小编Jis*_*hin的帖子

我正在尝试实现Tab Navigation,我有一个扩展Fragment Activity的Container Activity,而这个Activity使用ActionBar创建一个TabView.该应用程序将尝试创建三个选项卡并将它们添加到ActionBar,我想根据TabSelection更改片段.但是发生了错误07-04 12:17:33.534: E/AndroidRuntime(795): Caused by: java.lang.ClassCastException: com.freight.fragments.TruckStatus cannot be cast to android.support.v4.app.Fragment.

TruckActivity.java

package com.freight.activities;

import java.util.Locale;

import com.clacion.freightexchange.R;
import com.clacion.freightexchange.R.drawable;
import com.clacion.freightexchange.R.id;
import com.clacion.freightexchange.R.layout;
import com.clacion.freightexchange.R.menu;
import com.clacion.freightexchange.R.string;
import com.freight.fragments.TruckStatus;

import android.app.ActionBar;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.app.NavUtils;
import android.support.v4.view.ViewPager;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

public class TruckActivity extends FragmentActivity implements
        ActionBar.TabListener {

    /**
     * The {@link …

我正在尝试使用自动表单生成一个Android应用程序 http://labs.makemachine.net/2010/04/android-form-generator/

我一直在阅读很多关于"InstantiationException"的话题,但没有解决我的问题.

这是我的活动

    package com.example.makemachine;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Map;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import android.app.Activity;
import android.content.Context;
import android.util.Log;
import android.view.View;
import android.widget.LinearLayout;
import android.widget.ScrollView;
import android.widget.LinearLayout.LayoutParams;

/**
 * FormActivity allows you to create dynamic form layouts based upon a json schema file. 
 * This class should be sub-classed. 
 * 
 * @author Jeremy Brown
 */
public abstract class FormActivity extends Activity
{
    public static String SCHEMA_KEY_TYPE        = …