show a Rate us button to returning users

app/src/main/java/com/simplemobiletools/gallery/Config.java

@@ -0,0 +1,24 @@
+package com.simplemobiletools.gallery;
+
+import android.content.Context;
+import android.content.SharedPreferences;
+
+public class Config {
+    private SharedPreferences mPrefs;
+
+    public static Config newInstance(Context context) {
+        return new Config(context);
+    }
+
+    public Config(Context context) {
+        mPrefs = context.getSharedPreferences(Constants.PREFS_KEY, Context.MODE_PRIVATE);
+    }
+
+    public boolean getIsFirstRun() {
+        return mPrefs.getBoolean(Constants.IS_FIRST_RUN, true);
+    }
+
+    public void setIsFirstRun(boolean firstRun) {
+        mPrefs.edit().putBoolean(Constants.IS_FIRST_RUN, firstRun).apply();
+    }
+}

app/src/main/java/com/simplemobiletools/gallery/Constants.java

@@ -6,4 +6,8 @@ public class Constants {
     public static final String GET_IMAGE_INTENT = "get_image_intent";
     public static final String GET_VIDEO_INTENT = "get_video_intent";
     public static final String SET_WALLPAPER_INTENT = "set_wallpaper_intent";
+
+    // shared preferences
+    public static final String PREFS_KEY = "gallery";
+    public static final String IS_FIRST_RUN = "is_first_run";
 }

app/src/main/java/com/simplemobiletools/gallery/activities/AboutActivity.java

@@ -1,5 +1,6 @@
 package com.simplemobiletools.gallery.activities;
 
+import android.content.ActivityNotFoundException;
 import android.content.Intent;
 import android.content.res.Resources;
 import android.net.Uri;
@@ -7,9 +8,11 @@ import android.os.Bundle;
 import android.support.v7.app.AppCompatActivity;
 import android.text.Html;
 import android.text.method.LinkMovementMethod;
+import android.view.View;
 import android.widget.TextView;
 
 import com.simplemobiletools.gallery.BuildConfig;
+import com.simplemobiletools.gallery.Config;
 import com.simplemobiletools.gallery.R;
 
 import java.util.Calendar;
@@ -19,9 +22,10 @@ import butterknife.ButterKnife;
 import butterknife.OnClick;
 
 public class AboutActivity extends AppCompatActivity {
-    @BindView(R.id.about_copyright) TextView copyright;
-    @BindView(R.id.about_version) TextView version;
-    @BindView(R.id.about_email) TextView emailTV;
+    @BindView(R.id.about_copyright) TextView mCopyright;
+    @BindView(R.id.about_version) TextView mVersion;
+    @BindView(R.id.about_email) TextView mEmailTV;
+    @BindView(R.id.about_rate_us) View mRateUs;
 
     private static Resources mRes;
 
@@ -35,26 +39,43 @@ public class AboutActivity extends AppCompatActivity {
         setupEmail();
         setupVersion();
         setupCopyright();
+        setupRateUs();
     }
 
     private void setupEmail() {
         final String email = mRes.getString(R.string.email);
         final String appName = mRes.getString(R.string.app_name);
         final String href = "<a href=\"mailto:" + email + "?subject=" + appName + "\">" + email + "</a>";
-        emailTV.setText(Html.fromHtml(href));
-        emailTV.setMovementMethod(LinkMovementMethod.getInstance());
+        mEmailTV.setText(Html.fromHtml(href));
+        mEmailTV.setMovementMethod(LinkMovementMethod.getInstance());
     }
 
     private void setupVersion() {
         final String versionName = BuildConfig.VERSION_NAME;
         final String versionText = String.format(mRes.getString(R.string.version), versionName);
-        version.setText(versionText);
+        mVersion.setText(versionText);
     }
 
     private void setupCopyright() {
         final int year = Calendar.getInstance().get(Calendar.YEAR);
         final String copyrightText = String.format(mRes.getString(R.string.copyright), year);
-        copyright.setText(copyrightText);
+        mCopyright.setText(copyrightText);
+    }
+
+    private void setupRateUs() {
+        if (Config.newInstance(getApplicationContext()).getIsFirstRun()) {
+            mRateUs.setVisibility(View.GONE);
+        }
+    }
+
+    @OnClick(R.id.about_rate_us)
+    public void rateUsClicked() {
+        final Uri uri = Uri.parse("market://details?id=" + getPackageName());
+        try {
+            startActivity(new Intent(Intent.ACTION_VIEW, uri));
+        } catch (ActivityNotFoundException ignored) {
+            startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse("http://play.google.com/store/apps/details?id=" + getPackageName())));
+        }
     }
 
     @OnClick(R.id.about_license)

app/src/main/java/com/simplemobiletools/gallery/activities/MainActivity.java

@@ -28,6 +28,7 @@ import android.widget.EditText;
 import android.widget.GridView;
 import android.widget.TextView;
 
+import com.simplemobiletools.gallery.Config;
 import com.simplemobiletools.gallery.Constants;
 import com.simplemobiletools.gallery.R;
 import com.simplemobiletools.gallery.Utils;
@@ -121,6 +122,12 @@ public class MainActivity extends AppCompatActivity
             mState = mGridView.onSaveInstanceState();
     }
 
+    @Override
+    protected void onDestroy() {
+        super.onDestroy();
+        Config.newInstance(getApplicationContext()).setIsFirstRun(false);
+    }
+
     private void tryloadGallery() {
         if (Utils.hasStoragePermission(getApplicationContext())) {
             initializeGallery();

app/src/main/res/layout/activity_about.xml

@@ -29,11 +29,21 @@
         android:text="@string/email"/>
 
     <TextView
-        android:id="@+id/about_license"
+        android:id="@+id/about_rate_us"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:layout_below="@+id/about_email"
         android:layout_marginTop="@dimen/activity_margin"
+        android:paddingTop="@dimen/activity_margin"
+        android:text="@string/rate_us_underlined"
+        android:textColor="@color/colorPrimary"/>
+
+    <TextView
+        android:id="@+id/about_license"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_below="@+id/about_rate_us"
+        android:layout_marginTop="@dimen/activity_margin"
         android:paddingBottom="@dimen/activity_margin"
         android:paddingTop="@dimen/activity_margin"
         android:text="@string/third_party_licences_underlined"

app/src/main/res/values/strings.xml

@@ -35,6 +35,7 @@
     <string name="email_label">Send your feedback or suggestions at:</string>
     <string name="email">hello@simplemobiletools.com</string>
     <string name="third_party_licences_underlined"><u>Third party licences</u></string>
+    <string name="rate_us_underlined"><u>Rate us in the Play Store</u></string>
     <string name="follow_us">Follow us at:</string>
     <string name="version">v %1$s</string>
     <string name="copyright">Copyright © Simple Mobile Tools %1$d</string>