Start with Android implementation

android/.classpath

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<classpath>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.8/"/>
+	<classpathentry kind="con" path="org.eclipse.buildship.core.gradleclasspathcontainer"/>
+	<classpathentry kind="output" path="bin/default"/>
+</classpath>

android/.project

@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>flutter_braintree</name>
+	<comment>Project flutter_braintree created by Buildship.</comment>
+	<projects>
+	</projects>
+	<buildSpec>
+		<buildCommand>
+			<name>org.eclipse.jdt.core.javabuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+		<buildCommand>
+			<name>org.eclipse.buildship.core.gradleprojectbuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+	</buildSpec>
+	<natures>
+		<nature>org.eclipse.jdt.core.javanature</nature>
+		<nature>org.eclipse.buildship.core.gradleprojectnature</nature>
+	</natures>
+</projectDescription>

android/.settings/org.eclipse.buildship.core.prefs

@@ -0,0 +1,2 @@
+connection.project.dir=
+eclipse.preferences.version=1

android/build.gradle

@@ -31,4 +31,7 @@ android {
     lintOptions {
         disable 'InvalidPackage'
     }
+    dependencies {
+        compile 'com.braintreepayments.api:drop-in:3.7.1'
+    }
 }

android/src/main/java/info/keepinmind/flutter_braintree/FlutterBraintreePlugin.java

@@ -1,25 +1,65 @@
 package info.keepinmind.flutter_braintree;
 
+import android.app.Activity;
+import android.content.Intent;
+
+import com.braintreepayments.api.dropin.DropInActivity;
+import com.braintreepayments.api.dropin.DropInRequest;
+import com.braintreepayments.api.dropin.DropInResult;
+
 import io.flutter.plugin.common.MethodCall;
 import io.flutter.plugin.common.MethodChannel;
 import io.flutter.plugin.common.MethodChannel.MethodCallHandler;
 import io.flutter.plugin.common.MethodChannel.Result;
+import io.flutter.plugin.common.PluginRegistry;
 import io.flutter.plugin.common.PluginRegistry.Registrar;
 
-/** FlutterBraintreePlugin */
-public class FlutterBraintreePlugin implements MethodCallHandler {
-  /** Plugin registration. */
+public class FlutterBraintreePlugin implements MethodCallHandler, PluginRegistry.ActivityResultListener {
+  private final Registrar mRegistrar;
+  private final static int REQUEST_CODE = 1;
+
+  private FlutterBraintreePlugin(Registrar registrar) {
+    this.mRegistrar = registrar;
+    this.mRegistrar.addActivityResultListener(this);
+  }
+
   public static void registerWith(Registrar registrar) {
-    final MethodChannel channel = new MethodChannel(registrar.messenger(), "flutter_braintree");
-    channel.setMethodCallHandler(new FlutterBraintreePlugin());
+    final MethodChannel channel = new MethodChannel(registrar.messenger(), "info.keepinmind.flutter_braintree");
+    channel.setMethodCallHandler(new FlutterBraintreePlugin(registrar));
   }
 
   @Override
   public void onMethodCall(MethodCall call, Result result) {
-    if (call.method.equals("getPlatformVersion")) {
-      result.success("Android " + android.os.Build.VERSION.RELEASE);
+    if (call.method.equals("showDropIn")) {
+      String clientToken = call.argument("clientToken");
+
+      DropInRequest dropInRequest = new DropInRequest()
+              .clientToken(clientToken);
+
+      mRegistrar.activity().startActivityForResult(dropInRequest.getIntent(mRegistrar.activity()), REQUEST_CODE);
+
+      result.success("OK");
     } else {
       result.notImplemented();
     }
   }
+
+  @Override
+  public boolean onActivityResult(int requestCode, int resultCode, Intent data) {
+    if (requestCode == REQUEST_CODE) {
+      if (resultCode == Activity.RESULT_OK) {
+        DropInResult result = data.getParcelableExtra(DropInResult.EXTRA_DROP_IN_RESULT);
+        // use the result to update your UI and send the payment method nonce to your server
+      } else if (resultCode == Activity.RESULT_CANCELED) {
+        // the user canceled
+      } else {
+        // handle errors here, an exception may be available in
+        Exception error = (Exception) data.getSerializableExtra(DropInActivity.EXTRA_ERROR);
+      }
+
+      return true;
+    }
+
+    return false;
+  }
 }

example/android/.project

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>android</name>
+	<comment>Project android created by Buildship.</comment>
+	<projects>
+	</projects>
+	<buildSpec>
+		<buildCommand>
+			<name>org.eclipse.buildship.core.gradleprojectbuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+	</buildSpec>
+	<natures>
+		<nature>org.eclipse.buildship.core.gradleprojectnature</nature>
+	</natures>
+</projectDescription>

example/android/.settings/org.eclipse.buildship.core.prefs

@@ -0,0 +1,2 @@
+connection.project.dir=
+eclipse.preferences.version=1

example/android/app/.classpath

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<classpath>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.8/"/>
+	<classpathentry kind="con" path="org.eclipse.buildship.core.gradleclasspathcontainer"/>
+	<classpathentry kind="output" path="bin/default"/>
+</classpath>

example/android/app/.project

@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>app</name>
+	<comment>Project app created by Buildship.</comment>
+	<projects>
+	</projects>
+	<buildSpec>
+		<buildCommand>
+			<name>org.eclipse.jdt.core.javabuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+		<buildCommand>
+			<name>org.eclipse.buildship.core.gradleprojectbuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+	</buildSpec>
+	<natures>
+		<nature>org.eclipse.jdt.core.javanature</nature>
+		<nature>org.eclipse.buildship.core.gradleprojectnature</nature>
+	</natures>
+</projectDescription>

example/android/app/.settings/org.eclipse.buildship.core.prefs

@@ -0,0 +1,2 @@
+connection.project.dir=..
+eclipse.preferences.version=1

example/android/app/src/main/AndroidManifest.xml

@@ -29,5 +29,15 @@
                 <category android:name="android.intent.category.LAUNCHER"/>
             </intent-filter>
         </activity>
+
+        <activity android:name="com.braintreepayments.api.BraintreeBrowserSwitchActivity"
+            android:launchMode="singleTask">
+            <intent-filter>
+                <action android:name="android.intent.action.VIEW" />
+                <category android:name="android.intent.category.DEFAULT" />
+                <category android:name="android.intent.category.BROWSABLE" />
+                <data android:scheme="${applicationId}.braintree" />
+            </intent-filter>
+        </activity>
     </application>
 </manifest>