Android功能模塊化之版本更新

在開發過程，版本更新不可或缺的一個功能之一。主要通過VersionName或VersionCode值來判斷版本是否需要更新，其整個更新的流程如下：

（1）訪問服務器，獲取服務器最新版本信息；

（2）比較服務器與客戶端的版本信息；

（3）如版本信息不相符，提示用戶更新；

（4）若用戶選擇更新，則下載更新文件；

（5）下載完畢，安裝。

實現代碼如下：

1）獲取客戶端的versionName和versionCode值

private String getInfo(int type) {
		PackageInfo packageInfo = getPackageInfo();
		if (packageInfo != null) {
			switch (type) {
			case 0:
				return packageInfo.versionName;
			case 1:
				return String.valueOf(packageInfo.versionCode);
			default:
				break;
			}
		}
		return null;
	}

2）比較服務器與當前客戶端的版本信息

private boolean isVersionEquals(String serviceVersion) {
		return (getVersionName() != null && !versionName
				.equalsIgnoreCase(serviceVersion));
	}

3）調用版本更新函數

	public void updateVersion(String downloadUrl, String path,
			String serviceVersion) {
		// 判斷版本號是否相等
		if (isVersionEquals(serviceVersion)) {
			// 判斷內存卡狀態
			if (Environment.MEDIA_MOUNTED.equals(Environment
					.getExternalStorageState())) {
				savePath = Environment.getExternalStorageDirectory()
						.getAbsolutePath() + path;
			} else {
				savePath = context.getFilesDir().toString() + path;
			}
			this.downloadUrl = downloadUrl;
			showUpdateVersionDialog();
		}
	}

4）顯示更新版本對話框

	private void showUpdateVersionDialog() {
		Builder builder = new AlertDialog.Builder(context);
		builder.setTitle("軟件版本更新")
				.setMessage("檢測服務器有新的版本，是否立即下載更新？")
				.setPositiveButton("確定更新",
						new DialogInterface.OnClickListener() {

							@Override
							public void onClick(DialogInterface dialog,
									int which) {
								showDownloadSoftwardDialog();
							}
						}).setNegativeButton("以後再說", null).create().show();

	}

5）下載新的APK

private void downloadApk() {
		new Thread(new Runnable() {

			@Override
			public void run() {
				try {
					URL url = new URL(downloadUrl);
					HttpURLConnection httpURLConnection = (HttpURLConnection) url
							.openConnection();
					httpURLConnection.connect();
					int length = httpURLConnection.getContentLength();
					InputStream inputStream = httpURLConnection
							.getInputStream();
					File file = new File(savePath);
					if (!file.exists()) {
						file.mkdir();
					}
					saveFileName = savePath
							+ "/"
							+ downloadUrl.substring(
									downloadUrl.lastIndexOf("/"),
									downloadUrl.length());
					File apkFile = new File(saveFileName);
					FileOutputStream fos = new FileOutputStream(apkFile);
					int count = 0;
					byte[] buffer = new byte[1024];
					do {
						int readNum = inputStream.read(buffer);
						count += readNum;
						downloadProgress = (int) (((float) count / length) * 100);
						handler.sendEmptyMessage(DOWNLOAD_UPDATE);
						if (readNum <= 0) {
							handler.sendEmptyMessage(DOWNLOAD_OVER);
							break;
						}
						fos.write(buffer, 0, readNum);
					} while (cancelFlag);
					fos.flush();
					inputStream.close();
					fos.close();
				} catch (MalformedURLException e) {
					e.printStackTrace();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}).start();
	}

6)安裝APK

	private void installApk() {
		File apkFile = new File(saveFileName);
		if (apkFile.exists()) {
			Intent intent = new Intent(Intent.ACTION_VIEW);
			intent.setDataAndType(Uri.parse("file://" + apkFile.toString()),
					"application/vnd.android.package-archive");
			context.startActivity(intent);
			updateFlag = true;
		}
	}