Android实现整理PackageManager获取所有安装程序信息

list<packageinfo> packs = getpackagemanager().getinstalledpackages(0);//获取安装程序的包名
for (int i = 0; i < packs.size(); i++) {
 packageinfo p = packs.get(i);//某个包信息
 //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();
}

// 通过检测包名，判断apk是否安装
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);//获取当前包名
 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;
 }
 //安装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();
 }
}