下载apk并自动安装

package com.android.settings;

import android.app.Activity;
import android.app.DownloadManager;
import android.content.ActivityNotFoundException;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;

import java.io.File;
import android.app.PendingIntent;
import android.content.IntentSender;
import android.content.pm.PackageInstaller;
import android.util.Log;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.FileInputStream;

import com.android.setupwizardlib.util.WizardManagerHelper;

public class DownloadAndInstallActivity extends Activity {
    private static final String TAG = "DownloadAndInstallActivity";
    private static final String APKPATH = "/storage/emulated/0/Download/*******.apk";

    private DownloadManager downloader;
    private Uri uri;
    private long reference;
    private BroadcastReceiver myReceiver;
    private int mSessionId =-1;
    private PackageInstaller.SessionCallback mSessionCallback;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
		setContentView(R.layout.download_and_install_page);
        mSessionCallback = new InstallSessionCallback();
        getPackageManager().getPackageInstaller().registerSessionCallback(mSessionCallback);
        downLoadManager();
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        getPackageManager().getPackageInstaller().unregisterSessionCallback(mSessionCallback);
        unregisterReceiver(myReceiver);
    }

    private void downLoadManager() {
        downloader = (DownloadManager) getSystemService(Context.DOWNLOAD_SERVICE);
        uri = Uri.parse("https://****/*******..apk");
        DownloadManager.Request request = new DownloadManager.Request(uri);
        request.setAllowedNetworkTypes(request.NETWORK_WIFI);
        request.setNotificationVisibility(request.VISIBILITY_VISIBLE);
        request.setTitle("Download App");
        request.setDescription("App is downloading");
        request.setAllowedOverRoaming(false);
        request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, "*******.apk");

        reference = downloader.enqueue(request);

        IntentFilter intentFilter = new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE);

        myReceiver = new BroadcastReceiver() {
            @Override
            public void onReceive(Context context, Intent intent) {
                long referenceTo = intent.getLongExtra(DownloadManager.EXTRA_DOWNLOAD_ID, -1);
                if (referenceTo == reference) {
                    install();
                }
            }
        };
        registerReceiver(myReceiver, intentFilter);
    }

    private class InstallSessionCallback extends PackageInstaller.SessionCallback {
        @Override
        public void onCreated(int sessionId) {
            // empty
            Log.d(TAG, "onCreated()" + sessionId);
        }

        @Override
        public void onBadgingChanged(int sessionId) {
            // empty
            Log.d(TAG, "onBadgingChanged()" + sessionId + "active");
        }

        @Override
        public void onActiveChanged(int sessionId, boolean active) {
            Log.d(TAG, "onActiveChanged()" + sessionId + "active" + active);
        }

        @Override
        public void onProgressChanged(int sessionId, float progress) {
            Log.d(TAG, "onProgressChanged()" + sessionId);
            if (sessionId == mSessionId) {
                int progres = (int) (Integer.MAX_VALUE * progress);
                Log.d(TAG, "onProgressChanged" + progres);
            }
        }

        @Override
        public void onFinished(int sessionId, boolean success) {
            // empty, finish is handled by InstallResultReceiver
            Log.d(TAG, "onFinished()" + sessionId + "success" + success);
            if (mSessionId == sessionId) {
                if (success) {
                    Log.d(TAG, "onFinished() install success");
                    onNext(Activity.RESULT_OK);
                } else {
                    Log.d(TAG, "onFinished() install failed");
                }
            }
        }
    }

    public void onNext(int requestCode) {
        int resultCode =  Activity.RESULT_OK;
        Intent intent = WizardManagerHelper.getNextIntent(getIntent(), resultCode);
        try {
            startActivityForResult(intent, requestCode);
        } catch (ActivityNotFoundException e) {
            Log.e(TAG, e.getMessage());
        }
    }


    private IntentSender createIntentSender(Context context, int sessionId) {
        PendingIntent pendingIntent = PendingIntent.getBroadcast(context, sessionId,
                new Intent("android.intent.action.INSTALL_COMPLETE"), PendingIntent.FLAG_IMMUTABLE/*0*/);
        return pendingIntent.getIntentSender();
    }

    private void addApkToInstallSession(String assetName, PackageInstaller.Session session)
            throws IOException {
        // It's recommended to pass the file size to openWrite(). Otherwise installation may fail
        // if the disk is almost full.
        OutputStream packageInSession = session.openWrite("package", 0, -1);
        File file = new File(assetName);
        InputStream is = new FileInputStream(file);//getAssets().open(assetName)) {
        try {
            byte[] buffer = new byte[16384];
            int n =0;
            while ((n = is.read(buffer)) >= 0) {
                packageInSession.write(buffer, 0, n);
            }
        } catch (IOException e) {
            throw new RuntimeException("Couldn't ssssssss", e);
        } finally{
            packageInSession.close();
            is.close();
        }
    }

    public void install (){
        Thread thread = new Thread(new Runnable() {
            @Override
            public void run() {
                PackageInstaller.Session session = null;
                try {
                    PackageInstaller packageInstaller = getPackageManager().getPackageInstaller();
                    PackageInstaller.SessionParams params = new PackageInstaller.SessionParams(
                            PackageInstaller.SessionParams.MODE_FULL_INSTALL);
                    int sessionId = packageInstaller.createSession(params);
                    mSessionId =sessionId;
                    Log.d(TAG, "sessionId = " + sessionId);
                    session = packageInstaller.openSession(sessionId);
                    addApkToInstallSession(APKPATH, session);
                    Log.d(TAG, "session.commit ");
                    session.commit(createIntentSender(getApplicationContext(), sessionId));
                } catch (IOException e) {
                    throw new RuntimeException("Couldn't install package", e);
                } catch (RuntimeException e) {
                    if (session != null) {
                        session.abandon();
                    }
                    throw e;
                }
            }
        });
        thread.start();
    }
}