Add an ApiDemo for showing an overlay window.

Test: manually.
Change-Id: I9eaa9c0eeb3bc04389c27a7fe5e74fc5acdc59fd

3 files changed, 180 insertions, 0 deletions

diff --git a/samples/ApiDemos/AndroidManifest.xml b/samples/ApiDemos/AndroidManifest.xml
index df4232dd1..9c5c4bd14 100644
--- a/samples/ApiDemos/AndroidManifest.xml
+++ b/samples/ApiDemos/AndroidManifest.xml
@@ -41,6 +41,8 @@
     <uses-permission android:name="android.permission.WAKE_LOCK"/>
     <uses-permission android:name="android.permission.REQUEST_INSTALL_PACKAGES"/>
     <uses-permission android:name="android.permission.REQUEST_DELETE_PACKAGES"/>
+    <!-- Required for drawing overlay windows (TYPE_SYSTEM_ALERT, TYPE_APPLICATION_OVERLAY) -->
+    <uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW"/>
 
     <!-- For android.media.audiofx.Visualizer -->
     <uses-permission android:name="android.permission.RECORD_AUDIO" />
@@ -2519,6 +2521,13 @@
             </intent-filter>
         </activity>
 
+        <activity android:name=".view.OverlayWindowActivity" android:label="Views/Overlay Window">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.SAMPLE_CODE" />
+            </intent-filter>
+        </activity>
+
         <activity android:name=".view.RatingBar1" android:label="Views/Rating Bar">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
diff --git a/samples/ApiDemos/res/layout/overlay_window.xml b/samples/ApiDemos/res/layout/overlay_window.xml
new file mode 100644
index 000000000..ffa3fde71
--- /dev/null
+++ b/samples/ApiDemos/res/layout/overlay_window.xml
@@ -0,0 +1,41 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2017 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+-->
+
+
+<!-- Demonstrates displaying overlay windows. -->
+
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:padding="4dip"
+    android:gravity="center_horizontal"
+    android:layout_width="match_parent" android:layout_height="match_parent">
+
+    <TextView
+        android:layout_width="match_parent" android:layout_height="wrap_content"
+        android:layout_weight="0"
+        android:paddingBottom="4dip"
+        android:textAppearance="?android:attr/textAppearanceMedium"
+        android:text="Demonstrates displaying overlay windows (on top of other apps)."/>
+
+    <Button android:id="@+id/show_overlay"
+        android:layout_width="wrap_content" android:layout_height="wrap_content"
+        android:text="Show Overlay">
+    </Button>
+
+    <Button android:id="@+id/hide_overlay"
+        android:layout_width="wrap_content" android:layout_height="wrap_content"
+        android:text="Hide Overlay">
+    </Button>
+
+</LinearLayout>
\ No newline at end of file
diff --git a/samples/ApiDemos/src/com/example/android/apis/view/OverlayWindowActivity.java b/samples/ApiDemos/src/com/example/android/apis/view/OverlayWindowActivity.java
new file mode 100644
index 000000000..df6c91440
--- /dev/null
+++ b/samples/ApiDemos/src/com/example/android/apis/view/OverlayWindowActivity.java
@@ -0,0 +1,130 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.example.android.apis.view;
+
+import com.example.android.apis.R;
+
+import android.app.Activity;
+import android.content.Context;
+import android.content.Intent;
+import android.graphics.Color;
+import android.graphics.PixelFormat;
+import android.net.Uri;
+import android.os.Build;
+import android.os.Bundle;
+import android.provider.Settings;
+import android.view.Gravity;
+import android.view.View;
+import android.view.View.OnClickListener;
+import android.view.WindowManager;
+import android.view.WindowManager.LayoutParams;
+import android.widget.Button;
+import android.widget.TextView;
+
+/**
+ * Demonstrates the display of overlay windows, i.e. windows that are drawn on top of other apps.
+ */
+public class OverlayWindowActivity extends Activity {
+
+    private static int MANAGE_OVERLAY_PERMISSION_REQUEST_CODE = 1;
+    private View mOverlayView;
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+
+        setContentView(R.layout.overlay_window);
+
+        Button button = (Button)findViewById(R.id.show_overlay);
+        button.setOnClickListener(mShowOverlayListener);
+        button = (Button)findViewById(R.id.hide_overlay);
+        button.setOnClickListener(mHideOverlayListener);
+    }
+
+    private OnClickListener mShowOverlayListener = new OnClickListener() {
+        @Override
+        public void onClick(View view) {
+            if (Settings.canDrawOverlays(OverlayWindowActivity.this)) {
+                drawOverlay();
+            } else {
+                // Need to ask the user's permission first. We'll redirect them to Settings.
+                Intent intent = new Intent(Settings.ACTION_MANAGE_OVERLAY_PERMISSION,
+                        Uri.parse("package:" + getPackageName()));
+                startActivityForResult(intent, MANAGE_OVERLAY_PERMISSION_REQUEST_CODE);
+            }
+        }
+    };
+
+    private OnClickListener mHideOverlayListener = new OnClickListener() {
+        @Override
+        public void onClick(View view) {
+            if (mOverlayView != null) {
+                WindowManager wm = getWindowManager();
+                wm.removeView(mOverlayView);
+                mOverlayView = null;
+            }
+        }
+    };
+
+    /**
+     * This is called after the user chooses whether they grant permission to the app to display
+     * overlays or not.
+     */
+    @Override
+    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
+        if (requestCode == MANAGE_OVERLAY_PERMISSION_REQUEST_CODE) {
+            // Check if the user granted permission to draw overlays.
+            if (Settings.canDrawOverlays(this)) {
+                drawOverlay();
+            }
+        }
+    }
+
+    private void drawOverlay() {
+        if (mOverlayView != null) {
+            // Already shown.
+            return;
+        }
+
+        TextView textView = new TextView(this);
+        textView.setText("I'm an overlay");
+        textView.setBackgroundColor(Color.WHITE);
+        textView.setTextColor(Color.BLACK);
+        textView.setPadding(10, 10, 10, 10);
+
+        WindowManager wm = getWindowManager();
+        LayoutParams params = new LayoutParams();
+
+        params.type = (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O)
+                ? LayoutParams.TYPE_APPLICATION_OVERLAY
+                : LayoutParams.TYPE_PHONE;
+        params.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
+                | WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL
+                | WindowManager.LayoutParams.FLAG_WATCH_OUTSIDE_TOUCH;
+        params.format = PixelFormat.TRANSPARENT;
+
+        params.width = LayoutParams.WRAP_CONTENT;
+        params.height = LayoutParams.WRAP_CONTENT;
+        // Snap to the upper right corner of the screen.
+        params.gravity = Gravity.TOP | Gravity.RIGHT;
+        // Set position relative to upper right corner.
+        params.x = 10;
+        params.y = 10;
+
+        wm.addView(textView, params);
+        mOverlayView = textView;
+    }
+}