fixed #1088

android/AndroidManifest.xml

@@ -6,21 +6,21 @@
       android:versionName="2.18.0">
     <uses-sdk android:minSdkVersion="14" android:targetSdkVersion="25"/>
 	<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
-    <uses-permission android:name="android.permission.INTERNET"/>
+    <uses-permission android:name="android.permission.INTERNET"/><!-- normal perm, per https://developer.android.com/guide/topics/permissions/normal-permissions.html -->
-    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
+    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/><!-- normal perm -->
-	<application android:label="@string/app_name" android:allowBackup="true" android:icon="@drawable/icon" >
+	<application android:label="@string/app_name" android:allowBackup="true" android:icon="@drawable/icon" android:theme="@style/Theme.AppCompat">
 	    <receiver android:name=".NetworkStateChangeReceiver">
 	        <intent-filter>
 	            <action android:name="android.net.conn.CONNECTIVITY_CHANGE"/>
 	        </intent-filter>
 	    </receiver>
-	    <activity android:name=".I2PDActivity"
+        <activity android:name=".I2PDPermsAskerActivity" android:label="@string/app_name">
-                  android:label="@string/app_name">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
         </activity>
+        <activity android:name=".I2PDActivity" android:label="@string/app_name"/>
         <service android:enabled="true" android:name=".ForegroundService"/>
     </application>
 </manifest>

android/build.gradle

@@ -1,15 +1,31 @@
 buildscript {
         repositories {
-                mavenCentral()
+            mavenCentral()
-                jcenter()
+            jcenter()
         }
         dependencies {
-                classpath 'com.android.tools.build:gradle:2.3.3'
+            classpath 'com.android.tools.build:gradle:2.3.3'
         }
 }
 
 apply plugin: 'com.android.application'
 
+repositories {
+    jcenter()
+    maven {
+        url 'https://maven.google.com'
+    }
+}
+
+dependencies {
+//    compile "com.android.support:support-v4:26.1.0"
+//    compile "com.android.support:support-v13:26.1.0"
+//    compile "com.android.support:cardview-v7:26.1.0"
+//    compile "com.android.support:appcompat-v7:26.1.0"
+    compile 'com.android.support:support-v4:25.3.1'
+    compile 'com.android.support:design:25.3.1'
+}
+
 android {
         compileSdkVersion 25
         buildToolsVersion "25.0.2"

android/res/layout/activity_perms_asker.xml

@@ -0,0 +1,27 @@
+<LinearLayout android:id="@+id/main_layout"
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical"
+    android:paddingBottom="@dimen/vertical_page_margin"
+    android:paddingLeft="@dimen/horizontal_page_margin"
+    android:paddingRight="@dimen/horizontal_page_margin"
+    android:paddingTop="@dimen/vertical_page_margin"
+    tools:context=".I2PDPermsAskerActivity">
+
+    <TextView
+        android:id="@+id/textview_retry"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginBottom="@dimen/horizontal_page_margin"
+        android:visibility="gone"
+        />
+
+    <Button
+        android:id="@+id/button_request_write_ext_storage_perms"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="Retry requesting the SD card write permissions"
+        android:visibility="gone"/>
+</LinearLayout>

android/res/values/template-dimens.xml

@@ -0,0 +1,16 @@
+<resources>
+
+    <!-- Define standard dimensions to comply with Holo-style grids and rhythm. -->
+
+    <dimen name="margin_tiny">4dp</dimen>
+    <dimen name="margin_small">8dp</dimen>
+    <dimen name="margin_medium">16dp</dimen>
+    <dimen name="margin_large">32dp</dimen>
+    <dimen name="margin_huge">64dp</dimen>
+
+    <!-- Semantic definitions -->
+
+    <dimen name="horizontal_page_margin">@dimen/margin_medium</dimen>
+    <dimen name="vertical_page_margin">@dimen/margin_medium</dimen>
+
+</resources>

android/src/org/purplei2p/i2pd/I2PDActivity.java

@@ -12,13 +12,14 @@ import android.content.Intent;
 import android.content.ServiceConnection;
 import android.os.Bundle;
 import android.os.IBinder;
+import android.support.v7.app.AppCompatActivity;
 import android.util.Log;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.widget.TextView;
 import android.widget.Toast;
 
-public class I2PDActivity extends Activity {
+public class I2PDActivity extends AppCompatActivity {
     private static final String TAG = "i2pdActvt";
     public static final int GRACEFUL_DELAY_MILLIS = 10 * 60 * 1000;
 

android/src/org/purplei2p/i2pd/I2PDPermsAskerActivity.java

@@ -0,0 +1,121 @@
+package org.purplei2p.i2pd;
+
+import android.Manifest;
+import android.app.Activity;
+import android.content.Intent;
+import android.content.pm.PackageManager;
+import android.os.Bundle;
+import android.support.v4.app.ActivityCompat;
+import android.support.design.widget.Snackbar;
+import android.support.v7.app.AppCompatActivity;
+import android.view.View;
+import android.widget.Button;
+import android.widget.TextView;
+
+//dangerous perms, per https://developer.android.com/guide/topics/permissions/normal-permissions.html :
+//android.permission.WRITE_EXTERNAL_STORAGE
+public class I2PDPermsAskerActivity extends AppCompatActivity {
+
+    private static final int PERMISSION_WRITE_EXTERNAL_STORAGE = 0;
+
+    private View mLayout;
+    private Button button_request_write_ext_storage_perms;
+    private TextView textview_retry;
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+
+        setContentView(R.layout.activity_perms_asker);
+        mLayout = findViewById(R.id.main_layout);
+        button_request_write_ext_storage_perms = (Button) findViewById(R.id.button_request_write_ext_storage_perms);
+        textview_retry = (TextView) findViewById(R.id.textview_retry);
+
+        button_request_write_ext_storage_perms.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View view) {
+                request_write_ext_storage_perms();
+            }
+        });
+        request_write_ext_storage_perms();
+    }
+
+    private void request_write_ext_storage_perms() {
+
+        textview_retry.setVisibility(TextView.GONE);
+        button_request_write_ext_storage_perms.setVisibility(Button.GONE);
+
+        // Here, thisActivity is the current activity
+        if (ActivityCompat.checkSelfPermission(this,
+                Manifest.permission.WRITE_EXTERNAL_STORAGE)
+                != PackageManager.PERMISSION_GRANTED) {
+
+            // Should we show an explanation?
+            if (ActivityCompat.shouldShowRequestPermissionRationale(this,
+                    Manifest.permission.WRITE_EXTERNAL_STORAGE)) {
+
+                // Show an explanation to the user *asynchronously* -- don't block
+                // this thread waiting for the user's response! After the user
+                // sees the explanation, try again to request the permission.
+
+                Snackbar.make(mLayout, "SD card write access is required to write the keys and other files to the I2PD folder on SD card.",
+                        Snackbar.LENGTH_INDEFINITE).setAction("OK", new View.OnClickListener() {
+                    @Override
+                    public void onClick(View view) {
+                        // Request the permission
+                        ActivityCompat.requestPermissions(I2PDPermsAskerActivity.this,
+                                new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},
+                                PERMISSION_WRITE_EXTERNAL_STORAGE);
+                    }
+                }).show();
+
+            } else {
+
+                // No explanation needed, we can request the permission.
+
+                ActivityCompat.requestPermissions(this,
+                        new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},
+                        PERMISSION_WRITE_EXTERNAL_STORAGE);
+
+                // MY_PERMISSIONS_REQUEST_READ_CONTACTS is an
+                // app-defined int constant. The callback method gets the
+                // result of the request.
+            }
+        } else startMainActivity();
+    }
+
+    @Override
+    public void onRequestPermissionsResult(int requestCode,
+                                           String permissions[], int[] grantResults) {
+        switch (requestCode) {
+            case PERMISSION_WRITE_EXTERNAL_STORAGE: {
+                // If request is cancelled, the result arrays are empty.
+                if (grantResults.length > 0
+                        && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
+
+                    // permission was granted, yay! Do the
+                    // contacts-related task you need to do.
+
+                    startMainActivity();
+
+                } else {
+
+                    // permission denied, boo! Disable the
+                    // functionality that depends on this permission.
+                    textview_retry.setText("SD card write permission denied, you need to allow this to continue");
+                    textview_retry.setVisibility(TextView.VISIBLE);
+                    button_request_write_ext_storage_perms.setVisibility(Button.VISIBLE);
+                }
+                return;
+            }
+
+            // other 'case' lines to check for other
+            // permissions this app might request.
+        }
+    }
+
+    private void startMainActivity() {
+        startActivity(new Intent(this, I2PDActivity.class));
+        finish();
+    }
+}