OnTabListener在Android中不起作用

Question

I have run into a problem where when I put the name of a fragment, an error occurs as shows:

Type mismatch: cannot convert from Fragment1 to Fragment

Here is my MainActivity.java code:

package com.example.currencyconverter;

import java.io.IOException;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.text.DecimalFormat;

import org.apache.http.client.HttpClient;
import org.apache.http.client.ResponseHandler;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.BasicResponseHandler;
import org.apache.http.impl.client.DefaultHttpClient;

import android.app.ActionBar;
import android.app.ActionBar.Tab;
import android.app.Activity;
import android.app.Fragment;
import android.app.FragmentTransaction;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.Bundle;
import android.os.StrictMode;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity implements OnClickListener {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    ActionBar actionBar = getActionBar();
    actionBar.setSubtitle("Created By Rohit Nandakumar");
    actionBar.setTitle("Currency Converter"); 
    actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

    ActionBar.Tab Frag1 = actionBar.newTab().setText("Converter");
    ActionBar.Tab Frag2 = actionBar.newTab().setText("Currencies");

    Fragment fragment1 = new Fragment1();
    Fragment fragment2 = new Fragment2();

    Frag1.setTabListener(new MyTabsListener(fragment1));
    Frag2.setTabListener(new MyTabsListener(fragment2));

    actionBar.addTab(Frag1);
    actionBar.addTab(Frag2);
}

Here is my Fragment1 code:

package com.example.currencyconverter;

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class Fragment1 {
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    return inflater.inflate(R.layout.activity_main, container, false);
}

}

This is my Fragment 2 code:

package com.example.currencyconverter;

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class Fragment2 {
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    return inflater.inflate(R.layout.activity_first, container, false);
}

}

Here is the MyTabsListener.java file:

package com.example.currencyconverter;

import android.app.ActionBar.Tab;
import android.app.ActionBar.TabListener;
import android.app.ActionBar;
import android.app.Fragment;
import android.app.FragmentTransaction;

public class MyTabsListener implements TabListener {

    public Fragment fragment;

    public MyTabsListener(Fragment fragment) {
        this.fragment = fragment;
    }

    @Override
    public void onTabReselected(Tab tab, FragmentTransaction ft) {
        // TODO Auto-generated method stub
    }

    @Override
    public void onTabSelected(Tab tab, FragmentTransaction ft) {
        // TODO Auto-generated method stub
        ft.replace(R.id.fragment_container, fragment);

    }

    @Override
    public void onTabUnselected(Tab tab, FragmentTransaction ft) {
        // TODO Auto-generated method stub

    }



}

The problem occurs right here in the MainActivity.java file:

Fragment fragment1 = new Fragment1();
Fragment fragment2 = new Fragment2();

The

new Fragment1();

and the

new Fragment2();

part of the code is highlighted and it says:

Type mismatch: cannot convert from Fragment1 to Fragment

What is happening? What am i doing wrong? Any help is greatly appreciated.

Answer 1

Your Fragment1 and Fragment2 classes do not extend Fragment :

public Fragment1 extends Fragment {
    ...
}

Answer 2

Try replacing

Fragment fragment1 = new Fragment1();
Fragment fragment2 = new Fragment2();

to

Fragment1 fragment1 = new Fragment1();
Fragment2 fragment2 = new Fragment2();