Question

我的Android应用未打开。我真的不知道为什么任何帮助将不胜感激。谢谢！顺便说一句，它里面有谷歌地图和firebase。

两个gradle文件都在底部

下面是logcat /运行时的输出：

                  --------- beginning of crash
E/AndroidRuntime: FATAL EXCEPTION: main
                  Process: com.lrtapp.ardentmap, PID: 2781
                  java.lang.RuntimeException: Unable to start activity ComponentInfo{com.lrtapp.ardentmap/com.lrtapp.ardentmap.MainActivity}: java.lang.NullPointerException: println needs a message
                      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2925)
                      at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3060)
                      at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
                      at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:110)
                      at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:70)
                      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1800)
                      at android.os.Handler.dispatchMessage(Handler.java:106)
                      at android.os.Looper.loop(Looper.java:164)
                      at android.app.ActivityThread.main(ActivityThread.java:6649)
                      at java.lang.reflect.Method.invoke(Native Method)
                      at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:826)
                   Caused by: java.lang.NullPointerException: println needs a message
                      at android.util.Log.d(Log.java:145)
                      at com.lrtapp.ardentmap.MainActivity.onCreate(MainActivity.java:79)
                      at android.app.Activity.performCreate(Activity.java:7130)
                      at android.app.Activity.performCreate(Activity.java:7121)
                      at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1262)
                      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2905)
                      at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3060) 
                      at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78) 
                      at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:110) 
                      at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:70) 
                      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1800) 
                      at android.os.Handler.dispatchMessage(Handler.java:106) 
                      at android.os.Looper.loop(Looper.java:164) 
                      at android.app.ActivityThread.main(ActivityThread.java:6649) 
                      at java.lang.reflect.Method.invoke(Native Method) 
                      at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493) 
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:826) 
I/rtapp.ardentma: NativeAlloc concurrent copying GC freed 7646(2MB) AllocSpace objects, 2(40KB) LOS objects, 49% free, 1588KB/3MB, paused 8.189ms total 105.027ms
I/Process: Sending signal. PID: 2781 SIG: 9
Application terminated.                   at android.util.Log.println_native(Native Method)

下面是代码：

主要活动课程

package com.lrtapp.ardentmap;

import android.app.Activity;
import android.app.Dialog;
import android.app.NotificationChannel;
import android.app.NotificationManager;
import android.content.Intent;
import android.graphics.Color;
import android.nfc.Tag;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GoogleApiAvailability;
import com.google.firebase.iid.FirebaseInstanceId;

public class MainActivity extends AppCompatActivity {

    private static final String TAG = "MainActivity";

    private static final int ERROR_DIALOG_REQUEST = 9001;

    private Button btnAbout;
    private Button btnContact;
    private Button btnVideos;


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

        btnAbout = (Button) findViewById(R.id.btnAbout);
        btnAbout.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                openAbout();
            }
        });

        btnContact = (Button) findViewById(R.id.btnContact);
        btnContact.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View v){
                openContact();
            }
        });

        btnVideos = (Button) findViewById(R.id.btnVideos);
        btnVideos.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View v){
                openVideos();
            }
        });

        NotificationManager mNotificationManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);

        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {
            NotificationChannel mChannel =
                    new NotificationChannel(Constants.CHANNEL_ID, Constants.CHANNEL_NAME, NotificationManager.IMPORTANCE_HIGH);

            mChannel.setDescription(Constants.CHANNEL_DESCRIPTION);
            mChannel.enableLights(true);
            mChannel.setLightColor(Color.RED);
            mChannel.enableVibration(true);

            mChannel.setVibrationPattern(new long[]{100, 200, 300, 400 ,500 ,400, 300, 200, 400});

            mNotificationManager.createNotificationChannel(mChannel);
        }

        common.currentToken = FirebaseInstanceId.getInstance().getToken();

        Log.d("My Token", common.currentToken);

        if(isServicesOK())

            init();
    }

    private void init(){

        Button btnMap = (Button) findViewById(R.id.btnMap);
        btnMap.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(MainActivity.this, MapActivity.class);
                startActivity(intent);
            }
        });
    }

    public boolean isServicesOK(){
        Log.d(TAG, "isServicesOK: checking google services version");

        int available = GoogleApiAvailability.getInstance().isGooglePlayServicesAvailable(MainActivity.this);

        if(available == ConnectionResult.SUCCESS){
            //everything is okay
            Log.d(TAG, "isServicesOK: Google Play services is working");
            return true;
        }else if(GoogleApiAvailability.getInstance().isUserResolvableError(available)){
            // an error occured but we can resolve it
            Log.d(TAG, "isServicesOK: an error occured but we can fix it");
            Dialog dialog = GoogleApiAvailability.getInstance().getErrorDialog(MainActivity.this, available, ERROR_DIALOG_REQUEST);
            dialog.show();

        }else{
            Toast.makeText(this, "we cant make map requests", Toast.LENGTH_SHORT).show();
        }
        return false;
    }

    public void openAbout(){
        Intent intent = new Intent(this, About.class);
        startActivity(intent);
    }

    public void openContact(){
        Intent intent = new Intent(this, Contact.class);
        startActivity(intent);
    }

    public void openVideos(){
        Intent intent = new Intent(this, Videos.class);
        startActivity(intent);
    }


}

FirebaseMessagingService类

package com.lrtapp.ardentmap;

import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.media.RingtoneManager;
import android.net.Uri;
import android.nfc.Tag;
import android.support.v4.app.NotificationCompat;
import android.util.Log;


import com.google.firebase.messaging.RemoteMessage;

public class FirebaseMessagingService extends com.google.firebase.messaging.FirebaseMessagingService {
    private static final String TAG = "FirebaseMessagingService";

    public FirebaseMessagingService() {
    }

    @Override
    public void onMessageReceived(RemoteMessage remoteMessage) {


        String title = remoteMessage.getNotification().getTitle();
        String body = remoteMessage.getNotification().getBody();

        MyNotificationManager.getInstance(getApplicationContext())
                .displayNotification(title, body);
    }

    @Override
    public void onDeletedMessages() {

    }

}

Android清单

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

    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/erlogo"
        android:label="EaseRoute"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <meta-data
            android:name="com.google.android.geo.API_KEY"
            android:value="AIzaSyALC_Pis5w391INiqcvnXO7dipxuMP0-JA" />
        <meta-data
            android:name="com.google.android.gms.version"
            android:value="@integer/google_play_services_version" />

        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name=".MapActivity" />
        <activity android:name=".About" />
        <activity android:name=".Contact" />
        <activity android:name=".Videos"></activity>

        <service android:name=".FirebaseMessagingService">
            <intent-filter>
                <action android:name="com.google.firebase.MESSAGING_EVENT"/>
            </intent-filter>
        </service>

        <service android:name=".MyFirebaseIdService">
            <intent-filter>
                <action android:name="com.google.firebase.INSTANCE_ID_EVENT"/>
            </intent-filter>
        </service>



        <meta-data
            android:name="com.google.firebase.messaging.default_notification_color"
            android:resource="@color/colorAccent"/>
    </application>

</manifest>

我的通知管理器类

package com.lrtapp.ardentmap;

import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.support.v4.app.NotificationCompat;

public class MyNotificationManager {

    private Context mCtx;
    private static MyNotificationManager mInstance;

    private MyNotificationManager(Context context){
        mCtx = context;
    }

    public static synchronized MyNotificationManager getInstance(Context context){
        if(mInstance == null){
            mInstance = new MyNotificationManager(context);
        }
        return mInstance;
    }

    public void displayNotification(String title, String body){

        NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(mCtx, Constants.CHANNEL_ID)
                .setSmallIcon(R.mipmap.ic_launcher)
                .setContentTitle(title)
                .setContentText(body);

        Intent intent = new Intent(mCtx, MainActivity.class);

        PendingIntent pendingIntent = PendingIntent.getActivity(mCtx, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);


        mBuilder.setContentIntent(pendingIntent);


        NotificationManager mNotificationManager = (NotificationManager) mCtx.getSystemService(Context.NOTIFICATION_SERVICE);

        if(mNotificationManager != null){
            mNotificationManager.notify(1, mBuilder.build());
        }

    }
}

常量类

package com.lrtapp.ardentmap;

public class Constants {

    public static final String CHANNEL_ID = "mychannelid";
    public static final String CHANNEL_NAME = "mychannelname";
    public static final String CHANNEL_DESCRIPTION = "myDescription";

}

Google地图类

package com.lrtapp.ardentmap;

import android.Manifest;
import android.content.pm.PackageManager;
import android.location.Address;
import android.location.Geocoder;
import android.location.Location;
import android.media.Image;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.KeyEvent;
import android.view.View;
import android.view.WindowManager;
import android.view.inputmethod.EditorInfo;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;

import com.google.android.gms.gcm.Task;
import com.google.android.gms.location.FusedLocationProviderClient;
import com.google.android.gms.location.LocationServices;
import com.google.android.gms.maps.CameraUpdate;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
import com.google.android.gms.tasks.OnCompleteListener;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

public class MapActivity extends AppCompatActivity implements OnMapReadyCallback {

    @Override
    public void onMapReady(GoogleMap googleMap) {
        Toast.makeText(this, "map is ready", Toast.LENGTH_SHORT).show();
        Log.d(TAG, "onMapReady: map is ready");
        mMap = googleMap;

        if (mLocationPermissionGranted) {
            getDeviceLocation();

            if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
                    != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this,
                    Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {

                return;
            }
            mMap.setMyLocationEnabled(true);
            mMap.getUiSettings().setMyLocationButtonEnabled(false);

            init();
        }
    }

    private static final String TAG = "MapActivity";

    private static final String FINE_LOCATION = Manifest.permission.ACCESS_FINE_LOCATION;
    private static final String COURSE_LOCATION = Manifest.permission.ACCESS_COARSE_LOCATION;
    private static final int LOCATION_PERMISSION_REQUEST_CODE = 1234;
    private static final float DEFAULT_ZOOM = 15f;

    //widgets
    private EditText mSearchText;
    private ImageView mGps;

    //vars

    private boolean mLocationPermissionGranted = false;
    private GoogleMap mMap;
    private FusedLocationProviderClient mFusedLocationProviderClient;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_map);
        mSearchText = (EditText) findViewById(R.id.input_search);
        mGps = (ImageView) findViewById(R.id.ic_gps);

        getLocationPermission();

    }

    private void init(){
        Log.d(TAG, "init: Initializing");

        mSearchText.setOnEditorActionListener(new TextView.OnEditorActionListener() {
            @Override
            public boolean onEditorAction(TextView textView, int actionId, KeyEvent keyEvent) {
                if (actionId == EditorInfo.IME_ACTION_SEARCH
                        || actionId == EditorInfo.IME_ACTION_DONE
                        ||  keyEvent.getAction() == keyEvent.ACTION_DOWN
                        || keyEvent.getAction() == keyEvent.KEYCODE_ENTER){

                    //execute method for searching
                    geoLocate();

                }
                return false;
            }
        });

        mGps.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Log.d(TAG, "onClick: clicked gps icon");
                getDeviceLocation();

            }
        });

        hideSoftKeyboard();
    }

    private void geoLocate(){
        Log.d(TAG, "geoLocate: geolocating");

        String searchString = mSearchText.getText().toString();

        Geocoder geocoder = new Geocoder(MapActivity.this);
        List<Address> list = new ArrayList<>();
        try{
            list = geocoder.getFromLocationName(searchString, 1);
        }catch(IOException e){
            Log.e(TAG, "geoLocate: IOException" + e.getMessage());
        }
        if(list.size() > 0){
            Address address = list.get(0);

            Log.d(TAG, "GeoLocate: found a Location: " +address.toString());

           // Toast.makeText(this, address.toString(), Toast.LENGTH_SHORT()).show();

            moveCamera(new LatLng(address.getLatitude(), address.getLongitude()), DEFAULT_ZOOM,
                    address.getAddressLine(0));
        }
    }

    private void getDeviceLocation(){
        Log.d(TAG, "getDeviceLocation: getting the device's current location.");

        mFusedLocationProviderClient = LocationServices.getFusedLocationProviderClient(this);

        try {
            if (mLocationPermissionGranted){

                final com.google.android.gms.tasks.Task location = mFusedLocationProviderClient.getLastLocation();
                location.addOnCompleteListener(new OnCompleteListener() {
                    @Override
                    public void onComplete(@NonNull com.google.android.gms.tasks.Task task) {
                        if(task.isSuccessful()){
                            Log.d(TAG, "Found Location");
                            Location currentLocation = (Location) task.getResult();

                                moveCamera(new LatLng(currentLocation.getLatitude(), currentLocation.getLongitude()),
                                        DEFAULT_ZOOM,
                                        "My Location");

                        }else{
                            Log.d(TAG, "onComplete: current Location is null");
                            Toast.makeText(MapActivity.this, "unable to get current location", Toast.LENGTH_SHORT).show();
                        }
                    }
                });

            }
        }catch (SecurityException e){
            Log.e(TAG, "getDeviceLocation: SecurityException: " + e.getMessage());
        }
    }

    @Override
    protected void finalize() throws Throwable {
        super.finalize();
    }

    private void moveCamera(LatLng latLng, float zoom, String title){
        Log.d(TAG, "moving the camera to: lat: " + latLng.latitude + ", lng: " +latLng.longitude);
        mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(latLng,zoom));

        if(!title.equals("My Location")){
            MarkerOptions options = new MarkerOptions()
                    .position(latLng)
                    .title(title);

            mMap.addMarker(options);
        }
        hideSoftKeyboard();

    }

    private void initMap(){
        Log.d(TAG, "initMap: initializing map");
        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);

        mapFragment.getMapAsync(MapActivity.this);
    }

    private void getLocationPermission(){
        Log.d(TAG, "getLocationPermission: getting location permissions");
        String[] permissions = {Manifest.permission.ACCESS_FINE_LOCATION, Manifest.permission.ACCESS_COARSE_LOCATION};

        if(ContextCompat.checkSelfPermission(this.getApplicationContext(), FINE_LOCATION) == PackageManager.PERMISSION_GRANTED){

        if(ContextCompat.checkSelfPermission(this.getApplicationContext(), COURSE_LOCATION) == PackageManager.PERMISSION_GRANTED){
            mLocationPermissionGranted = true;
            initMap();

        }else{
            ActivityCompat.requestPermissions(this, permissions, LOCATION_PERMISSION_REQUEST_CODE);
        }

        }else{
            ActivityCompat.requestPermissions(this, permissions, LOCATION_PERMISSION_REQUEST_CODE);
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        Log.d(TAG, "onRequestPermissionsResult: called.");
        mLocationPermissionGranted = false;

        switch (requestCode){
            case LOCATION_PERMISSION_REQUEST_CODE:{
                if(grantResults.length > 0){
                    for(int i = 0; i < grantResults.length; i++){
                        if(grantResults[i] != PackageManager.PERMISSION_GRANTED){
                            mLocationPermissionGranted = false;
                            Log.d(TAG, "onRequestPermissionsResult: permission failed.");
                            return;
                        }
                    }

                    mLocationPermissionGranted = true;
                    Log.d(TAG, "onRequestPermissionsResult: permission granted.");
                    //initializing map
                    initMap();

                }
            }
        }
    }

    private void hideSoftKeyboard(){
        this.getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_HIDDEN);
    }

}

项目摇篮

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {

    repositories {
        google()
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.1.4'
        classpath 'com.google.gms:google-services:4.1.0'


        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        google()
        jcenter()
        maven{
            url "https://maven.google.com"
        }
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}



**Module/App Gradle**
apply plugin: 'com.android.application'

android {
    compileSdkVersion 27
    defaultConfig {
        applicationId "com.lrtapp.ardentmap"
        minSdkVersion 16
        targetSdkVersion 27
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'com.android.support:appcompat-v7:27.1.1'
    implementation 'com.android.support.constraint:constraint-layout:1.1.3'
    implementation 'com.google.firebase:firebase-messaging:17.3.1'
    testImplementation 'junit:junit:4.12'
    implementation 'com.google.firebase:firebase-core:16.0.3'
    androidTestImplementation 'com.android.support.test:runner:1.0.2'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'

    implementation 'me.biubiubiu.justifytext:library:1.1'

    //Google Play Services
    implementation 'com.google.android.gms:play-services-gcm:15.0.1'
    //implementation 'com.google.android.gms:play-services:11.4.0'
    implementation 'com.google.android.gms:play-services-maps:15.0.1'
    implementation 'com.google.android.gms:play-services-location:15.0.1'
}
apply plugin: 'com.google.gms.google-services'

任何一种答案将不胜感激。预先感谢！

Answer 1

在MainActivity中更改第79行

Log.d（“我的令牌”，common.currentToken +“”）;

Answer 2

日志显示：

Caused by: java.lang.NullPointerException: println needs a message
                  at android.util.Log.d(Log.java:145)
                  at com.lrtapp.ardentmap.MainActivity.onCreate(MainActivity.java:79)

在您记录的common.currentToken的第79行，该记录为空。

  FirebaseInstanceId.getInstance().getToken();

从那时起，您可以看到此答案以及令牌为何返回null的一些可能性：

FirebaseInstanceIdService getToken returning null

一种快速的肮脏解决方法是对第79行进行注释，但是您的通知将无法正常工作。

Answer 3

这不是答案，而是您获取日志所需遵循的步骤。在模拟器上运行应用程序时，在Android Studio上打开运行窗口，您可以在左下角找到它。

在此窗口中，您可以找到日志，只需将日志复制并粘贴到此处，以便我们提供帮助。

Answer 4

据我所见，build.gradle缺乏以下依赖性：

implementation "com.google.android.gms:play-services-base:15.0.1"

可能也是：

implementation "com.google.android.gms:play-services-auth:16.0.0"

请首先添加这些内容-如果仍然需要，然后将logcat输出添加到问题中。

Android APK即使在模拟器上也无法打开

4 个答案: