android - 如何在 fragment 中实现按钮 SetOnClickListener？

Question

我正在做一个小项目，我想使用 slider 菜单。长话短说，我碰巧从某个网站找到了使用抽屉的 slider 菜单的源代码，它在我的设备上运行良好。但是，我对将我以前的 Activity 迁移到此 slider 菜单感到有点困惑，因为它们为 listView 上的每个单独项目使用 fragment 。

为了简单起见，我想迁移一个能够执行 Ping 功能的 Activity 。它的 xml 文件由一个 EditText、一个 Button 和一个用于显示输出的 TextView 组成。

现在我确实设法“成功”将该 Activity 迁移到此 fragment 中。抽屉运行良好，但我卡住了，因为在我点击 ping 按钮后应用程序总是强制关闭。

PS:我还没有更改类名，不好意思

下面是我的代码:

这是我最初的 Ping Activity :

package my.jlm;

import java.io.IOException;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.InetAddress;
import java.net.UnknownHostException;

import android.app.Activity;
import android.os.Bundle;
import android.text.Editable;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;


public class Ping extends Activity {
    EditText edit;
    TextView text;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_ping);
    edit = (EditText)findViewById(R.id.editText1);
    edit.setText("192.168.1.1");
    text = (TextView)findViewById(R.id.textView1);
    Button button = (Button)findViewById(R.id.button1);
    button.setOnClickListener(new View.OnClickListener() {

    @Override
    public void onClick(View v) {
    // TODO Auto-generated method stub

    Editable host = edit.getText();
    try {
    String pingCmd = "ping -c 5 " + host;
    String pingResult = "";
    Runtime r = Runtime.getRuntime();
    Process p = r.exec(pingCmd);
    BufferedReader in = new BufferedReader(new
    InputStreamReader(p.getInputStream()));
    String inputLine;
    while ((inputLine = in.readLine()) != null) {
    System.out.println(inputLine);
    text.setText(inputLine + "\n\n");
    pingResult += inputLine;
    text.setText(pingResult);
    }
    in.close();
    }//try
    catch (IOException e) {
    System.out.println(e);
    }


    }
    });
    }}

这个 FindPeopleFragment.java(这应该是 PingFragment.java)。我认为这是一次成功的尝试，因为 eclipse 没有显示任何红色标记，但如果我错了，请纠正我。

package info.androidhive.slidingmenu;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

import android.app.Fragment;
import android.content.Intent;
import android.os.Bundle;
import android.text.Editable;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;


public class FindPeopleFragment extends Fragment 
        implements OnClickListener
{
        EditText edit;
        TextView text;
        Button button;





    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {

        View rootView = inflater.inflate(R.layout.activity_ping, container, false);


        EditText edit = (EditText) rootView.findViewById(R.id.editText1);
        edit.setText("192.168.1.1");
        text = (TextView) rootView.findViewById(R.id.textView1);
        button = (Button)rootView.findViewById(R.id.button1);
        button.setOnClickListener(onClickListener);





        return rootView;
    }

    @Override
    public void onClick(View v) {
        Editable host = edit.getText();
        try {
        String pingCmd = "ping -c 5 " + host;
        String pingResult = "";
        Runtime r = Runtime.getRuntime();
        Process p = r.exec(pingCmd);
        BufferedReader in = new BufferedReader(new
        InputStreamReader(p.getInputStream()));
        String inputLine;
        while ((inputLine = in.readLine()) != null) {
        System.out.println(inputLine);
        text.setText(inputLine + "\n\n");
        pingResult += inputLine;
        text.setText(pingResult);
        }
        in.close();
        }//try
        catch (IOException e) {
        System.out.println(e);
        }

    }

};;

最后这是我上述项目的 list

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="info.androidhive.slidingmenu"
    android:versionCode="1"
    android:versionName="1.0" >

    <permission
        android:name="my.jlm.permission.MAPS_RECEIVE"
        android:protectionLevel="signature"/>

    <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED"/>
    <uses-permission android:name="museumjakarta.source.permission.MAPS_RECEIVE"/>    
    <uses-permission android:name="android.permission.INTERNET"/>
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
    <uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES"/>
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
    <uses-permission android:name="android.permission.INTERNET"/>
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>


      <uses-permission android:name="android.permission.CALL_PHONE" />
      <uses-permission android:name="android.permission.READ_PHONE_STATE" />

    <uses-sdk
        android:minSdkVersion="11"
        android:targetSdkVersion="17" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="info.androidhive.slidingmenu.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>




    </application>

</manifest>

这是我的 LogCat 错误日志:

03-15 09:07:41.160: E/AndroidRuntime(1267): FATAL EXCEPTION: main
03-15 09:07:41.160: E/AndroidRuntime(1267): Process: info.androidhive.slidingmenu, PID: 1267
03-15 09:07:41.160: E/AndroidRuntime(1267): java.lang.NullPointerException
03-15 09:07:41.160: E/AndroidRuntime(1267):     at info.androidhive.slidingmenu.FindPeopleFragment.onClick(FindPeopleFragment.java:53)
03-15 09:07:41.160: E/AndroidRuntime(1267):     at android.view.View.performClick(View.java:4424)
03-15 09:07:41.160: E/AndroidRuntime(1267):     at android.view.View$PerformClick.run(View.java:18383)
03-15 09:07:41.160: E/AndroidRuntime(1267):     at android.os.Handler.handleCallback(Handler.java:733)
03-15 09:07:41.160: E/AndroidRuntime(1267):     at android.os.Handler.dispatchMessage(Handler.java:95)
03-15 09:07:41.160: E/AndroidRuntime(1267):     at android.os.Looper.loop(Looper.java:137)
03-15 09:07:41.160: E/AndroidRuntime(1267):     at android.app.ActivityThread.main(ActivityThread.java:4998)
03-15 09:07:41.160: E/AndroidRuntime(1267):     at java.lang.reflect.Method.invokeNative(Native Method)
03-15 09:07:41.160: E/AndroidRuntime(1267):     at java.lang.reflect.Method.invoke(Method.java:515)
03-15 09:07:41.160: E/AndroidRuntime(1267):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:777)
03-15 09:07:41.160: E/AndroidRuntime(1267):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:593)
03-15 09:07:41.160: E/AndroidRuntime(1267):     at dalvik.system.NativeStart.main(Native Method)

这里简单说说我的经历:从 Drawer ListView 中单击后，Ping xml 页面显示出来，但是当我单击其中的 Ping 按钮时，应用程序崩溃，导致上述错误日志。帮我解决这个问题，非常感谢。

PS:我正在使用 eclipse adt，因为我无法在我的 AMD 处理器上运行 AS。

编辑:认为这可能有帮助，我将发布此 fragment 的 mainActivity.java:

package info.androidhive.slidingmenu;

import info.androidhive.slidingmenu.adapter.NavDrawerListAdapter;
import info.androidhive.slidingmenu.model.NavDrawerItem;

import java.util.ArrayList;

import android.app.Activity;
import android.app.Fragment;
import android.app.FragmentManager;
import android.content.res.Configuration;
import android.content.res.TypedArray;
import android.os.Bundle;
import android.support.v4.app.ActionBarDrawerToggle;
import android.support.v4.widget.DrawerLayout;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;

public class MainActivity extends Activity {
    private DrawerLayout mDrawerLayout;
    private ListView mDrawerList;
    private ActionBarDrawerToggle mDrawerToggle;

    // nav drawer title
    private CharSequence mDrawerTitle;

    // used to store app title
    private CharSequence mTitle;

    // slide menu items
    private String[] navMenuTitles;
    private TypedArray navMenuIcons;

    private ArrayList<NavDrawerItem> navDrawerItems;
    private NavDrawerListAdapter adapter;

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

        mTitle = mDrawerTitle = getTitle();

        // load slide menu items
        navMenuTitles = getResources().getStringArray(R.array.nav_drawer_items);

        // nav drawer icons from resources
        navMenuIcons = getResources()
                .obtainTypedArray(R.array.nav_drawer_icons);

        mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
        mDrawerList = (ListView) findViewById(R.id.list_slidermenu);

        navDrawerItems = new ArrayList<NavDrawerItem>();

        // adding nav drawer items to array
        // Home
        navDrawerItems.add(new NavDrawerItem(navMenuTitles[0], navMenuIcons.getResourceId(0, -1)));
        // Find People
        navDrawerItems.add(new NavDrawerItem(navMenuTitles[1], navMenuIcons.getResourceId(1, -1)));
        // Photos
        navDrawerItems.add(new NavDrawerItem(navMenuTitles[2], navMenuIcons.getResourceId(2, -1)));
        // Communities, Will add a counter here
        navDrawerItems.add(new NavDrawerItem(navMenuTitles[3], navMenuIcons.getResourceId(3, -1), true, "22"));
        // Pages
        navDrawerItems.add(new NavDrawerItem(navMenuTitles[4], navMenuIcons.getResourceId(4, -1)));
        // What's hot, We  will add a counter here
        navDrawerItems.add(new NavDrawerItem(navMenuTitles[5], navMenuIcons.getResourceId(5, -1), true, "50+"));


        // Recycle the typed array
        navMenuIcons.recycle();

        mDrawerList.setOnItemClickListener(new SlideMenuClickListener());

        // setting the nav drawer list adapter
        adapter = new NavDrawerListAdapter(getApplicationContext(),
                navDrawerItems);
        mDrawerList.setAdapter(adapter);

        // enabling action bar app icon and behaving it as toggle button
        getActionBar().setDisplayHomeAsUpEnabled(true);
        getActionBar().setHomeButtonEnabled(true);

        mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout,
                R.drawable.ic_drawer, //nav menu toggle icon
                R.string.app_name, // nav drawer open - description for accessibility
                R.string.app_name // nav drawer close - description for accessibility
        ) {
            public void onDrawerClosed(View view) {
                getActionBar().setTitle(mTitle);
                // calling onPrepareOptionsMenu() to show action bar icons
                invalidateOptionsMenu();
            }

            public void onDrawerOpened(View drawerView) {
                getActionBar().setTitle(mDrawerTitle);
                // calling onPrepareOptionsMenu() to hide action bar icons
                invalidateOptionsMenu();
            }
        };
        mDrawerLayout.setDrawerListener(mDrawerToggle);

        if (savedInstanceState == null) {
            // on first time display view for first nav item
            displayView(0);
        }
    }

    /**
     * Slide menu item click listener
     * */
    private class SlideMenuClickListener implements
            ListView.OnItemClickListener {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position,
                long id) {
            // display view for selected nav drawer item
            displayView(position);
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // toggle nav drawer on selecting action bar app icon/title
        if (mDrawerToggle.onOptionsItemSelected(item)) {
            return true;
        }
        // Handle action bar actions click
        switch (item.getItemId()) {
        case R.id.action_settings:
            return true;
        default:
            return super.onOptionsItemSelected(item);
        }
    }

    /* *
     * Called when invalidateOptionsMenu() is triggered
     */
    @Override
    public boolean onPrepareOptionsMenu(Menu menu) {
        // if nav drawer is opened, hide the action items
        boolean drawerOpen = mDrawerLayout.isDrawerOpen(mDrawerList);
        menu.findItem(R.id.action_settings).setVisible(!drawerOpen);
        return super.onPrepareOptionsMenu(menu);
    }

    /**
     * Diplaying fragment view for selected nav drawer list item
     * */
    private void displayView(int position) {
        // update the main content by replacing fragments
        Fragment fragment = null;
        switch (position) {
        case 0:
            fragment = new HomeFragment();
            break;
        case 1:
            fragment = new FindPeopleFragment();
            break;
        case 2:
            fragment = new PhotosFragment();
            break;
        case 3:
            fragment = new CommunityFragment();
            break;
        case 4:
            fragment = new PagesFragment();
            break;
        case 5:
            fragment = new WhatsHotFragment();
            break;

        default:
            break;
        }

        if (fragment != null) {
            FragmentManager fragmentManager = getFragmentManager();
            fragmentManager.beginTransaction()
                    .replace(R.id.frame_container, fragment).commit();

            // update selected item and title, then close the drawer
            mDrawerList.setItemChecked(position, true);
            mDrawerList.setSelection(position);
            setTitle(navMenuTitles[position]);
            mDrawerLayout.closeDrawer(mDrawerList);
        } else {
            // error in creating fragment
            Log.e("MainActivity", "Error in creating fragment");
        }
    }

    @Override
    public void setTitle(CharSequence title) {
        mTitle = title;
        getActionBar().setTitle(mTitle);
    }

    /**
     * When using the ActionBarDrawerToggle, you must call it during
     * onPostCreate() and onConfigurationChanged()...
     */

    @Override
    protected void onPostCreate(Bundle savedInstanceState) {
        super.onPostCreate(savedInstanceState);
        // Sync the toggle state after onRestoreInstanceState has occurred.
        mDrawerToggle.syncState();
    }

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        // Pass any configuration change to the drawer toggls
        mDrawerToggle.onConfigurationChanged(newConfig);
    }

}

Answer 1

使用以下代码行:

button = (Button)rootView.findViewById(R.id.button1);
button.setOnClickListener(this); // Best Solution <---
button.setOnClickListener(rootView);

或

button.setOnClickListener(getActivity());

---

然后，您必须调用 onClick() 方法，如下所示:

@Override
public void onClick(View v) {
    switch (v.getId()) {
        case R.id.button1:
            // CODE TO DO
            break;
    }
}

此外，您还可以:

import android.view.View.OnClickListener;

button = (Button) rootView.findViewById(R.id.button1);
button.setOnClickListener(new OnClickListener() {
    public void onClick(View v) {
        // Your Code Lines
    }

编辑

我认为您的代码很好。您唯一需要做的就是添加:button.setOnClickListener(this); 然后，添加 switch OnClick 方法中的 v.getId() 语句。

编辑2

package info.androidhive.slidingmenu;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

import android.app.Fragment;
import android.content.Intent;
import android.os.Bundle;
import android.text.Editable;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;


public class FindPeopleFragment extends Fragment
implements View.OnClickListener {
        EditText edit;
        TextView text;
        Button button;

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {

            View rootView = inflater.inflate(R.layout.activity_ping, container, false);


            EditText edit = (EditText) rootView.findViewById(R.id.editText1);
            edit.setText("192.168.1.1");
            text = (TextView) rootView.findViewById(R.id.textView1);
            button = (Button) rootView.findViewById(R.id.button1);
            button.setOnClickListener(this);

            return rootView;
        }

        @Override
        public void onClick(View v) {

            switch (v.getId()) {
                case R.id.button1:
                    Editable host = edit.getText();
                    try {
                        String pingCmd = "ping -c 5 " + host;
                        String pingResult = "";
                        Runtime r = Runtime.getRuntime();
                        Process p = r.exec(pingCmd);
                        BufferedReader in = new BufferedReader(new InputStreamReader(p.getInputStream()));
                        String inputLine;
                        while ((inputLine = in .readLine()) != null) {
                            System.out.println(inputLine);
                            text.setText(inputLine + "\n\n");
                            pingResult += inputLine;
                            text.setText(pingResult);
                        } in .close();
                    } //try
                    catch (IOException e) {
                        System.out.println(e);
                    }
                    break;
                    case default:
                    log.i("Inf", "there's no click");
                    break;
            }
     }
     }

编辑3

package info.androidhive.slidingmenu;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

import android.app.Fragment;
import android.content.Intent;
import android.os.Bundle;
import android.text.Editable;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;


public class FindPeopleFragment extends Fragment
implements OnClickListener {
        EditText edit;
        TextView text;
        Button button;
        Editable Edit2 ;

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {

            View rootView = inflater.inflate(R.layout.activity_ping, container, false);


            EditText edit = (EditText) rootView.findViewById(R.id.editText1);
            edit.setText("192.168.1.1");
            Edit2 = edit.getText();
            text = (TextView) rootView.findViewById(R.id.textView1);
            button = (Button) rootView.findViewById(R.id.button1);
            button.setOnClickListener(this);

            return rootView;
        }



        @Override
        public void onClick(View v) {

            switch (v.getId()) {
                case R.id.button1:


                    try {
                        String pingCmd = "ping -c 5 " + Edit2;
                        String pingResult = "";
                        Runtime r = Runtime.getRuntime();
                        Process p = r.exec(pingCmd);
                        BufferedReader in = new BufferedReader(new InputStreamReader(p.getInputStream()));
                        String inputLine;
                        while ((inputLine = in .readLine()) != null) {
                            System.out.println(inputLine);
                            text.setText(inputLine + "\n\n");
                            pingResult += inputLine;
                            text.setText(pingResult);
                        } in .close();
                    } //try
                    catch (IOException e) {
                        System.out.println(e);
                    }
                    break;


            }
        }
     }