TabHost_新的Activity仍然持有Tab_Tab内跳转新的Activity

 

TabHost_新的Activity仍然持有Tab_Tab内跳转新的Activity

 

问题：

  TabHost内的一个页面例如tab3，如果startActivity跳入新页面，则新页面是没有Tab栏的。而很多需求和蹩脚的产品非得这么搞（而且tab栏居然不能是样式不变的）。

 

解决方法：

用ActivityGroup，以LocalActivityManager（而这个类已经被deprecated了，参考这里官方文档）来管理当前的页面的显示和历史页面的切换。

 

其他问题：

Tab内很多页面跳转，有些如果不作处理，又会跳出本Tab。

比如tab3的页面A，跳入页面B，跳入页面C，C此时已经和页面A失去了联系，如果再调准，怎么能够仍在页面A的group管理范围内呢？

可以作singleton处理，或者其他共享方式，比如static的共享变量，虽然说这样不太好。

 

import java.util.ArrayList;

import android.app.Activity;
import android.app.ActivityGroup;
import android.app.LocalActivityManager;

import android.content.Intent;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.Window;

/*
 * The purpose of this Activity is to manage the activities in a tab.
 * Note: Child Activities can handle Key Presses before they are seen here.
 * @author Eric Harlow
 */
public class TabGroupActivity extends ActivityGroup {

    private ArrayList<String> mIdList;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);       
        if (mIdList == null) mIdList = new ArrayList<String>();
    }

    /*
     * This is called when a child activity of this one calls its finish method. 
     * This implementation calls {@link LocalActivityManager#destroyActivity} on the child activity
     * and starts the previous activity.
     * If the last child activity just called finish(),this activity (the parent),
     * calls finish to finish the entire group.
     */
  @Override
  public void finishFromChild(Activity child) {
      LocalActivityManager manager = getLocalActivityManager();
      int index = mIdList.size()-1;

      if (index < 1) {
              finish();
              return;
          }

          manager.destroyActivity(mIdList.get(index), true);
          mIdList.remove(index);
          index--;
          String lastId = mIdList.get(index);
          Intent lastIntent = manager.getActivity(lastId).getIntent();
          Window newWindow = manager.startActivity(lastId, lastIntent);
          setContentView(newWindow.getDecorView());
  }

  /*
   * Starts an Activity as a child Activity to this.
   * @param Id Unique identifier of the activity to be started.
   * @param intent The Intent describing the activity to be started.
   * @throws android.content.ActivityNotFoundException.
   */
  public void startChildActivity(String Id, Intent intent) {     
      Window window = getLocalActivityManager().startActivity(Id,intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP));
      if (window != null) {
          mIdList.add(Id);
          setContentView(window.getDecorView()); 
      }    
  }

  /*
   * The primary purpose is to prevent systems before android.os.Build.VERSION_CODES.ECLAIR
   * from calling their default KeyEvent.KEYCODE_BACK during onKeyDown.
   */
  @Override
  public boolean onKeyDown(int keyCode, KeyEvent event) {
      if (keyCode == KeyEvent.KEYCODE_BACK) {
          //preventing default implementation previous to android.os.Build.VERSION_CODES.ECLAIR
          return true;
      }
      return super.onKeyDown(keyCode, event);
  }

  /*
   * Overrides the default implementation for KeyEvent.KEYCODE_BACK 
   * so that all systems call onBackPressed().
   */
  @Override
  public boolean onKeyUp(int keyCode, KeyEvent event) {
      if (keyCode == KeyEvent.KEYCODE_BACK) {
          onBackPressed();
          return true;
      }
      return super.onKeyUp(keyCode, event);
  }

  /*
   * If a Child Activity handles KeyEvent.KEYCODE_BACK.
   * Simply override and add this method.
   */
  @Override
  public void  onBackPressed  () {
      int length = mIdList.size();
      if ( length >=1) {
          Activity current = getLocalActivityManager().getActivity(mIdList.get(length-1));
          current.finish();
      }
  }
}

 

此类的使用 方法：

public class Tab_BookCityActivity extends TabGroupActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        startChildActivity("BookCityActivity", new Intent(this, BookCityActivity.class));
    }
}

 

 

参考资料：

Use Android ActivityGroup within TabHost to show different Activity

how to Keep Tabhost when start other activity