android - 如何在选项卡活动中创建子活动

Question

我使用 tabHost 在我的应用程序中创建了 4 个选项卡，它工作正常。当我单击我的第一个选项卡时，它将加载相应的 xml 页面并显示一些详细信息。在该页面中有一个按钮，当我单击该按钮时，它将使用 Intent 加载另一个活动。我的问题是如何在同一个选项卡中显示该活动？

Answer 1

你必须使用这个类

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;

public class TabActivityGroup 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();
        }
    }
}

将此类扩展到另一个活动，如下所示

import android.content.Intent;
import android.os.Bundle;
import android.util.Log;

public class InterMediateActivity extends TabActivityGroup{
    String TabID;
    String TabName;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        TabID=getIntent().getStringExtra("TabID");
        TabName=getIntent().getStringExtra("TabName");
        Log.i("Tab from intermediate",""+TabID+"   "+TabName);
        filterTabs(TabID);
    }
    private void filterTabs(String TabID)
    {
              startChildActivity("Options", new Intent(this,HomePage.class));


    }



}

而不是直接从选项卡调用内部活动，首先导航到InterMediateActivity

如下

Intent intent = new Intent(this, InterMediateActivity.class);
            intent.putExtra("TabID", item.elementAt(0));
            intent.putExtra("TabName", item.elementAt(1));
            specTab.setContent(intent);

            mTabHost.addTab(specTab);