我已经在libs目录osmdroid jar文件中添加了这个库。slf4j jar文件。
我按照教程在https://androidcookbook.com/Recipe.seam?recipeId=2521，但Map没有显示，我不知道发生了什么

这是我的MainAcitvity.java

package com.example.pc_parinussa.osm;

import android.app.Activity;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

import org.osmdroid.tileprovider.tilesource.TileSourceFactory;
import org.osmdroid.util.GeoPoint;
import org.osmdroid.views.MapController;
import org.osmdroid.views.MapView;
import org.osmdroid.views.overlay.ScaleBarOverlay;

public class MainActivity extends Activity {
    private MapView         mMapView;
    private MapController   mMapController;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mMapView = (MapView) findViewById(R.id.mapview);
        mMapView.setTileSource(TileSourceFactory.MAPQUESTOSM);
        mMapView.setBuiltInZoomControls(true);
        mMapController = (MapController) mMapView.getController();
        mMapController.setZoom(13);
        GeoPoint gPt = new GeoPoint(51500000, -150000);
        mMapController.setCenter(gPt);
    }
}

我的activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
    <org.osmdroid.views.MapView
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:id="@+id/mapview">
    </org.osmdroid.views.MapView>

</LinearLayout>

我的摇篮

apply plugin: 'com.android.application'

android {
    compileSdkVersion 25
    buildToolsVersion "25.0.2"
    defaultConfig {
        applicationId "com.example.pc_parinussa.osm"
        minSdkVersion 15
        targetSdkVersion 25
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    compile fileTree(include: ['*.jar'], dir: 'libs')
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
    compile 'com.android.support:appcompat-v7:25.2.0'
    compile 'com.android.support.constraint:constraint-layout:1.0.2'
    testCompile 'junit:junit:4.12'
    compile files('libs/osmdroid-android-4.0.jar')
}