Androis-studio GPS maps don't show

Question

I'm trying to create an app GPS maps, so this compiled without some problem, but I installed it in my phone(android v 8.1.1) but don't show up the maps. this is a photo:

cremshop

this is my code:

build.gradle(module app)

apply plugin: 'com.android.application'

android {
    compileSdkVersion 28
    defaultConfig {
        applicationId "com.example.ejemplogpsmaps"
        minSdkVersion 19
        targetSdkVersion 28
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'com.android.support:appcompat-v7:28.0.0'
    implementation 'com.android.support.constraint:constraint-layout:1.1.3'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.2'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'

    implementation 'com.google.android.gms:play-services-maps:16.1.0'

}

here all project APP GPS

what happends? why the maps don't show up!

Answer 1

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/tvMensaje"
        android:layout_width="match_parent"
        android:layout_height="80dp"
        android:layout_marginLeft="8dp"
        android:layout_marginTop="8dp"
        android:layout_marginRight="8dp"
        android:text="Ubicacion"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <fragment
        android:id="@+id/fragment"
        android:name="com.example.ejemplogpsmaps.FragmentMaps"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginBottom="8dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/tvMensaje" />

</android.support.constraint.ConstraintLayout>

Answer 2

MainActivity.Java

package com.example.ejemplogpsmaps;

import android.Manifest;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.location.LocationManager;
import android.provider.Settings;
import android.support.v4.app.ActivityCompat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    TextView tvMensaje;

    // Minimo tiempo para updates en Milisegundos
    private static final long MIN_TIME = 10000; // 10 segundos

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

        tvMensaje = findViewById(R.id.tvMensaje);

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

            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.ACCESS_FINE_LOCATION,}, 1000);

        } else {
            iniciarLocalizacion();
        }
    }

    private void iniciarLocalizacion() {
        LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);

        Localizacion local = new Localizacion();

        local.setMainActivity(this, tvMensaje);

        final boolean gpsEnabled = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
        if(!gpsEnabled) {
            Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
            startActivity(intent);
        }

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

            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.ACCESS_FINE_LOCATION,}, 1000);
            return;
        }

        locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, MIN_TIME, 0, local);
        locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, MIN_TIME, 0, local);

        tvMensaje.setText("Localizacion agregada");
    }

    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[]grantResults) {
        if(requestCode == 1000) {
            if(grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                iniciarLocalizacion();
                return;
            }
        }
    }
}