ViewPager With FragmentPagerAdapter

时间:2023-01-11 04:12:04

采用PagerAdapter中的FragmentPagerAdapter来实现页面切换,适用于a handful of typically more static fragments to be paged through

1.Layout ViewPager

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"> <android.support.v4.view.ViewPager
android:id="@+id/vpPager"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<!-- PagerTabStrip automatically display the page indicator for your pager -->
<android.support.v4.view.PagerTabStrip
android:id="@+id/pager_header"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="top"
android:paddingBottom="4dp"
android:paddingTop="4dp" /> </android.support.v4.view.ViewPager>
</LinearLayout>

2.Define Fragments

FirstFragment is like SecondFragment

 package com.example.fragmentpagerdemo;

 import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView; public class FirstFragment extends Fragment{ //Store instance variables
private String title;
private int page; /**
* 每一个fragment实例都可以附带一个bundle对象: bundle-->(key-value)
* @param title
* @param page
* @return
*/
//newInstance constructor for creating fragment with arguments
public static FirstFragment newsInstance(String title, int page)
{
//首先创建fragment实例
FirstFragment fragment = new FirstFragment();
//创建bundle对象
Bundle bundle = new Bundle();
//向该bundle对象中添加参数
bundle.putInt("page", page);
bundle.putString("title", title);
//将bundle附加给fragment
fragment.setArguments(bundle);
return fragment;
}
// Store instance variables based on arguments passed
@Override
public void onCreate(Bundle savedInstanceState) {
//
super.onCreate(savedInstanceState);
page = getArguments().getInt("page", 0);
title = getArguments().getString("title", null);
} @Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
//
View view = inflater.inflate(R.layout.first_fragment, container, false);
TextView text = (TextView) view.findViewById(R.id.textView);
text.setText(page + "--" + title);
return view;
} }

3.MainActivity

 package com.example.fragmentpagerdemo;

 import android.annotation.SuppressLint;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.widget.Toast; public class MainActivity extends FragmentActivity{
FragmentPagerAdapter adapterViewPager;
ViewPager vpPager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main); vpPager = (ViewPager) findViewById(R.id.vpPager);
adapterViewPager = new MyPagerAdapter(getSupportFragmentManager());
vpPager.setAdapter(adapterViewPager);
//setup OnPageChangeListener
vpPager.setOnPageChangeListener(new OnPageChangeListener()
{ // Called when the scroll state changes:
// SCROLL_STATE_IDLE, SCROLL_STATE_DRAGGING, SCROLL_STATE_SETTLING
@Override
public void onPageScrollStateChanged(int arg0) {
// }
// This method will be invoked when the current page is scrolled
@Override
public void onPageScrolled(int arg0, float arg1, int arg2) {
// }
// This method will be invoked when a new page becomes selected.
@SuppressLint("ShowToast")
@Override
public void onPageSelected(int arg0) {
//
System.out.println("The page is cahnged to:" + vpPager.getCurrentItem());
// Toast.makeText(this, "The page is changed to:" + vpPager.getCurrentItem(), Toast.LENGTH_LONG);
}
});
}
public static class MyPagerAdapter extends FragmentPagerAdapter
{
private static int NUM_ITEMS = 3;
public MyPagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int position) {
//
switch(position)
{
case 0:
return FirstFragment.newsInstance("Page @ 1", 0);
case 1:
return FirstFragment.newsInstance("Page @ 2", 1);
case 2:
return SecondFragment.newsInstance("Page @ 3", 2);
default:
return null;
}
}
@Override
public int getCount() {
//
return NUM_ITEMS;
}
// Returns the page title for the top indicator
@Override
public CharSequence getPageTitle(int position) {
//
return "Page" + position;
}
}
}

ViewPager With FragmentPagerAdapter

Google recommended method to implement Tab:  Google Play style sliding tabs

First need to copy the following two java source files into your application:

SlidingTabLayout.java

 /*
* Copyright 2014 Google Inc. All rights reserved.
*
* 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.google.samples.apps.iosched.ui.widget; import android.content.Context;
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.SparseArray;
import android.util.TypedValue;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.HorizontalScrollView;
import android.widget.LinearLayout;
import android.widget.TextView; /**
* 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...)}. 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 SlidingTabLayout extends HorizontalScrollView {
/**
* 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); } private static final int TITLE_OFFSET_DIPS = 24;
private static final int TAB_VIEW_PADDING_DIPS = 16;
private static final int TAB_VIEW_TEXT_SIZE_SP = 12; private int mTitleOffset; private int mTabViewLayoutId;
private int mTabViewTextViewId;
private boolean mDistributeEvenly; private ViewPager mViewPager;
private SparseArray<String> mContentDescriptions = new SparseArray<String>();
private ViewPager.OnPageChangeListener mViewPagerPageChangeListener; private final SlidingTabStrip mTabStrip; public SlidingTabLayout(Context context) {
this(context, null);
} public SlidingTabLayout(Context context, AttributeSet attrs) {
this(context, attrs, 0);
} public SlidingTabLayout(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle); // Disable the Scroll Bar
setHorizontalScrollBarEnabled(false);
// Make sure that the Tab Strips fills this View
setFillViewport(true); mTitleOffset = (int) (TITLE_OFFSET_DIPS * getResources().getDisplayMetrics().density); mTabStrip = new SlidingTabStrip(context);
addView(mTabStrip, LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
} /**
* Set the custom {@link TabColorizer} to be used.
*
* If you only require simple custmisation then you can use
* {@link #setSelectedIndicatorColors(int...)} to achieve
* similar effects.
*/
public void setCustomTabColorizer(TabColorizer tabColorizer) {
mTabStrip.setCustomTabColorizer(tabColorizer);
} public void setDistributeEvenly(boolean distributeEvenly) {
mDistributeEvenly = distributeEvenly;
} /**
* 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) {
mTabStrip.setSelectedIndicatorColors(colors);
} /**
* Set the {@link ViewPager.OnPageChangeListener}. When using {@link SlidingTabLayout} 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;
} /**
* 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;
} /**
* 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) {
mTabStrip.removeAllViews(); mViewPager = viewPager;
if (viewPager != null) {
viewPager.setOnPageChangeListener(new InternalViewPagerListener());
populateTabStrip();
}
} /**
* 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);
textView.setLayoutParams(new LinearLayout.LayoutParams(
ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT)); TypedValue outValue = new TypedValue();
getContext().getTheme().resolveAttribute(android.R.attr.selectableItemBackground,
outValue, true);
textView.setBackgroundResource(outValue.resourceId);
textView.setAllCaps(true); int padding = (int) (TAB_VIEW_PADDING_DIPS * getResources().getDisplayMetrics().density);
textView.setPadding(padding, padding, padding, padding); return textView;
} private void populateTabStrip() {
final PagerAdapter adapter = mViewPager.getAdapter();
final View.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, mTabStrip,
false);
tabTitleView = (TextView) tabView.findViewById(mTabViewTextViewId);
} if (tabView == null) {
tabView = createDefaultTabView(getContext());
} if (tabTitleView == null && TextView.class.isInstance(tabView)) {
tabTitleView = (TextView) tabView;
} if (mDistributeEvenly) {
LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams) tabView.getLayoutParams();
lp.width = 0;
lp.weight = 1;
} tabTitleView.setText(adapter.getPageTitle(i));
tabView.setOnClickListener(tabClickListener);
String desc = mContentDescriptions.get(i, null);
if (desc != null) {
tabView.setContentDescription(desc);
} mTabStrip.addView(tabView);
if (i == mViewPager.getCurrentItem()) {
tabView.setSelected(true);
}
}
} public void setContentDescription(int i, String desc) {
mContentDescriptions.put(i, desc);
} @Override
protected void onAttachedToWindow() {
super.onAttachedToWindow(); if (mViewPager != null) {
scrollToTab(mViewPager.getCurrentItem(), 0);
}
} private void scrollToTab(int tabIndex, int positionOffset) {
final int tabStripChildCount = mTabStrip.getChildCount();
if (tabStripChildCount == 0 || tabIndex < 0 || tabIndex >= tabStripChildCount) {
return;
} View selectedChild = mTabStrip.getChildAt(tabIndex);
if (selectedChild != null) {
int targetScrollX = selectedChild.getLeft() + positionOffset; if (tabIndex > 0 || positionOffset > 0) {
// If we're not at the first child and are mid-scroll, make sure we obey the offset
targetScrollX -= mTitleOffset;
} scrollTo(targetScrollX, 0);
}
} private class InternalViewPagerListener implements ViewPager.OnPageChangeListener {
private int mScrollState; @Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
int tabStripChildCount = mTabStrip.getChildCount();
if ((tabStripChildCount == 0) || (position < 0) || (position >= tabStripChildCount)) {
return;
} mTabStrip.onViewPagerPageChanged(position, positionOffset); View selectedTitle = mTabStrip.getChildAt(position);
int extraOffset = (selectedTitle != null)
? (int) (positionOffset * selectedTitle.getWidth())
: 0;
scrollToTab(position, extraOffset); 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) {
mTabStrip.onViewPagerPageChanged(position, 0f);
scrollToTab(position, 0);
}
for (int i = 0; i < mTabStrip.getChildCount(); i++) {
mTabStrip.getChildAt(i).setSelected(position == i);
}
if (mViewPagerPageChangeListener != null) {
mViewPagerPageChangeListener.onPageSelected(position);
}
} } private class TabClickListener implements View.OnClickListener {
@Override
public void onClick(View v) {
for (int i = 0; i < mTabStrip.getChildCount(); i++) {
if (v == mTabStrip.getChildAt(i)) {
mViewPager.setCurrentItem(i);
return;
}
}
}
} }

SlidingTabStrip.java

 /*
* Copyright 2014 Google Inc. All rights reserved.
*
* 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.google.samples.apps.iosched.ui.widget; import android.R;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.util.TypedValue;
import android.view.View;
import android.widget.LinearLayout; class SlidingTabStrip extends LinearLayout { private static final int DEFAULT_BOTTOM_BORDER_THICKNESS_DIPS = 0;
private static final byte DEFAULT_BOTTOM_BORDER_COLOR_ALPHA = 0x26;
private static final int SELECTED_INDICATOR_THICKNESS_DIPS = 3;
private static final int DEFAULT_SELECTED_INDICATOR_COLOR = 0xFF33B5E5; private final int mBottomBorderThickness;
private final Paint mBottomBorderPaint; private final int mSelectedIndicatorThickness;
private final Paint mSelectedIndicatorPaint; private final int mDefaultBottomBorderColor; private int mSelectedPosition;
private float mSelectionOffset; private SlidingTabLayout.TabColorizer mCustomTabColorizer;
private final SimpleTabColorizer mDefaultTabColorizer; SlidingTabStrip(Context context) {
this(context, null);
} SlidingTabStrip(Context context, AttributeSet attrs) {
super(context, attrs);
setWillNotDraw(false); 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); mBottomBorderThickness = (int) (DEFAULT_BOTTOM_BORDER_THICKNESS_DIPS * density);
mBottomBorderPaint = new Paint();
mBottomBorderPaint.setColor(mDefaultBottomBorderColor); mSelectedIndicatorThickness = (int) (SELECTED_INDICATOR_THICKNESS_DIPS * density);
mSelectedIndicatorPaint = new Paint();
} void setCustomTabColorizer(SlidingTabLayout.TabColorizer customTabColorizer) {
mCustomTabColorizer = customTabColorizer;
invalidate();
} void setSelectedIndicatorColors(int... colors) {
// Make sure that the custom colorizer is removed
mCustomTabColorizer = null;
mDefaultTabColorizer.setIndicatorColors(colors);
invalidate();
} 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 SlidingTabLayout.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);
} /**
* 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 SlidingTabLayout.TabColorizer {
private int[] mIndicatorColors; @Override
public final int getIndicatorColor(int position) {
return mIndicatorColors[position % mIndicatorColors.length];
} void setIndicatorColors(int... colors) {
mIndicatorColors = colors;
}
}
}

You may choose to move them to a suitable package in your project.Once you have included SlidingTabLayout.java andSlidingTabStrip.java files within your app, you can use the SlidingTabLayout in your layout file to display tabs. Your layout file will have tabs on the top and a ViewPager on the bottom as shown below:

ViewPager With FragmentPagerAdapter

https://github.com/codepath/android_guides/wiki/Google-Play-Style-Tabs-using-SlidingTabLayout