src/com/android/messaging/ui/ViewPagerTabs.java - platform/packages/apps/Messaging - Git at Google

 /*
  * Copyright (C) 2015 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 com.android.messaging.ui;

 import android.content.Context;
 import android.content.res.ColorStateList;
 import android.content.res.TypedArray;
 import android.graphics.Outline;
 import android.graphics.drawable.ColorDrawable;
 import androidx.viewpager.widget.PagerAdapter;
 import androidx.viewpager.widget.ViewPager;
 import android.util.AttributeSet;
 import android.util.TypedValue;
 import android.view.Gravity;
 import android.view.View;
 import android.view.ViewOutlineProvider;
 import android.widget.FrameLayout;
 import android.widget.HorizontalScrollView;
 import android.widget.LinearLayout;
 import android.widget.TextView;
 import android.widget.Toast;

 import com.android.messaging.Factory;
 import com.android.messaging.R;
 import com.android.messaging.util.OsUtil;

 /**
  * Lightweight implementation of ViewPager tabs. This looks similar to traditional actionBar tabs,
  * but allows for the view containing the tabs to be placed anywhere on screen. Text-related
  * attributes can also be assigned in XML - these will get propogated to the child TextViews
  * automatically.
  *
  * Note: this file is taken from the AOSP /packages/apps/ContactsCommon/src/com/android/contacts/
  * common/list/ViewPagerTabs.java. Some platform specific API calls (e.g. ViewOutlineProvider which
  * assumes L and above) have been modified to support down to Api Level 16.
  */
 public class ViewPagerTabs extends HorizontalScrollView implements ViewPager.OnPageChangeListener {

     ViewPager mPager;
     private ViewPagerTabStrip mTabStrip;

     /**
      * Linearlayout that will contain the TextViews serving as tabs. This is the only child
      * of the parent HorizontalScrollView.
      */
     final int mTextStyle;
     final ColorStateList mTextColor;
     final int mTextSize;
     final boolean mTextAllCaps;
     int mPrevSelected = -1;
     int mSidePadding;

     private static final int TAB_SIDE_PADDING_IN_DPS = 10;

     // TODO: This should use <declare-styleable> in the future
     private static final int[] ATTRS = new int[] {
         android.R.attr.textSize,
         android.R.attr.textStyle,
         android.R.attr.textColor,
         android.R.attr.textAllCaps
     };

     /**
      * Shows a toast with the tab description when long-clicked.
      */
     private class OnTabLongClickListener implements OnLongClickListener {
         final String mTabDescription;

         public OnTabLongClickListener(String tabDescription) {
             mTabDescription = tabDescription;
         }

         @Override
         public boolean onLongClick(View v) {
             final int[] screenPos = new int[2];
             getLocationOnScreen(screenPos);

             final Context context = getContext();
             final int width = getWidth();
             final int height = getHeight();
             final int screenWidth = context.getResources().getDisplayMetrics().widthPixels;

             Toast toast = Toast.makeText(context, mTabDescription, Toast.LENGTH_SHORT);

             // Show the toast under the tab
             toast.setGravity(Gravity.TOP | Gravity.CENTER_HORIZONTAL,
                     (screenPos[0] + width / 2) - screenWidth / 2, screenPos[1] + height);

             toast.show();
             return true;
         }
     }

     public ViewPagerTabs(Context context) {
         this(context, null);
     }

     public ViewPagerTabs(Context context, AttributeSet attrs) {
         this(context, attrs, 0);
     }

     public ViewPagerTabs(Context context, AttributeSet attrs, int defStyle) {
         super(context, attrs, defStyle);
         setFillViewport(true);

         mSidePadding = (int) (getResources().getDisplayMetrics().density * TAB_SIDE_PADDING_IN_DPS);

         final TypedArray a = context.obtainStyledAttributes(attrs, ATTRS);
         mTextSize = a.getDimensionPixelSize(0, 0);
         mTextStyle = a.getInt(1, 0);
         mTextColor = a.getColorStateList(2);
         mTextAllCaps = a.getBoolean(3, false);

         mTabStrip = new ViewPagerTabStrip(context);
         addView(mTabStrip,
                 new FrameLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.MATCH_PARENT));
         a.recycle();

         // enable shadow casting from view bounds
         if (OsUtil.isAtLeastL()) {
             setOutlineProvider(new ViewOutlineProvider() {
                 @Override
                 public void getOutline(View view, Outline outline) {
                     outline.setRect(0, 0, view.getWidth(), view.getHeight());
                 }
             });
         }
     }

     public void setViewPager(ViewPager viewPager) {
         mPager = viewPager;
         addTabs(mPager.getAdapter());
     }

     private void addTabs(PagerAdapter adapter) {
         mTabStrip.removeAllViews();

         final int count = adapter.getCount();
         for (int i = 0; i < count; i++) {
             addTab(adapter.getPageTitle(i), i);
         }
     }

     private void addTab(CharSequence tabTitle, final int position) {
         final TextView textView = new TextView(getContext());
         textView.setText(tabTitle);
         textView.setBackgroundResource(R.drawable.contact_picker_tab_background_selector);
         textView.setGravity(Gravity.CENTER);
         textView.setOnClickListener(new OnClickListener() {
             @Override
             public void onClick(View v) {
                 mPager.setCurrentItem(getRtlPosition(position));
             }
         });

         // Assign various text appearance related attributes to child views.
         if (mTextStyle > 0) {
             textView.setTypeface(textView.getTypeface(), mTextStyle);
         }
         if (mTextSize > 0) {
             textView.setTextSize(TypedValue.COMPLEX_UNIT_PX, mTextSize);
         }
         if (mTextColor != null) {
             textView.setTextColor(mTextColor);
         }
         textView.setAllCaps(mTextAllCaps);
         textView.setPadding(mSidePadding, 0, mSidePadding, 0);
         mTabStrip.addView(textView, new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT,
                 LayoutParams.MATCH_PARENT, 1));
         // Default to the first child being selected
         if (position == 0) {
             mPrevSelected = 0;
             textView.setSelected(true);
         }
     }

     @Override
     public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
         position = getRtlPosition(position);
         int tabStripChildCount = mTabStrip.getChildCount();
         if ((tabStripChildCount == 0) || (position < 0) || (position >= tabStripChildCount)) {
             return;
         }

         mTabStrip.onPageScrolled(position, positionOffset, positionOffsetPixels);
     }

     @Override
     public void onPageSelected(int position) {
         position = getRtlPosition(position);
         int tabStripChildCount = mTabStrip.getChildCount();
         if ((tabStripChildCount == 0) || (position < 0) || (position >= tabStripChildCount)) {
             return;
         }

         if (mPrevSelected >= 0 && mPrevSelected < tabStripChildCount) {
             mTabStrip.getChildAt(mPrevSelected).setSelected(false);
         }
         final View selectedChild = mTabStrip.getChildAt(position);
         selectedChild.setSelected(true);

         // Update scroll position
         final int scrollPos = selectedChild.getLeft() - (getWidth() - selectedChild.getWidth()) / 2;
         smoothScrollTo(scrollPos, 0);
         mPrevSelected = position;
     }

     @Override
     public void onPageScrollStateChanged(int state) {
     }

     private int getRtlPosition(int position) {
         if (OsUtil.isAtLeastJB_MR2() && Factory.get().getApplicationContext().getResources()
                 .getConfiguration().getLayoutDirection() == View.LAYOUT_DIRECTION_RTL) {
             return mTabStrip.getChildCount() - 1 - position;
         }
         return position;
     }

     public int getSelectedItemPosition() {
         return mPrevSelected;
     }
 }
	/*
	* Copyright (C) 2015 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 com.android.messaging.ui;

	import android.content.Context;
	import android.content.res.ColorStateList;
	import android.content.res.TypedArray;
	import android.graphics.Outline;
	import android.graphics.drawable.ColorDrawable;
	import androidx.viewpager.widget.PagerAdapter;
	import androidx.viewpager.widget.ViewPager;
	import android.util.AttributeSet;
	import android.util.TypedValue;
	import android.view.Gravity;
	import android.view.View;
	import android.view.ViewOutlineProvider;
	import android.widget.FrameLayout;
	import android.widget.HorizontalScrollView;
	import android.widget.LinearLayout;
	import android.widget.TextView;
	import android.widget.Toast;

	import com.android.messaging.Factory;
	import com.android.messaging.R;
	import com.android.messaging.util.OsUtil;

	/**
	* Lightweight implementation of ViewPager tabs. This looks similar to traditional actionBar tabs,
	* but allows for the view containing the tabs to be placed anywhere on screen. Text-related
	* attributes can also be assigned in XML - these will get propogated to the child TextViews
	* automatically.
	*
	* Note: this file is taken from the AOSP /packages/apps/ContactsCommon/src/com/android/contacts/
	* common/list/ViewPagerTabs.java. Some platform specific API calls (e.g. ViewOutlineProvider which
	* assumes L and above) have been modified to support down to Api Level 16.
	*/
	public class ViewPagerTabs extends HorizontalScrollView implements ViewPager.OnPageChangeListener {

	ViewPager mPager;
	private ViewPagerTabStrip mTabStrip;

	/**
	* Linearlayout that will contain the TextViews serving as tabs. This is the only child
	* of the parent HorizontalScrollView.
	*/
	final int mTextStyle;
	final ColorStateList mTextColor;
	final int mTextSize;
	final boolean mTextAllCaps;
	int mPrevSelected = -1;
	int mSidePadding;

	private static final int TAB_SIDE_PADDING_IN_DPS = 10;

	// TODO: This should use <declare-styleable> in the future
	private static final int[] ATTRS = new int[] {
	android.R.attr.textSize,
	android.R.attr.textStyle,
	android.R.attr.textColor,
	android.R.attr.textAllCaps
	};

	/**
	* Shows a toast with the tab description when long-clicked.
	*/
	private class OnTabLongClickListener implements OnLongClickListener {
	final String mTabDescription;

	public OnTabLongClickListener(String tabDescription) {
	mTabDescription = tabDescription;
	}

	@Override
	public boolean onLongClick(View v) {
	final int[] screenPos = new int[2];
	getLocationOnScreen(screenPos);

	final Context context = getContext();
	final int width = getWidth();
	final int height = getHeight();
	final int screenWidth = context.getResources().getDisplayMetrics().widthPixels;

	Toast toast = Toast.makeText(context, mTabDescription, Toast.LENGTH_SHORT);

	// Show the toast under the tab
	toast.setGravity(Gravity.TOP \| Gravity.CENTER_HORIZONTAL,
	(screenPos[0] + width / 2) - screenWidth / 2, screenPos[1] + height);

	toast.show();
	return true;
	}
	}

	public ViewPagerTabs(Context context) {
	this(context, null);
	}

	public ViewPagerTabs(Context context, AttributeSet attrs) {
	this(context, attrs, 0);
	}

	public ViewPagerTabs(Context context, AttributeSet attrs, int defStyle) {
	super(context, attrs, defStyle);
	setFillViewport(true);

	mSidePadding = (int) (getResources().getDisplayMetrics().density * TAB_SIDE_PADDING_IN_DPS);

	final TypedArray a = context.obtainStyledAttributes(attrs, ATTRS);
	mTextSize = a.getDimensionPixelSize(0, 0);
	mTextStyle = a.getInt(1, 0);
	mTextColor = a.getColorStateList(2);
	mTextAllCaps = a.getBoolean(3, false);

	mTabStrip = new ViewPagerTabStrip(context);
	addView(mTabStrip,
	new FrameLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.MATCH_PARENT));
	a.recycle();

	// enable shadow casting from view bounds
	if (OsUtil.isAtLeastL()) {
	setOutlineProvider(new ViewOutlineProvider() {
	@Override
	public void getOutline(View view, Outline outline) {
	outline.setRect(0, 0, view.getWidth(), view.getHeight());
	}
	});
	}
	}

	public void setViewPager(ViewPager viewPager) {
	mPager = viewPager;
	addTabs(mPager.getAdapter());
	}

	private void addTabs(PagerAdapter adapter) {
	mTabStrip.removeAllViews();

	final int count = adapter.getCount();
	for (int i = 0; i < count; i++) {
	addTab(adapter.getPageTitle(i), i);
	}
	}

	private void addTab(CharSequence tabTitle, final int position) {
	final TextView textView = new TextView(getContext());
	textView.setText(tabTitle);
	textView.setBackgroundResource(R.drawable.contact_picker_tab_background_selector);
	textView.setGravity(Gravity.CENTER);
	textView.setOnClickListener(new OnClickListener() {
	@Override
	public void onClick(View v) {
	mPager.setCurrentItem(getRtlPosition(position));
	}
	});

	// Assign various text appearance related attributes to child views.
	if (mTextStyle > 0) {
	textView.setTypeface(textView.getTypeface(), mTextStyle);
	}
	if (mTextSize > 0) {
	textView.setTextSize(TypedValue.COMPLEX_UNIT_PX, mTextSize);
	}
	if (mTextColor != null) {
	textView.setTextColor(mTextColor);
	}
	textView.setAllCaps(mTextAllCaps);
	textView.setPadding(mSidePadding, 0, mSidePadding, 0);
	mTabStrip.addView(textView, new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT,
	LayoutParams.MATCH_PARENT, 1));
	// Default to the first child being selected
	if (position == 0) {
	mPrevSelected = 0;
	textView.setSelected(true);
	}
	}

	@Override
	public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
	position = getRtlPosition(position);
	int tabStripChildCount = mTabStrip.getChildCount();
	if ((tabStripChildCount == 0) \|\| (position < 0) \|\| (position >= tabStripChildCount)) {
	return;
	}

	mTabStrip.onPageScrolled(position, positionOffset, positionOffsetPixels);
	}

	@Override
	public void onPageSelected(int position) {
	position = getRtlPosition(position);
	int tabStripChildCount = mTabStrip.getChildCount();
	if ((tabStripChildCount == 0) \|\| (position < 0) \|\| (position >= tabStripChildCount)) {
	return;
	}

	if (mPrevSelected >= 0 && mPrevSelected < tabStripChildCount) {
	mTabStrip.getChildAt(mPrevSelected).setSelected(false);
	}
	final View selectedChild = mTabStrip.getChildAt(position);
	selectedChild.setSelected(true);

	// Update scroll position
	final int scrollPos = selectedChild.getLeft() - (getWidth() - selectedChild.getWidth()) / 2;
	smoothScrollTo(scrollPos, 0);
	mPrevSelected = position;
	}

	@Override
	public void onPageScrollStateChanged(int state) {
	}

	private int getRtlPosition(int position) {
	if (OsUtil.isAtLeastJB_MR2() && Factory.get().getApplicationContext().getResources()
	.getConfiguration().getLayoutDirection() == View.LAYOUT_DIRECTION_RTL) {
	return mTabStrip.getChildCount() - 1 - position;
	}
	return position;
	}

	public int getSelectedItemPosition() {
	return mPrevSelected;
	}
	}