如何获取没有标签的当前视图寻呼机视图？

Question

我有一个视图寻呼机，其中每个页面都是我使用Fragment进行充气的自定义视图（...而不是LayoutInflator）。每个自定义视图中都有一个ImageView，其中使用Glide库填充了来自网络的图片。

我的任务是当用户每次更改我需要检索填充当前显示的Bitmap的{​​{1}}的页面时滚动查看寻呼机。

我尝试在视图寻呼机上使用ImageView设置，并使用OnPageChangeListener方法使用onPageSelected方法或viewPager.getChildAt()获取当前视图。

以下是代码：

活动：

viewPager.getFocusedChild()

适配器：

public class TimelineMomentActivity extends ActivityBase implements ViewPager.OnPageChangeListener, View.OnClickListener,
    TimelineCommentsGetRequest.Callback, CreativeHandler.CreativeHandleCallback {
...
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    AppInstance.sharedInstance().getBus().register(this);

    mShouldSaveToDB = AppInstance.sharedInstance().isSelf();
    mStory = getIntent().getParcelableExtra(StoryDB.KEY_NAME);

    final String storyID = getIntent().getStringExtra(KEY_STORY_ID);
    final String momentID = getIntent().getStringExtra(KEY_MOMENT_ID);
    mSelectedIndex = getIntent().getIntExtra(ARG_SELECTED_INDEX, 0);

    if (!mShouldSaveToDB) {
        if (mStory == null) {
            sendRequest(storyID, momentID);
        } else {
            mMoments = mStory.getMoments();
            setViewPager();
        }
    } else {
        if (mStory != null) {
            mStoryDB = DBManager.getStory(mStory.getID());
        } else {
            mStoryDB = DBManager.getStory(storyID);
        }
        if (mStoryDB == null) {
            sendRequest(storyID, momentID);
        } else {
            setGlobalDataWithStoryDB();
            setViewPager();
        }
    }

    mCreativeHandler = new CreativeHandler(this, this);

    File cacheDir = Glide.getPhotoCacheDir(this, MyGlideModule.DISK_IMAGE_CACHE_NAME);
    File[] filesList = cacheDir.listFiles();
    for (File cachedFile : filesList) {
        Log.d(TAG, "cachedFileName = " + cachedFile.getName() + " ,path = " + cachedFile.getAbsolutePath());
    }
}

@Override
public Toolbar setToolbar() {
    Toolbar mToolbar = (Toolbar) findViewById(R.id.mToolbar);
    mToolbar.setBackgroundColor(getResources().getColor(R.color.black_color));
    mToolbar.setVisibility(View.VISIBLE);
    return mToolbar;
}

@Override
public void findViews() {
    setContentView(R.layout.timeline_moment_activity);
    mVp = (HackyViewPager) findViewById(R.id.mVp);
    mTvName = (TextView) findViewById(R.id.mTvName);
    mTvContent = (TextView) findViewById(R.id.mTvVpContent);
    mTvDate = (TextView) findViewById(R.id.mTvUsername);
    mTvNumberOfLikes = (TextView) findViewById(R.id.mTvNumberOfLikes);
    mBtnLike = (ImageView) findViewById(R.id.mBtnLike);
    mTvNumberOfComments = (TextView) findViewById(R.id.mTvNumberOfComments);
    mBtnComments = (ImageView) findViewById(R.id.mBtnComments);
    mTvNumberOfShares = (TextView) findViewById(R.id.mTvNumberOfShares);
    mBtnShare = (ImageView) findViewById(R.id.mBtnShare);

    mBtnLike.setOnClickListener(this);
    mTvNumberOfLikes.setOnClickListener(this);

    mBtnShare.setOnClickListener(this);
    mTvNumberOfShares.setOnClickListener(this);

    mBtnComments.setOnClickListener(this);
    mTvNumberOfComments.setOnClickListener(this);
}

…..

private void setGlobalDataWithStoryDB () {
    if (mStoryDB == null) {
        return;
    }
    mMomentsDB = mStoryDB.getMoments();
    mStory = mStoryDB.converter();
    mMoments = mStory.getMoments();
}

// MARK: View Pager

private void setViewPager() {
    mAdapter = new TimelineMomentPagerAdapter(this, mMoments, mStoryDB);
    mVp.setOffscreenPageLimit(-1);
    mVp.addOnPageChangeListener(this);
    mVp.setAdapter(mAdapter);
    mVp.setCurrentItem(mSelectedIndex);
}

@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
    if (mMoments.isEmpty()) {
        return;
    }

    /*View currentView = mVp.getChildAt(position);
    if (currentView != null) {
        mAdapter.setBitmap(currentView);
    } else {
        currentView = mVp.getFocusedChild();
        if (currentView != null) {
            mAdapter.setBitmap(currentView);
        }
    }*/

    mSelectedIndex = position;
    final MomentPojo moment = mMoments.get(position);

    if (getSupportActionBar() != null)
        getSupportActionBar().setTitle(mStory.getTitle() + " " + (position + 1) + "/" + mMoments.size());

    mTvNumberOfShares.setText(""); // TODO: No API for number of shares

    handleLikeState(moment);
    handleComments(moment);
    mTvName.setText(moment.getOwnerName());
    if (moment.getTimestamp() != null) {
        mTvDate.setText(Utility.timestampToDateString(moment.getTimestamp()));
    } else {
        mTvDate.setVisibility(View.INVISIBLE);
    }

    if (moment.getTitle().equals("")) {
        mTvContent.setVisibility(View.GONE);
    } else {
        mTvContent.setVisibility(View.VISIBLE);
        mTvContent.setText(moment.getTitle());
    }
}

@Override
public void onPageSelected(int position) {
    View currentView = mVp.getChildAt(1);
    if (currentView != null) {
        mAdapter.setBitmap(currentView);
    } else {
        currentView = mVp.getFocusedChild();
        if (currentView != null) {
            mAdapter.setBitmap(currentView);
        }
    }
}

@Override
public void onPageScrollStateChanged(int state) {
}

private void handleComments(MomentPojo moment) {
    final int comments = Integer.parseInt(moment.getCommentsNumber());
    if (comments > 0) {
        mTvNumberOfComments.setText(Utility.showNumInNumK(comments));
    } else {
        mTvNumberOfComments.setText("");
    }
}

private void handleLikeState(MomentPojo moment) {
    if (moment.wasLiked()) {
        mBtnLike.setImageResource(R.drawable.ic_favorite_clicked);
    } else {
        mBtnLike.setImageResource(R.drawable.ic_favorite_unclicked);
    }

    final int likes = Integer.parseInt(moment.getLikesNumber());
    if (likes > 0) {
        mTvNumberOfLikes.setText(Utility.showNumInNumK(likes));
    } else {
        mTvNumberOfLikes.setText("");
    }
}

// MARK: OnClick and OnClick actions

@Override
public void onClick(View v) {
    final MomentPojo moment = mMoments.get(mSelectedIndex);
    if (v == mBtnComments || v == mTvNumberOfComments) {
        actionComment(mMoments.get(mSelectedIndex).getID());
    } else if (v == mBtnLike || v == mTvNumberOfLikes) {
        actionLike(moment);
    } else if (v == mBtnShare || v == mTvNumberOfShares) {
        actionShare();
    }
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent result) {
    mCreativeHandler.onActivityResult(requestCode, resultCode, result);
    if (resultCode == RESULT_OK) {
        switch (requestCode) {
            case Crop.REQUEST_PICK:
                beginCrop(result.getData());
                break;

            case Crop.REQUEST_CROP:
                handleEdit(resultCode, result, cropFileUri);
                break;
        }

    }
    super.onActivityResult(requestCode, resultCode, result);
}

private void actionShare() {
    MomentPojo momentPojo = mMoments.get(mVp.getCurrentItem());
    MomentOptions.actionShare(this, momentPojo);
}

private void actionComment(String momentID) {
    ProgressBarClass.startLoading(this);
    new TimelineCommentsGetRequest(momentID, this);
}

private void actionLike(MomentPojo moment) {
    new LinkerLikePostRequest(LinkerPojo.KEY_SOURCE_TYPE_MOMENT, moment.getID(), new LinkerLikePostRequest.Callback() {
        @Override
        public void onErrorResult(String err) {
            // TODO: handle error
        }
    });
    Utility.d("like state: " + moment.wasLiked());
    final int likes = Integer.parseInt(moment.getLikesNumber());
    if (moment.wasLiked()) {
        moment.setWasLiked(false);
        moment.setLikesNumber((likes - 1) + "");
        mBtnLike.setImageResource(R.drawable.ic_favorite_unclicked);
    } else {
        moment.setWasLiked(true);
        moment.setLikesNumber((likes + 1) + "");
        mBtnLike.setImageResource(R.drawable.ic_favorite_clicked);
    }
    handleLikeState(moment);

    if (mShouldSaveToDB) {
        MomentDB momentDB = mMomentsDB.get(mSelectedIndex);
        if (momentDB.wasLiked()) {
            momentDB.setWasLiked(false);
            momentDB.setLikesNumber((likes - 1) + "");
        } else {
            momentDB.setWasLiked(true);
            momentDB.setLikesNumber((likes + 1) + "");
        }
        momentDB.save();
    }

    mMoments.set(mSelectedIndex, moment);
    AppInstance.sharedInstance().getBus().post(new TimelineBusMomentChanged(moment, TimelineBusMomentChanged.KEY_STATE_LIKED));

}

@Override
public void onFinishedImageEditing(Uri outputFilePath) {
    handleEdit(RESULT_OK, null, outputFilePath);
}

// MARK: Comments
@Override
public void onMomentResult(ArrayList<CommentPojo> comments) {
    final LinkerPojo pojo = new LinkerPojo(mMoments.get(mSelectedIndex));
    ProgressBarClass.dismissLoading();
    CommentsActivity.setInstance(this, pojo, comments);
}

@Override
public void onErrorResult(String err) {
    ProgressBarClass.dismissLoading();
    MyToast.makeText(getString(R.string.gen_Something_went_wrong), MyToast.KEY_TYPE_RED).show();
}

// MARK: Settings

private class SettingsDialog implements ImageRotatePutRequest.Callback {

    private MomentDB mMomentDB;
    private ArrayList<String> mOptions;

    public SettingsDialog(MomentDB momentDB) {
        this.mMomentDB = momentDB;

        final String type = momentDB.getType();
        setOptions(type);
        createDialog();
    }

    private void setOptions(String type) {
        mOptions = new ArrayList<>();
        switch (type) {
            case TimelineUtils.KEY_TYPE_IMAGE:
                mOptions.add(getString(R.string.rotate_left));
                mOptions.add(getString(R.string.rotate_right));
                //mOptions.add(getString(R.string.timeline_moment_crop));
                mOptions.add(getString(R.string.timeline_moment_edit));
                break;

            case TimelineUtils.KEY_TYPE_TEXT:
                break;

            case TimelineUtils.KEY_TYPE_LINK:
                break;

            case TimelineUtils.KEY_TYPE_VIDEO:
                break;
        }
        mOptions.add(getString(R.string.gen_Delete));
    }

    private void createDialog() {
        final ListViewDialog dialog = new ListViewDialog(TimelineMomentActivity.this);
        dialog.setOnItemClickListener(mOptions, new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int i, long id) {
                final String option = mOptions.get(i);

                if (option.equals(getString(R.string.gen_Delete))) {
                    actionDelete();
                } else if (option.equals(getString(R.string.rotate_left))) {
                    actionRotate(false);
                } else if (option.equals(getString(R.string.rotate_right))) {
                    actionRotate(true);
                } /*else if (option.equals(getString(R.string.timeline_moment_crop))) {
                    actionCrop();
                }*/ else if (option.equals(getString(R.string.timeline_moment_edit))) {
                    actionEdit();
                }
                dialog.dismiss();
            }
        });
        dialog.show();
    }

    private void actionEdit() {

        File bitmapFile = mAdapter.getBitmap();
        if (bitmapFile != null) {
            mCreativeHandler.startFeather(Uri.fromFile(bitmapFile));
        }


        //final MomentPojo momentPojo = mMoments.get(mVp.getCurrentItem());
        //final String picUrl = Utility.getImageBySize(momentPojo.getContent(), MediaUtils.SIZE_MEDIUM, MediaUtils.SIZE_ORIGINAL);
        //Uri picUri = Uri.parse(picUrl);
        //mCreativeHandler.startFeather(picUri);
        //File imageFile = DBManager.getImageFile(TimelineMomentActivity.this, momentPojo.toMomentDB(mStoryDB));=
    }

    private void actionDelete() {
        MomentPojo currentMomentPojo = mMoments.get(mVp.getCurrentItem());
        MomentOptions.actionDeleteMoment(TimelineMomentActivity.this, currentMomentPojo, mMoments.size(), mStory.getID());
        finish();
    }

    private void actionRotate(boolean isClockWise) {
        MomentPojo momentPojo = mMoments.get(mVp.getCurrentItem());

        new ImageRotatePutRequest(momentPojo.getID(), isClockWise, this);

        float currentRotation = Float.parseFloat(mMomentDB.getRotation());
        if (isClockWise) {
            currentRotation += 90;
        } else {
            currentRotation -= 90;
        }

        if (mShouldSaveToDB) {
            mMomentDB.setRotation(currentRotation + "");
            mMomentDB.save();
            momentPojo = mMomentDB.converter();
        }

        momentPojo.setRotation(currentRotation + "");
        mMoments.set(mSelectedIndex, momentPojo);
        setViewPager();

        AppInstance.sharedInstance().getBus().post(new TimelineBusMomentChanged(momentPojo, TimelineBusMomentChanged.KEY_STATE_ROTATE));
    }

    @Override
    public void onImageRotateResult() {
        Utility.d("image rotated ");
    }

    @Override
    public void onErrorResult(String err) {}

}

@Override
protected void onDestroy() {
    AppInstance.sharedInstance().getBus().unregister(this);
    super.onDestroy();
}
….
// MARK: Crop

private void beginCrop(Uri source) {
    Crop.of(source, cropFileUri).asSquare().start(this);
}
…..
}

此代码有效，但并非总是如此，在传递此方法后，有些情况下currentView为null。在一些调试会话之后，我发现虽然public class TimelineMomentPagerAdapter extends PagerAdapter { … public TimelineMomentPagerAdapter(Context mContext, List<MomentPojo> mArray, StoryDB aStoryDB) { this.mContext = mContext; this.mArray = mArray; this.mStoryDB = aStoryDB; } public File getBitmap() { convertBitmapToFile(); return mCurrentBitmapFile; } public void setBitmap(View aView) { ImageView imageView = (ImageView) aView.findViewById(R.id.mIvVpContent); if (imageView != null) { mCurrentImageViewBitmap = getBitmap(imageView); } } private void convertBitmapToFile() { /*View currentPagerView = mVp.getChildAt(mVp.getCurrentItem()); ImageView contentView = (ImageView) currentPagerView.findViewById(R.id.mIvVpContent); Bitmap bitmap = getBitmap(contentView);*/ final File bitmapFolder = new File(mContext.getCacheDir(), "bitmap"); if (!bitmapFolder.exists()) { bitmapFolder.mkdir(); } mCurrentBitmapFile = new File(bitmapFolder, "currentBitmap"); try { if (mCurrentBitmapFile.exists()) { mCurrentBitmapFile.delete(); } mCurrentBitmapFile.createNewFile(); FileOutputStream stream = new FileOutputStream(mCurrentBitmapFile); if (mCurrentImageViewBitmap != null) { mCurrentImageViewBitmap.compress(Bitmap.CompressFormat.JPEG, 75, stream); } stream.close(); } catch (IOException e) { e.printStackTrace(); } } @Override public int getCount() { return mArray.size(); } @Override public boolean isViewFromObject(View view, Object object) { return view == object; } @Override public void destroyItem(ViewGroup container, int position, Object object) { container.removeView((RelativeLayout) object); } @Override public Object instantiateItem(ViewGroup container, final int position) { final LayoutInflater inflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE); final View v = inflater.inflate(R.layout.timeline_moment_viewpager, container, false); final MomentPojo momentPojo = mArray.get(position); mIvContent = (ImageView) v.findViewById(R.id.mIvVpContent); mTvContent = (TextView) v.findViewById(R.id.mTvVpContent); mIvPlay = (ImageView) v.findViewById(R.id.mIvPlay); mPbProgressBar = (ProgressBar) v.findViewById(R.id.pbProgress); final String type = momentPojo.getType(); final String content = momentPojo.getContent(); switch (type) { case TimelineUtils.KEY_TYPE_IMAGE: //---------------------------------------------------IMAGE mIvPlay.setVisibility(View.GONE); mIvContent.setVisibility(View.VISIBLE); mTvContent.setVisibility(View.GONE); final String contentHigherQuality = momentPojo.getContentHigherQuality(); final String newContent; if (JavaUtils.isNotNullNotEmptyNotWhiteSpaceOnly(contentHigherQuality)) { newContent = contentHigherQuality; } else if (JavaUtils.isNotNullNotEmptyNotWhiteSpaceOnly(content)) { newContent = content; } else { newContent = momentPojo.getLocalPath(); } mPbProgressBar.setVisibility(View.VISIBLE); Glide.with(BaseApplication.getInstance()).load(newContent).asBitmap().placeholder(R.drawable.ic_action_picture).into(new SimpleTarget<Bitmap>() { @Override public void onResourceReady(Bitmap bitmap, GlideAnimation<? super Bitmap> glideAnimation) { if (bitmap != null) { mIvContent.setImageBitmap(bitmap); } mPbProgressBar.setVisibility(View.INVISIBLE); } @Override public void onLoadFailed(final Exception e, final Drawable errorDrawable) { mPbProgressBar.setVisibility(View.INVISIBLE); } }); setImageRotation(momentPojo.getRotation()); if (position == 0 && !mWasCurrentImageBitmapInitialized) { mCurrentImageViewBitmap = getBitmap(mIvContent); mWasCurrentImageBitmapInitialized = true; } break; case TimelineUtils.KEY_TYPE_TEXT: //---------------------------------------------------TEXT case TimelineUtils.KEY_TYPE_LINK: //---------------------------------------------------LINK …. break; case TimelineUtils.KEY_TYPE_AUDIO: //---------------------------------------------------AUDIO case TimelineUtils.KEY_TYPE_VIDEO: //---------------------------------------------------VIDEO … break; case TimelineUtils.KEY_TYPE_PDF: //-----------------------------------------------------PDF …. break; case TimelineUtils.KEY_TYPE_YOUTUBE: //---------------------------------------------------VIDEO …. break; } container.addView(v); return v; } …. public Bitmap getBitmap(ImageView aImageView) { Bitmap image = null; if (aImageView == null) return null; Drawable drawable = aImageView.getDrawable(); if (drawable != null) { if (drawable instanceof GlideBitmapDrawable) { GlideBitmapDrawable bitmapDrawable = (GlideBitmapDrawable) aImageView.getDrawable(); image = bitmapDrawable.getBitmap(); } else if (drawable instanceof BitmapDrawable) { BitmapDrawable bitmapDrawable = (BitmapDrawable) aImageView.getDrawable(); image = bitmapDrawable.getBitmap(); } } return image; } …. } 给了我真正的索引，例如10，但是视图寻呼机保持它的视图总是在0-2位置。因此，在滑动时，所有三个项目都被交换，但它们仍保持在0-2位置。

我如何完成任务？

Answer 1

首先，删除修改适配器中某些内容的OnPageChangeListener中的所有代码。

将位图地图添加到适配器：

private Map<Integer, Bitmap> mBitmapMap;
private Map<Integer, View> mViewMap;

通货膨胀后的instantiateItem()：

mViewMap.put(position, v);

在你的回调中onResourceReady()：

mBitmap.put(position, bitmap); // position is final

在destroyItem()：

mBitmapMap.put(position, null);  // remove from map
mViewMap.put(position, null);

然后实施新方法：

public Bitmap getBitmapAt(int position) {
    return mBitmapMap.get(position);
}

public View getViewAt(position) {
    return mViewMap.get(position);
}

来自活动的电话：

bitmap = mAdapter.getBitmapAt(mVp.getCurrentItem());
view = mAdapter.getViewAt(mVp.getCurrentItem());

现在，您可以将屏幕外页面限制保留为默认值。