Long press definition at XML layout, like android:onClick does

Question

There is any way to define into XML layout longKeyLongPress definition like onClick does ?.

i.e this is my view

Answer 1

The attribute is not defined, however you can implement it.

1. Extend TextView and let's call it MyTextView.

2. Then add file attrs.xml in res/values/ with following content:

   <xml version="1.0" encoding="utf-8"?>
   <resources>
       <declare-styleable name="MyTextView">
           <attr name="onKeyLongPress" format="string"/>
       </declare-styleable>
   </resources>
   

3. In MyTextView constructor add logic to read data from xml:

   public MyTextView(final Context context, final AttributeSet attrs) {
   super(context, attrs);
   TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.MyTextView);
   
   for (int i = 0; i < a.getIndexCount(); ++i)
   {
       int attr = a.getIndex(i);
       switch (attr)
       {
           case R.styleable.MyTextView_onKeyLongPress: {
               if (context.isRestricted()) {
                   throw new IllegalStateException("The "+getClass().getCanonicalName()+":onKeyLongPress attribute cannot "
                           + "be used within a restricted context");
               }
   
               final String handlerName = a.getString(attr);
               if (handlerName != null) {
                   setOnLongClickListener(new OnLongClickListener() {
                       private Method mHandler;
   
                       @Override
                       public boolean onLongClick(final View p_v) {
                           boolean result = false;
                           if (mHandler == null) {
                               try {
                                   mHandler = getContext().getClass().getMethod(handlerName, View.class);
                               } catch (NoSuchMethodException e) {
                                   int id = getId();
                                   String idText = id == NO_ID ? "" : " with id '"
                                           + getContext().getResources().getResourceEntryName(
                                               id) + "'";
                                   throw new IllegalStateException("Could not find a method " +
                                           handlerName + "(View) in the activity "
                                           + getContext().getClass() + " for onKeyLongPress handler"
                                           + " on view " + MyTextView.this.getClass() + idText, e);
                               }
                           }
   
                           try {
                               mHandler.invoke(getContext(), MyTextView.this);
                               result = true;
                           } catch (IllegalAccessException e) {
                               throw new IllegalStateException("Could not execute non "
                                       + "public method of the activity", e);
                           } catch (InvocationTargetException e) {
                               throw new IllegalStateException("Could not execute "
                                       + "method of the activity", e);
                           }
                           return result;
                       }
                   });
               }
               break;
           }
           default: 
               break;
       }
   }
   a.recycle();
   
   }
   

4. Use new attribute in your layout xml:

   <LinearLayout
       xmlns:android="http://schemas.android.com/apk/res/android"
       xmlns:custom="http://schemas.android.com/apk/res/res-auto"
       android:layout_width="fill_parent"
       android:layout_height="fill_parent"
       android:orientation="vertical"
       >
   
       <your.package.MyTextView
           android:id="@+id/theId"
           android:layout_width="wrap_content"
           android:layout_height="wrap_content"
           custom:onKeyLongPress="myDoSomething"
       />
       <!-- Other stuff -->
   </LinearLayout>
   

Credits:

• I have learned how to do this from this post: http://kevindion.com/2011/01/custom-xml-attributes-for-android-widgets/
• Snippet for constructor with slight modifications was taken from original android View class.

Answer 2

Looking at the current documentation, such an XML parameter does not currently exist. The longClickable is a boolean parameter to define simply whether a View is responds to long clicks or not.