ViewPager+Fragment实现Tabhost，动态添加删除Fragment，可供第三方使用的类库

小咪咪 2023-10-16 20:59 15阅读 0赞

效果图：

![Center][]

代码实现：ViewPager+Fragment实现了Tabhost，动态添加删除Fragment，暴露三个可重写的多态方法供第三方调用：

protected Fragment getFragmentAt(int pos) {
    		return null;
    	}
    
    	protected View getIndicatorAt(int pos) {
    		return null;
    	}
    
    	protected int getItemsCount() {
    		return 0;
    	}

项目第三方类库测试用的主MainActivity.java

import java.util.ArrayList;
    import java.util.Random;
    import android.graphics.Color;
    import android.os.Bundle;
    import android.support.v4.app.Fragment;
    import android.support.v4.app.FragmentActivity;
    import android.support.v4.app.FragmentTransaction;
    import android.util.Log;
    import android.view.Gravity;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.TextView;
    
    public class MainActivity extends FragmentActivity {
    
    	@Override
    	protected void onCreate(Bundle savedInstanceState) {
    		super.onCreate(savedInstanceState);
    		setContentView(R.layout.activity_main);
    
    		Fragment newFragment = new HowToUseThisView();
    		FragmentTransaction transaction = getSupportFragmentManager()
    				.beginTransaction();
    		transaction.replace(R.id.fragment, newFragment);
    		transaction.commit();
    	}
    
    	public static class HowToUseThisView extends ViewPagerAndFragmentTabHost {
    
    		private ArrayList<Fragment> mArrayList;
    		private int id = 0;
    
    		@Override
    		public void onCreate(Bundle savedInstanceState) {
    			super.onCreate(savedInstanceState);
    			mArrayList = new ArrayList<Fragment>();
    		}
    
    		@Override
    		protected Fragment getFragmentAt(int pos) {
    
    			Fragment fragment = null;
    
    			try {
    				fragment = mArrayList.get(pos);
    			} catch (Exception e) {
    				Log.d(this.getClass().getName(), "队列中不存在，创建新Fragment");
    			}
    
    			if (fragment == null) {
    				fragment = new TestFragment();
    				((TestFragment) fragment).setID(id++);
    
    				mArrayList.add(fragment);
    			}
    
    			return fragment;
    		}
    
    		@Override
    		protected View getIndicatorAt(int pos) {
    
    			// 简单期间，先就用TextView作为底部Tab的选项卡
    			TextView tv = new TextView(getActivity());
    			tv.setGravity(Gravity.CENTER);
    			tv.setText("Tab " + pos);
    			return tv;
    		}
    
    		@Override
    		protected int getItemsCount() {
    			// 假设随机生成此数目的一组Fragment和Tab选项卡
    			Random rand = new Random();
    			return rand.nextInt(5);
    		}
    
    		@Override
    		public void onStart() {
    			super.onStart();
    			super.notifyDataSetChanged();
    		}
    	}
    
    	//
    	// 仅仅用于测试的Fragment，在ViewPager中加载
    	//
    	public static class TestFragment extends Fragment {
    
    		private int id;
    
    		public void setID(int id) {
    			this.id = id;
    		}
    
    		public int getID() {
    			return id;
    		}
    
    		@Override
    		public View onCreateView(LayoutInflater inflater, ViewGroup container,
    				Bundle savedInstanceState) {
    
    			TextView tv = new TextView(getActivity());
    			String str = "序号: " + getID();
    			tv.setTextColor(Color.LTGRAY);
    			tv.setText(str);
    			tv.setTextSize(50);
    			tv.setGravity(Gravity.CENTER);
    
    			return tv;
    		}
    	}
    }

MainActivity.java需要的activity\_main.xml

可供第三方调用的ViewPagerAndFragmentTabHost.java类，重点。

import java.util.ArrayList;
    import java.util.HashMap;
    import java.util.UUID;
    
    import android.graphics.Color;
    import android.os.Bundle;
    import android.support.v4.app.Fragment;
    import android.support.v4.app.FragmentManager;
    import android.support.v4.app.FragmentPagerAdapter;
    import android.support.v4.app.FragmentStatePagerAdapter;
    import android.support.v4.view.ViewPager;
    import android.util.Log;
    import android.view.LayoutInflater;
    import android.view.Menu;
    import android.view.MenuInflater;
    import android.view.MenuItem;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.LinearLayout;
    import android.widget.LinearLayout.LayoutParams;
    
    public class ViewPagerAndFragmentTabHost extends Fragment {
    
    	private MyFragmentPagerAdapter mPagerAdapter;
    	private ViewPager mViewPager;
    	private LinearLayout mLinearLayout;
    
    	private ArrayList<HashMap<String, Object>> mArrayList = null;
    	private final String FRAGMENT = "fragment_tag", TAB = "tab_tag",
    			UUID_TAG = "uuid_tag";
    
    	@Override
    	public void onCreate(Bundle savedInstanceState) {
    		super.onCreate(savedInstanceState);
    		setHasOptionsMenu(true);
    		mArrayList = new ArrayList<HashMap<String, Object>>();
    	}
    
    	@Override
    	public View onCreateView(LayoutInflater inflater, ViewGroup container,
    			Bundle savedInstanceState) {
    		View mView = inflater.inflate(R.layout.viewpager_fragment, null);
    
    		mViewPager = (ViewPager) mView.findViewById(R.id.viewpager);
    		mLinearLayout = (LinearLayout) mView
    				.findViewById(R.id.indicator_LinearLayout);
    
    		mPagerAdapter = new MyFragmentPagerAdapter(getFragmentManager());
    		mViewPager.setAdapter(mPagerAdapter);
    		mViewPager
    				.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
    
    					@Override
    					public void onPageSelected(int pos) {
    						set(pos);
    					}
    
    					@Override
    					public void onPageScrolled(int arg0, float arg1, int arg2) {
    
    					}
    
    					@Override
    					public void onPageScrollStateChanged(int arg0) {
    
    					}
    				});
    
    		return mView;
    	}
    
    	@Override
    	public void onStart() {
    		super.onStart();
    
    		// 初始化选择第一项
    		if (mPagerAdapter.getCount() > 0) {
    			set(0);
    		}
    
    		for (int i = 0; i < getItemsCount(); i++) {
    			add(getFragmentAt(i), getIndicatorAt(i));
    		}
    	}
    
    	public void notifyDataSetChanged() {
    		mPagerAdapter.notifyDataSetChanged();
    	}
    
    	protected Fragment getFragmentAt(int pos) {
    		return null;
    	}
    
    	protected View getIndicatorAt(int pos) {
    		return null;
    	}
    
    	protected int getItemsCount() {
    		return 0;
    	}
    
    	private void add(Fragment fragment, View indicatorView) {
    
    		HashMap<String, Object> map = new HashMap<String, Object>();
    
    		UUID uuid = UUID.randomUUID();
    		map.put(UUID_TAG, uuid);
    
    		Bundle args = new Bundle();
    		fragment.setArguments(args);
    		map.put(FRAGMENT, fragment);
    
    		indicatorView.setBackgroundColor(Color.GRAY);
    
    		LayoutParams params = new LayoutParams(LayoutParams.WRAP_CONTENT,
    				LayoutParams.MATCH_PARENT, 1);
    		indicatorView.setTag(uuid);
    		mLinearLayout.addView(indicatorView, params);
    		indicatorView.setOnClickListener(new View.OnClickListener() {
    
    			@Override
    			public void onClick(View v) {
    				setIndicatorViewSelected(v);
    			}
    		});
    
    		map.put(TAB, indicatorView);
    
    		mArrayList.add(map);
    	}
    
    	private void setIndicatorViewSelected(View v) {
    		UUID uuid = (UUID) v.getTag();
    
    		for (int i = 0; i < mArrayList.size(); i++) {
    			HashMap<String, Object> map = mArrayList.get(i);
    			if (uuid == map.get(UUID_TAG)) {
    				set(i);
    			}
    		}
    	}
    
    	private final void delete(int pos) {
    		UUID uuid = (UUID) mArrayList.get(pos).get(UUID_TAG);
    		View view = mLinearLayout.findViewWithTag(uuid);
    		mLinearLayout.removeView(view);
    
    		mArrayList.remove(pos);
    		mPagerAdapter.notifyDataSetChanged();
    	}
    
    	private void setIndicatorViewSelectedColor(int pos) {
    
    		for (int i = 0; i < mArrayList.size(); i++) {
    			HashMap<String, Object> map = mArrayList.get(i);
    			View view = (View) map.get(TAB);
    
    			if (i == pos)
    				view.setBackgroundColor(Color.RED);
    			else
    				view.setBackgroundColor(Color.GRAY);
    		}
    	}
    
    	private void set(int pos) {
    		mViewPager.setCurrentItem(pos, true);
    		setIndicatorViewSelectedColor(pos);
    	}
    
    	private class MyFragmentPagerAdapter extends FragmentStatePagerAdapter {
    
    		public MyFragmentPagerAdapter(FragmentManager fm) {
    			super(fm);
    		}
    
    		@Override
    		public Fragment getItem(int pos) {
    			return (Fragment) mArrayList.get(pos).get(FRAGMENT);
    		}
    
    		@Override
    		public int getItemPosition(Object object) {
    			return FragmentPagerAdapter.POSITION_NONE;
    		}
    
    		@Override
    		public int getCount() {
    			return mArrayList.size();
    		}
    
    		@Override
    		public void notifyDataSetChanged() {
    			super.notifyDataSetChanged();
    			Log.d(this.getClass().getName(), "notifyDataSetChanged");
    		}
    	}
    
    	private void onActionAdd() {
    		add(getFragmentAt(mPagerAdapter.getCount()),
    				getIndicatorAt(mPagerAdapter.getCount()));
    		mPagerAdapter.notifyDataSetChanged();
    	}
    
    	private void onActionDelete() {
    		delete(mViewPager.getCurrentItem());
    		set(mViewPager.getCurrentItem());
    	}
    
    	@Override
    	public boolean onOptionsItemSelected(MenuItem item) {
    
    		switch (item.getItemId()) {
    		case R.id.action_add:
    			onActionAdd();
    			break;
    
    		case R.id.action_dele:
    			onActionDelete();
    			break;
    
    		default:
    			break;
    		}
    
    		return super.onOptionsItemSelected(item);
    	}
    
    	@Override
    	public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
    		inflater.inflate(R.menu.main, menu);
    	}
    }

ViewPagerAndFragmentTabHost.java需要的viewpager\_fragment.xml :

<?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"
        >
        
        
       <FrameLayout 
        android:layout_weight="1"
        android:layout_width="match_parent"
        android:layout_height="match_parent" >
    
        <android.support.v4.view.ViewPager
            android:id="@+id/viewpager"
            android:layout_width="match_parent"
            android:layout_height="match_parent" />
    
    </FrameLayout>
       
    
        <LinearLayout
            android:id="@+id/indicator_LinearLayout"
            android:layout_width="match_parent"
            android:layout_height="50dip"
            android:orientation="horizontal" >
        </LinearLayout>
    
    </LinearLayout>

res\\menu\\main.xml文件：

[Center]: https://img-blog.csdn.net/20150210112439241?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvemhhbmdwaGls/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center