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      1 /*
      2  * Copyright (C) 2015 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.documentsui;
     18 
     19 import static com.android.documentsui.Shared.DEBUG;
     20 
     21 import android.app.Activity;
     22 import android.app.ActivityManager;
     23 import android.app.ActivityManager.AppTask;
     24 import android.content.Context;
     25 import android.content.Intent;
     26 import android.net.Uri;
     27 import android.os.Bundle;
     28 import android.provider.DocumentsContract;
     29 import android.support.annotation.Nullable;
     30 import android.util.Log;
     31 
     32 import java.util.List;
     33 
     34 /**
     35  * Provides FilesActivity task grouping support. This allows multiple FilesActivities to be
     36  * launched (a behavior imparted by way of {@code documentLaunchMode="intoExisting"} and
     37  * our use of pseudo document {@link Uri}s. This also lets us move an existing task
     38  * to the foreground when a suitable task exists.
     39  *
     40  * Requires that {@code documentLaunchMode="intoExisting"} be set on target activity.
     41  *
     42  */
     43 public class LauncherActivity extends Activity {
     44 
     45     private static final String LAUNCH_CONTROL_AUTHORITY = "com.android.documentsui.launchControl";
     46     private static final String TAG = "LauncherActivity";
     47 
     48     // Array of boolean extras that should be copied when creating new launch intents.
     49     // Missing intents will be ignored.
     50     private static final String[] PERSISTENT_BOOLEAN_EXTRAS = {
     51         DocumentsContract.EXTRA_SHOW_FILESIZE,
     52         DocumentsContract.EXTRA_SHOW_ADVANCED,
     53         DocumentsContract.EXTRA_FANCY_FEATURES,
     54         Shared.EXTRA_PRODUCTIVITY_MODE
     55     };
     56 
     57     @Override
     58     protected void onCreate(Bundle savedInstanceState) {
     59         super.onCreate(savedInstanceState);
     60 
     61         ActivityManager activities = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);
     62 
     63         Intent intent = findTask(activities);
     64         if (intent != null) {
     65             restoreTask(intent);
     66         } else {
     67             startTask();
     68         }
     69 
     70         finish();
     71     }
     72 
     73     private @Nullable Intent findTask(ActivityManager activities) {
     74         List<AppTask> tasks = activities.getAppTasks();
     75         for (AppTask task : tasks) {
     76             Intent intent = task.getTaskInfo().baseIntent;
     77             Uri uri = intent.getData();
     78             if (isLaunchUri(uri)) {
     79                 return intent;
     80             }
     81         }
     82         return null;
     83     }
     84 
     85     private void startTask() {
     86         Intent intent = createLaunchIntent(this);
     87 
     88         // Forward any flags from the original intent.
     89         intent.setFlags(getIntent().getFlags());
     90         if (DEBUG) Log.d(TAG, "Starting new task > " + intent.getData());
     91         startActivity(intent);
     92     }
     93 
     94     private void restoreTask(Intent intent) {
     95         if (DEBUG) Log.d(TAG, "Restoring existing task > " + intent.getData());
     96         // TODO: This doesn't appear to restore a task once it has stopped running.
     97         startActivity(intent);
     98     }
     99 
    100     static final Intent createLaunchIntent(Activity activity) {
    101         Intent intent = new Intent(activity, FilesActivity.class);
    102         intent.setData(buildLaunchUri());
    103 
    104         // Relay any config overrides bits present in the original intent.
    105         Intent original = activity.getIntent();
    106         if (original != null) {
    107             copyExtras(original, intent);
    108             if (original.hasExtra(Intent.EXTRA_TITLE)) {
    109                 intent.putExtra(
    110                         Intent.EXTRA_TITLE,
    111                         original.getStringExtra(Intent.EXTRA_TITLE));
    112             }
    113         }
    114         return intent;
    115     }
    116 
    117     private static void copyExtras(Intent src, Intent dest) {
    118         for (String extra : PERSISTENT_BOOLEAN_EXTRAS) {
    119             if (src.hasExtra(extra)) {
    120                 dest.putExtra(extra, src.getBooleanExtra(extra, false));
    121             }
    122         }
    123     }
    124 
    125     private static Uri buildLaunchUri() {
    126         return new Uri.Builder()
    127                 .authority(LAUNCH_CONTROL_AUTHORITY)
    128                 .fragment(String.valueOf(System.currentTimeMillis()))
    129                 .build();
    130     }
    131 
    132     static boolean isLaunchUri(@Nullable Uri uri) {
    133         boolean result = uri != null && LAUNCH_CONTROL_AUTHORITY.equals(uri.getAuthority());
    134         return result;
    135     }
    136 }
    137