我试图创建一个底部导航栏，但是当我尝试运行该应用程序时，它始终显示“导航栏已停止”。 我正在使用以下网站的代码：https://www.androidhive.info/2017/12/android-working-with-bottom-navigation/
public class MainActivity extends AppCompatActivity {
private ActionBar toolbar;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
toolbar = getSupportActionBar();
toolbar.setTitle("Home");
loadFragment(new HomeFragment());
}
private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
= new BottomNavigationView.OnNavigationItemSelectedListener() {
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
Fragment fragment;
switch (item.getItemId()) {
case R.id.navigation_home:
toolbar.setTitle("Home");
fragment = new HomeFragment();
loadFragment(fragment);
return true;
case R.id.navigation_search:
toolbar.setTitle("Search");
fragment = new SearchFragment();
loadFragment(fragment);
return true;
case R.id.navigation_category:
toolbar.setTitle("Category");
fragment = new CategoryFragment();
loadFragment(fragment);
return true;
case R.id.navigation_share:
toolbar.setTitle("Share");
fragment = new ShareFragment();
loadFragment(fragment);
return true;
case R.id.navigation_more_horiz:
toolbar.setTitle("More");
fragment = new MoreFragment();
loadFragment(fragment);
return true;
}
return false;
}
};
private void loadFragment(Fragment fragment) {
// load fragment
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.frame_container, fragment);
transaction.addToBackStack(null);
transaction.commit();
}
}
我需要做什么
这是logcat，但是我很新，不知道该怎么办：
2019-07-16 20:57:32.007 7235-7235/com.example.myapplication E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.myapplication, PID: 7235
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.myapplication/com.example.myapplication.MainActivity}: java.lang.RuntimeException: com.example.myapplication.MainActivity@51ea29f must implement OnFragmentInteractionListener
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2778)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2856)
at android.app.ActivityThread.-wrap11(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1589)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6494)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
Caused by: java.lang.RuntimeException: com.example.myapplication.MainActivity@51ea29f must implement OnFragmentInteractionListener
at com.example.myapplication.HomeFragment.onAttach(HomeFragment.java:83)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1404)
at android.support.v4.app.FragmentTransition.addToFirstInLastOut(FragmentTransition.java:1195)
at android.support.v4.app.FragmentTransition.calculateFragments(FragmentTransition.java:1078)
at android.support.v4.app.FragmentTransition.startTransitions(FragmentTransition.java:117)
at android.support.v4.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2408)
at android.support.v4.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManager.java:2366)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:2273)
at android.support.v4.app.FragmentManagerImpl.dispatchStateChange(FragmentManager.java:3273)
at android.support.v4.app.FragmentManagerImpl.dispatchActivityCreated(FragmentManager.java:3229)
at android.support.v4.app.FragmentController.dispatchActivityCreated(FragmentController.java:201)
at android.support.v4.app.FragmentActivity.onStart(FragmentActivity.java:620)
at android.support.v7.app.AppCompatActivity.onStart(AppCompatActivity.java:178)
at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1334)
at android.app.Activity.performStart(Activity.java:7029)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2741)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2856)
at android.app.ActivityThread.-wrap11(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1589)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6494)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
答案 0 :(得分：0)
在MainActivity中，您必须实现接口
G:\Software\ML>pip list
Package Version
--------------- ----------
cycler 0.10.0
joblib 0.13.2
kiwisolver 1.1.0
matplotlib 3.1.1
numpy 1.16.4+mkl
pandas 0.25.0rc0
pip 19.1.1
pyparsing 2.4.0
python-dateutil 2.8.0
pytz 2019.1
scikit-learn 0.21.2
scipy 1.3.0
setuptools 40.8.0
six 1.12.0
G:\Software\ML>python
>>> import sklearn
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "C:\Users\akarasin\AppData\Local\Programs\Python\Python38\lib\site-packages\sklearn\__init__.py", line 76, in <module>
from .base import clone
File "C:\Users\akarasin\AppData\Local\Programs\Python\Python38\lib\site-packages\sklearn\base.py", line 16, in <module>
from .utils import _IS_32BIT
File "C:\Users\akarasin\AppData\Local\Programs\Python\Python38\lib\site-packages\sklearn\utils\__init__.py", line 17, in <module>
from . import _joblib
File "C:\Users\akarasin\AppData\Local\Programs\Python\Python38\lib\site-packages\sklearn\utils\_joblib.py", line 8, in <module>
import joblib
File "C:\Users\akarasin\AppData\Local\Programs\Python\Python38\lib\site-packages\joblib\__init__.py", line 119, in <module>
from .parallel import Parallel
File "C:\Users\akarasin\AppData\Local\Programs\Python\Python38\lib\site-packages\joblib\parallel.py", line 28, in <module>
from ._parallel_backends import (FallbackToBackend, MultiprocessingBackend,
File "C:\Users\akarasin\AppData\Local\Programs\Python\Python38\lib\site-packages\joblib\_parallel_backends.py", line 22, in <module>
from .executor import get_memmapping_executor
File "C:\Users\akarasin\AppData\Local\Programs\Python\Python38\lib\site-packages\joblib\executor.py", line 14, in <module>
from .externals.loky.reusable_executor import get_reusable_executor
File "C:\Users\akarasin\AppData\Local\Programs\Python\Python38\lib\site-packages\joblib\externals\loky\__init__.py", line 12, in <module>
from .backend.reduction import set_loky_pickler
File "C:\Users\akarasin\AppData\Local\Programs\Python\Python38\lib\site-packages\joblib\externals\loky\backend\reduction.py", line 125, in <module>
from joblib.externals import cloudpickle # noqa: F401
File "C:\Users\akarasin\AppData\Local\Programs\Python\Python38\lib\site-packages\joblib\externals\cloudpickle\__init__.py", line 3, in <module>
from .cloudpickle import *
File "C:\Users\akarasin\AppData\Local\Programs\Python\Python38\lib\site-packages\joblib\externals\cloudpickle\cloudpickle.py", line 152, in <module>
_cell_set_template_code = _make_cell_set_template_code()
File "C:\Users\akarasin\AppData\Local\Programs\Python\Python38\lib\site-packages\joblib\externals\cloudpickle\cloudpickle.py", line 133, in _make_cell_set_template_code
return types.CodeType(
TypeError: an integer is required (got type bytes)
>>>
}