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我有一个奇怪的问题 - 我正在使用带有 ViewSwitcher 的活动,这个 ViewSwitcher 有 aListView和 aGridView使用相同的ArrayAdapter{SomeContent}.

我已经制作了适配器,以便我可以将它们R.layout.value用于膨胀的内容传递给它们——这就是我管理 ListView / GridView 一致性的方式,因为我想要这两种形式的视图有所不同。

所有这一切都有些完美,只是不是第一次。

不,我第一次在 GRID 显示模式下运行我的应用程序时,我的 gridview 尝试使用错误的 XML,并最终尝试使用(回收?) ListView 的 XML。我知道是因为 GridView 的 XML 没有对复选框的引用,而且我经常看到它们。

但是当我离开这个屏幕(甚至不会说“活动”)并回到它时,一切都完美地膨胀了。列表总是能立即工作,GridViews ~80% 只在第一次工作。

有任何想法吗?

这是一些帮助您入门的代码。适配器:

public class AudioAdapter extends ArrayAdapter<MusicContent>
{
private Context context;

private ImageView albumArt;
private TextView songName;
private TextView artistName;
private TextView albumName;
private TextView genre;
private TextView duration;
private int viewToUse;

private CheckBox checkbox;
private OnItemClickListener clickListener;
private OnItemSelectedListener focusListener;

private List<MusicContent> content = new ArrayList<MusicContent>();


public AudioAdapter(Context context, int textViewResourceId, List<MusicContent> objects,
        OnItemClickListener clickListener, OnItemSelectedListener focusListener)
{
    super(context, textViewResourceId, objects);
    this.context = context;
    this.content = objects;
    this.clickListener = clickListener;
    this.focusListener = focusListener;
    this.viewToUse = textViewResourceId;
}

@Override
public View getView(int position, View convertView, ViewGroup parent)
{
    View row = convertView;

    /**
     * Removed following optimization on purpose due to dynamically using
     * different layouts which may result in wrong view being recycled for
     * use
     */
    //removing it fixed nothing really
    if (row == null)
    {
        // ROW INFLATION
        LayoutInflater inflater = (LayoutInflater) this.getContext().getSystemService(
                Context.LAYOUT_INFLATER_SERVICE);
        row = inflater.inflate(viewToUse, parent, false);
    }
    // initiate helpers for onClick hack
    final AdapterView fParent = (AdapterView) parent;
    final View fView = row;
    final int fInt = position;
    final long fLong = row.getId();

    // Get item
    MusicContent item = getItem(position);
    if (item == null)
        return row;

    RelativeLayout root = (RelativeLayout) row.findViewById(R.id.list_cell_layout);

    // perform a series of checks to maintain customizability
    albumArt = (ImageView) row.findViewById(R.id.list_cell_image);
    if (albumArt != null)
    {
        if (item.hasAlbumArt()) {
            albumArt.setImageBitmap(item.getAlbumBitmap(context));
        }
        else
            albumArt.setImageDrawable(context.getResources().getDrawable(
                    R.drawable.ic_music_album));
    }

    LinearLayout checkLL = (LinearLayout) row.findViewById(R.id.list_cell_music_info);
    if (checkLL != null)
    {
        // display some song info
        songName = (TextView) checkLL.findViewById(R.id.list_cell_title);
        if (songName != null)
        {
            songName.setText(item.getDisplayName());
            songName.setVisibility(View.VISIBLE);
        }

        // attach artificial OnItemClick and OnItemSelected listeners
        if (clickListener != null)
        {
            OnClickListener cross = new OnClickListener() {
                @Override
                public void onClick(View v) {
                    Log.d("SHARK", "internal onClick from adapter!!" + fView);
                    clickListener.onItemClick(fParent, fView, fInt, fLong);
                }
            };
            checkLL.setOnClickListener(cross);
        }
        if (focusListener != null)
        {
            OnFocusChangeListener cross = new OnFocusChangeListener() {

                @Override
                public void onFocusChange(View v, boolean hasFocus) {
                    if (hasFocus)
                        focusListener.onItemSelected(fParent, fView, fInt, fLong);
                }
            };
            checkLL.setOnFocusChangeListener(cross);
        }

        checkLL = (LinearLayout) row.findViewById(R.id.list_cell_artist_info);
        if (checkLL != null)
        {
            // display artist info too
            artistName = (TextView) checkLL.findViewById(R.id.list_cell_artist_name);
            if (artistName != null)
                artistName.setText(item.getArtist());

            albumName = (TextView) checkLL.findViewById(R.id.list_cell_album);
            if (albumName != null)
                albumName.setText(item.getAlbum());

            duration = (TextView) checkLL.findViewById(R.id.list_cell_duration);
            if (duration != null)
                duration.setText(item.getDurationString());

            genre = (TextView) checkLL.findViewById(R.id.list_cell_genre);
            if (genre != null)
                genre.setText(item.getGenre());

            // block focus on descendants
            checkLL.setDescendantFocusability(RelativeLayout.FOCUS_BLOCK_DESCENDANTS);

            // attach artificial listeners
            if (clickListener != null)
            {
                OnClickListener cross = new OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        Log.d("SHARK", "internal onClick from adapter!!" + fView);
                        clickListener.onItemClick(fParent, fView, fInt, fLong);
                    }
                };
                checkLL.setOnClickListener(cross);
            }
            if (focusListener != null)
            {
                OnFocusChangeListener cross = new OnFocusChangeListener() {

                    @Override
                    public void onFocusChange(View v, boolean hasFocus) {
                        if (hasFocus)
                            focusListener.onItemSelected(fParent, fView, fInt, fLong);
                    }
                };
                checkLL.setOnFocusChangeListener(cross);
            }
        }

        // FrameLayout checkFL = (FrameLayout)
        // row.findViewById(R.id.endoflineinfo);
        checkLL = (LinearLayout) row.findViewById(R.id.endoflineinfo);
        if (checkLL != null)
        {
            checkbox = (CheckBox) checkLL.findViewById(R.id.in_playlist);
            if (checkbox != null)
            {
                checkbox.setVisibility(View.VISIBLE);
                if (item.getPlaylist() != null)
                    checkbox.setChecked(!item.getPlaylist().isEmpty());
            }
            checkLL.setDescendantFocusability(RelativeLayout.FOCUS_BLOCK_DESCENDANTS);
            if (clickListener != null)
            {
                OnClickListener cross = new OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        Log.d("SHARK", "internal onClick from adapter!!" + fView);
                        clickListener.onItemClick(fParent, fView, fInt, fLong);
                    }
                };
                checkLL.setOnClickListener(cross);
            }
            if (focusListener != null)
            {
                OnFocusChangeListener cross = new OnFocusChangeListener() {

                    @Override
                    public void onFocusChange(View v, boolean hasFocus) {
                        if (hasFocus)
                            focusListener.onItemSelected(fParent, fView, fInt, fLong);
                    }
                };
                checkLL.setOnFocusChangeListener(cross);
            }
        }
    }

    // magic happens where we bind an OnItemClick call to OnClick
    root.setDescendantFocusability(RelativeLayout.FOCUS_BLOCK_DESCENDANTS);

    if (clickListener != null)
    {
        OnClickListener cross = new OnClickListener() {
            @Override
            public void onClick(View v) {
                Log.d("SHARK", "internal onClick from adapter!!");
                clickListener.onItemClick(fParent, fView, fInt, fLong);
            }
        };
        // assign this listener
        root.setOnClickListener(cross);
    }
    if (focusListener != null)
    {
        OnFocusChangeListener cross = new OnFocusChangeListener() {

            @Override
            public void onFocusChange(View v, boolean hasFocus) {
                if (hasFocus)
                    focusListener.onItemSelected(fParent, fView, fInt, fLong);
            }
        };
        root.setOnFocusChangeListener(cross);
    }

    return row;
}

至于为什么这么多 if 和检查 - 它必须能够在缺少元素的不同底层 XML 中生存(可定制性),并且不要太担心 onClick / onFocus hacks - 它们是非常需要的解决方法......

4

1 回答 1

0

在研究了我的视图是如何被回收的之后,我得出一个结论,即我在与上次离开时​​不同的视图模式下运行应用程序——这导致 GRID 视图被保存并在 LIST 中使用,反之亦然。

修改后,我确保以以前使用的相同模式重新启动应用程序,或者在重新启动时强制新视图重新创建适配器并将其重新分配给我的视图。

于 2013-06-28T14:09:18.790 回答