Fragment 和 FragmentList 不显示 Android Studio
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【中文标题】Fragment 和 FragmentList 不显示 Android Studio【英文标题】：Fragment and FragmentList doesn't display Android Studio 【发布时间】：2015-06-28 20:05:26 【问题描述】：我想用 FragmentActivity 实现 Tab 栏列表。我的目标是 API 14 (4.0)。我的应用工作正常，但标签栏列表没有出现...我不知道我做错了什么...感谢您的帮助！
MainActivity.java：
import android.app.ActionBar;
import android.app.FragmentTransaction;
import android.content.Intent;
import android.annotation.TargetApi;
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.content.Context;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.AsyncTask;
import android.os.Build;
import android.support.v4.app.FragmentActivity;
import android.support.v4.view.ViewPager;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.text.html;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.Window;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import com.squareup.okhttp.Call;
import com.squareup.okhttp.Callback;
import com.squareup.okhttp.OkHttpClient;
import com.squareup.okhttp.Request;
import com.squareup.okhttp.Response;
import org.json.JSONException;
import org.json.JSONObject;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import butterknife.ButterKnife;
import butterknife.InjectView;
import static android.location.Location.convert;
public class MainActivity extends ActionBarActivity implements
ActionBar.TabListener
public static final String TAG = MainActivity.class.getSimpleName();
SectionsPagerAdapter mSectionsPagerAdapter;
/**
* The @link android.support.v4.view.ViewPager that will host the section contents.
*/
ViewPager mViewPager;
private CurrentReportString mCurrentReportString;
@InjectView(R.id.jsonText) TextView mJsonText;
@InjectView(R.id.imageReport) ImageView mImageReport;
@InjectView(R.id.imageReport2) ImageView mImageReport2;
@InjectView(R.id.imageReport3) ImageView mImageReport3;
@InjectView(R.id.adminText) TextView mAdminText;
@Override
protected void onCreate(Bundle savedInstanceState)
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ButterKnife.inject(this);
mAdminText.setOnClickListener(new View.OnClickListener()
@Override
public void onClick(View v)
Intent intent = new Intent(MainActivity.this, LoginActivity.class);
startActivity(intent);
);
String urlWebSite = "http://www.bundoransurfco.com/surf-report/surf-report/?json=1";
if (isNetworkAvailable())
OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder()
.url(urlWebSite)
.build();
Call call = client.newCall(request);
call.enqueue(new Callback()
@Override
public void onFailure(Request request, IOException e)
@Override
public void onResponse(Response response) throws IOException
try
String jsonData = response.body().string();
if (response.isSuccessful())
mCurrentReportString = getCurrentDetails(jsonData);
int numberOfPhotos = mCurrentReportString.getNumberOfPhotos();
if (numberOfPhotos == 1)
new DownloadImageTask(mImageReport)
.execute(mCurrentReportString.getUrlImages());
if (numberOfPhotos == 2)
new DownloadImageTask(mImageReport)
.execute(mCurrentReportString.getUrlImages());
new DownloadImageTask(mImageReport2)
.execute(mCurrentReportString.getUrlImages2());
if (numberOfPhotos == 3)
new DownloadImageTask(mImageReport)
.execute(mCurrentReportString.getUrlImages());
new DownloadImageTask(mImageReport2)
.execute(mCurrentReportString.getUrlImages2());
new DownloadImageTask(mImageReport3)
.execute(mCurrentReportString.getUrlImages3());
if (numberOfPhotos > 3)
new DownloadImageTask(mImageReport)
.execute(mCurrentReportString.getUrlImages());
new DownloadImageTask(mImageReport2)
.execute(mCurrentReportString.getUrlImages2());
new DownloadImageTask(mImageReport3)
.execute(mCurrentReportString.getUrlImages3());
// Write in the main Thread.
runOnUiThread(new Runnable()
@Override
public void run()
updateReport();
);
else
alertUserAboutError();
catch (IOException e)
Log.e(TAG, "Exception caught: ", e);
catch (JSONException e)
Log.e(TAG, "Exception caught: ", e);
);
else
Toast.makeText(this, getString(R.string.network_unavailable_message), Toast.LENGTH_LONG).show();
Log.d(TAG, "Main UI code is running!");
@Override
protected void onResume()
super.onResume();
initUI();
private void updateReport()
mJsonText.setText(mCurrentReportString.getJsonContent());
if (mCurrentReportString.imageBackground == Boolean.FALSE)
Log.i(TAG, "No Background1");
mImageReport.setVisibility(View.INVISIBLE);
if (mCurrentReportString.imageBackground2 == Boolean.FALSE)
Log.i(TAG, "No Background2");
mImageReport2.setVisibility(View.INVISIBLE);
if (mCurrentReportString.imageBackground3 == Boolean.FALSE)
Log.i(TAG, "No Background3");
mImageReport3.setVisibility(View.INVISIBLE);
@TargetApi(Build.VERSION_CODES.JELLY_BEAN)
private CurrentReportString getCurrentDetails(String jsonData) throws JSONException
JSONObject report = new JSONObject(jsonData);
JSONObject postJson = report.getJSONObject("post");
CurrentReportString currentReportString = new CurrentReportString();
String contentString = postJson.getString("content");
//Report String
String contentWithoutWebcam = contentString.replace("CLICK HERE FOR LIVE PEAK WEBCAM", "");
int lastCharacter = contentWithoutWebcam.indexOf("#gallery-1");
String contentFirstPart = contentWithoutWebcam.substring(0, lastCharacter);
String jsonText = stripHtml(contentFirstPart);
currentReportString.setJsonContent(jsonText);
//Images
Document doc = Jsoup.parse(contentString);
Elements relLinks = doc.select("a[rel]");
//Elements relLinks = doc.select("a[rel=prettyPhoto[gallery-113]]");//
System.out.println("number of `rel`: "+relLinks.size());
currentReportString.setNumberOfPhotos(relLinks.size());
ArrayList<String> urls=new ArrayList<String>();
for (Element el : relLinks)
// Log.i(TAG, el.attr("href"));
urls.add(el.attr("href"));
if (relLinks.size() == 0)
Log.i(TAG, "0 image");
currentReportString.setImageBackground(Boolean.FALSE);
currentReportString.setImageBackground2(Boolean.FALSE);
currentReportString.setImageBackground3(Boolean.FALSE);
else if (relLinks.size() == 1)
// Log.i(TAG, String.valueOf(urls));
currentReportString.setUrlImages(urls.get(0));
Log.i(TAG, "first URL : " + currentReportString.getUrlImages());
currentReportString.setImageBackground2(Boolean.FALSE);
currentReportString.setImageBackground3(Boolean.FALSE);
/* new DownloadImageTask(mImageReport)
.execute(mCurrentReportString.getUrlImages());*/
else if (relLinks.size() == 2)
currentReportString.setUrlImages(urls.get(0));
currentReportString.setUrlImages2(urls.get(1));
currentReportString.setImageBackground3(Boolean.FALSE);
Log.i(TAG, "first URL : "+currentReportString.getUrlImages());
Log.i(TAG, "second URL : "+currentReportString.getUrlImages2());
/* new DownloadImageTask(mImageReport)
.execute(mCurrentReportString.getUrlImages());
new DownloadImageTask(mImageReport2)
.execute(mCurrentReportString.getUrlImages2());*/
else if (relLinks.size() == 3)
currentReportString.setUrlImages(urls.get(0));
currentReportString.setUrlImages2(urls.get(1));
currentReportString.setUrlImages3(urls.get(2));
Log.i(TAG, "first URL : "+currentReportString.getUrlImages());
Log.i(TAG, "second URL : "+currentReportString.getUrlImages2());
Log.i(TAG, "third URL : "+currentReportString.getUrlImages3());
/* new DownloadImageTask(mImageReport2)
.execute(mCurrentReportString.getUrlImages2());
new DownloadImageTask(mImageReport3)
.execute(mCurrentReportString.getUrlImages3());*/
else if (relLinks.size() > 3)
currentReportString.setUrlImages(urls.get(0));
currentReportString.setUrlImages2(urls.get(1));
currentReportString.setUrlImages3(urls.get(2));
Log.i(TAG, "first URL : "+currentReportString.getUrlImages());
Log.i(TAG, "second URL : "+currentReportString.getUrlImages2());
Log.i(TAG, "third URL : "+currentReportString.getUrlImages3());
/* new DownloadImageTask(mImageReport)
.execute(mCurrentReportString.getUrlImages());
new DownloadImageTask(mImageReport2)
.execute(mCurrentReportString.getUrlImages2());
new DownloadImageTask(mImageReport3)
.execute(mCurrentReportString.getUrlImages3());*/
return currentReportString;
private boolean isNetworkAvailable()
ConnectivityManager manager = (ConnectivityManager)
getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo networkInfo = manager.getActiveNetworkInfo();
boolean isAvailable = false;
if (networkInfo != null && networkInfo.isConnected())
isAvailable = true;
return isAvailable;
//Delete HTML Markup
public String stripHtml(String html)
return Html.fromHtml(html).toString();
private void alertUserAboutError()
AlertDialogFragment dialog = new AlertDialogFragment();
dialog.show(getFragmentManager(), "error_dialog");
@Override
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction ft)
mViewPager.setCurrentItem(tab.getPosition());
@Override
public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction ft)
@Override
public void onTabReselected(ActionBar.Tab tab, FragmentTransaction ft)
//Change Image from ImageView in Asynch with URL.
private class DownloadImageTask extends AsyncTask<String, Void, Bitmap>
ImageView bmImage;
public DownloadImageTask(ImageView bmImage)
this.bmImage = bmImage;
protected Bitmap doInBackground(String... urls)
String urldisplay = urls[0];
Bitmap mIcon11 = null;
try
InputStream in = new java.net.URL(urldisplay).openStream();
mIcon11 = BitmapFactory.decodeStream(in);
catch (Exception e)
Log.e("Error", e.getMessage());
e.printStackTrace();
return mIcon11;
protected void onPostExecute(Bitmap result)
bmImage.setImageBitmap(result);
/* @Override
public void onTabSelected(android.support.v7.app.ActionBar.Tab tab,
FragmentTransaction fragmentTransaction)
// When the given tab is selected, switch to the corresponding page in
// the ViewPager.
mViewPager.setCurrentItem(tab.getPosition());
@Override
public void onTabUnselected(android.support.v7.app.ActionBar.Tab tab,
FragmentTransaction fragmentTransaction)
@Override
public void onTabReselected(android.support.v7.app.ActionBar.Tab tab,
FragmentTransaction fragmentTransaction)
*/
private void initUI()
final android.support.v7.app.ActionBar actionBar = getSupportActionBar();
actionBar.setNavigationMode(android.support.v7.app.ActionBar.NAVIGATION_MODE_TABS);
mSectionsPagerAdapter = new SectionsPagerAdapter(this,
getSupportFragmentManager());
mViewPager = (ViewPager) findViewById(R.id.pager);
mViewPager.setAdapter(mSectionsPagerAdapter);
mViewPager
.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener()
@Override
public void onPageSelected(int position)
actionBar.setSelectedNavigationItem(position);
);
for (int i = 0; i < mSectionsPagerAdapter.getCount(); i++)
actionBar.addTab(actionBar.newTab()
.setText(mSectionsPagerAdapter.getPageTitle(i))
.setTabListener((android.support.v7.app.ActionBar.TabListener) this));
/* public boolean onCreateOptionsMenu(Menu menu)
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
*/
AndroidManifest.xml：
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="jardelcompany.bundoransurfco" >
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.USE_CREDENTIALS" /> <!-- To retrieve the account name (email) as part of sign-in: -->
<uses-permission android:name="android.permission.GET_ACCOUNTS" /> <!-- To auto-complete the email text field in the login form with the user's emails -->
<uses-permission android:name="android.permission.READ_PROFILE" />
<uses-permission android:name="android.permission.READ_CONTACTS" />
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="@string/app_name"
android:screenOrientation="portrait" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".LoginActivity"
android:label="@string/title_activity_login"
android:parentActivityName=".MainActivity"
android:screenOrientation="portrait"
android:windowSoftInputMode="adjustResize|stateVisible" >
</activity>
</application>
</manifest>
styles.xml：
<resources>
<!-- Base application theme. -->
<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
<!-- Customize your theme here. -->
</style>
</resources>
SectionsPagerAdapter.java：
import java.util.Locale;
import android.content.Context;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
public class SectionsPagerAdapter extends FragmentPagerAdapter
protected Context mContext;
public SectionsPagerAdapter(Context context, FragmentManager fm)
super(fm);
mContext = context;
@Override
public Fragment getItem(int position)
switch(position)
case 0:
return new FirstFragment();
case 1:
return new LoginFragment();
return null;
@Override
public int getCount()
return 2;
@Override
public CharSequence getPageTitle(int position)
Locale l = Locale.getDefault();
switch (position)
case 0:
return mContext.getString(R.string.title_section1).toUpperCase(l);
case 1:
return mContext.getString(R.string.title_section2).toUpperCase(l);
return null;
LoginFragment.java：
import android.os.Bundle;
import android.support.v4.app.ListFragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class LoginFragment extends ListFragment
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState)
View rootView = inflater.inflate(R.layout.activity_login,
container, false);
return rootView;
activity_login.xml：
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_
android:layout_
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
android:background="#FFFFFF"
tools:context="jardelcompany.bundoransurfco.LoginFragment">
</RelativeLayout>
FirstFragment.java：
import android.os.Bundle;
import android.support.v4.app.ListFragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class FirstFragment extends ListFragment
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState)
View rootView = inflater.inflate(R.layout.activity_main,
container, false);
return rootView;
activity_main.xml：
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_
android:layout_
tools:context=".MainActivity"
android:id="@+id/mainLayout"
android:background="#FFFFFF"> />
<view
android:layout_
android:layout_
class="android.support.v4.view.ViewPager"
android:id="@+id/pager"/>
</RelativeLayout>
Logcat 崩溃：
FATAL EXCEPTION: main
Process: jardelcompany.bundoransurfco, PID: 2250
java.lang.RuntimeException: Your content must have a ListView whose id attribute is 'android.R.id.list'
【问题讨论】：
请完整发布您的 MainActivity.java @HeshanSandeepa 已编辑 ;) 如果出现崩溃，请发布 logcat @HeshanSandeepa 谢谢你的帮助，用 logcat 编辑 【参考方案1】：对于ActionBarActivity，您应该使用getSupportFragmentManager() 和getSupportActionBar()
【讨论】：
谢谢你的回复，我已经导入了android.support.v7.app.ActionBarActivity;并导入android.support.v7.app.ActionBar；并输入：final android.support.v7.app.ActionBar actionBar = getSupportActionBar(); ？？？但下一行 actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);不起作用，并且 .setTabListener(this));也是红色的…… 请看看我上次的编辑，应用程序崩溃在新的一行：actionBar.addTab(actionBar.newTab() 如错误所示，您的MainActivity 不是 implements ActionBar.TabListener
哦，没关系，看起来它是由您的错误导入引起的。您应该从支持库中实现 TabListener。
很好，没关系！ :) 现在，最后一个错误：您的内容必须有一个 id 属性为“android.R.id.list”的 ListView，我要把 ListView 放在哪里？ activity_main.xml ?【参考方案2】：
您的 MainActivity 中的 onResume(Bundle savedInstanceState) 方法永远不会因为错误的参数而被调用，而且您也不会调用 super.onResume()。正确的方法是：
@Override
protected void onResume()
super.onResume();
initUI();
查看这里的一些文档：http://developer.android.com/training/basics/activity-lifecycle/pausing.html#Resume
【讨论】：
我用这段代码测试了我的应用程序崩溃：致命异常：主进程：jardelcompany.bundoransurfco，PID：1386 java.lang.RuntimeException：无法恢复活动jardelcompany.bundoransurfco/jardelcompany.bundoransurfco。 MainActivity：java.lang.NullPointerException 原因：jardelcompany.bundoransurfco.MainActivity.initUI(MainActivity.java:342) at jardelcompany.bundoransurfco.MainActivity.onResume(MainActivity.java:169) 处的 java.lang.NullPointerException 不调用超级方法就不会调用 现在您的 initUI 方法已执行，它在第 342 行崩溃 @udduk 是的，就是这一行：actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS); 所以 getActionBar 似乎返回 null。尝试调用 getSupportActionBar()【参考方案3】：如下更新你的代码，
@Override
protected void onResume()
super.onResume();
initUI();
【讨论】：
请最后看一下我编辑的代码：我的应用在 actionBar.addTab(actionBar.newTab() 上崩溃 用import android.support.v7.app.ActionBar替换你的actionbar导入；而不是 import app.ActionBar; 你是对的！最后一个错误：您的内容必须有一个 id 属性为 'android.R.id.list' 的 ListView ...我需要在哪里放置 ListView ？在activity_main.xml 中？ 你试图把列表视图放在哪里？ 我不知道，我没有 ListView... 也许我需要在我的 XML 中创建它？因为我使用的是自定义视图：以上是关于Fragment 和 FragmentList 不显示 Android Studio的主要内容，如果未能解决你的问题，请参考以下文章
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