Java tutorial
package com.daiv.android.twitter.manipulations.widgets; /* * 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. */ import android.app.Activity; import android.content.res.Configuration; import android.graphics.*; import android.graphics.drawable.Drawable; import android.os.Build; import android.support.v4.view.GravityCompat; import android.support.v4.widget.DrawerLayout; import android.view.MenuItem; import android.view.View; /** * 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/> * <p>To use <code>ActionBarDrawerToggle</code>, create one in your Activity and call through * to the following methods corresponding to your Activity callbacks:</p> * <p/> * <ul> * <li>{@link Activity#onConfigurationChanged(android.content.res.Configuration) onConfigurationChanged}</li> * <li>{@link Activity#onOptionsItemSelected(android.view.MenuItem) onOptionsItemSelected}</li> * </ul> * <p/> * <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/> * <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 { /** * 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 interface ActionBarDrawerToggleImpl { Drawable getThemeUpIndicator(Activity activity); Object setActionBarUpIndicator(Object info, Activity activity, Drawable themeImage, int contentDescRes); Object setActionBarDescription(Object info, Activity activity, int contentDescRes); } private static class ActionBarDrawerToggleImplBase implements ActionBarDrawerToggleImpl { @Override public Drawable getThemeUpIndicator(Activity activity) { return null; } @Override public Object setActionBarUpIndicator(Object info, Activity activity, Drawable themeImage, int contentDescRes) { // No action bar to set. return info; } @Override public Object setActionBarDescription(Object info, Activity activity, int contentDescRes) { // No action bar to set return info; } } private static class ActionBarDrawerToggleImplHC implements ActionBarDrawerToggleImpl { @Override public Drawable getThemeUpIndicator(Activity activity) { return ActionBarDrawerToggleHoneycomb.getThemeUpIndicator(activity); } @Override public Object setActionBarUpIndicator(Object info, Activity activity, Drawable themeImage, int contentDescRes) { return ActionBarDrawerToggleHoneycomb.setActionBarUpIndicator(info, activity, themeImage, contentDescRes); } @Override public Object setActionBarDescription(Object info, Activity activity, int contentDescRes) { return ActionBarDrawerToggleHoneycomb.setActionBarDescription(info, activity, contentDescRes); } } private static final ActionBarDrawerToggleImpl IMPL; static { final int version = Build.VERSION.SDK_INT; if (version >= 11) { IMPL = new ActionBarDrawerToggleImplHC(); } else { IMPL = new ActionBarDrawerToggleImplBase(); } } // 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 NotificationDrawerLayout mDrawerLayout; private boolean mDrawerIndicatorEnabled = true; private Drawable mThemeImage; private Drawable mDrawerImage; private SlideDrawable mSlider; private final int mDrawerImageResource; private final int mOpenDrawerContentDescRes; private final int mCloseDrawerContentDescRes; private Object mSetIndicatorInfo; /** * Construct a new ActionBarDrawerToggle. * <p/> * <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/> * <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, NotificationDrawerLayout drawerLayout, int drawerImageRes, int openDrawerContentDescRes, int closeDrawerContentDescRes) { mActivity = activity; mDrawerLayout = drawerLayout; mDrawerImageResource = drawerImageRes; mOpenDrawerContentDescRes = openDrawerContentDescRes; mCloseDrawerContentDescRes = closeDrawerContentDescRes; mThemeImage = getThemeUpIndicator(); mDrawerImage = activity.getResources().getDrawable(drawerImageRes); mSlider = new SlideDrawable(mDrawerImage); mSlider.setOffsetBy(1.f / 3); // Allow the Activity to provide an impl if (activity instanceof DelegateProvider) { mActivityImpl = ((DelegateProvider) activity).getDrawerToggleDelegate(); } else { mActivityImpl = null; } } /** * Synchronize the state of the drawer indicator/affordance with the linked DrawerLayout. * <p/> * <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.setOffset(1.f); } else { mSlider.setOffset(0.f); } if (mDrawerIndicatorEnabled) { setActionBarUpIndicator(mSlider, mDrawerLayout.isDrawerOpen(GravityCompat.START) ? mOpenDrawerContentDescRes : mCloseDrawerContentDescRes); } } /** * Enable or disable the drawer indicator. The indicator defaults to enabled. * <p/> * <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(GravityCompat.START) ? mOpenDrawerContentDescRes : mCloseDrawerContentDescRes); } 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 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(GravityCompat.START)) { mDrawerLayout.closeDrawer(GravityCompat.START); } else { mDrawerLayout.openDrawer(GravityCompat.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.getOffset(); if (slideOffset > 0.5f) { glyphOffset = Math.max(glyphOffset, Math.max(0.f, slideOffset - 0.5f) * 2); } else { glyphOffset = Math.min(glyphOffset, slideOffset * 2); } mSlider.setOffset(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.setOffset(1.f); 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 drawerView Drawer view that is now closed */ @Override public void onDrawerClosed(View drawerView) { mSlider.setOffset(0.f); 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 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 static class SlideDrawable extends Drawable implements Drawable.Callback { private Drawable mWrapped; private float mOffset; private float mOffsetBy; private final Rect mTmpRect = new Rect(); public SlideDrawable(Drawable wrapped) { mWrapped = wrapped; } public void setOffset(float offset) { mOffset = offset; invalidateSelf(); } public float getOffset() { return mOffset; } public void setOffsetBy(float offsetBy) { mOffsetBy = offsetBy; invalidateSelf(); } @Override public void draw(Canvas canvas) { mWrapped.copyBounds(mTmpRect); canvas.save(); canvas.translate(mOffsetBy * mTmpRect.width() * -mOffset, 0); mWrapped.draw(canvas); canvas.restore(); } @Override public void setChangingConfigurations(int configs) { mWrapped.setChangingConfigurations(configs); } @Override public int getChangingConfigurations() { return mWrapped.getChangingConfigurations(); } @Override public void setDither(boolean dither) { mWrapped.setDither(dither); } @Override public void setFilterBitmap(boolean filter) { mWrapped.setFilterBitmap(filter); } @Override public void setAlpha(int alpha) { mWrapped.setAlpha(alpha); } @Override public void setColorFilter(ColorFilter cf) { mWrapped.setColorFilter(cf); } @Override public void setColorFilter(int color, PorterDuff.Mode mode) { mWrapped.setColorFilter(color, mode); } @Override public void clearColorFilter() { mWrapped.clearColorFilter(); } @Override public boolean isStateful() { return mWrapped.isStateful(); } @Override public boolean setState(int[] stateSet) { return mWrapped.setState(stateSet); } @Override public int[] getState() { return mWrapped.getState(); } @Override public Drawable getCurrent() { return mWrapped.getCurrent(); } @Override public boolean setVisible(boolean visible, boolean restart) { return super.setVisible(visible, restart); } @Override public int getOpacity() { return mWrapped.getOpacity(); } @Override public Region getTransparentRegion() { return mWrapped.getTransparentRegion(); } @Override protected boolean onStateChange(int[] state) { mWrapped.setState(state); return super.onStateChange(state); } @Override protected void onBoundsChange(Rect bounds) { super.onBoundsChange(bounds); mWrapped.setBounds(bounds); } @Override public int getIntrinsicWidth() { return mWrapped.getIntrinsicWidth(); } @Override public int getIntrinsicHeight() { return mWrapped.getIntrinsicHeight(); } @Override public int getMinimumWidth() { return mWrapped.getMinimumWidth(); } @Override public int getMinimumHeight() { return mWrapped.getMinimumHeight(); } @Override public boolean getPadding(Rect padding) { return mWrapped.getPadding(padding); } @Override public ConstantState getConstantState() { return super.getConstantState(); } @Override public void invalidateDrawable(Drawable who) { if (who == mWrapped) { invalidateSelf(); } } @Override public void scheduleDrawable(Drawable who, Runnable what, long when) { if (who == mWrapped) { scheduleSelf(what, when); } } @Override public void unscheduleDrawable(Drawable who, Runnable what) { if (who == mWrapped) { unscheduleSelf(what); } } } }