Sample code for Android to install and uninstall another app in one app

<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:andro>
 <external-path name="external_files" path="."/>
</paths>

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:andro
 xmlns:tools="/tools"
 package="">
 <uses-permission android:name=".WRITE_EXTERNAL_STORAGE"/>
 <uses-permission android:name=".READ_EXTERNAL_STORAGE"/>
 <application
  android:allowBackup="true"
  android:icon="@mipmap/ic_launcher"
  android:label="@string/app_name"
  android:roundIcon="@mipmap/ic_launcher_round"
  android:supportsRtl="true"
  android:requestLegacyExternalStorage="true"
  android:theme="@style/">
  <provider
   android:name=""
   android:authorities="Bail Name"
   android:exported="false"
   android:grantUriPermissions="true">
   <meta-data
   android:name=".FILE_PROVIDER_PATHS"
    android:resource="@xml/filepaths file in step 2"
    />
  </provider>
  <activity android:name=".MainActivity">
   <intent-filter>
    <action android:name="" />
    <category android:name="" />
   </intent-filter>
  </activity>
 </application>
</manifest>

public class MainActivity extends AppCompatActivity {
 Context mContext;
 private Button bt,bt0;
 private TextView tx;
 public static boolean isGrantExternalRW(Activity activity) {
 //Permission determination  if (.SDK_INT >= Build.VERSION_CODES.M && (
    .WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
   (new String[]{
     .READ_EXTERNAL_STORAGE,
     .WRITE_EXTERNAL_STORAGE
   }, 1);
   return false;
  }
  return true;
 }
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  (savedInstanceState);
  setContentView(.activity_main);
  mContext = this;
  tx=findViewById();
  bt=findViewById();//Install  bt0=findViewById(.button0);//uninstall//  (this, ""+().getAbsolutePath(), 0).show();
  if(!()){return;}//It is very important to determine whether there is permission to modify it.  else{
  if(copyApkFromAssets(this, "", ().getAbsolutePath()+"/")){
   (new () {
    @Override
    public void onClick(View v) {
     new (mContext)
       .setIcon(.ic_launcher)
       .setMessage("Is it installed?")
       .setPositiveButton("yes", new () {
        @Override
        public void onClick(DialogInterface dialog, int which) {
         Intent intent = new Intent(Intent.ACTION_VIEW);
         (Intent.FLAG_ACTIVITY_NEW_TASK);
//         (("file://" + ().getAbsolutePath()+"/"),
//           "application/-archive");
         File apkFile = new File(()+"/");
         if (.SDK_INT >= Build.VERSION_CODES.N) {
          (Intent.FLAG_GRANT_READ_URI_PERMISSION);
          Uri uri = (, "", apkFile);
          (uri, "application/-archive");
         } else {
          ((apkFile), "application/-archive");
         }
         (intent);

        }
       }).show();
    }
   });
   (new () {
    @Override
    public void onClick(View v) {
     Uri packageURI = ("package:.a22");//package:+The package name you want to uninstall     Intent intent =new Intent(Intent.ACTION_DELETE);
     (packageURI);
     (intent);
    }
   });
  }

 }}
 public boolean copyApkFromAssets(Context context, String fileName, String path) {
 //Copy the apk file in asserts to the mobile phone storage //You can check from the mobile phone storage to the bottom, it is a separate file, no folder is set  boolean copyIsFinish = false;
  try {
   InputStream is = ().open(fileName);
   File file = new File(path);
   ();
   FileOutputStream fos = new FileOutputStream(file);
   int length = ();
   byte[] temp = new byte[length];
   int i = 0;
   while ((i = (temp)) > 0) {
    (temp, 0, i);
   }
   ();
   ();

   copyIsFinish = true;
  } catch (IOException e) {
   ();
  }
  return copyIsFinish;
 }
}