Java tutorial
/* * Copyright (C) 2013 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. * * * (modified from android.support.v4.app) */ package com.cyanogenmod.filemanager.ui.widgets; import java.lang.reflect.Method; import android.R; import android.app.ActionBar; import android.app.Activity; import android.content.res.Configuration; import android.content.res.TypedArray; import android.graphics.Canvas; import android.graphics.Rect; import android.graphics.drawable.Drawable; import android.graphics.drawable.LevelListDrawable; import android.os.Build; import android.util.Log; import android.view.Gravity; import android.view.MenuItem; import android.view.View; import android.view.ViewGroup; import android.widget.ImageView; /** * This class provides a handy way to tie together the functionality of * {@link 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 Activity#onConfigurationChanged(android.content.res.Configuration) * onConfigurationChanged}</li> * <li>{@link Activity#onOptionsItemSelected(android.view.MenuItem) * onOptionsItemSelected}</li> * </ul> * * <p> * Call {@link #syncState()} from your <code>Activity</code>'s * {@link 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 DrawerLayout.DrawerListener}, or if you are already providing your own * listener, call through to each of the listener methods from your own. * </p> */ public class ActionBarDrawerToggle implements DrawerLayout.DrawerListener { private static final String TAG = "ActionBarDrawerToggle"; /** * 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. */ Delegate getDrawerToggleDelegate(); } public interface Delegate { /** * @return Up indicator drawable as defined in the Activity's theme, or * null if one is not defined. */ Drawable getThemeUpIndicator(); /** * 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, int contentDescRes); /** * Set the Action Bar's up indicator content description. * * @param contentDescRes * - Content description to set */ void setActionBarDescription(int contentDescRes); } private static final int[] THEME_ATTRS = new int[] { R.attr.homeAsUpIndicator }; private static class ActionBarDrawerToggleImpl { public static Drawable getThemeUpIndicator(Activity activity) { final TypedArray a = activity.obtainStyledAttributes(THEME_ATTRS); final Drawable result = a.getDrawable(0); a.recycle(); return result; } public static Object setActionBarUpIndicator(Object info, Activity activity, Drawable drawable, int contentDescRes) { if (info == null) { info = new SetIndicatorInfo(activity); } final ActionBar actionBar = activity.getActionBar(); actionBar.setHomeAsUpIndicator(drawable); actionBar.setHomeActionContentDescription(contentDescRes); return info; } public static Object setActionBarDescription(Object info, Activity activity, int contentDescRes) { if (info == null) { info = new SetIndicatorInfo(activity); } final ActionBar actionBar = activity.getActionBar(); actionBar.setHomeActionContentDescription(contentDescRes); return info; } } private static class SetIndicatorInfo { public Method setHomeAsUpIndicator; public Method setHomeActionContentDescription; public ImageView upIndicatorView; SetIndicatorInfo(Activity activity) { try { setHomeAsUpIndicator = ActionBar.class.getDeclaredMethod("setHomeAsUpIndicator", Drawable.class); setHomeActionContentDescription = ActionBar.class .getDeclaredMethod("setHomeActionContentDescription", Integer.TYPE); // If we got the method we won't need the stuff below. return; } catch (NoSuchMethodException e) { // Oh well. We'll use the other mechanism below instead. } final View home = activity.findViewById(android.R.id.home); if (home == null) { // Action bar doesn't have a known configuration, an OEM messed // with things. return; } final ViewGroup parent = (ViewGroup) home.getParent(); final int childCount = parent.getChildCount(); if (childCount != 2) { // No idea which one will be the right one, an OEM messed with // things. return; } final View first = parent.getChildAt(0); final View second = parent.getChildAt(1); final View up = first.getId() == android.R.id.home ? second : first; if (up instanceof ImageView) { // Jackpot! (Probably...) upIndicatorView = (ImageView) up; } } } private static final ActionBarDrawerToggleImpl IMPL = new ActionBarDrawerToggleImpl(); /** Fraction of its total width by which to offset the toggle drawable. */ private static final float TOGGLE_DRAWABLE_OFFSET = 1 / 3f; // android.R.id.home as defined by public API in v11 private static final int ID_HOME = 0x0102002c; private final Activity mActivity; private final Delegate mActivityImpl; private final DrawerLayout mDrawerLayout; private boolean mDrawerIndicatorEnabled = true; private Drawable mThemeImage; private Drawable mDrawerImage; private SlideDrawable mSlider; private int mDrawerImageResource; private final int mOpenDrawerContentDescRes; private final int mCloseDrawerContentDescRes; private Object mSetIndicatorInfo; /** * Construct a new ActionBarDrawerToggle. * * <p> * The given {@link Activity} will be linked to the specified * {@link DrawerLayout}. The provided drawer indicator drawable will animate * slightly off-screen as the drawer is opened, indicating that in the open * state the drawer will move off-screen when pressed and in the closed * state the drawer will move on-screen when pressed. * </p> * * <p> * String resources must be provided to describe the open/close drawer * actions for accessibility services. * </p> * * @param activity * The Activity hosting the drawer * @param drawerLayout * The DrawerLayout to link to the given Activity's ActionBar * @param drawerImageRes * A Drawable resource to use as the drawer indicator * @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, int drawerImageRes, int openDrawerContentDescRes, int closeDrawerContentDescRes) { mActivity = activity; // Allow the Activity to provide an impl if (activity instanceof DelegateProvider) { mActivityImpl = ((DelegateProvider) activity).getDrawerToggleDelegate(); } else { mActivityImpl = null; } mDrawerLayout = drawerLayout; mDrawerImageResource = drawerImageRes; mOpenDrawerContentDescRes = openDrawerContentDescRes; mCloseDrawerContentDescRes = closeDrawerContentDescRes; mThemeImage = getThemeUpIndicator(); mDrawerImage = activity.getResources().getDrawable(drawerImageRes); mSlider = new SlideDrawable(mDrawerImage); mSlider.setOffset(TOGGLE_DRAWABLE_OFFSET); } /** * 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(Gravity.START)) { mSlider.setPosition(1); } else { mSlider.setPosition(0); } if (mDrawerIndicatorEnabled) { setActionBarUpIndicator(mSlider, mDrawerLayout.isDrawerOpen(Gravity.START) ? mCloseDrawerContentDescRes : mOpenDrawerContentDescRes); } } /** * 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(mSlider, mDrawerLayout.isDrawerOpen(Gravity.START) ? mCloseDrawerContentDescRes : mOpenDrawerContentDescRes); } else { setActionBarUpIndicator(mThemeImage, 0); } mDrawerIndicatorEnabled = enable; } } /** * @return true if the enhanced drawer indicator is enabled, false otherwise * @see #setDrawerIndicatorEnabled(boolean) */ public boolean isDrawerIndicatorEnabled() { return mDrawerIndicatorEnabled; } /** * This method replaces the drawer image resource with a new one. * * @param newDrawerImageRes * The new resource id */ public void setDrawerImageResource(int newDrawerImageRes) { mDrawerImageResource = newDrawerImageRes; mDrawerImage = mActivity.getResources().getDrawable(mDrawerImageResource); mSlider = new SlideDrawable(mDrawerImage); mSlider.setOffset(TOGGLE_DRAWABLE_OFFSET); syncState(); } /** * 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 mThemeImage = getThemeUpIndicator(); mDrawerImage = mActivity.getResources().getDrawable(mDrawerImageResource); 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() == ID_HOME && mDrawerIndicatorEnabled) { if (mDrawerLayout.isDrawerVisible(Gravity.START)) { mDrawerLayout.closeDrawer(Gravity.START); } else { mDrawerLayout.openDrawer(Gravity.START); } return true; } return false; } /** * {@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) { float glyphOffset = mSlider.getPosition(); if (slideOffset > 0.5f) { glyphOffset = Math.max(glyphOffset, Math.max(0.f, slideOffset - 0.5f) * 2); } else { glyphOffset = Math.min(glyphOffset, slideOffset * 2); } mSlider.setPosition(glyphOffset); } /** * {@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) { } Drawable getThemeUpIndicator() { if (mActivityImpl != null) { return mActivityImpl.getThemeUpIndicator(); } return IMPL.getThemeUpIndicator(mActivity); } void setActionBarUpIndicator(Drawable upDrawable, int contentDescRes) { if (mActivityImpl != null) { mActivityImpl.setActionBarUpIndicator(upDrawable, contentDescRes); return; } mSetIndicatorInfo = IMPL.setActionBarUpIndicator(mSetIndicatorInfo, mActivity, upDrawable, contentDescRes); } void setActionBarDescription(int contentDescRes) { if (mActivityImpl != null) { mActivityImpl.setActionBarDescription(contentDescRes); return; } mSetIndicatorInfo = IMPL.setActionBarDescription(mSetIndicatorInfo, mActivity, contentDescRes); } private class SlideDrawable extends LevelListDrawable implements Drawable.Callback { private final boolean mHasMirroring = Build.VERSION.SDK_INT > 18; private final Rect mTmpRect = new Rect(); private float mPosition; private float mOffset; private SlideDrawable(Drawable wrapped) { super(); if (wrapped.isAutoMirrored()) { this.setAutoMirrored(true); } addLevel(0, 0, wrapped); } /** * Sets the current position along the offset. * * @param position * a value between 0 and 1 */ public void setPosition(float position) { mPosition = position; invalidateSelf(); } public float getPosition() { return mPosition; } /** * Specifies the maximum offset when the position is at 1. * * @param offset * maximum offset as a fraction of the drawable width, * positive to shift left or negative to shift right. * @see #setPosition(float) */ public void setOffset(float offset) { mOffset = offset; invalidateSelf(); } @Override public void draw(Canvas canvas) { copyBounds(mTmpRect); canvas.save(); // Layout direction must be obtained from the activity. final boolean isLayoutRTL = mActivity.getWindow().getDecorView() .getLayoutDirection() == View.LAYOUT_DIRECTION_RTL; final int flipRtl = isLayoutRTL ? -1 : 1; final int width = mTmpRect.width(); canvas.translate(-mOffset * width * mPosition * flipRtl, 0); // Force auto-mirroring if it's not supported by the platform. if (isLayoutRTL && !mHasMirroring) { canvas.translate(width, 0); canvas.scale(-1, 1); } super.draw(canvas); canvas.restore(); } } }