Android 利用ViewPager實現底部圓點導航左右滑動效果以及Fragment頁面切換

上一篇博文我們介紹了利用ViewPager和Fragment實現頂部滑塊左右滑動效果，具體參考(http://blog.csdn.net/a123demi/article/details/39480385)。

而本篇博文將實例講解利用ViewPager實現底部圓點導航左右滑動效果，以及被滑動界面實現監聽事件，同時通過Fragment實現頁面的切換。

對於該效果的實現，需要實現以下幾個問題：

1. 底部圓點加載和實現方法？

2. 怎樣實現左右滑動效果？

3. 被滑動頁面，怎樣實現監聽事件？

4. 滑動頁面怎樣和其他頁面切換？

一.實現效果如下

二.具體代碼如下

1.XML布局文件

1>主布局activity_main.xml

 

 

 

注意：id為fragment_switch_ll的LinearLayout是為Fragment切換預留的。

 

2>Fragment頁面切換布局fragment_other.xml

 

3>左右滑動布局fragment_switch.xml(Fragment頁面切換中的另一個布局)

 

 

 

 

注意：id為viewGroup的LinearLayout是實現圓點ImageView的父容器。

 

4>左右滑動界面布局view_one.xml(本例帶監聽事件)，view_one.xml，view_one.xml(只給出其中一個，其他類似)

 

 

 

2.java代碼實現

 

1>主函數MainActivity.java

 

package com.example.pagerdemo;

import android.app.Activity;
import android.app.Fragment;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class MainActivity extends Activity {

	private Button fgSwitchBtn;
	private boolean isSwitch = true;//true:進入SwitchFragment,false:進入OtherFragment

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);

		fgSwitchBtn = (Button) this.findViewById(R.id.fragment_switch_btn);
		
		fgSwitchBtn.setOnClickListener(new OnClickListener() {

			@Override
			public void onClick(View v) {
				// TODO Auto-generated method stub
				switchFragment();
			}

		});
	}
	
	@Override
	public void onResume(){
		super.onResume();
		switchFragment();
	}
	
	/**
	 * Fragment界面切換
	 */
	private void switchFragment(){
		Fragment fragment = null;
		if(isSwitch){
			fragment = new SwitchFragment();
		}else{
			fragment = new OtherFragment();
		}
		isSwitch = !isSwitch;
		FragmentTransaction ft = this.getFragmentManager().beginTransaction();
		ft.replace(R.id.fragment_switch_ll, fragment);
		ft.commitAllowingStateLoss();
	}

}

 

 

注意：switchFragment()實現了Fragment的切換，解決了問題4.

2>Fragment切換頁面OtherFragment.java

 

package com.example.pagerdemo;

import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class OtherFragment extends Fragment {
	@Override
	public View onCreateView(LayoutInflater inflater, ViewGroup container,
			Bundle savedInstanceState) {
		super.onCreateView(inflater, container, savedInstanceState);
		View otherView = inflater.inflate(R.layout.fragment_other, container,
				false);
		return otherView;
	}
}

3>Fragment切換界面及滑動界面SwitchFragment.java

 

 

package com.example.pagerdemo;

import java.util.ArrayList;
import java.util.List;

import android.app.Activity;
import android.app.Fragment;
import android.content.Context;
import android.os.Bundle;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.View.OnClickListener;
import android.view.ViewGroup.LayoutParams;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.Toast;

public class SwitchFragment extends Fragment {

	private LinearLayout groupViewLl;
	private ViewPager viewPager;

	private ImageView[] imageViews;
	private ImageView imageView;
	private Button btn;

	private List viewList = new ArrayList();
	private LayoutInflater mInflater;

	public View onCreateView(LayoutInflater inflater, ViewGroup container,
			Bundle savedInstanceState) {
		super.onCreateView(inflater, container, savedInstanceState);
		View switchView = inflater.inflate(R.layout.fragment_switch, container,
				false);
		mInflater = inflater;

		groupViewLl = (LinearLayout) switchView.findViewById(R.id.viewGroup);
		viewPager = (ViewPager) switchView.findViewById(R.id.viewPager);

		return switchView;

	}

	@Override
	public void onActivityCreated(Bundle savedInstanceState) {
		super.onActivityCreated(savedInstanceState);
		/**
		 * 將需要滑動的View加入到viewList
		 */
		View oneView = mInflater.inflate(R.layout.view_one, null);
		viewList.add(oneView);
		viewList.add(mInflater.inflate(R.layout.view_two, null));
		viewList.add(mInflater.inflate(R.layout.view_three, null));

		/**
		 * 定義個圓點滑動導航ImageView，根據View的個數而定
		 */
		imageViews = new ImageView[viewList.size()];
		//滑動界面事件監聽，解決問題3
		btn = (Button) oneView.findViewById(R.id.btn);
		btn.setOnClickListener(new OnClickListener() {

			@Override
			public void onClick(View v) {
				Toast.makeText(SwitchFragment.this.getActivity(),
						this is view_one, Toast.LENGTH_SHORT).show();
			}

		});
		//動態生成ImageView，實現底部圓點(圓點數量根據左右滑動View而確定)，解決問題1	
		for (int i = 0; i < viewList.size(); i++) {
			imageView = new ImageView(this.getActivity());
			imageView.setLayoutParams(new LayoutParams(20, 20));
			imageView.setPadding(20, 0, 20, 0);
			imageViews[i] = imageView;

			if (i == 0) {
				// 默認選中第一張圖片
				imageViews[i]
						.setBackgroundResource(R.drawable.page_indicator_focused);
			} else {
				imageViews[i].setBackgroundResource(R.drawable.page_indicator);
			}

			groupViewLl.addView(imageViews[i]);
		}
		//通過滑動適配器實現滑動效果，解決問題2
		viewPager.setAdapter(new MyPagerAdapter(viewList));
		viewPager.setOnPageChangeListener(new SwitchPageChangeListener());
	}

	@Override
	public void onResume() {
		super.onResume();
	}

	// 指引頁面更改事件監聽器，設置圓點滑動時的背景變化。
	class SwitchPageChangeListener implements OnPageChangeListener {
		@Override
		public void onPageScrollStateChanged(int arg0) {
		}

		@Override
		public void onPageScrolled(int arg0, float arg1, int arg2) {
		}

		@Override
		public void onPageSelected(int arg0) {
			for (int i = 0; i < imageViews.length; i++) {
				imageViews[arg0]
						.setBackgroundResource(R.drawable.page_indicator_focused);

				if (arg0 != i) {
					imageViews[i]
							.setBackgroundResource(R.drawable.page_indicator);
				}
			}
		}
	}

}

 

 

注意：SwitchPageChangeListener實現了底部導航圓點滑動變色的效果。

4>滑動適配器MyPagerAdapter.java

 

package com.example.pagerdemo;

import java.util.List;

import android.os.Parcelable;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.View;

public class MyPagerAdapter extends PagerAdapter {
	private List viewList;
	public MyPagerAdapter(List viewList){
		this.viewList = viewList;
	}

	@Override
	public int getCount() {
		return viewList.size();
	}

	@Override
	public boolean isViewFromObject(View arg0, Object arg1) {
		return arg0 == arg1;
	}

	@Override
	public int getItemPosition(Object object) {
		return super.getItemPosition(object);
	}

	@Override
	public void destroyItem(View arg0, int arg1, Object arg2) {
		((ViewPager) arg0).removeView(viewList.get(arg1));
	}

	@Override
	public Object instantiateItem(View arg0, int arg1) {
		((ViewPager) arg0).addView(viewList.get(arg1));
		return viewList.get(arg1);
	}

	@Override
	public void restoreState(Parcelable arg0, ClassLoader arg1) {
	}

	@Override
	public Parcelable saveState() {
		return null;
	}

	@Override
	public void startUpdate(View arg0) {
	}

	@Override
	public void finishUpdate(View arg0) {
	}

}

注意：適配器通過添加或刪除View來實現頁面滑動時，頁面變化的效果