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. */ package com.vgaw.androidtest.view; import android.R; import android.content.Context; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.graphics.Typeface; import android.os.Build; import android.support.v4.view.PagerAdapter; import android.support.v4.view.ViewPager; import android.util.AttributeSet; import android.util.TypedValue; import android.view.Gravity; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.LinearLayout; import android.widget.RadioGroup; import android.widget.TextView; /** * Tablayout_weight=1. */ /** * To be used with ViewPager to provide a tab indicator component which give constant feedback as to * the user's scroll progress. * <p> * To use the component, simply add it to your view hierarchy. Then in your * {@link android.app.Activity} or {@link android.support.v4.app.Fragment} call * {@link #setViewPager(ViewPager)} providing it the ViewPager this layout is being used for. * <p> * The colors can be customized in two ways. The first and simplest is to provide an array of colors * via {@link #setSelectedIndicatorColors(int...)} and {@link #setDividerColors(int...)}. The * alternative is via the {@link TabColorizer} interface which provides you complete control over * which color is used for any individual position. * <p> * The views used as tabs can be customized by calling {@link #setCustomTabView(int, int)}, * providing the layout ID of your custom layout. */ public class SlidingTabStrip extends RadioGroup { private static final int DEFAULT_BOTTOM_BORDER_THICKNESS_DIPS = 2; private static final byte DEFAULT_BOTTOM_BORDER_COLOR_ALPHA = 0x26; private static final int SELECTED_INDICATOR_THICKNESS_DIPS = 8; private static final int DEFAULT_SELECTED_INDICATOR_COLOR = 0xFF33B5E5; private static final int DEFAULT_DIVIDER_THICKNESS_DIPS = 1; private static final byte DEFAULT_DIVIDER_COLOR_ALPHA = 0x20; private static final float DEFAULT_DIVIDER_HEIGHT = 0.5f; private static final int TAB_VIEW_PADDING_DIPS = 16; private static final int TAB_VIEW_TEXT_SIZE_SP = 12; private final int mBottomBorderThickness; private final Paint mBottomBorderPaint; private final int mSelectedIndicatorThickness; private final Paint mSelectedIndicatorPaint; private final int mDefaultBottomBorderColor; private final Paint mDividerPaint; private final float mDividerHeight; private int mSelectedPosition; private float mSelectionOffset; private ViewPager mViewPager; private ViewPager.OnPageChangeListener mViewPagerPageChangeListener; private TabColorizer mCustomTabColorizer; private final SimpleTabColorizer mDefaultTabColorizer; private int mTabViewLayoutId; private int mTabViewTextViewId; public SlidingTabStrip(Context context) { this(context, null); } public SlidingTabStrip(Context context, AttributeSet attrs) { super(context, attrs); setWillNotDraw(false); setOrientation(HORIZONTAL); final float density = getResources().getDisplayMetrics().density; TypedValue outValue = new TypedValue(); context.getTheme().resolveAttribute(R.attr.colorForeground, outValue, true); final int themeForegroundColor = outValue.data; mDefaultBottomBorderColor = setColorAlpha(themeForegroundColor, DEFAULT_BOTTOM_BORDER_COLOR_ALPHA); mDefaultTabColorizer = new SimpleTabColorizer(); mDefaultTabColorizer.setIndicatorColors(DEFAULT_SELECTED_INDICATOR_COLOR); mDefaultTabColorizer.setDividerColors(setColorAlpha(themeForegroundColor, DEFAULT_DIVIDER_COLOR_ALPHA)); mBottomBorderThickness = (int) (DEFAULT_BOTTOM_BORDER_THICKNESS_DIPS * density); mBottomBorderPaint = new Paint(); mBottomBorderPaint.setColor(mDefaultBottomBorderColor); mSelectedIndicatorThickness = (int) (SELECTED_INDICATOR_THICKNESS_DIPS * density); mSelectedIndicatorPaint = new Paint(); mDividerHeight = DEFAULT_DIVIDER_HEIGHT; mDividerPaint = new Paint(); mDividerPaint.setStrokeWidth((int) (DEFAULT_DIVIDER_THICKNESS_DIPS * density)); } public void setCustomTabColorizer(TabColorizer customTabColorizer) { mCustomTabColorizer = customTabColorizer; invalidate(); } /** * Sets the colors to be used for indicating the selected tab. These colors are treated as a * circular array. Providing one color will mean that all tabs are indicated with the same color. */ public void setSelectedIndicatorColors(int... colors) { // Make sure that the custom colorizer is removed mCustomTabColorizer = null; mDefaultTabColorizer.setIndicatorColors(colors); invalidate(); } /** * Sets the colors to be used for tab dividers. These colors are treated as a circular array. * Providing one color will mean that all tabs are indicated with the same color. */ public void setDividerColors(int... colors) { // Make sure that the custom colorizer is removed mCustomTabColorizer = null; mDefaultTabColorizer.setDividerColors(colors); invalidate(); } private void onViewPagerPageChanged(int position, float positionOffset) { mSelectedPosition = position; mSelectionOffset = positionOffset; invalidate(); } @Override protected void onDraw(Canvas canvas) { final int height = getHeight(); final int childCount = getChildCount(); final int dividerHeightPx = (int) (Math.min(Math.max(0f, mDividerHeight), 1f) * height); final TabColorizer tabColorizer = mCustomTabColorizer != null ? mCustomTabColorizer : mDefaultTabColorizer; // Thick colored underline below the current selection if (childCount > 0) { View selectedTitle = getChildAt(mSelectedPosition); int left = selectedTitle.getLeft(); int right = selectedTitle.getRight(); int color = tabColorizer.getIndicatorColor(mSelectedPosition); if (mSelectionOffset > 0f && mSelectedPosition < (getChildCount() - 1)) { int nextColor = tabColorizer.getIndicatorColor(mSelectedPosition + 1); if (color != nextColor) { color = blendColors(nextColor, color, mSelectionOffset); } // Draw the selection partway between the tabs View nextTitle = getChildAt(mSelectedPosition + 1); left = (int) (mSelectionOffset * nextTitle.getLeft() + (1.0f - mSelectionOffset) * left); right = (int) (mSelectionOffset * nextTitle.getRight() + (1.0f - mSelectionOffset) * right); } mSelectedIndicatorPaint.setColor(color); canvas.drawRect(left, height - mSelectedIndicatorThickness, right, height, mSelectedIndicatorPaint); } // Thin underline along the entire bottom edge canvas.drawRect(0, height - mBottomBorderThickness, getWidth(), height, mBottomBorderPaint); // Vertical separators between the titles int separatorTop = (height - dividerHeightPx) / 2; for (int i = 0; i < childCount - 1; i++) { View child = getChildAt(i); mDividerPaint.setColor(tabColorizer.getDividerColor(i)); canvas.drawLine(child.getRight(), separatorTop, child.getRight(), separatorTop + dividerHeightPx, mDividerPaint); } } /** * Set the alpha value of the {@code color} to be the given {@code alpha} value. */ private static int setColorAlpha(int color, byte alpha) { return Color.argb(alpha, Color.red(color), Color.green(color), Color.blue(color)); } /** * Blend {@code color1} and {@code color2} using the given ratio. * * @param ratio of which to blend. 1.0 will return {@code color1}, 0.5 will give an even blend, * 0.0 will return {@code color2}. */ private static int blendColors(int color1, int color2, float ratio) { final float inverseRation = 1f - ratio; float r = (Color.red(color1) * ratio) + (Color.red(color2) * inverseRation); float g = (Color.green(color1) * ratio) + (Color.green(color2) * inverseRation); float b = (Color.blue(color1) * ratio) + (Color.blue(color2) * inverseRation); return Color.rgb((int) r, (int) g, (int) b); } private static class SimpleTabColorizer implements TabColorizer { private int[] mIndicatorColors; private int[] mDividerColors; @Override public final int getIndicatorColor(int position) { return mIndicatorColors[position % mIndicatorColors.length]; } @Override public final int getDividerColor(int position) { return mDividerColors[position % mDividerColors.length]; } void setIndicatorColors(int... colors) { mIndicatorColors = colors; } void setDividerColors(int... colors) { mDividerColors = colors; } } /** * Allows complete control over the colors drawn in the tab layout. Set with * {@link #setCustomTabColorizer(TabColorizer)}. */ public interface TabColorizer { /** * @return return the color of the indicator used when {@code position} is selected. */ int getIndicatorColor(int position); /** * @return return the color of the divider drawn to the right of {@code position}. */ int getDividerColor(int position); } /** * Sets the associated view pager. Note that the assumption here is that the pager content * (number of tabs and tab titles) does not change after this call has been made. */ public void setViewPager(ViewPager viewPager) { removeAllViews(); mViewPager = viewPager; if (viewPager != null) { viewPager.setOnPageChangeListener(new InternalViewPagerListener()); populateTabStrip(); } } private class InternalViewPagerListener implements ViewPager.OnPageChangeListener { private int mScrollState; @Override public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { int tabStripChildCount = getChildCount(); if ((tabStripChildCount == 0) || (position < 0) || (position >= tabStripChildCount)) { return; } // ?? if (mViewPager.getCurrentItem() == position) { if (positionOffset > 0.5) { check(getChildAt(position + 1 > tabStripChildCount ? tabStripChildCount : position + 1) .getId()); } else { check(getChildAt(position).getId()); } } // ? else { if (positionOffset < 0.5) { check(getChildAt(position).getId()); } else { check(getChildAt(position + 1 > tabStripChildCount ? tabStripChildCount : position + 1) .getId()); } } onViewPagerPageChanged(position, positionOffset); View selectedTitle = getChildAt(position); int extraOffset = (selectedTitle != null) ? (int) (positionOffset * selectedTitle.getWidth()) : 0; if (mViewPagerPageChangeListener != null) { mViewPagerPageChangeListener.onPageScrolled(position, positionOffset, positionOffsetPixels); } } @Override public void onPageScrollStateChanged(int state) { mScrollState = state; if (mViewPagerPageChangeListener != null) { mViewPagerPageChangeListener.onPageScrollStateChanged(state); } } @Override public void onPageSelected(int position) { if (mScrollState == ViewPager.SCROLL_STATE_IDLE) { check(getChildAt(position).getId()); onViewPagerPageChanged(position, 0f); } if (mViewPagerPageChangeListener != null) { mViewPagerPageChangeListener.onPageSelected(position); } } } /** * Set the {@link ViewPager.OnPageChangeListener}. When using {@link SlidingTabStrip} you are * required to set any {@link ViewPager.OnPageChangeListener} through this method. This is so * that the layout can update it's scroll position correctly. * * @see ViewPager#setOnPageChangeListener(ViewPager.OnPageChangeListener) */ public void setOnPageChangeListener(ViewPager.OnPageChangeListener listener) { mViewPagerPageChangeListener = listener; } private void populateTabStrip() { final PagerAdapter adapter = mViewPager.getAdapter(); final OnClickListener tabClickListener = new TabClickListener(); for (int i = 0; i < adapter.getCount(); i++) { View tabView = null; TextView tabTitleView = null; if (mTabViewLayoutId != 0) { // If there is a custom tab view layout id set, try and inflate it tabView = LayoutInflater.from(getContext()).inflate(mTabViewLayoutId, this, false); if (mTabViewTextViewId != 0) { tabTitleView = (TextView) tabView.findViewById(mTabViewTextViewId); } } if (tabView == null) { tabView = createDefaultTabView(getContext()); } if (tabTitleView == null && TextView.class.isInstance(tabView)) { tabTitleView = (TextView) tabView; } tabTitleView.setText(adapter.getPageTitle(i)); tabView.setOnClickListener(tabClickListener); addView(tabView); } check(getChildAt(0).getId()); } private class TabClickListener implements OnClickListener { @Override public void onClick(View v) { for (int i = 0; i < getChildCount(); i++) { if (v == getChildAt(i)) { mViewPager.setCurrentItem(i); return; } } } } /** * Create a default view to be used for tabs. This is called if a custom tab view is not set via * {@link #setCustomTabView(int, int)}. */ protected TextView createDefaultTabView(Context context) { TextView textView = new TextView(context); textView.setGravity(Gravity.CENTER); textView.setTextSize(TypedValue.COMPLEX_UNIT_SP, TAB_VIEW_TEXT_SIZE_SP); textView.setTypeface(Typeface.DEFAULT_BOLD); LayoutParams params = new LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT, 1f); textView.setLayoutParams(params); if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) { // If we're running on Honeycomb or newer, then we can use the Theme's // selectableItemBackground to ensure that the View has a pressed state TypedValue outValue = new TypedValue(); getContext().getTheme().resolveAttribute(android.R.attr.selectableItemBackground, outValue, true); textView.setBackgroundResource(outValue.resourceId); } if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH) { // If we're running on ICS or newer, enable all-caps to match the Action Bar tab style textView.setAllCaps(true); } int padding = (int) (TAB_VIEW_PADDING_DIPS * getResources().getDisplayMetrics().density); textView.setPadding(padding, padding, padding, padding); return textView; } /** * Set the custom layout to be inflated for the tab views. * * @param layoutResId Layout id to be inflated * @param textViewId id of the {@link TextView} in the inflated view */ public void setCustomTabView(int layoutResId, int textViewId) { mTabViewLayoutId = layoutResId; mTabViewTextViewId = textViewId; } }