1. 可选
  2. 代码

主要使用DownloadManager.Request进行下载。

完整的项目：https://github.com/lijiancheng0614/android-NetworkConnect

参考：http://developer.android.com/reference/android/app/DownloadManager.html

可选

  • 注册一个BroadcastReceiver来监听下载完成，并使用Callback来执行下载完成后的事件。

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    IntentFilter filter = new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE);
    context.registerReceiver(downloadReceiver, filter);

  • 使用DownloadManager.Query查询是否下载成功。

  • 设置Notification。

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    request.setNotificationVisibility(Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);

  • 结合网络状况下载。

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    // Restrict the types of networks over which this download may proceed.
    request.setAllowedNetworkTypes(DownloadManager.Request.NETWORK_WIFI | DownloadManager.Request.NETWORK_MOBILE);
    // Set whether this download may proceed over a roaming connection.
    request.setAllowedOverRoaming(false);

代码

  • DownloadHelper.java

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    package com.example.android.networkconnect;

    import android.app.DownloadManager;
    import android.app.DownloadManager.Request;
    import android.app.DownloadManager.Query;
    import android.content.BroadcastReceiver;
    import android.content.Context;
    import android.content.Intent;
    import android.content.IntentFilter;
    import android.database.Cursor;
    import android.net.Uri;
    import android.os.Environment;

    /**
     * Download file helper.
     */
    public class DownloadHelper {
        private DownloadManager downloadManager;
        private Request request;
        private long downloadId = -1;
        /**
         * Broadcast when the download has successfully completed.
         */
        private BroadcastReceiver downloadReceiver = new BroadcastReceiver() {
            @Override
            public void onReceive(Context context, Intent intent) {
                long completeDownloadId = intent.getLongExtra(DownloadManager.EXTRA_DOWNLOAD_ID, -1);
                if (completeDownloadId == downloadId) {
                    // if download successful
                    if (getInt(downloadId, DownloadManager.COLUMN_STATUS) == DownloadManager.STATUS_SUCCESSFUL) {
                        mDownloadDoneCallback.onDownloadDone();
                    }
                }
            }
        };
        private DownloadDoneCallback mDownloadDoneCallback;

        public DownloadHelper(Context context, String uri, DownloadDoneCallback downloadDoneCallback) throws Exception {
            downloadManager = (DownloadManager) context.getSystemService(Context.DOWNLOAD_SERVICE);
            Uri downloadUri = Uri.parse(uri);
            request = new Request(downloadUri);
            String filename = downloadUri.getLastPathSegment();
            request.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, filename);
            request.setTitle(filename);
            request.setNotificationVisibility(Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
            mDownloadDoneCallback = downloadDoneCallback;

            // Set filter to only when download is complete and register broadcast receiver
            IntentFilter filter = new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE);
            context.registerReceiver(downloadReceiver, filter);
        }

        /**
         * Start downloading.
         */
        public void start() {
            if (request == null) {
                return;
            }
            //Enqueue a new download and same the referenceId
            downloadId = downloadManager.enqueue(request);
        }

        /**
         * Get int value of a column for the id.
         *
         * @param id         filter id.
         * @param columnName column name.
         * @return first value of the column for the id.
         */
        private int getInt(long id, String columnName) {
            int result = -1;
            Cursor cursor = null;
            try {
                Query query = new Query().setFilterById(id);
                cursor = downloadManager.query(query);
                if (cursor != null && cursor.moveToFirst()) {
                    result = cursor.getInt(cursor.getColumnIndex(columnName));
                }
            } finally {
                if (cursor != null) {
                    cursor.close();
                }
            }
            return result;
        }

        /**
         * Callback when the download has successfully completed.
         */
        public interface DownloadDoneCallback {
            public void onDownloadDone();
        }
    }