本文章的导航栏代码参考了viewpagerindicator的实现。本文叙述的是之前版本的qq或微信中,底部的图标加文字的导航栏的实现。
本例子依赖viewpagerindicator的两个接口:IconPagerAdapter及PageIndicator。这两个接口的方法如下:
package com.viewpagerindicator; public interface IconPagerAdapter { int getIconResId(int index); int getCount(); }
package com.viewpagerindicator; import android.support.v4.view.ViewPager; public interface PageIndicator extends ViewPager.OnPageChangeListener { void setViewPager(ViewPager view); void setViewPager(ViewPager view, int initialPosition); void setCurrentItem(int item); void setOnPageChangeListener(ViewPager.OnPageChangeListener listener); void notifyDataSetChanged(); }
下面先上两张效果图。
在图中,上面的内容区域是viewpager,下面的是导航栏indicator。点击导航栏可以切换上面的页面,当然,滑动上面的页面下面的导航栏也可以切换。
接着说一下它的实现。类的代码不复杂,大部分参照了viewpagerindicator中的TabPageIndicator类来实现,不过在这里我继承的是LinearLayout,代码如下:
package com.githang.navigatordemo; import android.content.Context; import android.support.v4.view.PagerAdapter; import android.support.v4.view.ViewPager; import android.util.AttributeSet; import android.view.View; import android.view.ViewGroup; import android.widget.ImageView; import android.widget.LinearLayout; import android.widget.TextView; import com.viewpagerindicator.IconPagerAdapter; import com.viewpagerindicator.PageIndicator; import static android.view.ViewGroup.LayoutParams.MATCH_PARENT; /** * User: Geek_Soledad(msdx.android@qq.com) * Date: 2014-08-27 * Time: 09:20 * FIXME */ public class IconTabPageIndicator extends LinearLayout implements PageIndicator { /** * Title text used when no title is provided by the adapter. */ private static final CharSequence EMPTY_TITLE = ""; /** * Interface for a callback when the selected tab has been reselected. */ public interface OnTabReselectedListener { /** * Callback when the selected tab has been reselected. * * @param position Position of the current center item. */ void onTabReselected(int position); } private Runnable mTabSelector; private final View.OnClickListener mTabClickListener = new View.OnClickListener() { public void onClick(View view) { TabView tabView = (TabView) view; final int oldSelected = mViewPager.getCurrentItem(); final int newSelected = tabView.getIndex(); mViewPager.setCurrentItem(newSelected); if (oldSelected == newSelected && mTabReselectedListener != null) { mTabReselectedListener.onTabReselected(newSelected); } } }; private final LinearLayout mTabLayout; private ViewPager mViewPager; private ViewPager.OnPageChangeListener mListener; private int mSelectedTabIndex; private OnTabReselectedListener mTabReselectedListener; private int mTabWidth; public IconTabPageIndicator(Context context) { this(context, null); } public IconTabPageIndicator(Context context, AttributeSet attrs) { super(context, attrs); setHorizontalScrollBarEnabled(false); mTabLayout = new LinearLayout(context, null, R.attr.tabPageIndicator); addView(mTabLayout, new ViewGroup.LayoutParams(MATCH_PARENT, MATCH_PARENT)); } public void setOnTabReselectedListener(OnTabReselectedListener listener) { mTabReselectedListener = listener; } @Override public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { final int widthMode = View.MeasureSpec.getMode(widthMeasureSpec); final boolean lockedExpanded = widthMode == View.MeasureSpec.EXACTLY; final int childCount = mTabLayout.getChildCount(); if (childCount > 1 && (widthMode == MeasureSpec.EXACTLY || widthMode == MeasureSpec.AT_MOST)) { mTabWidth = MeasureSpec.getSize(widthMeasureSpec) / childCount; } else { mTabWidth = -1; } final int oldWidth = getMeasuredWidth(); super.onMeasure(widthMeasureSpec, heightMeasureSpec); final int newWidth = getMeasuredWidth(); if (lockedExpanded && oldWidth != newWidth) { // Recenter the tab display if we're at a new (scrollable) size. setCurrentItem(mSelectedTabIndex); } } private void animateToTab(final int position) { final View tabView = mTabLayout.getChildAt(position); if (mTabSelector != null) { removeCallbacks(mTabSelector); } mTabSelector = new Runnable() { public void run() { final int scrollPos = tabView.getLeft() - (getWidth() - tabView.getWidth()) / 2; mTabSelector = null; } }; post(mTabSelector); } @Override public void onAttachedToWindow() { super.onAttachedToWindow(); if (mTabSelector != null) { // Re-post the selector we saved post(mTabSelector); } } @Override public void onDetachedFromWindow() { super.onDetachedFromWindow(); if (mTabSelector != null) { removeCallbacks(mTabSelector); } } private void addTab(int index, CharSequence text, int iconResId) { final TabView tabView = new TabView(getContext()); tabView.mIndex = index; tabView.setOnClickListener(mTabClickListener); tabView.setText(text); if (iconResId > 0) { tabView.setIcon(iconResId); } mTabLayout.addView(tabView, new LinearLayout.LayoutParams(0, MATCH_PARENT, 1)); } @Override public void onPageScrollStateChanged(int arg0) { if (mListener != null) { mListener.onPageScrollStateChanged(arg0); } } @Override public void onPageScrolled(int arg0, float arg1, int arg2) { if (mListener != null) { mListener.onPageScrolled(arg0, arg1, arg2); } } @Override public void onPageSelected(int arg0) { setCurrentItem(arg0); if (mListener != null) { mListener.onPageSelected(arg0); } } @Override public void setViewPager(ViewPager view) { if (mViewPager == view) { return; } if (mViewPager != null) { mViewPager.setOnPageChangeListener(null); } final PagerAdapter adapter = view.getAdapter(); if (adapter == null) { throw new IllegalStateException("ViewPager does not have adapter instance."); } mViewPager = view; view.setOnPageChangeListener(this); notifyDataSetChanged(); } public void notifyDataSetChanged() { mTabLayout.removeAllViews(); PagerAdapter adapter = mViewPager.getAdapter(); IconPagerAdapter iconAdapter = null; if (adapter instanceof IconPagerAdapter) { iconAdapter = (IconPagerAdapter) adapter; } final int count = adapter.getCount(); for (int i = 0; i < count; i++) { CharSequence title = adapter.getPageTitle(i); if (title == null) { title = EMPTY_TITLE; } int iconResId = 0; if (iconAdapter != null) { iconResId = iconAdapter.getIconResId(i); } addTab(i, title, iconResId); } if (mSelectedTabIndex > count) { mSelectedTabIndex = count - 1; } setCurrentItem(mSelectedTabIndex); requestLayout(); } @Override public void setViewPager(ViewPager view, int initialPosition) { setViewPager(view); setCurrentItem(initialPosition); } @Override public void setCurrentItem(int item) { if (mViewPager == null) { throw new IllegalStateException("ViewPager has not been bound."); } mSelectedTabIndex = item; mViewPager.setCurrentItem(item); final int tabCount = mTabLayout.getChildCount(); for (int i = 0; i < tabCount; i++) { final View child = mTabLayout.getChildAt(i); final boolean isSelected = (i == item); child.setSelected(isSelected); if (isSelected) { animateToTab(item); } } } @Override public void setOnPageChangeListener(ViewPager.OnPageChangeListener listener) { mListener = listener; } private class TabView extends LinearLayout { private int mIndex; private ImageView mImageView; private TextView mTextView; public TabView(Context context) { super(context, null, R.attr.tabView); View view = View.inflate(context, R.layout.tab_view, null); mImageView = (ImageView) view.findViewById(R.id.tab_image); mTextView = (TextView) view.findViewById(R.id.tab_text); this.addView(view); } @Override public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); // Re-measure if we went beyond our maximum size. if (mTabWidth > 0) { super.onMeasure(MeasureSpec.makeMeasureSpec(mTabWidth, MeasureSpec.EXACTLY), heightMeasureSpec); } } public void setText(CharSequence text) { mTextView.setText(text); } public void setIcon(int resId) { if (resId > 0) { mImageView.setImageResource(resId); } } public int getIndex() { return mIndex; } } }
public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { final int widthMode = View.MeasureSpec.getMode(widthMeasureSpec); final boolean lockedExpanded = widthMode == View.MeasureSpec.EXACTLY; final int childCount = mTabLayout.getChildCount(); if (childCount > 1 && (widthMode == MeasureSpec.EXACTLY || widthMode == MeasureSpec.AT_MOST)) { mTabWidth = MeasureSpec.getSize(widthMeasureSpec) / childCount; } else { mTabWidth = -1; } final int oldWidth = getMeasuredWidth(); super.onMeasure(widthMeasureSpec, heightMeasureSpec); final int newWidth = getMeasuredWidth(); if (lockedExpanded && oldWidth != newWidth) { // Recenter the tab display if we're at a new (scrollable) size. setCurrentItem(mSelectedTabIndex); } }
然后重写TabView的onMeasure方法,当mTabWidth大于0时,设置它的宽度为mTabWidth,如下:
@Override public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); // Re-measure if we went beyond our maximum size. if (mTabWidth > 0) { super.onMeasure(MeasureSpec.makeMeasureSpec(mTabWidth, MeasureSpec.EXACTLY), heightMeasureSpec); } }
在这里的TabView中,我则直接使用布局文件来写,上面是一个ImageView,下面是一个TextView,代码如下(tab_view.xml):
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="match_parent" android:background="@android:color/white" android:gravity="center_horizontal" android:addStatesFromChildren="true" android:layout_height="wrap_content"> <ImageView android:id="@+id/tab_image" android:layout_width="27dp" android:layout_marginTop="2dp" android:adjustViewBounds="true" android:contentDescription="@null" android:layout_height="27dp" /> <TextView android:id="@+id/tab_text" android:layout_marginTop="2dp" android:gravity="center_horizontal|bottom" android:padding="2dp" android:layout_width="wrap_content" android:textColor="@color/tab_text_selector" android:textSize="12sp" android:layout_height="match_parent" /> </LinearLayout>
private class TabView extends LinearLayout { public TabView(Context context) { super(context, null, R.attr.tabView); View view = View.inflate(context, R.layout.tab_view, null); mImageView = (ImageView) view.findViewById(R.id.tab_image); mTextView = (TextView) view.findViewById(R.id.tab_text); this.addView(view); } }
在IconTabPageIndicator的构造方法当中,你同样可以看到导航栏的容器——mTabLayout,同样是通过属性来创建的。如下代码:
public IconTabPageIndicator(Context context, AttributeSet attrs) { super(context, attrs); setHorizontalScrollBarEnabled(false); mTabLayout = new LinearLayout(context, null, R.attr.tabPageIndicator); addView(mTabLayout, new ViewGroup.LayoutParams(MATCH_PARENT, MATCH_PARENT)); }
<?xml version="1.0" encoding="utf-8"?> <resources> <declare-styleable name="TabView"> <attr name="tabPageIndicator" format="reference" /> <attr name="tabView" format="reference" /> </declare-styleable> </resources>
但仅仅这样还是不够的,因为我们只是声明了两个属性,并没有设定属性的具体内容,所以我们还需要在styles.xml文件当中设置我们的主题,代码如下(styles.xml):
<style name="AppTheme" parent="Theme.AppCompat.Light"> <item name="tabView">@style/TabView</item> <item name="tabPageIndicator">@style/TabIndicator</item> </style> <style name="TabIndicator"/> <style name="TabView"> <item name="android:addStatesFromChildren">true</item> <item name="android:orientation">vertical</item> <item name="android:gravity">bottom|center_horizontal</item> <item name="android:layout_width">0dp</item> <item name="android:background">@android:color/white</item> <item name="android:layout_height">match_parent</item> </style>
到此,我们的IconTabPageIndicator就实现好了。接下来在我们的程序中使用它:
activity的布局文件(activity_my.xml):
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".MyActivity"> <com.githang.navigatordemo.IconTabPageIndicator android:id="@+id/indicator" android:layout_alignParentBottom="true" android:layout_width="match_parent" android:layout_height="wrap_content"/> <android.support.v4.view.ViewPager android:layout_above="@id/indicator" android:id="@+id/view_pager" android:layout_width="match_parent" android:layout_height="match_parent"/> </RelativeLayout>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" android:gravity="center" android:paddingBottom="@dimen/activity_vertical_margin" android:background="#eee" tools:context=".MyActivity"> <TextView android:id="@+id/text" android:textAppearance="@android:style/TextAppearance.Large" android:layout_width="wrap_content" android:layout_height="wrap_content"/> </RelativeLayout>
MyActivity类的代码:
package com.githang.navigatordemo; 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 com.viewpagerindicator.IconPagerAdapter; import java.util.ArrayList; import java.util.List; public class MyActivity extends FragmentActivity { private ViewPager mViewPager; private IconTabPageIndicator mIndicator; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_my); initViews(); } private void initViews() { mViewPager = (ViewPager) findViewById(R.id.view_pager); mIndicator = (IconTabPageIndicator) findViewById(R.id.indicator); List<BaseFragment> fragments = initFragments(); FragmentAdapter adapter = new FragmentAdapter(fragments, getSupportFragmentManager()); mViewPager.setAdapter(adapter); mIndicator.setViewPager(mViewPager); } private List<BaseFragment> initFragments() { List<BaseFragment> fragments = new ArrayList<BaseFragment>(); BaseFragment userFragment = new BaseFragment(); userFragment.setTitle("用户"); userFragment.setIconId(R.drawable.tab_user_selector); fragments.add(userFragment); BaseFragment noteFragment = new BaseFragment(); noteFragment.setTitle("记事本"); noteFragment.setIconId(R.drawable.tab_record_selector); fragments.add(noteFragment); BaseFragment contactFragment = new BaseFragment(); contactFragment.setTitle("联系人"); contactFragment.setIconId(R.drawable.tab_user_selector); fragments.add(contactFragment); BaseFragment recordFragment = new BaseFragment(); recordFragment.setTitle("记录"); recordFragment.setIconId(R.drawable.tab_record_selector); fragments.add(recordFragment); return fragments; } class FragmentAdapter extends FragmentPagerAdapter implements IconPagerAdapter { private List<BaseFragment> mFragments; public FragmentAdapter(List<BaseFragment> fragments, FragmentManager fm) { super(fm); mFragments = fragments; } @Override public Fragment getItem(int i) { return mFragments.get(i); } @Override public int getIconResId(int index) { return mFragments.get(index).getIconId(); } @Override public int getCount() { return mFragments.size(); } @Override public CharSequence getPageTitle(int position) { return mFragments.get(position).getTitle(); } } }
package com.githang.navigatordemo; import android.os.Bundle; import android.support.annotation.Nullable; import android.support.v4.app.Fragment; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.TextView; /** * User: Geek_Soledad(msdx.android@qq.com) * Date: 2014-08-27 * Time: 09:01 * FIXME */ public class BaseFragment extends Fragment { private String title; private int iconId; public String getTitle() { return title; } public void setTitle(String title) { this.title = title; } public int getIconId() { return iconId; } public void setIconId(int iconId) { this.iconId = iconId; } @Override public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) { View view = inflater.inflate(R.layout.fragment, null, false); TextView textView = (TextView) view.findViewById(R.id.text); textView.setText(getTitle()); return view; } }
原文地址:http://blog.csdn.net/maosidiaoxian/article/details/38864679