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/* -*- Mode: Java; c-basic-offset: 4; tab-width: 4; indent-tabs-mode: nil; -*-
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
package org.mozilla.gecko.home;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.content.res.ColorStateList;
import org.mozilla.gecko.R;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewTreeObserver;
import android.view.accessibility.AccessibilityEvent;
import android.widget.TextView;
/**
* {@code TabMenuStripLayout} is the view that draws the {@code HomePager}
* tabs that are displayed in {@code TabMenuStrip}.
*/
class TabMenuStripLayout extends LinearLayout
implements View.OnFocusChangeListener {
private TabMenuStrip.OnTitleClickListener onTitleClickListener;
private Drawable strip;
private TextView selectedView;
// Data associated with the scrolling of the strip drawable.
private View toTab;
private View fromTab;
private int fromPosition;
private int toPosition;
private float progress;
// This variable is used to predict the direction of scroll.
private float prevProgress;
private int tabContentStart;
private boolean titlebarFill;
private int activeTextColor;
private ColorStateList inactiveTextColor;
TabMenuStripLayout(Context context, AttributeSet attrs) {
super(context, attrs);
TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.TabMenuStrip);
final int stripResId = a.getResourceId(R.styleable.TabMenuStrip_strip, -1);
titlebarFill = a.getBoolean(R.styleable.TabMenuStrip_titlebarFill, false);
tabContentStart = a.getDimensionPixelSize(R.styleable.TabMenuStrip_tabsMarginLeft, 0);
activeTextColor = a.getColor(R.styleable.TabMenuStrip_activeTextColor, R.color.text_and_tabs_tray_grey);
inactiveTextColor = a.getColorStateList(R.styleable.TabMenuStrip_inactiveTextColor);
a.recycle();
if (stripResId != -1) {
strip = getResources().getDrawable(stripResId);
}
setWillNotDraw(false);
}
void onAddPagerView(String title) {
final TextView button = (TextView) LayoutInflater.from(getContext()).inflate(R.layout.tab_menu_strip, this, false);
button.setText(title.toUpperCase());
button.setTextColor(inactiveTextColor);
// Set titles width to weight, or wrap text width.
if (titlebarFill) {
button.setLayoutParams(new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT, 1.0f));
} else {
button.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.MATCH_PARENT));
}
if (getChildCount() == 0) {
button.setPadding(button.getPaddingLeft() + tabContentStart,
button.getPaddingTop(),
button.getPaddingRight(),
button.getPaddingBottom());
}
addView(button);
button.setOnClickListener(new ViewClickListener(getChildCount() - 1));
button.setOnFocusChangeListener(this);
}
void onPageSelected(final int position) {
if (selectedView != null) {
selectedView.setTextColor(inactiveTextColor);
}
selectedView = (TextView) getChildAt(position);
selectedView.setTextColor(activeTextColor);
// Callback to measure and draw the strip after the view is visible.
ViewTreeObserver vto = selectedView.getViewTreeObserver();
if (vto.isAlive()) {
vto.addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
@Override
public void onGlobalLayout() {
selectedView.getViewTreeObserver().removeGlobalOnLayoutListener(this);
if (strip != null) {
strip.setBounds(selectedView.getLeft() + (position == 0 ? tabContentStart : 0),
selectedView.getTop(),
selectedView.getRight(),
selectedView.getBottom());
}
prevProgress = position;
}
});
}
}
// Page scroll animates the drawable and its bounds from the previous to next child view.
void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
if (strip == null) {
return;
}
setScrollingData(position, positionOffset);
if (fromTab == null || toTab == null) {
return;
}
final int fromTabLeft = fromTab.getLeft();
final int fromTabRight = fromTab.getRight();
final int toTabLeft = toTab.getLeft();
final int toTabRight = toTab.getRight();
// The first tab has a padding applied (tabContentStart). We don't want the 'strip' to jump around so we remove
// this padding slowly (modifier) when scrolling to or from the first tab.
final int modifier;
if (fromPosition == 0 && toPosition == 1) {
// Slowly remove extra padding (tabContentStart) based on scroll progress
modifier = (int) (tabContentStart * (1 - progress));
} else if (fromPosition == 1 && toPosition == 0) {
// Slowly add extra padding (tabContentStart) based on scroll progress
modifier = (int) (tabContentStart * progress);
} else {
// We are not scrolling tab 0 in any way, no modifier needed
modifier = 0;
}
strip.setBounds((int) (fromTabLeft + ((toTabLeft - fromTabLeft) * progress)) + modifier,
0,
(int) (fromTabRight + ((toTabRight - fromTabRight) * progress)),
getHeight());
invalidate();
}
/*
* position + positionOffset goes from 0 to 2 as we scroll from page 1 to 3.
* Normalized progress is relative to the the direction the page is being scrolled towards.
* For this, we maintain direction of scroll with a state, and the child view we are moving towards and away from.
*/
void setScrollingData(int position, float positionOffset) {
if (position >= getChildCount() - 1) {
return;
}
final float currProgress = position + positionOffset;
if (prevProgress > currProgress) {
toPosition = position;
fromPosition = position + 1;
progress = 1 - positionOffset;
} else {
toPosition = position + 1;
fromPosition = position;
progress = positionOffset;
}
toTab = getChildAt(toPosition);
fromTab = getChildAt(fromPosition);
prevProgress = currProgress;
}
@Override
public void onDraw(Canvas canvas) {
super.onDraw(canvas);
if (strip != null) {
strip.draw(canvas);
}
}
@Override
public void onFocusChange(View v, boolean hasFocus) {
if (v == this && hasFocus && getChildCount() > 0) {
selectedView.requestFocus();
return;
}
if (!hasFocus) {
return;
}
int i = 0;
final int numTabs = getChildCount();
while (i < numTabs) {
View view = getChildAt(i);
if (view == v) {
view.requestFocus();
if (isShown()) {
// A view is focused so send an event to announce the menu strip state.
sendAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_FOCUSED);
}
break;
}
i++;
}
}
void setOnTitleClickListener(TabMenuStrip.OnTitleClickListener onTitleClickListener) {
this.onTitleClickListener = onTitleClickListener;
}
private class ViewClickListener implements OnClickListener {
private final int mIndex;
public ViewClickListener(int index) {
mIndex = index;
}
@Override
public void onClick(View view) {
if (onTitleClickListener != null) {
onTitleClickListener.onTitleClicked(mIndex);
}
}
}
}
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