public class MainActivity extends Activity {    private DownloadManager downloadManager;    public static final String DOWNLOAD_FOLDER_NAME = "Trinea";    public static final String DOWNLOAD_FILE_NAME = "MeiLiShuo.apk";    public static final String APK_URL = "http://img.meilishuo.net/css/images/AndroidShare/Meilishuo_3.6.1_10006.apk";    public static final String KEY_NAME_DOWNLOAD_ID = "downloadId";    private long downloadId = 0;    private CompleteReceiver completeReceiver;    @TargetApi(Build.VERSION_CODES.HONEYCOMB)    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        init();        findViewById(R.id.button1).setOnClickListener(new OnClickListener() {            @Override            public void onClick(View v) {                // TODO Auto-generated method stub                File folder = Environment                        .getExternalStoragePublicDirectory(DOWNLOAD_FOLDER_NAME);                if (!folder.exists() || !folder.isDirectory()) {                    folder.mkdirs();                }                DownloadManager.Request request = new DownloadManager.Request(                        Uri.parse(APK_URL));                request.setDestinationInExternalPublicDir(DOWNLOAD_FOLDER_NAME,                        DOWNLOAD_FILE_NAME);                request.setTitle("美丽传说");                request.setDescription("meilishuo desc");                request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);                request.setVisibleInDownloadsUi(false);                // request.allowScanningByMediaScanner();                // request.setAllowedNetworkTypes(DownloadManager.Request.NETWORK_WIFI);                // request.setShowRunningNotification(false);                // request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_HIDDEN);                //application/cn.trinea.download.file                request.setMimeType("application/vnd.android.package-archive");                downloadId = downloadManager.enqueue(request);                /** save download id to preferences **/            }        });    }    private void init() {        // TODO Auto-generated method stub        completeReceiver = new CompleteReceiver();        /** register download success broadcast **/        registerReceiver(completeReceiver, new IntentFilter(                DownloadManager.ACTION_DOWNLOAD_COMPLETE));        downloadManager = (DownloadManager) getSystemService(DOWNLOAD_SERVICE);    }    private int getInt(long downloadId, String columnName) {        DownloadManager.Query query = new DownloadManager.Query()                .setFilterById(downloadId);        int result = -1;        Cursor c = null;        try {            c = downloadManager.query(query);            if (c != null && c.moveToFirst()) {                result = c.getInt(c.getColumnIndex(columnName));            }        } finally {            if (c != null) {                c.close();            }        }        return result;    }    @Override    protected void onDestroy() {        super.onDestroy();        unregisterReceiver(completeReceiver);    }    class CompleteReceiver extends BroadcastReceiver {        @Override        public void onReceive(Context context, Intent intent) {            /**             * get the id of download which have download success, if the id is             * my id and it‘s status is successful, then install it             **/            long completeDownloadId = intent.getLongExtra(                    DownloadManager.EXTRA_DOWNLOAD_ID, -1);            if (completeDownloadId == downloadId) {                // if download successful, install apk                // if (downloadManagerPro.getStatusById(downloadId) ==                // DownloadManager.STATUS_SUCCESSFUL) {                if (getInt(downloadId, DownloadManager.COLUMN_STATUS) == DownloadManager.STATUS_SUCCESSFUL) {                    String apkFilePath = new StringBuilder(Environment                            .getExternalStorageDirectory().getAbsolutePath())                            .append(File.separator)                            .append(DOWNLOAD_FOLDER_NAME)                            .append(File.separator).append(DOWNLOAD_FILE_NAME)                            .toString();                    install(context, apkFilePath);                }            }        }    };    /**     * install app     *      * @param context     * @param filePath     * @return whether apk exist     */    public static boolean install(Context context, String filePath) {        Intent i = new Intent(Intent.ACTION_VIEW);        File file = new File(filePath);        if (file != null && file.length() > 0 && file.exists() && file.isFile()) {            i.setDataAndType(Uri.parse("file://" + filePath),                    "application/vnd.android.package-archive");            i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);            context.startActivity(i);            return true;        }        return false;    }    @Override    public boolean onCreateOptionsMenu(Menu menu) {        // Inflate the menu; this adds items to the action bar if it is present.        getMenuInflater().inflate(R.menu.main, menu);        return true;    }}

 <uses-permission android:name="android.permission.INTERNET" />    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />    <uses-permission android:name="android.permission.BROADCAST_STICKY" />    <uses-permission android:name="android.permission.DOWNLOAD_WITHOUT_NOTIFICATION" />