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