Android：EditText焦点跳到ScrollView内部

Question

I have multiple fragments horizontally adjacent using a ViewPager. Each fragment has a ScrollView that contains a table with many EditText views. When I click on a EditText, it gains focus and then loses it to some other EditText in the leftmost fragment. Sometimes the focus switch happens immediately, sometimes while I am typing into a EditText. Usually, the topmost EditText in the leftmost fragment steals focus.

I don't see the problem when a EditText in the leftmost fragment is clicked, even if it is not the topmost one. Its like Android doesn't like focusing on a TextView that is not along the left edge. Does this sound familiar?

I have unsuccessfully tried overriding the findFocus() method in ScrollView as suggested by Skip in randomly-jumping . The source code attached is huge, but it may be useful to others...

package com.example.slideViewPager;

import java.util.ArrayList;

import com.example.slideViewPager.R;

import android.content.Context;
import android.graphics.Color;
import android.graphics.Typeface;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.view.inputmethod.EditorInfo;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.ScrollView;
import android.widget.TableLayout;
import android.widget.TableRow;
import android.widget.TextView;

public class SlideViewPager extends FragmentActivity {
    private static Context g;
    private static ArrayList<String> pages;
    private static int currentItem;    // restore page position after tilt
    private static int[] scrollStateY;
    private static NotesViewFragment[] fragmentArray;
    private static int id;            // to create unique view ids

    @Override
    public void onCreate(Bundle savedInstanceState) {
        g = getApplicationContext();
        setContentView(R.layout.activity_slide_view_pager);
        pages = new ArrayList<String>();
        for (int i = 0; i < 4; ++i)
            pages.add(Integer.toString(i));

        if (savedInstanceState == null) {
            currentItem = 0;
            scrollStateY = new int[pages.size()];    // assume all 0s
            id = 0;
        }
        else {
            currentItem = savedInstanceState.getInt("currentItem");
            scrollStateY = savedInstanceState.getIntArray("scrollStateY");
            id = savedInstanceState.getInt("id");
            System.out.println("Notes onCreate RESTORE: currentItem="+currentItem+"; id="+id);
        }

        fragmentArray = new NotesViewFragment[pages.size()];
        System.out.println("onCreate: start");
        super.onCreate(savedInstanceState);
        ViewPager viewPager = (ViewPager) findViewById(R.id.viewpager);
        NotesPagerAdapter pagerAdapter = new NotesPagerAdapter(getSupportFragmentManager());
        viewPager.setAdapter(pagerAdapter);
        viewPager.setCurrentItem(currentItem);
        viewPager.setOnPageChangeListener(onPageChangeListener);
        System.out.println("onCreate: done");
    }

    @Override
    public void onSaveInstanceState(Bundle bundle) {
        System.out.println("Notes: onSaveInstanceState: currentItem="+currentItem);
        super.onSaveInstanceState(bundle);
        bundle.putInt("currentItem", currentItem);
        bundle.putIntArray("scrollStateY", scrollStateY);
        bundle.putInt("id", id);
    }

    public void onBackPressed() {
        System.out.println("Notes: onBackPressed: currentItem="+currentItem);
        super.onBackPressed();
    }

    /////////////////////////////////////////////////////////////////
    public static class NotesPagerAdapter extends FragmentPagerAdapter {

        public NotesPagerAdapter(FragmentManager fm) {
            super(fm);
            System.out.println("NotesPagerAdapter: this="+this);
        }

        @Override
        public Fragment getItem(int position) {
            String pageNum = pages.get(position);
            NotesViewFragment notesViewFragment = NotesViewFragment.initialize(pageNum, position);        // create new fragment
            System.out.println("NotesPagerAdapter: getItem: CREATED position:"+position+" = page:"+pageNum+"; fragment="+notesViewFragment);
            return notesViewFragment;
        }

        @Override
        public int getCount() {
            return pages.size();
        }

        // nothing being done here
        @Override
        public void destroyItem(ViewGroup container, int position, Object object) {
            System.out.println("NotesPagerAdapter: destroyItem position="+position);
            super.destroyItem(container, position, object);
        }

        @Override
        public float getPageWidth(int position) {
            System.out.println("NotesPagerAdapter: getPageWidth position="+position);
            return (1.0f/2);    // vary # pages/view
        }
    }

    //////////////////////////////////////////////////////
    public static class NotesViewFragment extends Fragment {
        private int position;    // needed to save scrollY into scrollStateY[]
        private String pageNum;    // index
        private ScrollView itemScrollView;

        public NotesViewFragment() {
            super();
            System.out.println("NotesViewFragment: new this:"+this);
        }

        public static NotesViewFragment initialize(String page, int position) {
            NotesViewFragment notesViewFragment = new NotesViewFragment();
            System.out.println("NotesViewFragment: initialize: this:"+notesViewFragment+"; page: "+page+"; position="+position);
            Bundle args = new Bundle();
            args.putString("pageNum", page);
            args.putInt("position", position);
            scrollStateY[position] = 0;        // start at top
            notesViewFragment.setArguments(args);
            return notesViewFragment;
        }

        @Override
        public void onSaveInstanceState(Bundle outState) {
            super.onSaveInstanceState(outState);
            System.out.println("NotesViewFragment: onSaveInstanceState this:"+this+"; page: "+pageNum+"; scrollView="+itemScrollView);
            // itemScrollView will be null occasionally (attached but not createViewed)
            if (itemScrollView != null)
                scrollStateY[position] = itemScrollView.getScrollY();
            outState.putString("pageNum", pageNum);
        }

        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            Bundle args = getArguments();
            if (args != null) {
                pageNum = args.getString("pageNum");
                position = args.getInt("position");
                fragmentArray[position] = this;
                System.out.println("NotesViewFragment: onCreate: this:"+this+"; page: "+pageNum+"; position="+position+"; yPos="+scrollStateY[position]);
            }
            else    // should not happen
                System.out.println("NotesViewFragment: onCreate: NO ARGS !!! this:"+this);            
        }

        public void onDestroyView() {
            super.onDestroyView();
            if (itemScrollView != null)        // could be null if not createViewed
                scrollStateY[position] = itemScrollView.getScrollY();

            System.out.println("NotesViewFragment: onDestroyView: "+pageNum+" this="+this+"; scrollY="+scrollStateY[position]);
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
            if (savedInstanceState != null) {    // config change happened
                pageNum = savedInstanceState.getString("pageNum");
                System.out.println("NotesViewFragment: onCreateView: RESTORED "+pageNum+" this="+this+"; yPos="+scrollStateY[position]);
            }
            else
                System.out.println("NotesViewFragment: onCreateView: "+pageNum+"; this="+this);

            // Inflate the layout containing a title and body text.
            ViewGroup rootView = (ViewGroup) inflater.inflate(R.layout.fragment_screen_slide_page, container, false);
            TableLayout itemNotesTable = (TableLayout) rootView.findViewById(R.id.tableLayoutNotes);
            TextView itemTitle = (TextView) rootView.findViewById(R.id.textViewTitle);
            itemScrollView = (ScrollView) rootView.findViewById(R.id.scroll_form);
            itemTitle.setText("Team "+pageNum);

            for (int i = 0; i < 12; ++i) {
                TableRow tr = new TableRow(g);
                tr.setId(++id);

                ImageView itemThumbnail = new ImageView(g);
                itemThumbnail.setId(++id);
                itemThumbnail.setImageResource(R.drawable.notes);    // set icon
                tr.addView(itemThumbnail);

                LinearLayout ll = new LinearLayout(g);
                ll.setId(++id);
                ll.setOrientation(LinearLayout.VERTICAL);
                String text = " Team "+pageNum;
                ll.addView(makeTextItem(text, false));

                TextView textView;
                if ((id % 2) == 0) {    // make some entries editable
                    textView = new EditText(g);
                    textView.setFocusable(true);
                    textView.setFocusableInTouchMode(true);
                    textView.setImeOptions(EditorInfo.IME_FLAG_NO_ENTER_ACTION);
                    textView.setOnFocusChangeListener(onFocusChangeListener);
                }
                else
                    textView = new TextView(g);

                textView.setId(++id);
                String str = "Line "+i+" is blah blah blah and more blah blah blah";
                textView.setText(str);
                textView.setTextColor(Color.BLACK);
                textView.setTextSize(16);
                textView.setPadding(2, 2,  2,  2);        // start, top, end, bottom
                ll.addView(textView);
                tr.addView(ll);
                itemNotesTable.addView(tr);
                tr.setOnClickListener(noteClicked);        // make everything in table row clickable
            }

            if (scrollStateY[position] != 0) {
                itemScrollView.post(new Runnable() {
                    public void run() {
                        itemScrollView.scrollTo(0, scrollStateY[position]);
                    }
                });
            }
            return rootView;
        }

        // called from fillNotes
        private static TextView makeTextItem(String label, boolean bold) {
            TextView item = new TextView(g);
            item.setId(++id);
            item.setText(label);
            item.setTextColor(Color.BLACK);
            item.setTextSize(16);
            if (bold)
                item.setTypeface(null, Typeface.BOLD);
            return item;
        }
    }

    // listens for horizontal page scrolls
    ViewPager.OnPageChangeListener onPageChangeListener = new ViewPager.SimpleOnPageChangeListener() {
        @Override
        public void onPageSelected(int position) {
            System.out.println("onPageChangeListener: leaving page:"+currentItem+"; for page: "+position);
            currentItem = position;
        }
    };

    static View.OnFocusChangeListener onFocusChangeListener = new View.OnFocusChangeListener() {

        @Override
        public void onFocusChange(View view, boolean hasFocus) {
            System.out.println("onFocusChangeListener: "+hasFocus+"; "+view);
            if (! hasFocus) {
                EditText editText = (EditText) view;
                String text = editText.getText().toString();
                System.out.println("onFocusChangeListener: "+text);
            }
        }
    };

    static OnClickListener noteClicked = new OnClickListener() {
        public void onClick(View tr) {
            for (View parent = tr; parent != null; parent = (View) parent.getParent()) {
                for (NotesViewFragment fragment : fragmentArray)
                    if (fragment != null  &&  fragment.itemScrollView == parent) {
                        System.out.println("noteClicked: page: "+fragment.pageNum);
                        return;
                    }
            }
        }
    };
}

There are a couple of XML files: fragment_screen_slide_page.xml ..........

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/content"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:id="@+id/textViewTitle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:text=""
        android:textAppearance="?android:attr/textAppearanceLarge" />

    <View
        android:id="@+id/separator"
        android:layout_width="fill_parent"
        android:layout_height="1dip"
        android:layout_alignParentRight="true"
        android:layout_marginTop="4dp"
        android:layout_below="@+id/textViewTitle"
        android:background="#888888" />

    <ScrollView
        android:id="@+id/scroll_form"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_below="@+id/separator" >

        <TableLayout
            android:id="@+id/tableLayoutNotes"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:stretchColumns="1"  >
        </TableLayout>
    </ScrollView>
</RelativeLayout>

and activity_slide_view_pager.xml ----------

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"

    android:descendantFocusability="beforeDescendants"
    android:focusableInTouchMode="true"
    tools:context=".Page" >

    <android.support.v4.view.ViewPager
        android:id="@+id/viewpager"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>
</RelativeLayout>

Answer 1

Focus is changing to the leftmost fragment because that fragment is the current item of the ViewPager . You might try to use setCurrentItem(item) to set the current item to the other fragment (when the user clicks on it) so the left one doesn't steal focus.

This is happening because at the end of the populate() function of the ViewPager it will always give focus to a view that is in the current item. You could also fix this issue by copying the ViewPager source and changing this code to allow any fragment which is on the screen to have a child with focus.

Change this:

if (hasFocus()) {
    View currentFocused = findFocus();
    ItemInfo ii = currentFocused != null ? infoForAnyChild(currentFocused) : null;
    if (ii == null || ii.position != mCurItem) {
        for (int i = 0; i < getChildCount(); i++) {
            View child = getChildAt(i);
            ii = infoForChild(child);
            if (ii != null && ii.position == mCurItem) {
                if (child.requestFocus(FOCUS_FORWARD)) {
                    break;
                }
            }
        }
    }
}

To something like this:

if (hasFocus()) {
    View currentFocused = findFocus();
    ItemInfo ii = currentFocused != null ? infoForAnyChild(currentFocused) : null;
    if (ii == null || !infoIsOnScreen(ii)) {
        for (int i = 0; i < getChildCount(); i++) {
            View child = getChildAt(i);
            ii = infoForChild(child);
            if (ii != null && infoIsOnScreen(ii)) {
                if (child.requestFocus(FOCUS_FORWARD)) {
                    break;
                }
            }
        }
    }
}

public boolean infoIsOnScreen(ItemInfo info) {
    // Code to determine if the view is on the screen using ii.offset etc.
}

Answer 2

I found the problem, it was the lines in the main activity XML: activity_slide_view_pager.xml

    android:focusableInTouchMode="true"
    android:descendantFocusability="beforeDescendants"

This was causing the RelativeLayout to grab focus.

Answer 3

As an addition to @Cameron Ketcham answer, the best fix of the issue is Creating your own CustomViewpager class that extends from ViewPager and overriding the RequestChildFocus method with null so as to disable the automatic focus behavior.

Your customeViewPager class will look something like this

public class CustomeViewPager extends ViewPager {

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

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

   @Override
   public void requestChildFocus(View child, View focused) {
       //Do nothing, disables automatic focus behaviour

   }

}

You can now use this class in your xml and continue from there.