Question

我知道这里有一些关于此的话题，但我找不到一个可以为我的案子工作的解决方案。

我有一个使用自定义FragmentActivity和FragmentPagerAdapter的工作幻灯片库，其中包含片段列表。

在FragmentActivity内ImageView“删除”。如果单击，则会调用函数deleteMedia()，然后应删除当前Fragment，并显示以下Fragment。在我的例子中我该如何做到这一点？

FragmentActivity：

public class GalleryPagerActivity extends FragmentActivity implements OnClickListener {

    private Intent intent;
    private SharedPreferences settings;
    private PagerAdapter mPagerAdapter;
    private ViewPager mPager;
    private List<Fragment> fragments;
    private List<WhiteboardMedia> wiList;

    private int selectedPosition;
    private LinearLayout llTop;
    private TextView tvTop;
    private ImageView delete;
    private ImageView share;
    private TextView tvCounter;
    private TextView tvFilename;
    private TextView tvFilesize;
    private TextView tvDate;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        try {
            super.setContentView(R.layout.gallery_pager);

            intent = getIntent();

            Type collectionType = new TypeToken<List<WhiteboardMedia>>(){}.getType();

            wiList = gson.fromJson(intent.getStringExtra("wiList"), collectionType);
            selectedPosition = intent.getIntExtra("position", 1);

            llTop = (LinearLayout) findViewById(R.id.llTop);
            llTop.setOnClickListener(this);
            tvTop = (TextView) findViewById(R.id.tvTop);
            tvTop.setOnClickListener(this);
            delete = (ImageView) findViewById(R.id.imgDelete);
            delete.setOnClickListener(this);
            share = (ImageView) findViewById(R.id.imgShare);
            share.setOnClickListener(this);

            tvCounter = (TextView) findViewById(R.id.tvCounter);
            tvFilename = (TextView) findViewById(R.id.tvFilename);
            tvFilesize = (TextView) findViewById(R.id.tvFilesize);
            tvDate = (TextView) findViewById(R.id.tvDate);

            createContextMenu();
            initDropbox();
        } catch (Exception e) {
            Log.e("GalleryPagerActivity", e.getLocalizedMessage());
        }
    }

    /**
     * Initialise the pager
     */
    private void initialisePager() {
        mPager = (ViewPager) super.findViewById(R.id.viewpager);
        mPager.setAdapter(this.mPagerAdapter);
        mPager.setOnPageChangeListener(new GalleryPageListener(tvCounter, tvFilename, tvFilesize, tvDate, wiList));

        mPager.setCurrentItem(selectedPosition, true);
        updatePage(selectedPosition);
    }

    public void updatePage(int position)
    {
        int focusedPage = position + 1;
        Log.i("onPageSelected", "page selected " + position);

        WhiteboardMedia wiImage = wiList.get(position);

        String imageDate = "N/A";
        try {
            Date dateTaken= new Date(); //wiImage.getDate();
            SimpleDateFormat sdf = new SimpleDateFormat("yy/MM/dd");
            imageDate = sdf.format(dateTaken);
        } catch (Exception e) {
        }

        try {
            tvCounter.setText(focusedPage + "/" + wiList.size());
            tvFilename.setText(wiImage.getFilename());
            tvFilesize.setText(wiImage.getSize() + "a");
            tvDate.setText(imageDate);
        } catch (Exception e) {
        }
    }

    @Override
    protected void onResume() {
        super.onResume();
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
    }

    private WhiteboardMedia getActiveWhiteboardImage() {
        return wiList.get(mPager.getCurrentItem());
    }

    private final int DELETE = 1;

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        menu.add(1, DELETE, 2, R.string.delete).setIcon(R.drawable.menu_btn_trash);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
        case DELETE:
            deleteMedia();
            return true;
        }
        return super.onContextItemSelected(item);
    }

    @Override
    public void onClick(View v) {
        if (v == delete) {
            deleteMedia();
        }
    }

    private void deleteMedia() {
        // TODO delete the active Fragment and display the next Fragment in the list
    }

    /******************************************************************************
     * Context Menu
     *****************************************************************************/
    private void createContextMenu() {
        // context menu stuff
    }

    @Override
    protected Dialog onCreateDialog(int id) {
        // stuff
    }

}

FragmentPagerAdapter：

public class GalleryPagerAdapter extends FragmentPagerAdapter {

private final List<Fragment> fragments;

public GalleryPagerAdapter(FragmentManager fm, List<Fragment> fragments) {
    super(fm);
    this.fragments = fragments;
}

@Override
public Fragment getItem(int position) {
    return this.fragments.get(position);
}

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

感谢您的帮助！

Answer 1

这是我正在使用的解决方案：

mViewPager：是您用来设置片段的视图

mViewPager = (YourViewPager) findViewById(R.id.myPager);

表：只是我所有碎片位置的整数列表

    public void destroyAllItem() {
        int mPosition = mViewPager.getCurrentItem();
        int mPositionMax = mViewPager.getCurrentItem()+1;
        if (TABLE.size() > 0 && mPosition < TABLE.size()) {
            if (mPosition > 0) {
                mPosition--;
            }

            for (int i = mPosition; i < mPositionMax; i++) {
                try {
                    Object objectobject = this.instantiateItem(mViewPager, TABLE.get(i).intValue());
                    if (objectobject != null)
                        destroyItem(mViewPager, TABLE.get(i).intValue(), objectobject);
                } catch (Exception e) {
                    Log.i(TAG, "no more Fragment in FragmentPagerAdapter");
                }
            }
        }
    }

    @Override
    public void destroyItem(ViewGroup container, int position, Object object) {
        super.destroyItem(container, position, object);

        if (position <= getCount()) {
            FragmentManager manager = ((Fragment) object).getFragmentManager();
            FragmentTransaction trans = manager.beginTransaction();
            trans.remove((Fragment) object);
            trans.commit();
        }
    }

Answer 2

首先，我建议您考虑更改FragmentPagerAdapter，使其看起来更像the sample。您通常不会保留片段列表，只有ArrayAdapter通常包含行的Views列表。通常，您可以根据需要创建片段，而其他人则保留列表。

然后，要删除某些内容，请将其从模型数据中删除（FragmentPagerAdapter通常包含的内容）。确保getCount()然后返回正确数量的项目。然后，在notifyDataSetChanged()上调用FragmentPagerAdapter，这会触发ViewPager的重绘。

Answer 3

我找到了一个解决方法的解决方案＆＃34; onPostResume（）＆＃34;该活动并在其中调用notifyDataSetChanged。

@Override
protected void onPostResume() {
    super.onPostResume();
    if(this.mCustomPagerAdapter!=null){
        this.mCustomPagerAdapter.notifyDataSetChanged();
    }
}

Answer 4

如果您正在使用FragmentPagerAdapter动态地在随机位置（并非总是在末尾）添加和删除片段，那么您需要更多关注getItemId的方法。默认情况下，FragmentPagerAdapter使用position组合viewId作为片段的标记名称，但是如果添加或删除片段，位置会更改。因此，您可能会获得一个空页面，因为您添加的位置被现有片段占用。要解决此问题，请覆盖getItemId。

@Override
public long getItemId(int position) {
    long itemId = ...;  //Provide your unique ID here according to you logic
    return itemId;
}

如何从FragmentPagerAdapter中删除片段？

4 个答案: