Add check exists for certification page

Author: Takayuki Otake

README.md

@@ -28,10 +28,15 @@ dependencies {
 Open an Activity to connect with Studyplus.
 
 ```java
-AuthTransit.from(activity).startActivity(
-	context.getString("app_consumer_key"),
-	context.getString("app_consumer_key_secret")
-);
+try {
+    AuthTransit.from(activity).startActivity(
+	    context.getString("app_consumer_key"),
+	    context.getString("app_consumer_key_secret")
+    );
+} catch (ActivityNotFoundException e) {
+    e.printStackTrace();
+    Toast.makeText(context, "Need for Studyplus 2.14.0+", Toast.LENGTH_SHORT).show();
+}
 ```
 
 Then save its result.

SDKExample/src/main/java/jp/studyplus/android/sdk/example/ExampleActivity.java

@@ -1,6 +1,7 @@
 package jp.studyplus.android.sdk.example;
 
 import android.app.Activity;
+import android.content.ActivityNotFoundException;
 import android.content.Context;
 import android.content.Intent;
 import android.os.Bundle;
@@ -84,10 +85,16 @@ private OnClickToAuth(Activity activity) {
 		}
 		@Override
 		public void onClick(View v) {
-			AuthTransit.from(activity).startActivity(
-				context.getString(R.string.sample_consumer_key),
-				context.getString(R.string.sample_consumer_key_secret)
-			);
+			try {
+				AuthTransit.from(activity).startActivity(
+						context.getString(R.string.sample_consumer_key),
+						context.getString(R.string.sample_consumer_key_secret)
+				);
+			} catch (ActivityNotFoundException e) {
+				e.printStackTrace();
+				Toast.makeText(context, R.string.sample_certification_studyplus_not_found, Toast.LENGTH_SHORT)
+						.show();
+			}
 		}
 	}
 

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

@@ -4,4 +4,5 @@
     <string name="app_name">SDK Example</string>
     <string name="hello_world">Hello world!!!</string>
 
+    <string name="sample_certification_studyplus_not_found">Studyplus 2.14.0 以上のインストールが必要です。</string>
 </resources>

StudyplusAndroidSDK/src/main/java/jp/studyplus/android/sdk/service/auth/AuthTransit.java

@@ -1,6 +1,7 @@
 package jp.studyplus.android.sdk.service.auth;
 
 import android.app.Activity;
+import android.content.ActivityNotFoundException;
 import android.content.Intent;
 import android.net.Uri;
 
@@ -24,7 +25,8 @@ public AuthTransit setRequestCode(int requestCode){
 		return new AuthTransit(activity, requestCode);
 	}
 
-	public void startActivity(String consumerKey, String consumerSecret){
+	public void startActivity(String consumerKey, String consumerSecret)
+			throws ActivityNotFoundException {
 		Intent intent = new Intent();
 		intent.setAction(Intent.ACTION_VIEW);
 		intent.putExtra("consumer_key", consumerKey);