仿网易腾讯新闻主界面功能

来源：互联网发布：淘宝客api2.0接入流程编辑：程序博客网时间：2024/04/29 12:09

最近项目中有一个需求，类似网易、腾讯新闻客户端的频道管理界面，可以对频道进行排序、增加、删除功能。网上也找了相关的资料，但是发现他们都有同一个问题，就是改变频道的顺序后，对应频道的内容并不会改变。这是FragmentPagerAdapter的notifyDataSetChanged()方法没有效果导致的，知道这个原因，下面提供解决方法。这个主界面的源码：

    public class MainActivity extends FragmentActivity implements View.OnClickListener {    private TabLayout mNewsTab;    private ViewPager mNewsVp;    /** 调整返回的RESULTCODE */    public final static int CHANNELRESULT = 10;    private ArrayList<ChannelItem> mUserChannelList;    //    private List<String> titleArray;    private List<NewsFragment> mListFragment;    private NewsVpAdapter mNewsVpAdapter;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        //去掉系统标题        requestWindowFeature(Window.FEATURE_NO_TITLE);        setContentView(R.layout.activity_main);        findViewById(R.id.more_columns_tv).setOnClickListener(this);        initView();    }    private void initView() {        mNewsTab = (TabLayout) findViewById(R.id.news_tab);        mNewsVp = (ViewPager) findViewById(R.id.news_vp);        findViewById(R.id.more_columns_tv).setOnClickListener(this);        mListFragment = new ArrayList<>();        //设置TabLayout的模式        mNewsTab.setTabMode(TabLayout.MODE_SCROLLABLE);        mUserChannelList = ((ArrayList<ChannelItem>) ChannelManage.getManage(AppContext.getApp().getSQLHelper()).getUserChannel());        intData();        mNewsVpAdapter = new NewsVpAdapter(getSupportFragmentManager(),mListFragment,mUserChannelList);        mNewsVp.setAdapter(mNewsVpAdapter);        //TabLayout加载viewpager        mNewsTab.setupWithViewPager(mNewsVp);    }    private void intData() {        for (ChannelItem channelItem : mUserChannelList) {            NewsFragment newsFragment = new NewsFragment();            Bundle bundle = new Bundle();            //设置tag，区分不同频道的Fragment            bundle.putSerializable("tag", channelItem);            newsFragment.setArguments(bundle);            mListFragment.add(newsFragment);        }        //为TabLayout添加tab名称        initColumn();    }    private void initColumn() {        for (int i = 0; i < mUserChannelList.size(); i++) {            mNewsTab.addTab(mNewsTab.newTab().setText(mUserChannelList.get(i).getName()));        }    }    @Override    public void onClick(View v) {        //打开频道管理Activity        Intent intent_channel = new  Intent(this, ChannelActivity.class);        startActivityForResult(intent_channel, CHANNELRESULT);    }    @Override    public void onActivityResult(int requestCode, int resultCode, Intent data) {        switch (requestCode) {            case CHANNELRESULT:                //频道发生改变后，重新设置Fragment                if(resultCode == CHANNELRESULT){                    selectTab(0);                    setChangelView();                }                break;            default:                break;        }        super.onActivityResult(requestCode, resultCode, data);    }    private void selectTab(int position) {        mNewsTab.getTabAt(position).select();    }    private void setChangelView() {        mListFragment.clear();        mNewsTab.removeAllTabs();        mUserChannelList = ((ArrayList<ChannelItem>) ChannelManage.getManage(AppContext.getApp().getSQLHelper()).getUserChannel());        List<Integer> integers = mNewsVpAdapter.getIntegers();        for (int i = 0; i < mUserChannelList.size(); i++) {            ChannelItem channelItem = mUserChannelList.get(i);            if (integers.contains(i)) {//当Adapter上position为i的Fragment已经被初始化，就给他设置一个需要重新初始化的标记               channelItem.setNeedUpdate(true);            } else {                channelItem.setNeedUpdate(false);            }            NewsFragment newsFragment = new NewsFragment();            Bundle bundle = new Bundle();            bundle.putSerializable("tag", channelItem);            newsFragment.setArguments(bundle);            newsFragment.setIsUpdate(true);            mListFragment.add(newsFragment);        }        initColumn();        selectTab(0);        mNewsVpAdapter.setData(mListFragment,mUserChannelList);        mNewsVp.setCurrentItem(0, false);        mNewsTab.setScrollPosition(0, 0, true);        mNewsTab.scrollTo(0,0);        Log.e("size",mNewsTab.getTabCount()+"tab");        // 根据Tab的长度动态设置TabLayout的模式       dynamicSetTabLayoutMode(mNewsTab);    }    /**     * 根据Tab合起来的长度动态修改tab的模式     *     * @param tabLayout TabLayout     */    public static void dynamicSetTabLayoutMode(TabLayout tabLayout) {        int tabTotalWidth = 0;        for (int i = 0; i < tabLayout.getChildCount(); i++) {            final View view = tabLayout.getChildAt(i);            view.measure(0, 0);            tabTotalWidth += view.getMeasuredWidth();        }        if (tabTotalWidth <= getScreenSize(tabLayout.getContext()).x) {            tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);            tabLayout.setTabMode(TabLayout.MODE_FIXED);        } else {            tabLayout.setTabGravity(TabLayout.GRAVITY_CENTER);            tabLayout.setTabMode(TabLayout.MODE_SCROLLABLE);        }    }    /**     * 获取屏幕尺寸     *     * @param context 上下文     * @return 屏幕尺寸像素值，下标为0的值为宽，下标为1的值为高     */    public static Point getScreenSize(Context context) {        // 获取屏幕宽高        WindowManager wm = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);        Point screenSize = new Point();        wm.getDefaultDisplay().getSize(screenSize);        return screenSize;    }}

频道管理Activity的源码：

    public class ChannelActivity extends Activity implements OnItemClickListener, View.OnClickListener {    public static String TAG = "ChannelActivity";    /**     * 用户栏目的GRIDVIEW     */    private DragGrid userGridView;    /**     * 其它栏目的GRIDVIEW     */    private OtherGridView otherGridView;    /**     * 用户栏目对应的适配器，可以拖动     */    DragAdapter userAdapter;    /**     * 其它栏目对应的适配器     */    OtherAdapter otherAdapter;    /**     * 其它栏目列表     */    ArrayList<ChannelItem> otherChannelList = new ArrayList<ChannelItem>();    /**     * 用户栏目列表     */    ArrayList<ChannelItem> userChannelList = new ArrayList<ChannelItem>();    /**     * 是否在移动，由于这边是动画结束后才进行的数据更替，设置这个限制为了避免操作太频繁造成的数据错乱。     */    boolean isMove = false;    /**     * 手势监听     */    GestureDetector mGestureDetector;    /**     * 是否需要监听手势关闭功能     */    private boolean mNeedBackGesture = false;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        //去掉系统标题        requestWindowFeature(Window.FEATURE_NO_TITLE);        setContentView(R.layout.activity_channel);        initGestureDetector();        initView();        initData();    }    private void initGestureDetector() {        if (mGestureDetector == null) {            mGestureDetector = new GestureDetector(getApplicationContext(),                    new BackGestureListener(this));        }    }    @Override    public boolean dispatchTouchEvent(MotionEvent ev) {        // TODO Auto-generated method stub        if (mNeedBackGesture) {            return mGestureDetector.onTouchEvent(ev) || super.dispatchTouchEvent(ev);        }        return super.dispatchTouchEvent(ev);    }    /**     * 初始化数据     */    private void initData() {        userChannelList = ((ArrayList<ChannelItem>) ChannelManage.getManage(AppContext.getApp().getSQLHelper()).getUserChannel());        otherChannelList = ((ArrayList<ChannelItem>) ChannelManage.getManage(AppContext.getApp().getSQLHelper()).getOtherChannel());        userAdapter = new DragAdapter(this, userChannelList);        userGridView.setAdapter(userAdapter);        otherAdapter = new OtherAdapter(this, otherChannelList);        otherGridView.setAdapter(otherAdapter);        //设置GRIDVIEW的ITEM的点击监听        otherGridView.setOnItemClickListener(this);        userGridView.setOnItemClickListener(this);    }    /**     * 初始化布局     */    private void initView() {        userGridView = (DragGrid) findViewById(R.id.userGridView);        otherGridView = (OtherGridView) findViewById(R.id.otherGridView);        findViewById(R.id.title_bar).findViewById(R.id.back).setOnClickListener(this);    }    /**     * GRIDVIEW对应的ITEM点击监听接口     */    @Override    public void onItemClick(AdapterView<?> parent, final View view, final int position, long id) {        //如果点击的时候，之前动画还没结束，那么就让点击事件无效        if (isMove) {            return;        }        switch (parent.getId()) {            case R.id.userGridView:                //position为 0，1 的不可以进行任何操作//          if (position != 0 && position != 1) {                if (position != 0) {                    final ImageView moveImageView = getView(view);                    if (moveImageView != null) {                        TextView newTextView = (TextView) view.findViewById(R.id.text_item);                        final int[] startLocation = new int[2];                        newTextView.getLocationInWindow(startLocation);                        final ChannelItem channel = ((DragAdapter) parent.getAdapter()).getItem(position);//获取点击的频道内容                        otherAdapter.setVisible(false);                        //添加到最后一个                        otherAdapter.addItem(channel);                        new Handler().postDelayed(new Runnable() {                            public void run() {                                try {                                    int[] endLocation = new int[2];                                    //获取终点的坐标                                    otherGridView.getChildAt(otherGridView.getLastVisiblePosition()).getLocationInWindow(endLocation);                                    MoveAnim(moveImageView, startLocation, endLocation, channel, userGridView);                                    userAdapter.setRemove(position);                                } catch (Exception localException) {                                }                            }                        }, 50L);                    }                }                break;            case R.id.otherGridView:                final ImageView moveImageView = getView(view);                if (moveImageView != null) {                    TextView newTextView = (TextView) view.findViewById(R.id.text_item);                    final int[] startLocation = new int[2];                    newTextView.getLocationInWindow(startLocation);                    final ChannelItem channel = ((OtherAdapter) parent.getAdapter()).getItem(position);                    userAdapter.setVisible(false);                    //添加到最后一个                    userAdapter.addItem(channel);                    new Handler().postDelayed(new Runnable() {                        public void run() {                            try {                                int[] endLocation = new int[2];                                //获取终点的坐标                                userGridView.getChildAt(userGridView.getLastVisiblePosition()).getLocationInWindow(endLocation);                                MoveAnim(moveImageView, startLocation, endLocation, channel, otherGridView);                                otherAdapter.setRemove(position);                            } catch (Exception localException) {                            }                        }                    }, 50L);                }                break;            default:                break;        }    }    /**     * 点击ITEM移动动画     *     * @param moveView     * @param startLocation     * @param endLocation     * @param moveChannel     * @param clickGridView     */    private void MoveAnim(View moveView, int[] startLocation, int[] endLocation, final ChannelItem moveChannel,                          final GridView clickGridView) {        int[] initLocation = new int[2];        //获取传递过来的VIEW的坐标        moveView.getLocationInWindow(initLocation);        //得到要移动的VIEW,并放入对应的容器中        final ViewGroup moveViewGroup = getMoveViewGroup();        final View mMoveView = getMoveView(moveViewGroup, moveView, initLocation);        //创建移动动画        TranslateAnimation moveAnimation = new TranslateAnimation(                startLocation[0], endLocation[0], startLocation[1],                endLocation[1]);        moveAnimation.setDuration(300L);//动画时间        //动画配置        AnimationSet moveAnimationSet = new AnimationSet(true);        moveAnimationSet.setFillAfter(false);//动画效果执行完毕后，View对象不保留在终止的位置        moveAnimationSet.addAnimation(moveAnimation);        mMoveView.startAnimation(moveAnimationSet);        moveAnimationSet.setAnimationListener(new AnimationListener() {            @Override            public void onAnimationStart(Animation animation) {                isMove = true;            }            @Override            public void onAnimationRepeat(Animation animation) {            }            @Override            public void onAnimationEnd(Animation animation) {                moveViewGroup.removeView(mMoveView);                // instanceof 方法判断2边实例是不是一样，判断点击的是DragGrid还是OtherGridView                if (clickGridView instanceof DragGrid) {                    otherAdapter.setVisible(true);                    otherAdapter.notifyDataSetChanged();                    userAdapter.remove();                } else {                    userAdapter.setVisible(true);                    userAdapter.notifyDataSetChanged();                    otherAdapter.remove();                }                isMove = false;            }        });    }    /**     * 获取移动的VIEW，放入对应ViewGroup布局容器     *     * @param viewGroup     * @param view     * @param initLocation     * @return     */    private View getMoveView(ViewGroup viewGroup, View view, int[] initLocation) {        int x = initLocation[0];        int y = initLocation[1];        viewGroup.addView(view);        LinearLayout.LayoutParams mLayoutParams = new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);        mLayoutParams.leftMargin = x;        mLayoutParams.topMargin = y;        view.setLayoutParams(mLayoutParams);        return view;    }    /**     * 创建移动的ITEM对应的ViewGroup布局容器     */    private ViewGroup getMoveViewGroup() {        ViewGroup moveViewGroup = (ViewGroup) getWindow().getDecorView();        LinearLayout moveLinearLayout = new LinearLayout(this);        moveLinearLayout.setLayoutParams(new LinearLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));        moveViewGroup.addView(moveLinearLayout);        return moveLinearLayout;    }    /**     * 获取点击的Item的对应View，     *     * @param view     * @return     */    private ImageView getView(View view) {        view.destroyDrawingCache();        view.setDrawingCacheEnabled(true);        Bitmap cache = Bitmap.createBitmap(view.getDrawingCache());        view.setDrawingCacheEnabled(false);        ImageView iv = new ImageView(this);        iv.setImageBitmap(cache);        return iv;    }    /**     * 退出时候保存选择后数据库的设置     */    private void saveChannel() {        ChannelManage.getManage(AppContext.getApp().getSQLHelper()).deleteAllChannel();        ChannelManage.getManage(AppContext.getApp().getSQLHelper()).saveUserChannel(userAdapter.getChannnelLst());        ChannelManage.getManage(AppContext.getApp().getSQLHelper()).saveOtherChannel(otherAdapter.getChannnelLst());    }    @Override    public void onClick(View v) {        saveChannel();        if (userAdapter.isListChanged()) {            Intent intent = new Intent(getApplicationContext(), MainActivity.class);            setResult(MainActivity.CHANNELRESULT, intent);            finish();            Log.d(TAG, "数据发生改变");        } else {//            super.onBackPressed();        }        finish();    }    /**     * 返回手势监听接口     */    public class BackGestureListener implements GestureDetector.OnGestureListener {        ChannelActivity activity;        public BackGestureListener(ChannelActivity activity) {            this.activity = activity;        }        @Override        public boolean onDown(MotionEvent e) {            // TODO Auto-generated method stub            return false;        }        @Override        public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,                               float velocityY) {            // TODO Auto-generated method stub            return false;        }        @Override        public void onLongPress(MotionEvent e) {            // TODO Auto-generated method stub        }        @Override        public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX,                                float distanceY) {            if ((e2.getX() - e1.getX()) > 100 && Math.abs(e1.getY() - e2.getY()) < 60) {                activity.onBackPressed();                return true;            }            return false;        }        @Override        public void onShowPress(MotionEvent e) {            // TODO Auto-generated method stub        }        @Override        public boolean onSingleTapUp(MotionEvent e) {            // TODO Auto-generated method stub            return false;        }    }}

当你更新里fragment List集合后调用fragmentpageadpater的notifyDataSetChanged方法时发现数据根本就没有刷新。通过对fragmentpageadapter的源码查看你会在instantiateItem方法里面发现这一段：

    // Do we already have this fragment?        String name = makeFragmentName(container.getId(), position);        Fragment fragment = mFragmentManager.findFragmentByTag(name);        if (fragment != null) {            if (DEBUG) Log.v(TAG, "Attaching item #" + position + ": f=" + fragment);            mCurTransaction.attach(fragment);        } else {            fragment = getItem(position);            if (DEBUG) Log.v(TAG, "Adding item #" + position + ": f=" + fragment);            mCurTransaction.add(container.getId(), fragment,                    makeFragmentName(container.getId(), position));        }

原来他会先去FragmentManager里面去查找有没有相关的fragment如果有就直接使用如果没有才会触发fragmentpageadapter的getItem方法获取一个fragment。所以你更新的fragmentList集合是没有作用的，解决方法是在instantiateItem方法里作文章，具体请看源码：

    public class NewsVpAdapter extends FragmentPagerAdapter {    private List<NewsFragment> list_fragment; //fragment列表    private List<ChannelItem> channelItems; //tab名的列表    private FragmentManager fm;    public boolean fragmentsUpdateFlag;    /**保存已经被初始化的Fragment所在的position*/    private List<Integer> integers = new ArrayList<>();    public List<Integer> getIntegers() {        return integers;    }    public void setIntegers(List<Integer> integers) {        this.integers = integers;    }    public NewsVpAdapter(FragmentManager fm, List<NewsFragment> list_fragment, List<ChannelItem> channelItems) {        super(fm);        this.list_fragment = list_fragment;        this.channelItems = channelItems;        this.fm = fm;    }    public void setData(List<NewsFragment> list_fragment, List<ChannelItem> channelItems) {        this.list_fragment = list_fragment;        this.channelItems = channelItems;        fragmentsUpdateFlag = true;        notifyDataSetChanged();    }    @Override    public int getCount() {        return list_fragment.size();    }    @Override    public int getItemPosition(Object object) {        return POSITION_NONE;    }    //此方法用来显示tab上的名字    @Override    public CharSequence getPageTitle(int position) {        return channelItems.get(position).getName();    }    int count;    @Override    public Fragment getItem(int position) {        return list_fragment.get(position);    }    @Override    public Object instantiateItem(ViewGroup container, int position) {        if (!integers.contains(position)) {//如果这个positionFragment上的没有被初始化，就把这个position添加到集合中            integers.add(position);        }        //得到缓存的fragment        NewsFragment itemFragment = (NewsFragment) super.instantiateItem(container, position);        ChannelItem channelItem = channelItems.get(position);        //得到tag❶，这点很重要        String tag = itemFragment.getTag();        if (channelItem.getNeedUpdate() && integers.contains(position)) {            //如果这个fragment需要更新            FragmentTransaction ft = fm.beginTransaction();            //得到tag，这点很重要            ft.remove(itemFragment);            //移除旧的fragment            itemFragment = (NewsFragment) list_fragment.get(position);            //添加新fragment时必须用前面获得的tag，这点很重要            ft.add(container.getId(), itemFragment, tag);            ft.attach(itemFragment);            ft.commitAllowingStateLoss();            channelItem.setNeedUpdate(false);        }        return itemFragment;    }}

代码注释得很清楚了，主要思路就是用新的fragment替换FragmentManager里缓存的旧的fragment，重点解释❶的地方，

    String name = makeFragmentName(container.getId(), position);    Fragment fragment = mFragmentManager.findFragmentByTag(name);

说明fragmentpageadapter内部是用tag识别fragment的，并且有它自己的一套算法用于生成tag，所以我们这里必须用它生成的tag来添加新的fragment,否则fragmentpageadapter就无法识别这个新的fragment。通过channelItem.getNeedUpdate()得到的boolean类型来标识哪个fragment需要更新。[DEMO下载](http://download.csdn.net/detail/run_forrest_run/9722482)[DEMO apk下载](http://download.csdn.net/detail/run_forrest_run/9722517)

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