android - 默认展开 CustomExpandable View 的第一项

Question

我正在尝试默认展开自定义可扩展 ListView 的第一项，但没有得到结果...

这是我的来源....

public class MainActivity extends Activity {

    private final String[] array = {"Hello", "World", "Android", "is",   "Awesome", "World", "Android", "is", "Awesome", "World", "Android", "is", "Awesome", "World", "Android", "is", "Awesome"};
    ExpandableLayoutListView  expandableLayoutListView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        final ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(this, R.layout.view_row, R.id.header_text, array);
        expandableLayoutListView = (ExpandableLayoutListView) findViewById(R.id.listview);

        expandableLayoutListView.setAdapter(arrayAdapter);
        final Handler handler = new Handler();
        handler.postDelayed(new Runnable() {
          @Override
          public void run() {
            //Do something after 100ms
              try
              {
              View vi = getViewByPosition(0,expandableLayoutListView);
              //ExpandableLayout.expand(vi);*/
                expandableLayoutListView.setItemSelected(0,vi);
              //ExpandableLayout.expand(vi);
          }
              catch(Exception e)
              {e.printStackTrace();}
          }
        }, 1000);
        
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
    
    public static View getViewByPosition(int pos, ExpandableLayoutListView listView) {
        final int firstListItemPosition = listView.getFirstVisiblePosition();
        final int lastListItemPosition = firstListItemPosition + listView.getChildCount() - 1;

        if (pos < firstListItemPosition || pos > lastListItemPosition ) {
            return listView.getAdapter().getView(pos, null, listView);
        } else {
            final int childIndex = pos - firstListItemPosition;
            return listView.getChildAt(childIndex);
        }
    }

这是我的ExpandableLayoutListView

public class ExpandableLayoutListView extends ListView
     {
     Context ctx;
      private int mItemSelected = -1 ;
     private Integer position = -1;
    public ExpandableLayoutListView(Context context)
    {
        
        super(context);
        ctx = this.getContext();
        setOnScrollListener(new OnExpandableLayoutScrollListener());
    }

    public ExpandableLayoutListView(Context context, AttributeSet attrs)
    {
        super(context, attrs);
        setOnScrollListener(new OnExpandableLayoutScrollListener());
    }

    public ExpandableLayoutListView(Context context, AttributeSet attrs, int defStyle)
    {
        super(context, attrs, defStyle);
        setOnScrollListener(new OnExpandableLayoutScrollListener());
    }

    @Override
    public boolean performItemClick(View view, int position, long id)
    {
        this.position = position;

        for (int index = 0; index < getChildCount(); ++index)
        {
            if (index != (position - getFirstVisiblePosition()))
            {
                ExpandableLayoutItem currentExpandableLayout = (ExpandableLayoutItem) getChildAt(index).findViewWithTag(ExpandableLayoutItem.class.getName());
                currentExpandableLayout.hide();
            }
        }

        ExpandableLayoutItem expandableLayout = (ExpandableLayoutItem) getChildAt(position - getFirstVisiblePosition()).findViewWithTag(ExpandableLayoutItem.class.getName());

        if (expandableLayout.isOpened())
            expandableLayout.hide();
        else
            expandableLayout.show();


        return super.performItemClick(view, position, id);
    }

    @Override
    public void setOnScrollListener(OnScrollListener l)
    {
        if (!(l instanceof OnExpandableLayoutScrollListener))
            throw new IllegalArgumentException("OnScrollListner must be an OnExpandableLayoutScrollListener");

        super.setOnScrollListener(l);
    }

    public class OnExpandableLayoutScrollListener implements OnScrollListener
    {
        private int scrollState = 0;

        @Override
        public void onScrollStateChanged(AbsListView view, int scrollState)
        {
            this.scrollState = scrollState;
        }

        @Override
        public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount)
        {
            if (scrollState != SCROLL_STATE_IDLE)
            {
                for (int index = 0; index < getChildCount(); ++index)
                {
                    ExpandableLayoutItem currentExpandableLayout = (ExpandableLayoutItem) getChildAt(index).findViewWithTag(ExpandableLayoutItem.class.getName());
                    if (currentExpandableLayout.isOpened() && index != (position - getFirstVisiblePosition()))
                    {
                        currentExpandableLayout.hideNow();
                    }
                    else if (!currentExpandableLayout.getCloseByUser() && !currentExpandableLayout.isOpened() && index == (position - getFirstVisiblePosition()))
                    {
                        currentExpandableLayout.showNow();
                    }
                }
            }
        }
    }
    public void setItemSelected(int position,View vi){
        mItemSelected=position;
        getView(position,vi);
        }
    public void getView(int position, View convertView ){
        
     if(mItemSelected==position){
         convertView.setActivated(true);
     }else{
         convertView.setActivated(false);
     }
     }
    }

使用 ExpandableLayoutItem

public class ExpandableLayoutItem extends RelativeLayout
    {
    private Boolean isAnimationRunning = false;
    private static Boolean isOpened = false;
    private static Integer duration;
    private FrameLayout contentLayout;
    private FrameLayout headerLayout;
    private Boolean closeByUser = true;

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

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

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

    private void init(final Context context, AttributeSet attrs)
    {
        final View rootView = View.inflate(context, R.layout.view_expandable, this);
        headerLayout = (FrameLayout) rootView.findViewById(R.id.view_expandable_headerlayout);
        final TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.ExpandableLayout);
        final int headerID = typedArray.getResourceId(R.styleable.ExpandableLayout_el_headerLayout, -1);
        final int contentID = typedArray.getResourceId(R.styleable.ExpandableLayout_el_contentLayout, -1);
        contentLayout = (FrameLayout) rootView.findViewById(R.id.view_expandable_contentLayout);

        if (headerID == -1 || contentID == -1)
            throw new IllegalArgumentException("HeaderLayout and ContentLayout cannot be null!");

        if (isInEditMode())
            return;

        duration = typedArray.getInt(R.styleable.ExpandableLayout_el_duration, getContext().getResources().getInteger(android.R.integer.config_shortAnimTime));
        final View headerView = View.inflate(context, headerID, null);
        headerView.setLayoutParams(new ViewGroup.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT));
        headerLayout.addView(headerView);
        setTag(ExpandableLayoutItem.class.getName());
        final View contentView = View.inflate(context, contentID, null);
        contentView.setLayoutParams(new ViewGroup.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
        contentLayout.addView(contentView);
        contentLayout.setVisibility(GONE);

        headerLayout.setOnTouchListener(new OnTouchListener()
        {
            @Override
            public boolean onTouch(View v, MotionEvent event)
            {
                if (isOpened() && event.getAction() == MotionEvent.ACTION_UP)
                {
                    hide();
                    closeByUser = true;
                }

                return isOpened() && event.getAction() == MotionEvent.ACTION_DOWN;
            }
        });

    }

    public static void expand(final View v)
    {
        isOpened = true;
        v.measure(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
        final int targetHeight = v.getMeasuredHeight();
        v.getLayoutParams().height = 0;
        v.setVisibility(VISIBLE);

        Animation animation = new Animation()
        {
            @Override
            protected void applyTransformation(float interpolatedTime, Transformation t)
            {
                v.getLayoutParams().height = (interpolatedTime == 1) ? LayoutParams.WRAP_CONTENT : (int) (targetHeight * interpolatedTime);
                v.requestLayout();
            }


            @Override
            public boolean willChangeBounds() {
                return true;
            }
        };
        animation.setDuration(duration);
        v.startAnimation(animation);
    }

    private void collapse(final View v)
    {
        isOpened = false;
        final int initialHeight = v.getMeasuredHeight();
        Animation animation = new Animation()
        {
            @Override
            protected void applyTransformation(float interpolatedTime, Transformation t) {
                if(interpolatedTime == 1)
                {
                    v.setVisibility(View.GONE);
                    isOpened = false;
                }
                else{
                    v.getLayoutParams().height = initialHeight - (int)(initialHeight * interpolatedTime);
                    v.requestLayout();
                }
            }

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

        animation.setDuration(duration);
        v.startAnimation(animation);
    }

    public void hideNow()
    {
        contentLayout.getLayoutParams().height = 0;
        contentLayout.invalidate();
        contentLayout.setVisibility(View.GONE);
        isOpened = false;
    }

    public void showNow()
    {
        if (!this.isOpened())
        {
            contentLayout.setVisibility(VISIBLE);
            this.isOpened = true;
            contentLayout.getLayoutParams().height = LayoutParams.WRAP_CONTENT;
            contentLayout.invalidate();
        }
    }

    public Boolean isOpened()
    {
        return isOpened;
    }

    public void show()
    {
        if (!isAnimationRunning)
        {
            expand(contentLayout);
            isAnimationRunning = true;
            new Handler().postDelayed(new Runnable()
            {
                @Override
                public void run()
                {
                    isAnimationRunning = false;
                }
            }, duration);
        }
    }

    public FrameLayout getHeaderLayout()
    {
        return headerLayout;
    }

    public FrameLayout getContentLayout()
    {
        return contentLayout;
    }

    public void hide()
    {
        if (!isAnimationRunning)
        {
            collapse(contentLayout);
            isAnimationRunning = true;
            new Handler().postDelayed(new Runnable()
            {
                @Override
                public void run()
                {
                    isAnimationRunning = false;
                }
            }, duration);
        }
        closeByUser = false;
    }

    public Boolean getCloseByUser()
    {
        return closeByUser;
    }
    }

接下来我可以尝试什么？

Answer 1

因为您正在扩展 ListView，所以您应该尝试这样做:

expandableLayoutListView.expandGroup(position, false);

您还可以扩展 ExpandableListView 而不是 ListView，然后使用:

expandableLayoutListView.expandGroup(position);

因为ExpandableListView有这个方法:

public boolean expandGroup(int groupPos) {
       return expandGroup(groupPos, false);
   }