Question

我在我的应用程序中有tabhost，在我的第一个活动中有一个Listview就在那里。现在我滚动并点击listview时调用了子活动。现在，当我从secondActivity回到第一个活动时listview滚动到首先..实际上我希望该列表保持在我点击进入secondActivity的那个位置..我正在使用tabgroupActivity。这是TabgroupActivity类。

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;

        Log.v("onm", "My size"+mIdList.size());
        Log.v("onm", "My index====>>"+index);

        if (index < 1)
        {
            Log.v("click", "back click Event for Finish child if condition");
            finish();
            return;
        }

        try
        {
            Log.v("click", "back click Event for Finish child====>>>"+mIdList.get(index));
            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());
        }
        catch (Exception e)
        {
            Log.v("log", "trick");
            finish();
        }
    }

    /**
     * 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_NO_HISTORY));
        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.
     */
    public void onBackPressed() 
    {
        int length = mIdList.size();
        if (length > 1)
        {
            Log.v("click", "back click Event");
            Activity current = getLocalActivityManager().getActivity(mIdList.get(length - 1));
            current.finish();
        }
    }
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) 
    {
        // TODO Auto-generated method stub
        super.onActivityResult(requestCode, resultCode, data);
    }
}

Answer 1

package com.android.workingwithtabs;

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;

@SuppressWarnings("deprecation")
public class WorkoutTabGroupActivity extends ActivityGroup {

private ArrayList<String> mIdList;

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

@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
        finish();
        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();
    }
}
}

Tabhost中的活动和它的子活动问题

1 个答案: