Question

我正在根据teamtreehouse.com上的教程开发一个聊天应用程序

在EditFriendsActivity.java文件中编写完所有代码后，我运行了应用程序＆amp;我注意到编辑好友活动中没有ActionBar。

相反，ActionBar出现在其他活动中！

这里可能出现什么问题？

EditFriendsActivity.java：

public class EditFriendsActivity extends ListActivity {

    public static final String TAG = EditFriendsActivity.class.getSimpleName();

    protected List<ParseUser> mUsers;
    protected ParseRelation<ParseUser> mFriendsRelation;
    protected ParseUser mCurrentUser;

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

        getActionBar();

        getListView().setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);
    }

    @Override
    protected void onResume() {
        super.onResume();

        mCurrentUser = ParseUser.getCurrentUser();
        mFriendsRelation = mCurrentUser.getRelation(ParseConstants.KEY_FRIENDS_RELATION);

        ParseQuery<ParseUser> query = ParseUser.getQuery();
        query.orderByAscending(ParseConstants.KEY_USERNAME);
        query.setLimit(1000);
        query.findInBackground(new FindCallback<ParseUser>() {
            @Override
            public void done(List<ParseUser> users, ParseException e) {
                if (e == null) {
                    // Success!
                    mUsers = users;
                    String[] usernames = new String[mUsers.size()];
                    int i = 0;
                    for (ParseUser user : mUsers) {
                        usernames[i] = user.getUsername();
                        i++;
                    }
                    ArrayAdapter<String> adapter = new ArrayAdapter<String>(
                            EditFriendsActivity.this,
                            android.R.layout.simple_list_item_checked,
                            usernames);
                    setListAdapter(adapter);

                    addFriendCheckmarks();
                } else {
                    Log.e(TAG, e.getMessage());
                    AlertDialog.Builder builder = new AlertDialog.Builder(EditFriendsActivity.this);
                    builder.setTitle(R.string.error_title);
                    builder.setMessage(e.getMessage());
                    builder.setPositiveButton(android.R.string.ok, null);

                    AlertDialog dialog = builder.create();
                    dialog.show();
                }
            }
        });
    }

    @Override
    protected void onListItemClick(ListView l, View v, int position, long id) {
        super.onListItemClick(l, v, position, id);

        if (getListView().isItemChecked(position)){
            // add friend
            mFriendsRelation.add(mUsers.get(position));
        } else {
            // remove friend
            mFriendsRelation.remove(mUsers.get(position));
        }
        mCurrentUser.saveInBackground(new SaveCallback() {
            @Override
            public void done(ParseException e) {
                if (e != null) {
                    Log.e(TAG, e.getMessage());
                }
            }
        });
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
       /// -- menu ---///
    }

    private void addFriendCheckmarks() {
        mFriendsRelation.getQuery().findInBackground(new FindCallback<ParseUser>() {
            @Override
            public void done(List<ParseUser> friends, ParseException e) {
                if (e == null) {
                    // list returned - look for a match
                    for (int i = 0; i < mUsers.size(); i++) {
                        ParseUser user = mUsers.get(i);

                        for (ParseUser friend: friends) {
                            if (friend.getObjectId().equals(user.getObjectId()));
                            getListView().setItemChecked(i, true);
                        }
                    }
                } else {
                    Log.e(TAG, e.getMessage());
                }
            }
        });
    }
}

的AndroidManifest.xml：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.hammadnasir.ribbit" >

    <uses-sdk android:maxSdkVersion="22" />

    <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-feature
        android:name="android.hardware.camera"
        android:required="true" />

    <application
        android:name=".RibbitApplication"
        android:allowBackup="true"
        android:debuggable="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:screenOrientation="portrait" >
        </activity>
        <activity
            android:name=".SignUpActivity"
            android:label="@string/title_activity_sign_up"
            android:parentActivityName=".LoginActivity"
            android:screenOrientation="portrait" >
        </activity>
        <activity
            android:name=".EditFriendsActivity"
            android:label="@string/title_activity_edit_friends"
            android:parentActivityName=".MainActivity"
            android:screenOrientation="portrait" >
            <meta-data
                android:name="android.support.PARENT_ACTIVITY"
                android:value="com.hammadnasir.ribbit.MainActivity" />
        </activity>
        <activity
            android:name=".ChooseFriendsActivity"
            android:label="@string/title_activity_choose_friends"
            android:parentActivityName=".MainActivity"
            android:screenOrientation="portrait">
            <meta-data
                android:name="android.support.PARENT_ACTIVITY"
                android:value="com.hammadnasir.ribbit.MainActivity" />
        </activity>
    </application>

</manifest>

请帮我解决这个问题。

Answer 1

在扩展AppCompatActivity之后，您应该在ListView中添加RecyclerView（或layout.xml}，然后实现用于填充和操作相应适配器中的对象的代码

当你不延伸ActionBarActivity或AppCompatActivity时，你不应该得到一个ActionBar

Answer 2

在OnCreate方法下的类文件中包含它：

Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);

并导入：

import android.support.v7.widget.Toolbar;

我的EditFriendsActivity中没有出现ActionBar。我的代码出了什么问题？

2 个答案: