TabHost中，同一个页面向下级页面跳转时的解决方案

  android里面，TabHost确实应用很广泛，也很好用，但就是有一个问题，同一个Tab中的页面如果有下一级页面的话，如果用startActivity来跳转的话，会跳出TabHost,即Tab就不会显示了，这样确实很不方便，项目用到了，想跳到下级页面的时候还显示Tab，找了很多方案都不能解决，后来在国外的网站上面看到了别人的解决方案，确实很好用。

  第一步是添加一个这样的类

/**

 * 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.

     * 

     * 只适用于2.0及以上版本

     */

    @Override

    public void onBackPressed() {

        int length = mIdList.size();

        if (length > 1) {

            Activity current = getLocalActivityManager().getActivity(

                    mIdList.get(length - 1));

            current.finish();

        }else{

            System.exit(0);

        }

    }

}

 

  第二步是点击每一个Tab都会跳到相应的页面，让这些页面继承上面这个类

public class Tab1 extends TabGroupActivity {



    @Override

    public void onCreate(Bundle savedInstanceState) {

        // TODO Auto-generated method stub

        super.onCreate(savedInstanceState);

        Intent intent = new Intent(getParent(),HomeActivity.class);

        startChildActivity("HomeActivity", intent);

    }

}

用的时候注意

              Intent intent = new Intent(getParent(),HomeActivity.class);

              startChildActivity("HomeActivity", intent);

这两行就可以了。

这样的问题相信曾经缠绕了很多人，我也是用了很长的时间在找解决方案，希望会帮到你哦