Android实现网易新闻客户端效果

下面来简单实现一下网易新闻客户端左右切换的效果，当然实际项目上肯定不能这样写，还有很多需要优化的地方。

activity_main.xml

1. <?xml version="1.0" encoding="utf-8"?>  
2. <TabHost xmlns:android="http://schemas.android.com/apk/res/android"  
3. android:id="@android:id/tabhost"  
4. android:layout_width="match_parent"  
5. android:layout_height="match_parent" >  
6.   
7. <LinearLayout  
8. android:layout_width="match_parent"  
9. android:layout_height="match_parent"  
10. android:orientation="vertical" >  
11.   
12. <TabWidget  
13. android:id="@android:id/tabs"  
14. android:layout_width="match_parent"  
15. android:layout_height="wrap_content"  
16. android:orientation="horizontal" />  
17.   
18. <FrameLayout  
19. android:id="@android:id/tabcontent"  
20. android:layout_width="match_parent"  
21. android:layout_height="match_parent"/>  
22. <FrameLayout   
23. android:id="@+id/real_tabcontent"  
24. android:layout_width="match_parent"  
25. android:layout_height="0dp"  
26. android:layout_weight="0"/> -->  
27. </LinearLayout>  
28.   
29. </TabHost>

Java实现逻辑

​

package com.jackie.neteasedemo;

import android.os.Bundle;
import android.app.Activity;
import android.app.Fragment;
import android.app.FragmentTransaction;
import android.content.Context;
import android.text.TextUtils;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewConfiguration;
import android.widget.ImageView;
import android.widget.TabHost;
import android.widget.TabHost.OnTabChangeListener;

public class MainActivity extends Activity {

  private TabHost mTabHost;
  private Fragment mFragment;

  private float startX = 0;
  private float endX = 0;
  private int touchSlop;

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

    mTabHost = (TabHost) findViewById(android.R.id.tabhost);
    mTabHost.setup();
    mTabHost.setOnTabChangedListener(new OnTabChangeListener() {

      @Override
      public void onTabChanged(String tabId) {
        System.out.println("current tabid=" + tabId);
        FragmentTransaction ft = getFragmentManager()
            .beginTransaction();
        if (TextUtils.equals("first", tabId)) {
          // add/replace fragment first
          mFragment = new Fragment1();
          System.out.println("Load Frament1");
        } else if (TextUtils.equals("second", tabId)) {
          // add/replace fragment second
          mFragment = new Fragment2();
          System.out.println("Load Frament2");
        } else if (TextUtils.equals("third", tabId)) {
          // add/replace fragment third
          mFragment = new Fragment3();
          System.out.println("Load Frament3");
        }
        ft.replace(android.R.id.tabcontent, mFragment);
        ft.commit();
      }
    });

    mTabHost.addTab(mTabHost.newTabSpec("first").setIndicator("First")
        .setContent(new DummyTabFactory(this)));
    mTabHost.addTab(mTabHost.newTabSpec("second").setIndicator("Second")
        .setContent(new DummyTabFactory(this)));    
    mTabHost.addTab(mTabHost.newTabSpec("third").setIndicator("Third")
        .setContent(new DummyTabFactory(this)));
    
    touchSlop = ViewConfiguration.get(this).getScaledTouchSlop(); //默认是8，能够根据不同分辨率适配而改变
  }

  @Override
  public boolean onTouchEvent(MotionEvent event) {
    switch (event.getAction()) {
    case MotionEvent.ACTION_DOWN:
      startX = event.getX();
      break;
    case MotionEvent.ACTION_UP:
      endX = event.getX();
      break;
    default:
      break;
    }

    if (endX - startX > touchSlop) { // 向右滑动
      if (TextUtils.equals(mTabHost.getCurrentTabTag(), "third")) {
        mFragment = new Fragment2();
        mTabHost.setCurrentTabByTag("second");
      } else if (TextUtils.equals(mTabHost.getCurrentTabTag(), "second")) {
        mFragment = new Fragment1();
        mTabHost.setCurrentTabByTag("first");
      }

      FragmentTransaction ft = getFragmentManager().beginTransaction();
      ft.replace(android.R.id.tabcontent, mFragment);
      ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
      ft.commit();
    } else if (Math.abs(endX - startX) > touchSlop) { // 向左滑动
      if (TextUtils.equals(mTabHost.getCurrentTabTag(), "first")) {
        mFragment = new Fragment2();
        mTabHost.setCurrentTabByTag("second");
      } else if (TextUtils.equals(mTabHost.getCurrentTabTag(), "second")) {
        mFragment = new Fragment3();
        mTabHost.setCurrentTabByTag("third");
      }

      FragmentTransaction ft = getFragmentManager().beginTransaction();
      ft.replace(android.R.id.tabcontent, mFragment);
      ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
      ft.commit();
    }
    return super.onTouchEvent(event);
  }

  private class DummyTabFactory implements TabHost.TabContentFactory {
    private Context context;

    public DummyTabFactory(Context ctx) {
      this.context = ctx;
    }

    @Override
    public View createTabContent(String tag) {// 创建宽高均为0的view
      View v = new ImageView(context);
      v.setMinimumWidth(0);
      v.setMinimumHeight(0);
      return v;
    }
  }
}

效果如下：