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How to override default text selection of android webview os 4.1+?

由 坚强是说给别人听的谎言 提交于 2019-11-27 17:58:30
Sean Beach

I realize this is an old question, but there is not an accepted answer, and none of the provided answers have many votes.

I have achieved what you are trying to accomplish by creating a custom action mode callback. This allows the creation of a custom contextual action bar (CAB) when (in the case of a WebView) a user long-clicks the view. NOTE: This only works in 4.0+ and one piece only works in 4.4.

Create a new Android XML file containing the layout for your custom menu. Here is mine (context_menu.xml) as an example:

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android" >

    <item
        android:id="@+id/copy"
        android:icon="@drawable/ic_action_copy"
        android:showAsAction="always" <!-- Forces this button to be shown -->
        android:title="@string/copy">
    </item>
    <item
        android:id="@+id/button2"
        android:icon="@drawable/menu_button2icon"
        android:showAsAction="ifRoom" <!-- Show if there is room on the screen-->
        android:title="@string/button2">
    </item>
    <!-- Add as many more items as you want.
         Note that if you use "ifRoom", an overflow menu will populate
         to hold the action items that did not fit in the action bar. -->

</menu>

Now that the menu is defined, create a callback for it:

public class CustomWebView extends WebView {

    private ActionMode.Callback mActionModeCallback;

    private class CustomActionModeCallback implements ActionMode.Callback {

        // Called when the action mode is created; startActionMode() was called
        @Override
        public boolean onCreateActionMode(ActionMode mode, Menu menu) {
            // Inflate a menu resource providing context menu items
            MenuInflater inflater = mode.getMenuInflater();
            inflater.inflate(R.menu.context_menu, menu);
            return true;
        }

        // Called each time the action mode is shown.
        // Always called after onCreateActionMode, but
        // may be called multiple times if the mode is invalidated.
        @Override
        public boolean onPrepareActionMode(ActionMode mode, Menu menu) {
            // Note: This is called every time the selection handlebars move.
            return false; // Return false if nothing is done
        }

        // Called when the user selects a contextual menu item
        @Override
        public boolean onActionItemClicked(ActionMode mode, MenuItem item) {

            switch (item.getItemId()) {
                case R.id.copy:
                // Do some stuff for this button
                   mode.finish(); // Action picked, so close the CAB
                   return true;
                case R.id.button2:
                // Do some stuff for this button
                   mode.finish();
                   return true;
                // Create a case for every item
                ...
                default:
                   mode.finish();
                   return false;
            }
        }

        // Called when the user exits the action mode
        @Override
        public void onDestroyActionMode(ActionMode mode) {
            // This will clear the selection highlight and handlebars.
            // However, it only works in 4.4; I am still investigating
            // how to reliably clear the selection in 4.3 and earlier
            clearFocus();
        }
}

Once those pieces are in place, override the startActionMode method so that the callback will actually occur on a long-click:

public class CustomWebView extends WebView {
    @Override
    public ActionMode startActionMode(Callback callback) {
        ViewParent parent = getParent();
        if (parent == null) {
        return null;
        }
        mActionModeCallback = new CustomActionModeCallback();
        return parent.startActionModeForChild(this, mActionModeCallback);
    }
}

Now you have a custom menu that will be appear and populate when a user long-clicks your WebView. For reference, I found this information from an Android Developer tutorial and modified the suggestion from this answer.

One final note: This technique overrides the native copy/paste menu for selected text. If you want to maintain that functionality, you will need to implement it yourself. (That is why my first button is 'copy'.) If you need that, refer to this Google tutorial for more information and the proper way to implement it.

Use could the setOnTouchListener() for long/short long press. and return true so that nothing happens thereby overriding the default text selection feature.

I have been able to resolve this. I was also facing this issue and could not find any solution on the web.

So, if you set up a LongClick listener, the Webview would stop showing selection at all. After delving deep into the Webview code, I found that it was calling WebView's method startRunMode and passing an instance of SelectActionCallbackMode class.

I simply extended the Webview class and overrided the startRunMode method like this:

public ActionMode startActionMode(ActionMode.Callback callback) 
{
    actionModeCallback = new CustomizedSelectActionModeCallback();
    return super.startActionMode(actionModeCallback);
}

This forced the Webview to display my Callback instead of displaying Webview's default one. This ensured that selection worked as smoothly as before and my CAB was displayed each time selection was made. Only caveat was that I had to write code to dismiss the CAB myself.

Tested on 4.1, 4.2 and 4.3 devices.

Hope this helps.

I could suggest a workaround for this. You could use setOnTouchListener and then implement the long press yourself. 

onTouch --

 case MotionEvent.ACTION_DOWN:  
                    mHanlder.removeCallbacks(startActionBar);
                    mHandler.postDelayed(startActionBar,1000);

This way you could achieve the same aciton.

Khunt Nirav

some reason the KeyEvent down & up doesn't work in API LEVEL 16+ (Android 4.1+ JELLY_BEAN). It doesn't fire the WebView's loadUrl. So I had to replace the dispatchKeyEvent with dispatchTouchEvent. Here's the code:

...
MotionEvent touchDown = MotionEvent.obtain(SystemClock.uptimeMillis(), SystemClock.uptimeMillis(), MotionEvent.ACTION_DOWN, touchX, touchY, 0);
webView.dispatchTouchEvent(touchDown);
touchDown.recycle();

MotionEvent touchUp = MotionEvent.obtain(SystemClock.uptimeMillis(), SystemClock.uptimeMillis(), MotionEvent.ACTION_UP, touchX, touchY, 0);
webView.dispatchTouchEvent(touchUp);
touchUp.recycle();

String url = mUrl;
...

try it..

Khunt Nirav

For disabling your text selection from webview try this,

webView.setWebChromeClient(new WebChromeClient(){

    [.... other overrides....]

    // @Override
    // https://bugzilla.wikimedia.org/show_bug.cgi?id=31484
    // If you DO NOT want to start selection by long click,
    // the remove this function
    // (All this is undocumented stuff...)
    public void onSelectionStart(WebView view) {
        // By default we cancel the selection again, thus disabling
        // text selection unless the chrome client supports it.
        // view.notifySelectDialogDismissed();
    }

});

You might also try overriding View.performLongClick(), which is responsible for calling View.onLongPress(). You could also try going up to the parent View's long press events. Or all the way up to the Window.Callback for your activity (via Activity.getWindow().get/setCallback()).

I'm wondering whether there are other ways for the standard selection context menu to appear besides the long-press event, for example maybe with a trackball or hardware keyboard.

in case someone is trying to simply remove the default text selection, I had the same issue on a Samsung Galaxy Tab on Android 4.1.2 and ended up writing my own WebView:

public class CustomWebView extends WebView {

  public CustomWebView(Context context) {
    super(context);
    this.setUp(context);
  }

  public CustomWebView(Context context, AttributeSet attrs) {
    super(context, attrs);
    this.setUp(context);
  }

  public CustomWebView(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
    this.setUp(context);
  }

  private void setUp(Context context) {
    this.setOnLongClickListener(new OnLongClickListener() {
      @Override
      public boolean onLongClick(View v) {
        return true;
      }
    });
    this.setLongClickable(false);
  }

  @Override
  public boolean performLongClick() {
    return true;
  }

}

and referring it in my xml:

<com...CustomWebView
    android:id="@+id/webview"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" />

Use setOnTouchListener() implement long press

标签
android
android-webview
textselection
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