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

2022-02-10 09:40:50

效果图：

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

<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:id="@+id/fragment"  
        android:layout_width="match_parent"
    	android:layout_height="match_parent">	
    </FrameLayout>
    
    
 </LinearLayout>

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：

<menu xmlns:android="http://schemas.android.com/apk/res/android" >

    <item
        android:id="@+id/action_add"
        android:orderInCategory="100"
        android:showAsAction="never"
        android:title="添加"/>

    <item
        android:id="@+id/action_dele"
        android:orderInCategory="100"
        android:showAsAction="never"
        android:title="删除"/>
</menu>

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