本文主要介绍 Android APP 检测、安装、打开 APK，三步操作，分别是：检查 APP 是否已经安装，安装已经下载好的 APK，打开已经安装的 APK

1、检查 APP 是否已经安装

/** * 检查APP是否已经安装 * @param context * @param packagename 需求检查的APP包名 * @return  没有安装返回false，已经安装返回true */private boolean isAppInstalled(Context context, String packagename) {  PackageInfo packageInfo;  try {      packageInfo = context.getPackageManager().getPackageInfo(packagename, 0);  } catch (NameNotFoundException e) {      packageInfo = null;      e.printStackTrace();  }  if(packageInfo == null) {    //System.out.println("没有安装");    return false;  } else {    //System.out.println("已经安装");    return true;  }}

2、安装已经下载好的 apk

/** * 安装apk * @param info */private void install(String apkname) {  try {      Intent intent = new Intent(Intent.ACTION_VIEW);      String url = Environment.getExternalStorageDirectory().getAbsolutePath() + "/" + Environment.DIRECTORY_DOWNLOADS + apkname);      File file = new File(url);    if(file.exists()) {        intent.setDataAndType(Uri.fromFile(new File(url)), "application/vnd.android.package-archive");        context.startActivity(intent);    } else {      //安装包已经删除请重新下载    }  } catch (Exception e) {    // TODO: handle exception  }}

打开已经安装的 apk

/** * 打开已经安装好的apk * @param url  文件路径 */private void openApk(String url) {  try {    PackageManager manager = context.getPackageManager();    // 这里的是你下载好的文件路径    PackageInfo info = manager.getPackageArchiveInfo(url, PackageManager.GET_ACTIVITIES);    if (info != null) {      Intent intent = manager.getLaunchIntentForPackage(info.applicationInfo.packageName);      context.startActivity(intent);    }  } catch (Exception e) {    // TODO: handle exception  }}