我看到了一些关于如何将汉堡菜单转换成向上箭头导航的方案，反之亦然。但我只在使用DrawerLayout的情况下见过这种做法。
现在我有两个活动页面A和B。
A是启动页，它在操作栏中有一个汉堡图标，并实现了向上箭头/汉堡菜单的动画效果，可以滑动展开或收起一个DrawerLayout抽屉。
在A活动某个位置，有一个按钮可以启动B活动。B活动有一个support.v7 ActionBar。
ActionBar actionBar = getSupportActionBar();
actionBar.setDisplayHomeAsUpEnabled(true);
在onCreate中调用。这会设置一个向上按钮，当按下时可以返回到Activity A。
如何在Activity B中配置向上按钮以动画形式切换到Activity A中的汉堡菜单？
Gmail就是这样做的：当您在全屏电子邮件中单击向上按钮以返回电子邮件列表时，它会将向上按钮动画转换为汉堡菜单按钮。
好的，这需要解释一下。简单来说，你需要获取DrawerToogle的引用来进行操作。如何获取？你需要提供自己的ActionBarDrawerToggle类的实现。
这里有一个示例（大量复制粘贴自谷歌自己的实现）
package com.example.navigationdrawertest;
import android.app.Activity;
import android.content.Context;
import android.content.res.Configuration;
import android.graphics.drawable.Drawable;
import android.support.annotation.Nullable;
import android.support.annotation.StringRes;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.graphics.drawable.DrawerArrowDrawable;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.MenuItem;
import android.view.View;
/**
* This class provides a handy way to tie together the functionality of
* {@link android.support.v4.widget.DrawerLayout} and the framework <code>ActionBar</code> to
* implement the recommended design for navigation drawers.
*
* <p>To use <code>ActionBarDrawerToggle</code>, create one in your Activity and call through
* to the following methods corresponding to your Activity callbacks:</p>
*
* <ul>
* <li>{@link android.app.Activity#onConfigurationChanged(android.content.res.Configuration)
* onConfigurationChanged}
* <li>{@link android.app.Activity#onOptionsItemSelected(android.view.MenuItem)
* onOptionsItemSelected}</li>
* </ul>
*
* <p>Call {@link #syncState()} from your <code>Activity</code>'s
* {@link android.app.Activity#onPostCreate(android.os.Bundle) onPostCreate} to synchronize the
* indicator with the state of the linked DrawerLayout after <code>onRestoreInstanceState</code>
* has occurred.</p>
*
* <p><code>ActionBarDrawerToggle</code> can be used directly as a
* {@link android.support.v4.widget.DrawerLayout.DrawerListener}, or if you are already providing
* your own listener, call through to each of the listener methods from your own.</p>
*
* <p>
* You can customize the the animated toggle by defining the
* {@link android.support.v7.appcompat.R.styleable#DrawerArrowToggle drawerArrowStyle} in your
* ActionBar theme.
*/
public class ActionBarDrawerToggle implements DrawerLayout.DrawerListener {
/**
* Allows an implementing Activity to return an {@link ActionBarDrawerToggle.Delegate} to use
* with ActionBarDrawerToggle.
*/
public interface DelegateProvider {
/**
* @return Delegate to use for ActionBarDrawableToggles, or null if the Activity
* does not wish to override the default behavior.
*/
@Nullable
Delegate getDrawerToggleDelegate();
}
public interface Delegate {
/**
* Set the Action Bar's up indicator drawable and content description.
*
* @param upDrawable - Drawable to set as up indicator
* @param contentDescRes - Content description to set
*/
void setActionBarUpIndicator(Drawable upDrawable, @StringRes int contentDescRes);
/**
* Set the Action Bar's up indicator content description.
*
* @param contentDescRes - Content description to set
*/
void setActionBarDescription(@StringRes int contentDescRes);
/**
* Returns the drawable to be set as up button when DrawerToggle is disabled
*/
Drawable getThemeUpIndicator();
/**
* Returns the context of ActionBar
*/
Context getActionBarThemedContext();
/**
* Returns whether navigation icon is visible or not.
* Used to print warning messages in case developer forgets to set displayHomeAsUp to true
*/
boolean isNavigationVisible();
}
private final Delegate mActivityImpl;
private final DrawerLayout mDrawerLayout;
private DrawerToggle mSlider;
private Drawable mHomeAsUpIndicator;
private boolean mDrawerIndicatorEnabled = true;
private boolean mHasCustomUpIndicator;
private final int mOpenDrawerContentDescRes;
private final int mCloseDrawerContentDescRes;
// used in toolbar mode when DrawerToggle is disabled
private View.OnClickListener mToolbarNavigationClickListener;
// If developer does not set displayHomeAsUp, DrawerToggle won't show up.
// DrawerToggle logs a warning if this case is detected
private boolean mWarnedForDisplayHomeAsUp = false;
/**
* Construct a new ActionBarDrawerToggle with a Toolbar.
* <p>
* The given {@link Activity} will be linked to the specified {@link DrawerLayout} and
* the Toolbar's navigation icon will be set to a custom drawable. Using this constructor
* will set Toolbar's navigation click listener to toggle the drawer when it is clicked.
* <p>
* This drawable shows a Hamburger icon when drawer is closed and an arrow when drawer
* is open. It animates between these two states as the drawer opens.
* <p>
* String resources must be provided to describe the open/close drawer actions for
* accessibility services.
*
* @param activity The Activity hosting the drawer.
* @param toolbar The toolbar to use if you have an independent Toolbar.
* @param drawerLayout The DrawerLayout to link to the given Activity's ActionBar
* @param openDrawerContentDescRes A String resource to describe the "open drawer" action
* for accessibility
* @param closeDrawerContentDescRes A String resource to describe the "close drawer" action
* for accessibility
*/
public ActionBarDrawerToggle(Activity activity, DrawerLayout drawerLayout,
Toolbar toolbar, @StringRes int openDrawerContentDescRes,
@StringRes int closeDrawerContentDescRes) {
this(activity, toolbar, drawerLayout, null, openDrawerContentDescRes,
closeDrawerContentDescRes);
}
/**
* In the future, we can make this constructor public if we want to let developers customize
* the animation.
*/
<T extends Drawable & DrawerToggle> ActionBarDrawerToggle(Activity activity, Toolbar toolbar,
DrawerLayout drawerLayout, T slider,
@StringRes int openDrawerContentDescRes,
@StringRes int closeDrawerContentDescRes) {
mActivityImpl = new ToolbarCompatDelegate(toolbar);
toolbar.setNavigationOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (mDrawerIndicatorEnabled) {
toggle();
} else if (mToolbarNavigationClickListener != null) {
mToolbarNavigationClickListener.onClick(v);
}
}
});
mDrawerLayout = drawerLayout;
mOpenDrawerContentDescRes = openDrawerContentDescRes;
mCloseDrawerContentDescRes = closeDrawerContentDescRes;
if (slider == null) {
mSlider = new DrawerArrowDrawableToggle(activity,
mActivityImpl.getActionBarThemedContext());
} else {
mSlider = slider;
}
mHomeAsUpIndicator = getThemeUpIndicator();
}
/**
* Synchronize the state of the drawer indicator/affordance with the linked DrawerLayout.
*
* <p>This should be called from your <code>Activity</code>'s
* {@link Activity#onPostCreate(android.os.Bundle) onPostCreate} method to synchronize after
* the DrawerLayout's instance state has been restored, and any other time when the state
* may have diverged in such a way that the ActionBarDrawerToggle was not notified.
* (For example, if you stop forwarding appropriate drawer events for a period of time.)</p>
*/
public void syncState() {
if (mDrawerLayout.isDrawerOpen(GravityCompat.START)) {
mSlider.setPosition(1);
} else {
mSlider.setPosition(0);
}
if (mDrawerIndicatorEnabled) {
setActionBarUpIndicator((Drawable) mSlider,
mDrawerLayout.isDrawerOpen(GravityCompat.START) ?
mCloseDrawerContentDescRes : mOpenDrawerContentDescRes);
}
}
/**
* This method should always be called by your <code>Activity</code>'s
* {@link Activity#onConfigurationChanged(android.content.res.Configuration)
* onConfigurationChanged}
* method.
*
* @param newConfig The new configuration
*/
public void onConfigurationChanged(Configuration newConfig) {
// Reload drawables that can change with configuration
if (!mHasCustomUpIndicator) {
mHomeAsUpIndicator = getThemeUpIndicator();
}
syncState();
}
/**
* This method should be called by your <code>Activity</code>'s
* {@link Activity#onOptionsItemSelected(android.view.MenuItem) onOptionsItemSelected} method.
* If it returns true, your <code>onOptionsItemSelected</code> method should return true and
* skip further processing.
*
* @param item the MenuItem instance representing the selected menu item
* @return true if the event was handled and further processing should not occur
*/
public boolean onOptionsItemSelected(MenuItem item) {
if (item != null && item.getItemId() == android.R.id.home && mDrawerIndicatorEnabled) {
toggle();
return true;
}
return false;
}
private void toggle() {
int drawerLockMode = mDrawerLayout.getDrawerLockMode(GravityCompat.START);
if (mDrawerLayout.isDrawerVisible(GravityCompat.START)
&& (drawerLockMode != DrawerLayout.LOCK_MODE_LOCKED_OPEN)) {
mDrawerLayout.closeDrawer(GravityCompat.START);
} else if (drawerLockMode != DrawerLayout.LOCK_MODE_LOCKED_CLOSED) {
mDrawerLayout.openDrawer(GravityCompat.START);
}
}
/**
* Set the up indicator to display when the drawer indicator is not
* enabled.
* <p>
* If you pass <code>null</code> to this method, the default drawable from
* the theme will be used.
*
* @param indicator A drawable to use for the up indicator, or null to use
* the theme's default
* @see #setDrawerIndicatorEnabled(boolean)
*/
public void setHomeAsUpIndicator(Drawable indicator) {
if (indicator == null) {
mHomeAsUpIndicator = getThemeUpIndicator();
mHasCustomUpIndicator = false;
} else {
mHomeAsUpIndicator = indicator;
mHasCustomUpIndicator = true;
}
if (!mDrawerIndicatorEnabled) {
setActionBarUpIndicator(mHomeAsUpIndicator, 0);
}
}
/**
* Set the up indicator to display when the drawer indicator is not
* enabled.
* <p>
* If you pass 0 to this method, the default drawable from the theme will
* be used.
*
* @param resId Resource ID of a drawable to use for the up indicator, or 0
* to use the theme's default
* @see #setDrawerIndicatorEnabled(boolean)
*/
public void setHomeAsUpIndicator(int resId) {
Drawable indicator = null;
if (resId != 0) {
indicator = mDrawerLayout.getResources().getDrawable(resId);
}
setHomeAsUpIndicator(indicator);
}
/**
* @return true if the enhanced drawer indicator is enabled, false otherwise
* @see #setDrawerIndicatorEnabled(boolean)
*/
public boolean isDrawerIndicatorEnabled() {
return mDrawerIndicatorEnabled;
}
/**
* Enable or disable the drawer indicator. The indicator defaults to enabled.
*
* <p>When the indicator is disabled, the <code>ActionBar</code> will revert to displaying
* the home-as-up indicator provided by the <code>Activity</code>'s theme in the
* <code>android.R.attr.homeAsUpIndicator</code> attribute instead of the animated
* drawer glyph.</p>
*
* @param enable true to enable, false to disable
*/
public void setDrawerIndicatorEnabled(boolean enable) {
if (enable != mDrawerIndicatorEnabled) {
if (enable) {
setActionBarUpIndicator((Drawable) mSlider,
mDrawerLayout.isDrawerOpen(GravityCompat.START) ?
mCloseDrawerContentDescRes : mOpenDrawerContentDescRes);
} else {
setActionBarUpIndicator(mHomeAsUpIndicator, 0);
}
mDrawerIndicatorEnabled = enable;
}
}
public DrawerToggle getSlider() {
return mSlider;
}
/**
* {@link DrawerLayout.DrawerListener} callback method. If you do not use your
* ActionBarDrawerToggle instance directly as your DrawerLayout's listener, you should call
* through to this method from your own listener object.
*
* @param drawerView The child view that was moved
* @param slideOffset The new offset of this drawer within its range, from 0-1
*/
@Override
public void onDrawerSlide(View drawerView, float slideOffset) {
mSlider.setPosition(Math.min(1f, Math.max(0, slideOffset)));
}
/**
* {@link DrawerLayout.DrawerListener} callback method. If you do not use your
* ActionBarDrawerToggle instance directly as your DrawerLayout's listener, you should call
* through to this method from your own listener object.
*
* @param drawerView Drawer view that is now open
*/
@Override
public void onDrawerOpened(View drawerView) {
mSlider.setPosition(1);
if (mDrawerIndicatorEnabled) {
setActionBarDescription(mCloseDrawerContentDescRes);
}
}
/**
* {@link DrawerLayout.DrawerListener} callback method. If you do not use your
* ActionBarDrawerToggle instance directly as your DrawerLayout's listener, you should call
* through to this method from your own listener object.
*
* @param drawerView Drawer view that is now closed
*/
@Override
public void onDrawerClosed(View drawerView) {
mSlider.setPosition(0);
if (mDrawerIndicatorEnabled) {
setActionBarDescription(mOpenDrawerContentDescRes);
}
}
/**
* {@link DrawerLayout.DrawerListener} callback method. If you do not use your
* ActionBarDrawerToggle instance directly as your DrawerLayout's listener, you should call
* through to this method from your own listener object.
*
* @param newState The new drawer motion state
*/
@Override
public void onDrawerStateChanged(int newState) {
}
/**
* Returns the fallback listener for Navigation icon click events.
*
* @return The click listener which receives Navigation click events from Toolbar when
* drawer indicator is disabled.
* @see #setToolbarNavigationClickListener(android.view.View.OnClickListener)
* @see #setDrawerIndicatorEnabled(boolean)
* @see #isDrawerIndicatorEnabled()
*/
public View.OnClickListener getToolbarNavigationClickListener() {
return mToolbarNavigationClickListener;
}
/**
* When DrawerToggle is constructed with a Toolbar, it sets the click listener on
* the Navigation icon. If you want to listen for clicks on the Navigation icon when
* DrawerToggle is disabled ({@link #setDrawerIndicatorEnabled(boolean)}, you should call this
* method with your listener and DrawerToggle will forward click events to that listener
* when drawer indicator is disabled.
*
* @see #setDrawerIndicatorEnabled(boolean)
*/
public void setToolbarNavigationClickListener(
View.OnClickListener onToolbarNavigationClickListener) {
mToolbarNavigationClickListener = onToolbarNavigationClickListener;
}
void setActionBarUpIndicator(Drawable upDrawable, int contentDescRes) {
if (!mWarnedForDisplayHomeAsUp && !mActivityImpl.isNavigationVisible()) {
Log.w("ActionBarDrawerToggle", "DrawerToggle may not show up because NavigationIcon"
+ " is not visible. You may need to call "
+ "actionbar.setDisplayHomeAsUpEnabled(true);");
mWarnedForDisplayHomeAsUp = true;
}
mActivityImpl.setActionBarUpIndicator(upDrawable, contentDescRes);
}
void setActionBarDescription(int contentDescRes) {
mActivityImpl.setActionBarDescription(contentDescRes);
}
Drawable getThemeUpIndicator() {
return mActivityImpl.getThemeUpIndicator();
}
static class DrawerArrowDrawableToggle extends DrawerArrowDrawable implements DrawerToggle {
private final Activity mActivity;
public DrawerArrowDrawableToggle(Activity activity, Context themedContext) {
super(themedContext);
mActivity = activity;
}
public void setPosition(float position) {
if (position == 1f) {
setVerticalMirror(true);
} else if (position == 0f) {
setVerticalMirror(false);
}
setProgress(position);
}
public float getPosition() {
return getProgress();
}
}
/**
* Interface for toggle drawables. Can be public in the future
*/
public interface DrawerToggle {
public void setPosition(float position);
public float getPosition();
}
/**
* Used when DrawerToggle is initialized with a Toolbar
*/
static class ToolbarCompatDelegate implements Delegate {
final Toolbar mToolbar;
final Drawable mDefaultUpIndicator;
final CharSequence mDefaultContentDescription;
ToolbarCompatDelegate(Toolbar toolbar) {
mToolbar = toolbar;
mDefaultUpIndicator = toolbar.getNavigationIcon();
mDefaultContentDescription = toolbar.getNavigationContentDescription();
}
@Override
public void setActionBarUpIndicator(Drawable upDrawable, @StringRes int contentDescRes) {
mToolbar.setNavigationIcon(upDrawable);
setActionBarDescription(contentDescRes);
}
@Override
public void setActionBarDescription(@StringRes int contentDescRes) {
if (contentDescRes == 0) {
mToolbar.setNavigationContentDescription(mDefaultContentDescription);
} else {
mToolbar.setNavigationContentDescription(contentDescRes);
}
}
@Override
public Drawable getThemeUpIndicator() {
return mDefaultUpIndicator;
}
@Override
public Context getActionBarThemedContext() {
return mToolbar.getContext();
}
@Override
public boolean isNavigationVisible() {
return true;
}
}
}
通过调用 actionBarDrawerToggle.getSlider()，您可以获得对 DrawerToogle 的引用，并通过调用 drawerToogle.setPosition(some_float_between_0_and_1) 来动画化状态。
要查看完整的工作示例，请访问我的 Github 存储库 此处。