List<PackageInfo> packs = getPackageManager().getInstalledPackages(0);//獲取安裝程序的包名for (int i = 0; i < packs.size(); i++) { PackageInfo p = packs.get(i);//某個包信息 //打印：版本好，版本名，包名.... Log.i("", "-------" + p.versionCode + "-------" + p.versionName + "--------"   + p.packageName + "-------" + p.applicationInfo);}

<manifest xmlns:android="http://schemas.android.com/apk/res/android"   package="com.testapk"   android:versionCode="2" // p.versionCode    android:versionName="Version1" // p.versionName>

int versionCode = 0;try {  versionCode = getPackageManager().getPackageInfo(this.getPackageName(), 0).versionCode;} catch (NameNotFoundException e) {  e.printStackTrace();}

// 通過檢測包名，判斷APK是否安裝private boolean checkPackageExist(boolean getSysPackages) { boolean packageExist = false; int versionCode = 0; try {  versionCode = getPackageManager().getPackageInfo(this.getPackageName(), 0).versionCode; } catch (NameNotFoundException e) {  e.printStackTrace(); } Log.i("", "-------" + this.getPackageName() + "-------" + versionCode);//獲取當前包名 List<PackageInfo> packs = getPackageManager().getInstalledPackages(0); for (int i = 0; i < packs.size(); i++) {  PackageInfo p = packs.get(i);  Log.i("", "-------" + p.versionCode + "-------" + p.versionName + "--------"    + p.packageName + "-------" + p.applicationInfo);  if ((!getSysPackages) && (p.versionName == null)) {  continue;  }  if (p.packageName.equalsIgnoreCase(PACKAGENAME)) {  packageExist = true;  break;  } } return packageExist; } //安裝APK private void installApk() { if (checkFileExist(fileRoot + fileName)) {  Intent intent = new Intent();  intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);  intent.setAction(android.content.Intent.ACTION_VIEW);  String type = "application/vnd.android.package-archive";  intent.setDataAndType(Uri.parse("file://" + fileRoot + fileName),   type);  startActivity(intent); } else {  downloadapk(); }}