Java tutorial
/* * Copyright (C) 2011 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package android.support.v7.widget; import android.content.Context; import android.content.res.Configuration; import android.content.res.TypedArray; import android.os.Build; import android.support.v4.view.MotionEventCompat; import android.support.v4.view.ViewCompat; import android.support.v4.view.ViewPropertyAnimatorCompat; import android.support.v4.view.ViewPropertyAnimatorListener; import android.support.v7.appcompat.R; import android.util.AttributeSet; import android.util.TypedValue; import android.view.ContextThemeWrapper; import android.view.MotionEvent; import android.view.View; import android.view.ViewGroup; abstract class AbsActionBarView extends ViewGroup { private static final int FADE_DURATION = 200; protected final VisibilityAnimListener mVisAnimListener = new VisibilityAnimListener(); /** Context against which to inflate popup menus. */ protected final Context mPopupContext; protected ActionMenuView mMenuView; protected ActionMenuPresenter mActionMenuPresenter; protected int mContentHeight; protected ViewPropertyAnimatorCompat mVisibilityAnim; private boolean mEatingTouch; private boolean mEatingHover; AbsActionBarView(Context context) { this(context, null); } AbsActionBarView(Context context, AttributeSet attrs) { this(context, attrs, 0); } AbsActionBarView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); final TypedValue tv = new TypedValue(); if (context.getTheme().resolveAttribute(R.attr.actionBarPopupTheme, tv, true) && tv.resourceId != 0) { mPopupContext = new ContextThemeWrapper(context, tv.resourceId); } else { mPopupContext = context; } } @Override protected void onConfigurationChanged(Configuration newConfig) { if (Build.VERSION.SDK_INT >= 8) { super.onConfigurationChanged(newConfig); } // Action bar can change size on configuration changes. // Reread the desired height from the theme-specified style. TypedArray a = getContext().obtainStyledAttributes(null, R.styleable.ActionBar, R.attr.actionBarStyle, 0); setContentHeight(a.getLayoutDimension(R.styleable.ActionBar_height, 0)); a.recycle(); if (mActionMenuPresenter != null) { mActionMenuPresenter.onConfigurationChanged(newConfig); } } @Override public boolean onTouchEvent(MotionEvent ev) { // ActionBarViews always eat touch events, but should still respect the touch event dispatch // contract. If the normal View implementation doesn't want the events, we'll just silently // eat the rest of the gesture without reporting the events to the default implementation // since that's what it expects. final int action = MotionEventCompat.getActionMasked(ev); if (action == MotionEvent.ACTION_DOWN) { mEatingTouch = false; } if (!mEatingTouch) { final boolean handled = super.onTouchEvent(ev); if (action == MotionEvent.ACTION_DOWN && !handled) { mEatingTouch = true; } } if (action == MotionEvent.ACTION_UP || action == MotionEvent.ACTION_CANCEL) { mEatingTouch = false; } return true; } @Override public boolean onHoverEvent(MotionEvent ev) { // Same deal as onTouchEvent() above. Eat all hover events, but still // respect the touch event dispatch contract. final int action = MotionEventCompat.getActionMasked(ev); if (action == MotionEventCompat.ACTION_HOVER_ENTER) { mEatingHover = false; } if (!mEatingHover) { final boolean handled = super.onHoverEvent(ev); if (action == MotionEventCompat.ACTION_HOVER_ENTER && !handled) { mEatingHover = true; } } if (action == MotionEventCompat.ACTION_HOVER_EXIT || action == MotionEvent.ACTION_CANCEL) { mEatingHover = false; } return true; } public void setContentHeight(int height) { mContentHeight = height; requestLayout(); } public int getContentHeight() { return mContentHeight; } /** * @return Current visibility or if animating, the visibility being animated to. */ public int getAnimatedVisibility() { if (mVisibilityAnim != null) { return mVisAnimListener.mFinalVisibility; } return getVisibility(); } public ViewPropertyAnimatorCompat setupAnimatorToVisibility(int visibility, long duration) { if (mVisibilityAnim != null) { mVisibilityAnim.cancel(); } if (visibility == VISIBLE) { if (getVisibility() != VISIBLE) { ViewCompat.setAlpha(this, 0f); } ViewPropertyAnimatorCompat anim = ViewCompat.animate(this).alpha(1f); anim.setDuration(duration); anim.setListener(mVisAnimListener.withFinalVisibility(anim, visibility)); return anim; } else { ViewPropertyAnimatorCompat anim = ViewCompat.animate(this).alpha(0f); anim.setDuration(duration); anim.setListener(mVisAnimListener.withFinalVisibility(anim, visibility)); return anim; } } public void animateToVisibility(int visibility) { ViewPropertyAnimatorCompat anim = setupAnimatorToVisibility(visibility, FADE_DURATION); anim.start(); } @Override public void setVisibility(int visibility) { if (visibility != getVisibility()) { if (mVisibilityAnim != null) { mVisibilityAnim.cancel(); } super.setVisibility(visibility); } } public boolean showOverflowMenu() { if (mActionMenuPresenter != null) { return mActionMenuPresenter.showOverflowMenu(); } return false; } public void postShowOverflowMenu() { post(new Runnable() { public void run() { showOverflowMenu(); } }); } public boolean hideOverflowMenu() { if (mActionMenuPresenter != null) { return mActionMenuPresenter.hideOverflowMenu(); } return false; } public boolean isOverflowMenuShowing() { if (mActionMenuPresenter != null) { return mActionMenuPresenter.isOverflowMenuShowing(); } return false; } public boolean isOverflowMenuShowPending() { if (mActionMenuPresenter != null) { return mActionMenuPresenter.isOverflowMenuShowPending(); } return false; } public boolean isOverflowReserved() { return mActionMenuPresenter != null && mActionMenuPresenter.isOverflowReserved(); } public boolean canShowOverflowMenu() { return isOverflowReserved() && getVisibility() == VISIBLE; } public void dismissPopupMenus() { if (mActionMenuPresenter != null) { mActionMenuPresenter.dismissPopupMenus(); } } protected int measureChildView(View child, int availableWidth, int childSpecHeight, int spacing) { child.measure(MeasureSpec.makeMeasureSpec(availableWidth, MeasureSpec.AT_MOST), childSpecHeight); availableWidth -= child.getMeasuredWidth(); availableWidth -= spacing; return Math.max(0, availableWidth); } static protected int next(int x, int val, boolean isRtl) { return isRtl ? x - val : x + val; } protected int positionChild(View child, int x, int y, int contentHeight, boolean reverse) { int childWidth = child.getMeasuredWidth(); int childHeight = child.getMeasuredHeight(); int childTop = y + (contentHeight - childHeight) / 2; if (reverse) { child.layout(x - childWidth, childTop, x, childTop + childHeight); } else { child.layout(x, childTop, x + childWidth, childTop + childHeight); } return (reverse ? -childWidth : childWidth); } protected class VisibilityAnimListener implements ViewPropertyAnimatorListener { private boolean mCanceled = false; int mFinalVisibility; public VisibilityAnimListener withFinalVisibility(ViewPropertyAnimatorCompat animation, int visibility) { mVisibilityAnim = animation; mFinalVisibility = visibility; return this; } @Override public void onAnimationStart(View view) { AbsActionBarView.super.setVisibility(VISIBLE); mCanceled = false; } @Override public void onAnimationEnd(View view) { if (mCanceled) return; mVisibilityAnim = null; AbsActionBarView.super.setVisibility(mFinalVisibility); } @Override public void onAnimationCancel(View view) { mCanceled = true; } } }