由于遇到了Gradle问题，我尝试与删除的其他应用程序使用相同的代码。因此，我做了一个新项目，并遵循了从Github保存的相同代码。
现在的问题是，当我从导航抽屉中单击“销售”菜单（将向您显示“销售片段”）时，应用程序崩溃了。我尝试创建一个示例活动并使用了意图，但从来没有问题，仅使用片段。
谢谢您的帮助！
我已经尝试清理并重建项目，卸载了该应用程序并再次运行，但是没有运气。
DashboardActivity.java
package com.example.devcash;
import android.content.Intent;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentTransaction;
import android.view.View;
import android.support.v4.view.GravityCompat;
import android.support.v7.app.ActionBarDrawerToggle;
import android.view.MenuItem;
import android.support.design.widget.NavigationView;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.widget.Toast;
public class DashboardActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener {
DrawerLayout drawer;
NavigationView navigationView;
Toolbar toolbar;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_dashboard);
///
toolbar = findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
drawer = findViewById(R.id.drawer_layout);
navigationView = findViewById(R.id.nav_view);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.addDrawerListener(toggle);
toggle.syncState();
navigationView.setNavigationItemSelectedListener(this);
}
@Override
public void onBackPressed() {
drawer = findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.dashboard, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
//switch for nav drawer menu
private void displaySelectedScreen(int id){
Fragment fragment = null;
switch (id){
case R.id.nav_dashboard:
Toast.makeText(this, "Dashboard", Toast.LENGTH_SHORT).show();
break;
case R.id.nav_sales:
fragment = new SalesFragment();
break;
case R.id.nav_inventory:
Toast.makeText(this, "Inventory", Toast.LENGTH_SHORT).show();
break;
case R.id.nav_employee:
Toast.makeText(this, "Employee", Toast.LENGTH_SHORT).show();
break;
case R.id.nav_reports:
Toast.makeText(this, "Reports", Toast.LENGTH_SHORT).show();
break;
case R.id.nav_help:
Toast.makeText(this, "Help Center", Toast.LENGTH_SHORT).show();
break;
case R.id.nav_settings:
Intent sample = new Intent(DashboardActivity.this, SampleActivity.class);
startActivity(sample);
break;
}
if (fragment != null){
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.replace(R.id.flcontent, fragment);
ft.commit();
}
drawer = findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
}
@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
displaySelectedScreen(id);
drawer = findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
}
fragment_sales.xml
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="200dp"
tools:context=".SalesFragment">
<TextView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"
android:text="Sales Fragment"
android:textSize="50sp"/>
</FrameLayout>
SalesFragment.java
package com.example.devcash;
import android.content.Context;
import android.net.Uri;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
/**
* A simple {@link Fragment} subclass.
* Activities that contain this fragment must implement the
* {@link SalesFragment.OnFragmentInteractionListener} interface
* to handle interaction events.
* Use the {@link SalesFragment#newInstance} factory method to
* create an instance of this fragment.
*/
public class SalesFragment extends Fragment {
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;
private OnFragmentInteractionListener mListener;
public SalesFragment() {
// Required empty public constructor
}
/**
* Use this factory method to create a new instance of
* this fragment using the provided parameters.
*
* @param param1 Parameter 1.
* @param param2 Parameter 2.
* @return A new instance of fragment SalesFragment.
*/
// TODO: Rename and change types and number of parameters
public static SalesFragment newInstance(String param1, String param2) {
SalesFragment fragment = new SalesFragment();
Bundle args = new Bundle();
args.putString(ARG_PARAM1, param1);
args.putString(ARG_PARAM2, param2);
fragment.setArguments(args);
return fragment;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
mParam1 = getArguments().getString(ARG_PARAM1);
mParam2 = getArguments().getString(ARG_PARAM2);
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_sales, container, false);
}
@Override
public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
//
getActivity().setTitle("Sales");
}
// TODO: Rename method, update argument and hook method into UI event
public void onButtonPressed(Uri uri) {
if (mListener != null) {
mListener.onFragmentInteraction(uri);
}
}
@Override
public void onAttach(Context context) {
super.onAttach(context);
if (context instanceof OnFragmentInteractionListener) {
mListener = (OnFragmentInteractionListener) context;
} else {
throw new RuntimeException(context.toString()
+ " must implement OnFragmentInteractionListener");
}
}
@Override
public void onDetach() {
super.onDetach();
mListener = null;
}
/**
* This interface must be implemented by activities that contain this
* fragment to allow an interaction in this fragment to be communicated
* to the activity and potentially other fragments contained in that
* activity.
* <p>
* See the Android Training lesson <a href=
* "http://developer.android.com/training/basics/fragments/communicating.html"
* >Communicating with Other Fragments</a> for more information.
*/
public interface OnFragmentInteractionListener {
// TODO: Update argument type and name
void onFragmentInteraction(Uri uri);
}
}
这是我的logcat
2019-05-08 19:07:03.348 20884-20884/? D/CubicBezierInterpolator: CubicBezierInterpolator mControlPoint1x = 0.23, mControlPoint1y = 0.06, mControlPoint2x = 0.09, mControlPoint2y = 0.97
2019-05-08 19:07:03.348 20884-20884/? D/CubicBezierInterpolator: CubicBezierInterpolator mControlPoint1x = 0.6, mControlPoint1y = 0.9, mControlPoint2x = 0.8, mControlPoint2y = 1.0
2019-05-08 19:07:03.349 20884-20884/? D/CubicBezierInterpolator: CubicBezierInterpolator mControlPoint1x = 0.23, mControlPoint1y = 0.06, mControlPoint2x = 0.09, mControlPoint2y = 0.97
2019-05-08 19:07:03.349 20884-20884/? D/CubicBezierInterpolator: CubicBezierInterpolator mControlPoint1x = 0.6, mControlPoint1y = 0.9, mControlPoint2x = 0.8, mControlPoint2y = 1.0
2019-05-08 19:07:03.538 20884-20884/? D/ActivityThread: add activity client record, r= ActivityRecord{de5bc93 token=android.os.BinderProxy@ecaf2fe {com.example.devcash/com.example.devcash.OwnerLoginActivity}} token= android.os.BinderProxy@ecaf2fe
2019-05-08 19:07:03.560 20884-20884/? I/HwSecImmHelper: mSecurityInputMethodService is null
2019-05-08 19:07:03.580 20884-20884/? D/OpenGLRenderer: HWUI Binary is enabled
2019-05-08 19:07:03.587 20884-20908/? D/OpenGLRenderer: HWUI GL Pipeline
2019-05-08 19:07:03.628 20884-20884/? I/PressGestureDetector: HiTouch restricted: AboardArea.
2019-05-08 19:07:03.645 20884-20889/? I/zygote64: Do partial code cache collection, code=28KB, data=29KB
2019-05-08 19:07:03.646 20884-20889/? I/zygote64: After code cache collection, code=28KB, data=29KB
2019-05-08 19:07:03.646 20884-20889/? I/zygote64: Increasing code cache capacity to 128KB
2019-05-08 19:07:03.722 20884-20908/? I/OpenGLRenderer: Initialized EGL, version 1.4
2019-05-08 19:07:03.723 20884-20908/? D/OpenGLRenderer: Swap behavior 2
2019-05-08 19:07:03.735 20884-20908/? D/mali_winsys: EGLint new_window_surface(egl_winsys_display *, void *, EGLSurface, EGLConfig, egl_winsys_surface **, egl_color_buffer_format *, EGLBoolean) returns 0x3000
2019-05-08 19:07:03.751 20884-20908/? D/OpenGLRenderer: HWUI Binary is enabled
2019-05-08 19:07:03.884 20884-20884/? W/InputMethodManager: startInputReason = 1
2019-05-08 19:07:03.962 20884-20884/com.example.devcash W/View: dispatchProvideAutofillStructure(): not laid out, ignoring
2019-05-08 19:07:03.968 20884-20884/com.example.devcash I/AssistStructure: Flattened final assist data: 3444 bytes, containing 1 windows, 14 views
2019-05-08 19:07:04.003 20884-20884/com.example.devcash W/InputMethodManager: startInputReason = 5
2019-05-08 19:07:04.107 20884-20884/com.example.devcash E/SpannableStringBuilder: SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length
2019-05-08 19:07:04.107 20884-20884/com.example.devcash E/SpannableStringBuilder: SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length
2019-05-08 19:07:04.115 20884-20884/com.example.devcash E/SpannableStringBuilder: SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length
2019-05-08 19:07:04.115 20884-20884/com.example.devcash E/SpannableStringBuilder: SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length
2019-05-08 19:07:04.124 20884-20884/com.example.devcash E/SpannableStringBuilder: SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length
2019-05-08 19:07:04.156 20884-20889/com.example.devcash I/zygote64: Do partial code cache collection, code=61KB, data=57KB
2019-05-08 19:07:04.157 20884-20889/com.example.devcash I/zygote64: After code cache collection, code=61KB, data=57KB
2019-05-08 19:07:04.157 20884-20889/com.example.devcash I/zygote64: Increasing code cache capacity to 256KB
2019-05-08 19:07:04.272 20884-20884/com.example.devcash E/SpannableStringBuilder: SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length
2019-05-08 19:07:04.272 20884-20884/com.example.devcash E/SpannableStringBuilder: SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length
2019-05-08 19:07:07.928 20884-20884/com.example.devcash D/KeyEvent: obtain, mHwFlags=30
2019-05-08 19:07:07.990 20884-20884/com.example.devcash D/KeyEvent: obtain, mHwFlags=30
2019-05-08 19:07:09.123 20884-20884/com.example.devcash I/hwaps: JNI_OnLoad
2019-05-08 19:07:09.128 20884-20884/com.example.devcash W/Settings: mValues not put! needsGenerationTracker: true currentGeneration: -1 name: enable_navbar value: null
2019-05-08 19:07:09.183 20884-20884/com.example.devcash V/AudioManager: playSoundEffect effectType: 0
2019-05-08 19:07:09.252 20884-20889/com.example.devcash I/zygote64: Do full code cache collection, code=119KB, data=104KB
2019-05-08 19:07:09.253 20884-20889/com.example.devcash I/zygote64: After code cache collection, code=101KB, data=63KB
2019-05-08 19:07:09.829 20884-20884/com.example.devcash V/AudioManager: playSoundEffect effectType: 0
2019-05-08 19:07:09.906 20884-20884/com.example.devcash D/HwCust: Create obj success use class android.app.HwCustActivityImpl
2019-05-08 19:07:09.909 20884-20884/com.example.devcash D/HwCust: Create obj success use class android.app.HwCustHwWallpaperManagerImpl
2019-05-08 19:07:09.912 20884-20884/com.example.devcash V/ActivityThread: ActivityThread,callActivityOnCreate
2019-05-08 19:07:09.930 20884-20884/com.example.devcash D/CubicBezierInterpolator: CubicBezierInterpolator mControlPoint1x = 0.23, mControlPoint1y = 0.06, mControlPoint2x = 0.09, mControlPoint2y = 0.97
2019-05-08 19:07:09.931 20884-20884/com.example.devcash D/CubicBezierInterpolator: CubicBezierInterpolator mControlPoint1x = 0.6, mControlPoint1y = 0.9, mControlPoint2x = 0.8, mControlPoint2y = 1.0
2019-05-08 19:07:09.931 20884-20884/com.example.devcash D/CubicBezierInterpolator: CubicBezierInterpolator mControlPoint1x = 0.23, mControlPoint1y = 0.06, mControlPoint2x = 0.09, mControlPoint2y = 0.97
2019-05-08 19:07:09.931 20884-20884/com.example.devcash D/CubicBezierInterpolator: CubicBezierInterpolator mControlPoint1x = 0.6, mControlPoint1y = 0.9, mControlPoint2x = 0.8, mControlPoint2y = 1.0
2019-05-08 19:07:09.943 20884-20884/com.example.devcash D/HwRTBlurUtils: check blur style for HwPhoneWindow, themeResId : 0x7f100006, context : com.example.devcash.ForgotPasswordActivity@54f76ec, Nhwext : 0, get Blur : disable with , null
2019-05-08 19:07:09.944 20884-20884/com.example.devcash D/HwRTBlurUtils: check blur style for HwPhoneWindow, themeResId : 0x7f100006, context : com.example.devcash.ForgotPasswordActivity@54f76ec, Nhwext : 0, get Blur : disable with , null
2019-05-08 19:07:09.954 20884-20884/com.example.devcash D/CubicBezierInterpolator: CubicBezierInterpolator mControlPoint1x = 0.23, mControlPoint1y = 0.06, mControlPoint2x = 0.09, mControlPoint2y = 0.97
2019-05-08 19:07:09.954 20884-20884/com.example.devcash D/CubicBezierInterpolator: CubicBezierInterpolator mControlPoint1x = 0.6, mControlPoint1y = 0.9, mControlPoint2x = 0.8, mControlPoint2y = 1.0
2019-05-08 19:07:09.955 20884-20884/com.example.devcash D/CubicBezierInterpolator: CubicBezierInterpolator mControlPoint1x = 0.23, mControlPoint1y = 0.06, mControlPoint2x = 0.09, mControlPoint2y = 0.97
2019-05-08 19:07:09.955 20884-20884/com.example.devcash D/CubicBezierInterpolator: CubicBezierInterpolator mControlPoint1x = 0.6, mControlPoint1y = 0.9, mControlPoint2x = 0.8, mControlPoint2y = 1.0
2019-05-08 19:07:09.996 20884-20884/com.example.devcash D/ActivityThread: add activity client record, r= ActivityRecord{2b209b4 token=android.os.BinderProxy@854c33e {com.example.devcash/com.example.devcash.ForgotPasswordActivity}} token= android.os.BinderProxy@854c33e
2019-05-08 19:07:10.009 20884-20908/com.example.devcash D/OpenGLRenderer: HWUI Binary is enabled
2019-05-08 19:07:10.042 20884-20884/com.example.devcash I/PressGestureDetector: HiTouch restricted: AboardArea.
2019-05-08 19:07:10.102 20884-20908/com.example.devcash D/mali_winsys: EGLint new_window_surface(egl_winsys_display *, void *, EGLSurface, EGLConfig, egl_winsys_surface **, egl_color_buffer_format *, EGLBoolean) returns 0x3000
2019-05-08 19:07:10.116 20884-20908/com.example.devcash D/OpenGLRenderer: HWUI Binary is enabled
2019-05-08 19:07:10.163 20884-20884/com.example.devcash W/InputMethodManager: startInputReason = 1
2019-05-08 19:07:10.207 20884-20884/com.example.devcash W/View: dispatchProvideAutofillStructure(): not laid out, ignoring
2019-05-08 19:07:10.211 20884-20884/com.example.devcash I/AssistStructure: Flattened final assist data: 2840 bytes, containing 1 windows, 11 views
2019-05-08 19:07:10.220 20884-20908/com.example.devcash W/libEGL: EGLNativeWindowType 0x7cd9ac6010 disconnect failed
2019-05-08 19:07:10.242 20884-20884/com.example.devcash E/SpannableStringBuilder: SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length
2019-05-08 19:07:10.242 20884-20884/com.example.devcash E/SpannableStringBuilder: SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length
2019-05-08 19:07:10.292 20884-20889/com.example.devcash I/zygote64: Do partial code cache collection, code=122KB, data=99KB
2019-05-08 19:07:10.292 20884-20889/com.example.devcash I/zygote64: After code cache collection, code=122KB, data=99KB
2019-05-08 19:07:10.292 20884-20889/com.example.devcash I/zygote64: Increasing code cache capacity to 512KB
2019-05-08 19:07:20.871 20884-20889/com.example.devcash I/zygote64: Compiler allocated 6MB to compile void android.view.ViewRootImpl.performTraversals()
答案 0 :(得分：1)
一个显而易见的错误与您的FragmentInteractionListener有关。在您的SalesFragment中，指定以下内容：
@Override
public void onAttach(Context context) {
super.onAttach(context);
if (context instanceof OnFragmentInteractionListener) {
mListener = (OnFragmentInteractionListener) context;
} else {
throw new RuntimeException(context.toString()
+ " must implement OnFragmentInteractionListener");
}
}
但是您的Activity没有实现OnFragmentInteractionListener，因此您至少会在日志中看到一个异常，其中显示“ DashboardActivity必须实现OnFragmentInteractionListener”
答案 1 :(得分：0)
您正在呼叫：
drawer = findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
两次，一次在onNavigationItemSelected()中，一次在displaySelectedScreen()
通常，在调用抽屉之前，最好先检查抽屉的状态，如下所示：
if (drawer_layout.isDrawerOpen(Gravity.START)) {
drawer_layout.closeDrawer(Gravity.START)
}
更新
如上所述，您的片段交互侦听器存在问题。我看到这将崩溃，因为如上所述，DashboardActivity没有实现OnFragmentInteractionListener。将DashboardActivity的类标头更新为此：
public class DashboardActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener, SalesFragment.OnFragmentInteractionListener {
并按如下所示重写接口方法onFragmentInteraction(Uri uri)（在dashboardActivity中）
@Override
public void onFragmentInteraction(Uri uri) {
}