGroup.drawChild(ViewGroup.java:1640)
at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1367)
at android.view.ViewGroup.drawChild(ViewGroup.java:1638)
at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1367)
at android.view.View.draw(View.java:6743)
at android.widget.FrameLayout.draw(FrameLayout.java:352)
at com.android.layoutlib.bridge.Bridge.computeLayout(Bridge.java:452)
at com.android.ide.common.rendering.LayoutLibrary.createLegacySession(LayoutLibrary.java:404)
at com.android.ide.common.rendering.LayoutLibrary.createSession(LayoutLibrary.java:285)
at com.android.ide.eclipse.adt.internal.editors.layout.gle2.GraphicalEditorPart.renderWithBridge(GraphicalEditorPart.java:1506)
at com.android.ide.eclipse.adt.internal.editors.layout.gle2.GraphicalEditorPart.renderWithBridge(GraphicalEditorPart.java:1312)
at com.android.ide.eclipse.adt.internal.editors.layout.gle2.GraphicalEditorPart.recomputeLayout(GraphicalEditorPart.java:1043)
at com.android.ide.eclipse.adt.internal.editors.layout.gle2.GraphicalEditorPart.activated(GraphicalEditorPart.java:870)
at com.android.ide.eclipse.adt.internal.editors.layout.LayoutEditor.partActivated(LayoutEditor.java:378)
at com.android.ide.eclipse.adt.internal.editors.layout.LayoutEditor.partBroughtToTop(LayoutEditor.java:387)
at org.eclipse.ui.internal.PartListenerList$2.run(PartListenerList.java:87)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
at org.eclipse.core.runtime.Platform.run(Platform.java:888)
at org.eclipse.ui.internal.PartListenerList.fireEvent(PartListenerList.java:57)
at org.eclipse.ui.internal.PartListenerList.firePartBroughtToTop(PartListenerList.java:85)
at org.eclipse.ui.internal.PartService.firePartBroughtToTop(PartService.java:208)
at org.eclipse.ui.internal.WorkbenchPagePartList.firePartBroughtToTop(WorkbenchPagePartList.java:76)
at org.eclipse.ui.internal.WorkbenchPagePartList.fireActiveEditorChanged(WorkbenchPagePartList.java:52)
at org.eclipse.ui.internal.PartList.setActiveEditor(PartList.java:162)
at org.eclipse.ui.internal.WorkbenchPage.makeActiveEditor(WorkbenchPage.java:1281)
at org.eclipse.ui.internal.WorkbenchPage.setActivePart(WorkbenchPage.java:3530)
at org.eclipse.ui.internal.WorkbenchPage.requestActivation(WorkbenchPage.java:3077)
at org.eclipse.ui.internal.PartPane.requestActivation(PartPane.java:279)
at org.eclipse.ui.internal.EditorPane.requestActivation(EditorPane.java:98)
at org.eclipse.ui.internal.PartPane.setFocus(PartPane.java:325)
at org.eclipse.ui.internal.EditorPane.setFocus(EditorPane.java:127)
at org.eclipse.ui.internal.PartStack.presentationSelectionChanged(PartStack.java:844)
at org.eclipse.ui.internal.PartStack.access$1(PartStack.java:827)
at org.eclipse.ui.internal.PartStack$1.selectPart(PartStack.java:137)
at org.eclipse.ui.internal.presentations.util.TabbedStackPresentation$1.handleEvent(TabbedStackPresentation.java:133)
at org.eclipse.ui.internal.presentations.util.AbstractTabFolder.fireEvent(AbstractTabFolder.java:269)
at org.eclipse.ui.internal.presentations.util.AbstractTabFolder.fireEvent(AbstractTabFolder.java:278)
at org.eclipse.ui.internal.presentations.defaultpresentation.DefaultTabFolder.access$1(DefaultTabFolder.java:1)
at org.eclipse.ui.internal.presentations.defaultpresentation.DefaultTabFolder$2.handleEvent(DefaultTabFolder.java:88)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1053)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1077)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1062)
at org.eclipse.swt.widgets.Widget.notifyListeners(Widget.java:774)
at org.eclipse.swt.custom.CTabFolder.setSelection(CTabFolder.java:2743)
at org.eclipse.swt.custom.CTabFolder.onMouse(CTabFolder.java:1429)
at org.eclipse.swt.custom.CTabFolder$1.handleEvent(CTabFolder.java:257)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1053)
at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4066)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3657)
at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:2640)
at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2604)
at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2438)
at org.eclipse.ui.internal.Workbench$7.run(Workbench.java:开发者_如何学运维671)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:664)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:115)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:369)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:179)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:619)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:574)
at org.eclipse.equinox.launcher.Main.run(Main.java:1407)

Does anyone have any idea as to why I'm getting this error? Is what I'm trying to achieve even possible? thanks, e.

Just try:

normalTextView.setText(Html.fromHtml("<bold>Hello World!</bold>"));

For dealing with strings.xml you need to escape certain characters as in this answer. The example given there is:

<resources>
    <string name="somestring">
        &lt;B&gt;Title&lt;/B&gt;&lt;BR/&gt;
        Content
    </string>
</resources>

As Robby mentions, this is done for you automatically when you use the string editor.

The TextView class already supports some basic html tags using Html.fromHtml so I don't think you need to create an HtmlTextView.

Internally the SDK use's TagSoup to parse the html (which is the missing class). I am assuming that you are getting that Eclipse exception when you try to view your layout in design mode. To have your custom view render correctly in the Eclipse view, there are some special things you need to do.

Either way I think you can use the basic TextView for your needs.

Update:

Strings in strings.xml can include html for use with the TextView.

This works in Android Studio designer. Don't forget to clean and rebuild project as it will not work in designer immediately.

class HtmlTextView : AppCompatTextView {
    constructor(context: Context) : super(context)
    constructor(context: Context, attrs: AttributeSet) : super(context, attrs) {
        setHtml(text)
    }

    constructor(context: Context, attrs: AttributeSet, defStyleAttr: Int)
            : super(context, attrs, defStyleAttr) {
        setHtml(text)
    }

    fun setHtml(html: CharSequence) {
        @Suppress("DEPRECATION")
        text = Html.fromHtml(html.toString())
    }
}