The Android implementation collates PackageManager to get all installer information

This article illustrates the Android implementation's approach to collating PackageManager to obtain all installer information. To share for your reference, the details are as follows:

List<PackageInfo> packs = getPackageManager().getInstalledPackages(0);// Gets the package name of the installer 
for (int i = 0; i < packs.size(); i++) {
 PackageInfo p = packs.get(i);// Some package information 
 // Print: version good, version name, package name ....
 Log.i("", "-------" + p.versionCode + "-------" + p.versionName + "--------" 
  + p.packageName + "-------" + p.applicationInfo);
}

The versionCode, versionName value comes from the AndroidManifest.xml file

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

Gets versionCode, versionName for the current application in the code

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

Code:

//  By detecting the package name, determine APK Whether to install 
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);// Gets the current package name 
 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;
 }
 // The installation 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();
 }
}

Through the above code, plus 1 some network download code, you can do a simplified application market.

I hope this article has been helpful in Android programming.