com.google.android.material.appbar.AppBarLayout Java Examples

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.view_subreddit_detail_activity, menu);
    applyMenuItemTheme(menu);
    mMenu = menu;
    MenuItem lazyModeItem = mMenu.findItem(R.id.action_lazy_mode_view_subreddit_detail_activity);
    if (isInLazyMode) {
        lazyModeItem.setTitle(R.string.action_stop_lazy_mode);
        params.setScrollFlags(AppBarLayout.LayoutParams.SCROLL_FLAG_SCROLL | AppBarLayout.LayoutParams.SCROLL_FLAG_EXIT_UNTIL_COLLAPSED);
        collapsingToolbarLayout.setLayoutParams(params);
    } else {
        lazyModeItem.setTitle(R.string.action_start_lazy_mode);
        params.setScrollFlags(AppBarLayout.LayoutParams.SCROLL_FLAG_SCROLL | AppBarLayout.LayoutParams.SCROLL_FLAG_ENTER_ALWAYS |
                AppBarLayout.LayoutParams.SCROLL_FLAG_ENTER_ALWAYS_COLLAPSED);
        collapsingToolbarLayout.setLayoutParams(params);
    }
    return true;
}
 

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

    setContentView(R.layout.activity_post);
    mRootView = findViewById(R.id.main_activity_root_view);
    mAppBarLayout = (AppBarLayout) findViewById(R.id.appbar_layout);

    mToolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(mToolbar);

    if (getSupportActionBar() != null)
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);

    FragmentManager fragmentManager = getSupportFragmentManager();
    if (fragmentManager.findFragmentById(R.id.main_frame_container) == null) {
        Bundle arguments = getIntent().getExtras();
        PostFragment fragment = new PostFragment();
        fragment.setArguments(arguments);
        fragmentManager.beginTransaction()
                .add(R.id.main_frame_container, fragment).commit();
    }

    setSwipeBackEnable(false);
}
 

@Override
public boolean onStartNestedScroll(CoordinatorLayout parent, AppBarLayout child,
                                   View directTargetChild, View target, int nestedScrollAxes, int type) {
    if (super.onStartNestedScroll(parent, child, directTargetChild, target, nestedScrollAxes, type)
            && type == ViewCompat.TYPE_TOUCH) {
        bindAppBar(child);
        if (appBarLayout.nestedScrollingListener != null) {
            appBarLayout.nestedScrollingListener.onStartNestedScroll();
        }
        appBarLayout.stopScrollAnimator();
        appBarLayout.setStartY(child.getY());
        return true;
    } else {
        return false;
    }
}
 

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.account_saved_thing_activity, menu);
    applyMenuItemTheme(menu);
    mMenu = menu;
    MenuItem lazyModeItem = mMenu.findItem(R.id.action_lazy_mode_account_saved_thing_activity);
    if (isInLazyMode) {
        lazyModeItem.setTitle(R.string.action_stop_lazy_mode);
        params.setScrollFlags(AppBarLayout.LayoutParams.SCROLL_FLAG_NO_SCROLL);
        collapsingToolbarLayout.setLayoutParams(params);
    } else {
        lazyModeItem.setTitle(R.string.action_start_lazy_mode);
        params.setScrollFlags(AppBarLayout.LayoutParams.SCROLL_FLAG_SCROLL | AppBarLayout.LayoutParams.SCROLL_FLAG_ENTER_ALWAYS);
        collapsingToolbarLayout.setLayoutParams(params);
    }

    return true;
}
 

@Override public final void onOffsetChanged(AppBarLayout appBarLayout, int i) {
  if (i == 0) {
    if (mCurrentState != State.EXPANDED) {
      onStateChanged(appBarLayout, State.EXPANDED);
    }
    mCurrentState = State.EXPANDED;
  } else if (Math.abs(i) - appBarLayout.getTotalScrollRange() == 0) {
    if (mCurrentState != State.COLLAPSED) {
      onStateChanged(appBarLayout, State.COLLAPSED);
    }
    mCurrentState = State.COLLAPSED;
  } else if (Math.abs(i) >= appBarLayout.getTotalScrollRange()) {
    if (mCurrentState != State.MOVING) {
      onStateChanged(appBarLayout, State.MOVING);
    }
    mCurrentState = State.MOVING;
  } else {
    if (mCurrentState != State.IDLE) {
      onStateChanged(appBarLayout, State.IDLE);
    }
    mCurrentState = State.IDLE;
  }
}
 

@Test
public void testNavigate() {
    AppBarLayout appBar = mock(AppBarLayout.class);
    when(appBar.getBottom()).thenReturn(1);
    Navigable navigable = mock(Navigable.class);
    AppUtils.navigate(Navigable.DIRECTION_DOWN, appBar, navigable);
    verify(appBar).setExpanded(eq(false), anyBoolean());
    verify(navigable, never()).onNavigate(anyInt());

    when(appBar.getBottom()).thenReturn(0);
    AppUtils.navigate(Navigable.DIRECTION_DOWN, appBar, navigable);
    verify(navigable).onNavigate(eq(Navigable.DIRECTION_DOWN));

    AppUtils.navigate(Navigable.DIRECTION_RIGHT, appBar, navigable);
    verify(navigable).onNavigate(eq(Navigable.DIRECTION_RIGHT));

    AppUtils.navigate(Navigable.DIRECTION_UP, appBar, navigable);
    verify(navigable).onNavigate(eq(Navigable.DIRECTION_UP));

    AppUtils.navigate(Navigable.DIRECTION_LEFT, appBar, navigable);
    verify(navigable).onNavigate(eq(Navigable.DIRECTION_LEFT));
}
 

@Override
public boolean onLayoutChild(
    @NonNull CoordinatorLayout parent,
    @NonNull FloatingActionButton child,
    int layoutDirection) {
  // First, let's make sure that the visibility of the FAB is consistent
  final List<View> dependencies = parent.getDependencies(child);
  for (int i = 0, count = dependencies.size(); i < count; i++) {
    final View dependency = dependencies.get(i);
    if (dependency instanceof AppBarLayout) {
      if (updateFabVisibilityForAppBarLayout(parent, (AppBarLayout) dependency, child)) {
        break;
      }
    } else if (isBottomSheet(dependency)) {
      if (updateFabVisibilityForBottomSheet(dependency, child)) {
        break;
      }
    }
  }
  // Now let the CoordinatorLayout lay out the FAB
  parent.onLayoutChild(child, layoutDirection);
  // Now offset it if needed
  offsetIfNeeded(parent, child);
  return true;
}
 

/**
 * sets the title on the toolbar only if the toolbar is collapsed
 */
private void handleCollapsedToolbarTitle() {
    mBinding.appbar.addOnOffsetChangedListener(new AppBarLayout.OnOffsetChangedListener() {
        boolean isShow = true;
        int scrollRange = -1;

        @Override
        public void onOffsetChanged(AppBarLayout appBarLayout, int verticalOffset) {
            if (scrollRange == -1) {
                scrollRange = appBarLayout.getTotalScrollRange();
            }
            // verify if the toolbar is completely collapsed and set the movie name as the title
            if (scrollRange + verticalOffset == 0) {
                mBinding.collapsingToolbar.setTitle(
                        mViewModel.getResult().getValue().data.getMovie().getTitle());
                isShow = true;
            } else if (isShow) {
                // display an empty string when toolbar is expanded
                mBinding.collapsingToolbar.setTitle(" ");
                isShow = false;
            }
        }
    });
}
 

@Override
protected void onCreate(Bundle savedInstanceState) {
	super.onCreate(savedInstanceState);
	setContentView(R.layout.activity_flexible_space);

	mFab = findViewById(R.id.flexible_example_fab);

	Toolbar toolbar = (Toolbar) findViewById(R.id.flexible_example_toolbar);
	toolbar.setNavigationOnClickListener(new View.OnClickListener() {
		@Override public void onClick(View v) {
			onBackPressed();
		}
	});

	AppBarLayout appbar = (AppBarLayout) findViewById(R.id.flexible_example_appbar);
	appbar.addOnOffsetChangedListener(this);
}
 

@Override
public void onOffsetChanged(AppBarLayout appBarLayout, int verticalOffset) {
    // fab should scroll out down in sync with the appBarLayout scrolling out up.
    // let's see how far along the way the appBarLayout is
    // (if displacementFraction == 0.0f then no displacement, appBar is fully expanded;
    //  if displacementFraction == 1.0f then full displacement, appBar is totally collapsed)
    float displacementFraction = -verticalOffset / (float) appBarLayout.getTotalScrollRange();

    // top position, accounting for translation not coming from this behavior
    float topUntranslatedFromThis = fab.getTop() + fab.getTranslationY() - fabTranslationYByThis;

    // total length to displace by (from position uninfluenced by this behavior) for a full appBar collapse
    float fullDisplacement = parent.getBottom() - topUntranslatedFromThis;

    // calculate new value for displacement coming from this behavior
    float newTranslationYFromThis = fullDisplacement * displacementFraction;

    // update translation value by difference found in this step
    fab.setTranslationY(newTranslationYFromThis - fabTranslationYByThis + fab.getTranslationY());

    // store new value
    fabTranslationYByThis = newTranslationYFromThis;
}
 

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

    setContentView(R.layout.activity_sms);
    mRootView = findViewById(R.id.main_activity_root_view);
    mAppBarLayout = (AppBarLayout) findViewById(R.id.appbar_layout);

    mToolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(mToolbar);

    if (getSupportActionBar() != null)
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);

    showFragment();
}
 

@Override
public final void onOffsetChanged(AppBarLayout appBarLayout, int i) {
  if (i == 0) {
    if (mCurrentState != State.EXPANDED) {
      onStateChanged(appBarLayout, State.EXPANDED);
    }
    mCurrentState = State.EXPANDED;
  } else if (Math.abs(i) >= appBarLayout.getTotalScrollRange()) {
    if (mCurrentState != State.COLLAPSED) {
      onStateChanged(appBarLayout, State.COLLAPSED);
    }
    mCurrentState = State.COLLAPSED;
  } else {
    if (mCurrentState != State.IDLE) {
      onStateChanged(appBarLayout, State.IDLE);
    }
    mCurrentState = State.IDLE;
  }
}
 

private void recovery(final AppBarLayout abl) {
    if (mTotalDy > 0) {
        mTotalDy = 0;
        if (isAnimate) {
            ValueAnimator anim = ValueAnimator.ofFloat(mLastScale, 1f).setDuration(200);
            anim.addUpdateListener(animation -> {
                float value = (float) animation.getAnimatedValue();
                mTargetView.setScaleX(value);
                mTargetView.setScaleY(value);
                abl.setBottom((int) (mLastBottom - (mLastBottom - mParentHeight) * animation.getAnimatedFraction()));
            });
            anim.start();
        } else {
            mTargetView.setScaleX(1f);
            mTargetView.setScaleY(1f);
            abl.setBottom(mParentHeight);
        }
    }
}
 

@Override
public void onChildScrollingPreferenceChanged() {
    final int position = viewHolder.profileSectionTabs.getSelectedTabPosition();
    @AppBarLayout.LayoutParams.ScrollFlags
    final int scrollFlags;
    final Fragment fragment = (((StaticFragmentPagerAdapter) viewHolder.profileSectionPager.getAdapter()).getFragment(position));
    if (fragment != null) {
        if (position >= 0 &&
                ((ScrollingPreferenceChild) fragment).prefersScrollingHeader()) {
            scrollFlags = AppBarLayout.LayoutParams.SCROLL_FLAG_SCROLL;
        } else {
            scrollFlags = 0;
        }
        final AppBarLayout.LayoutParams params = (AppBarLayout.LayoutParams) viewHolder.profileHeader.getLayoutParams();
        params.setScrollFlags(scrollFlags);
        viewHolder.profileHeader.setLayoutParams(params);
    }
}
 

private void initBar() {
    ActionBar actionBar = getSupportActionBar();
    if (actionBar != null) {
        actionBar.setDisplayHomeAsUpEnabled(true);
        actionBar.setDisplayShowTitleEnabled(false);
    }
    mToolbar.setNavigationIcon(R.mipmap.ic_scan);
    mToolbar.setNavigationOnClickListener(v -> {
        refreshLoading();
    });
    mNavigationIcon = mToolbar.getNavigationIcon();
    mAppBar.addOnOffsetChangedListener((AppBarLayout appBarLayout, int verticalOffset) -> {
        int totalScrollRange = appBarLayout.getTotalScrollRange();
        float percent = Math.abs(verticalOffset * 1.0f / totalScrollRange);
        if (mNavigationIcon != null) {
            mNavigationIcon.setColorFilter((int) mArgbEvaluator.evaluate(percent, Color.WHITE, Color.BLACK), PorterDuff.Mode.SRC_IN);
        }
        if (mSearchItemIcon != null) {
            mSearchItemIcon.setColorFilter((int) mArgbEvaluator.evaluate(percent, Color.WHITE, Color.BLACK), PorterDuff.Mode.SRC_IN);
        }
        mTitle.setTextColor((int) mArgbEvaluator.evaluate(percent, Color.WHITE, Color.BLACK));
    });
}
 

@Override
public void onNestedPreScroll(CoordinatorLayout coordinatorLayout, AppBarLayout child,
        View target, int dx, int dy, int[] consumed, int type) {
    if (this.toolbar == null) {
        this.toolbar = findToolbar(child);
        if (this.toolbar == null) {
            return;
        }
    }
    int[] toolbarLocation = new int[2];
    toolbar.getLocationOnScreen(toolbarLocation);
    int[] targetLocation = new int[2];
    target.getLocationOnScreen(targetLocation);
    int toolbarBottomY = toolbarLocation[1] + toolbar.getHeight();
    int[] appbarLocation = new int[2];
    int nestedScrollViewTopY = targetLocation[1];
    child.getLocationOnScreen(appbarLocation);
    NestedWebView nestedWebView = (NestedWebView) target;
    if (nestedScrollViewTopY <= toolbarBottomY) {
        nestedWebView.onChangeCollapseToolbar(true, dy);
    } else {
        nestedWebView.onChangeCollapseToolbar(false, dy);
    }
    super.onNestedPreScroll(coordinatorLayout, child, target, dx, dy, consumed, type);
}
 

@Override
protected void onAttachedToWindow() {
    super.onAttachedToWindow();

    // Add an OnOffsetChangedListener if possible
    final ViewParent parent = getParent();
    if (parent instanceof AppBarLayout) {
        // Copy over from the ABL whether we should fit system windows
        ViewCompat.setFitsSystemWindows(this, ViewCompat.getFitsSystemWindows((View) parent));

        if (mOnOffsetChangedListener == null) {
            mOnOffsetChangedListener = new OffsetUpdateListener();
        }
        ((AppBarLayout) parent).addOnOffsetChangedListener(mOnOffsetChangedListener);

        // We're attached, so lets request an inset dispatch
        ViewCompat.requestApplyInsets(this);
    }
}
 

@Override
public boolean onStartNestedScroll(CoordinatorLayout parent, AppBarLayout child,
                                   View directTargetChild, View target,
                                   int nestedScrollAxes, int type) {
    LogUtil.d(TAG, "onStartNestedScroll");
    stopAppbarLayoutFling(child);
    return super.onStartNestedScroll(parent, child, directTargetChild, target,
            nestedScrollAxes, type);
}
 

private void initial(AppBarLayout abl) {
        abl.setClipChildren(false);
        mParentHeight = abl.getHeight();
        mTargetViewHeight = mTargetView.getHeight();

        Log.e(TAG, "initial: mParentHeight==" + mParentHeight);
        Log.e(TAG, "initial: mTargetViewHeight==" + mTargetViewHeight);
//        mMiddleHeight = middleLayout.getHeight();
    }
 

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    if (mCustomContentViewId != 0)
        setContentView(mCustomContentViewId);
    else
        setContentView(R.layout.activity_setup_big_header);

    AppBarLayout appBar = findViewById(R.id.appbar);

    CollapsingToolbarLayout toolbarLayout = findViewById(R.id.toolbar_layout);

    Toolbar toolbar = findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    mLayout = findViewById(R.id.layout);
    mLayout.getViewTreeObserver().addOnGlobalLayoutListener(() -> {
        int height = mLayout.getHeight();
        CoordinatorLayout.LayoutParams params = (CoordinatorLayout.LayoutParams)
                appBar.getLayoutParams();
        params.height = height / 3;
        appBar.setLayoutParams(params);

        int childHeight = (mContentView != null ? mContentView.getHeight() : 0);
        if (mContentView instanceof NestedScrollView)
            childHeight = ((NestedScrollView) mContentView).getChildAt(0).getHeight();
        boolean needsScroll = (mContentView != null && childHeight > height - params.height);

        AppBarLayout.LayoutParams paramsToolbar = (AppBarLayout.LayoutParams) toolbarLayout.getLayoutParams();
        paramsToolbar.setScrollFlags(needsScroll
                ? (AppBarLayout.LayoutParams.SCROLL_FLAG_SCROLL | AppBarLayout.LayoutParams.SCROLL_FLAG_EXIT_UNTIL_COLLAPSED)
                : 0);
        toolbarLayout.setLayoutParams(paramsToolbar);
    });
}
 

private static AppBarLayout.LayoutParams getLayoutParams(View v) {
  initialize();
  AppBarLayout.LayoutParams result = null;
  ViewGroup.LayoutParams layoutParams = v.getLayoutParams();
  if (null != layoutParams && layoutParams instanceof AppBarLayout.LayoutParams) {
    result = (AppBarLayout.LayoutParams) layoutParams;
  }
  return result;
}
 

@Override
public void onNestedPreScroll(CoordinatorLayout coordinatorLayout, AppBarLayout child, View target, int dx, int dy, int[] consumed, int type) {
    Log.e(TAG, "onNestedPreScroll: dy==" + dy);
    Log.e(TAG, "onNestedPreScroll: child.getBottom()==" + child.getBottom());

    if (!isRecovering) {
        if (mTargetView != null && ((dy < 0 && child.getBottom() >= mParentHeight)
                || (dy > 0 && child.getBottom() > mParentHeight))) {
            scale(child, target, dy);
            return;
        }
    }
    super.onNestedPreScroll(coordinatorLayout, child, target, dx, dy, consumed, type);
}
 

@Override
public boolean onNestedFling(@NonNull CoordinatorLayout coordinatorLayout, @NonNull AppBarLayout child, @NonNull View target, float velocityX, float velocityY, boolean consumed) {
    if (velocityY > 100) {
        isAnimate = false;
    }
    return super.onNestedFling(coordinatorLayout, child, target, velocityX, velocityY, consumed);
}
 

public static void hack(@NonNull AppBarLayout appBarLayout, int liftOnScrollTargetViewId) {
    appBarLayout.getViewTreeObserver().addOnPreDrawListener(() -> {
        // Invalidate the cached view reference so that this works after replacing fragment.
        appBarLayout.setLiftOnScrollTargetViewId(liftOnScrollTargetViewId);
        // Call AppBarLayout.Behavior.onNestedPreScroll() with dy == 0 to update lifted state.
        CoordinatorLayout.Behavior behavior =
                ((CoordinatorLayout.LayoutParams) appBarLayout.getLayoutParams()).getBehavior();
        CoordinatorLayout coordinatorLayout = (CoordinatorLayout) appBarLayout.getParent();
        behavior.onNestedPreScroll(coordinatorLayout, appBarLayout, coordinatorLayout, 0, 0,
                null, 0);
        return true;
    });
}
 

private void scale(AppBarLayout abl, View target, int dy) {
    mTotalDy += -dy;
    mTotalDy = Math.min(mTotalDy, TARGET_HEIGHT);
    mLastScale = Math.max(1f, 1f + mTotalDy / TARGET_HEIGHT);
    mTargetView.setScaleX(mLastScale);
    mTargetView.setScaleY(mLastScale);
    mLastBottom = mParentHeight + (int) (mTargetViewHeight / 2 * (mLastScale - 1));
    abl.setBottom(mLastBottom);
    target.setScrollY(0);
}
 

@Override
public void onOffsetChanged(AppBarLayout appBarLayout, int verticalOffset) {
    if (!enabled) {
        return;
    }

    if (verticalOffset == 0 && !visible) {
        showButton();
    } else if (Math.abs(verticalOffset) >= appBarLayout.getTotalScrollRange() && visible) {
        hideButton();
    }
}
 

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_collapsing_toolbar_layout);
    mIvPlaceholder = (ImageView) findViewById(R.id.main_iv_placeholder);
    mLlTitleContainer = (LinearLayout) findViewById(R.id.main_ll_title_container);
    mFlTitleContainer = (FrameLayout) findViewById(R.id.main_fl_title);
    mAblAppBar = (AppBarLayout) findViewById(R.id.main_abl_app_bar);
    mTvToolbarTitle = (TextView) findViewById(R.id.main_tv_toolbar_title);
    mTbToolbar = (Toolbar) findViewById(R.id.main_tb_toolbar);
    mTbToolbar.setTitle("");

    // AppBar的监听
    mAblAppBar.addOnOffsetChangedListener(new AppBarLayout.OnOffsetChangedListener() {
        @Override
        public void onOffsetChanged(AppBarLayout appBarLayout, int verticalOffset) {
            int maxScroll = appBarLayout.getTotalScrollRange();
            float percentage = (float) Math.abs(verticalOffset) / (float) maxScroll;
            handleAlphaOnTitle(percentage);
            handleToolbarTitleVisibility(percentage);
        }
    });

    findViewById(R.id.small_photo).setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            startActivity(new Intent(CollapsingToolbarLayoutActivity.this, SettingsActivity.class));
        }
    });

    initParallaxValues(); // 自动滑动效果
}
 

@Override
protected void onDetachedFromWindow() {
    // Remove our OnOffsetChangedListener if possible and it exists
    final ViewParent parent = getParent();
    if (mOnOffsetChangedListener != null && parent instanceof AppBarLayout) {
        ((AppBarLayout) parent).removeOnOffsetChangedListener(mOnOffsetChangedListener);
    }

    super.onDetachedFromWindow();
}
 

@Override
public View onCreateView(LayoutInflater inflater,
                         @Nullable ViewGroup container,
                         @Nullable Bundle savedInstanceState) {
  CoordinatorLayout view = new NotifyingCoordinatorLayout(getContext(), this);
  CoordinatorLayout.LayoutParams params = new CoordinatorLayout.LayoutParams(
          LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.MATCH_PARENT);
  params.setBehavior(new AppBarLayout.ScrollingViewBehavior());
  mScreenView.setLayoutParams(params);
  view.addView(recycleView(mScreenView));

  mAppBarLayout = new AppBarLayout(getContext());
  // By default AppBarLayout will have a background color set but since we cover the whole layout
  // with toolbar (that can be semi-transparent) the bar layout background color does not pay a
  // role. On top of that it breaks screens animations when alfa offscreen compositing is off
  // (which is the default)
  mAppBarLayout.setBackgroundColor(Color.TRANSPARENT);
  mAppBarLayout.setLayoutParams(new AppBarLayout.LayoutParams(
          AppBarLayout.LayoutParams.MATCH_PARENT, AppBarLayout.LayoutParams.WRAP_CONTENT));
  view.addView(mAppBarLayout);

  if (mShadowHidden) {
    mAppBarLayout.setTargetElevation(0);
  }

  if (mToolbar != null) {
    mAppBarLayout.addView(recycleView(mToolbar));
  }

  return view;
}
 

private void scale(AppBarLayout abl, View target, int dy) {
    mTotalDy += -dy;
    mTotalDy = Math.min(mTotalDy, TARGET_HEIGHT);
    mLastScale = Math.max(1f, 1f + mTotalDy / TARGET_HEIGHT);
    mTargetView.setScaleX(mLastScale);
    mTargetView.setScaleY(mLastScale);
    mLastBottom = mParentHeight + (int) (mTargetViewHeight / 2 * (mLastScale - 1));
    abl.setBottom(mLastBottom);
    target.setScrollY(0);
}