ACTION_OUTSIDEが切り開くAndroidアプリ間連携の可能性：実業務でちゃんと使えるAndroidアプリ開発入門（1）（4/4 ページ）

@Override
public boolean onTouch(View v, MotionEvent event) {
    if (event.getAction() != MotionEvent.ACTION_OUTSIDE) {  // 【1】
        return false;
    }
    String packageName = getTopActivityPackageName();  // 【2】
    boolean matched = packageName.equals("com.android.chrome") || packageName.equals("com.android.browser");  // 【3】
    if (!matched) {
        return false;
    }
    // 【4】
    mTimestamp[0] = event.getEventTime();
    Arrays.sort(mTimestamp);
    long diff = 0;
    for (int i = 0; i < mTimestamp.length - 1; i++) {
        diff += mTimestamp[i + 1] - mTimestamp[i];
    }
    if (diff < 500) {  // 【5】
        Intent intent = new Intent(Intent.ACTION_MAIN);
        intent.addCategory(Intent.CATEGORY_HOME);
        intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        startActivity(intent);
        Toast.makeText(getApplicationContext(), "Launch from " + packageName, Toast.LENGTH_SHORT).show();
    }
    return false;
}

@TargetApi(Build.VERSION_CODES.LOLLIPOP_MR1)
private String getTopActivityPackageName() {
    String packageName = "";
    if(Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {  // 【1】
        ActivityManager am = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);
        List<ActivityManager.RunningAppProcessInfo> list = am.getRunningAppProcesses();
        packageName = list.get(0).processName;
    } else { // 【2】
        UsageStatsManager usm = (UsageStatsManager) getSystemService(Context.USAGE_STATS_SERVICE);  // 【3】
        long endTime = System.currentTimeMillis();
        long beginTime = endTime - 7 * 24 * 60 * 60 * 1000;
        List<UsageStats> list = usm.queryUsageStats(UsageStatsManager.INTERVAL_BEST, beginTime, endTime);
  // 【4】
        if (list != null && list.size() > 0) {
            SortedMap<Long, UsageStats> map = new TreeMap<>();
            for (UsageStats usageStats : list) {
                map.put(usageStats.getLastTimeUsed(), usageStats);
            }
            if (!map.isEmpty()) {
                packageName = map.get(map.lastKey()).getPackageName();  // 【5】
            }
        }
    }
 
    return packageName;
}

intervalType = INTERVAL_YEARLY
beginTime = 2013
endTime = 2015 (exclusive)
 
Results:
2013 - com.example.alpha
2013 - com.example.beta
2014 - com.example.alpha
2014 - com.example.beta
2014 - com.example.charlie