Android應用自動更新功能實現使用AsyncTask!

我所開發應用不是面向大衆的應用,因此沒法放到應用市場去讓你們下載,而後經過應用市場更新.因此我必要作一個應用自動更新功能.可是不難,Thanks to下面這篇博客:

Android應用自動更新功能的實現！！！

若是你是之前沒有作過此類功能,建議你先看上面的文章.而後再來看個人.由於我也是參考了上面的實現.

  其實這個自動更新功能大致就是兩個三個步驟:

   (1)檢查更新

   (2)下載更新

  (3)安裝更新  

    檢查更新和下載更新其實能夠算是一步.由於都比較簡單,都是主要是下載.

    1) 當你有新的版本發佈時,在一個位置放一個更新的文件.

裏面到少放有最新應用的版本號.而後你拿當前應用的版本號和服務器上的版本號對比,就知道要不要下載更新了.

   2 ) 下載這個過程,對於Java來講不是什麼難事,由於Java提供了豐富的API.更況且Android內置了HttpClient可用.

   3) 這個,安裝過程,其實就是使用一個打開查看此下載文件的 Intent.

  這時須要考慮的是文件下載後放到哪裏,安全否.:

 通常就是先檢測SD卡.而後選擇一個合適的目錄.

private void checkUpdate() {

		RequestFileInfo requestFileInfo = new RequestFileInfo();
		requestFileInfo.fileUrl = "http://www.waitab.com/demo/demo.apk";
		String status = Environment.getExternalStorageState();
		if (!Environment.MEDIA_MOUNTED.equals(status)) {
			ToastUtils.showFailure(getApplicationContext(),
					"SDcard cannot use!");
			return;
		}
		requestFileInfo.saveFilePath = Environment
				.getExternalStoragePublicDirectory(
						Environment.DIRECTORY_DOWNLOADS).getAbsolutePath();
		requestFileInfo.saveFileName = "DiTouchClient.apk";
		showHorizontalFragmentDialog(R.string.title_wait,
				R.string.title_download_update);
		new DownlaodUpdateTask().execute(requestFileInfo);

	}

上面的進度條顯示我已經封裝好的了.showHorizontalFragmentDialog()

顯然我使用了android-support-v4兼容包來使用Fragment的.

  在進度條中有顯示,下載文件大小,已經下載了多少.速度等信息.

   因爲涉及到網絡操做.因此把這整個邏輯放在AsyncTask中. 

代碼以下:

private class DownlaodUpdateTask extends
			AsyncTask<RequestFileInfo, ProgressValue, BasicCallResult> {

		@Override
		protected BasicCallResult doInBackground(RequestFileInfo... params) {
			final RequestFileInfo req = params[0];
			String apkFileName = "";
			try {
				URL url = new URL(req.fileUrl); // throw MalformedURLException
				HttpURLConnection conn = (HttpURLConnection) url
						.openConnection();// throws IOException
				Log.i(TAG, "response code:" + conn.getResponseCode());
				// 1檢查網絡鏈接性
				if (HttpURLConnection.HTTP_OK != conn.getResponseCode()) {
					return new BasicCallResult(
							"Can not connect to the update Server! ", false);
				}
				int length = conn.getContentLength();
				double total = StringUtils.bytes2M(length);
				InputStream is = conn.getInputStream();
				File path = new File(req.saveFilePath);
				if (!path.exists())
					path.mkdir();
				File apkFile = new File(req.saveFilePath, req.saveFileName);
				apkFileName = apkFile.getAbsolutePath();
				FileOutputStream fos = new FileOutputStream(apkFile);
				ProgressValue progressValue = new ProgressValue(0, " downlaod…");
				int count = 0;
				long startTime, endTime;
				byte buffer[] = new byte[1024];
				do {
					startTime = System.currentTimeMillis();
					int numread = is.read(buffer);
					endTime = System.currentTimeMillis();
					count += numread;
					if (numread <= 0) {
						// publish end
						break;
					}
					fos.write(buffer, 0, numread);

					double kbPerSecond = Math
							.ceil((endTime - startTime) / 1000f);
					double current = StringUtils.bytes2M(count);
					progressValue.message = String.format(
							"%.2f M/%.2f M\t\t%.2fKb/S", total, current,
							kbPerSecond);
					progressValue.progress = (int) (((float) count / length) * DialogUtil.LONG_PROGRESS_MAX);
					publishProgress(progressValue);

				} while (true);
				fos.flush();
				fos.close();

			} catch (MalformedURLException e) {
				e.printStackTrace();
				return new BasicCallResult("Wrong url! ", false);
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
				return new BasicCallResult("Error: " + e.getLocalizedMessage(),
						false);
			}
			BasicCallResult callResult = new BasicCallResult(
					"download finish!", true);
			callResult.result = apkFileName;
			return callResult;
		}

		@Override
		protected void onPostExecute(BasicCallResult result) {
			removeFragmentDialog();
			if (result.ok) {
				installApk(result.result);
			} else {
				ToastUtils.showFailure(getApplicationContext(), result.message);
			}
		}

		@Override
		protected void onProgressUpdate(ProgressValue... values) {
			ProgressValue value = values[0];
			updateProgressDialog(value);

		}

	}

	/**
	 * 安裝更新APK.
	 * 
	 * @param fileUri
	 */
	private void installApk(String fileUri) {
		Intent intent = new Intent(Intent.ACTION_VIEW);
		intent.setDataAndType(Uri.parse("file://" + fileUri),
				"application/vnd.android.package-archive");
		startActivity(intent);
		this.finish();

	}

PS:Java中傳遞或者返回多個值,我經常使用的辦法就是將數據封裝到一個對象中去.上面用到的一些封裝對象以下:

傳遞多個值用對象是由於AsyncTask設計讓你傳遞一個對象做爲傳遞參數,因此傳遞對象也須要這樣使用.

/**
 * 傳遞給android 設置進度條對象
 * 
 * @author  banxi1988
 * 
 */
public final class ProgressValue {
	/**
	 * 須要設置的進度
	 */
	public int progress;
	/**
	 * 提示信息
	 */
	public String message;

	public ProgressValue(int progress, String message) {
		super();
		this.progress = progress;
		this.message = message;
	}

}

基本的調用返回對象:

public class BasicCallResult {
	public String message;
	public boolean ok;
	public String result;

	public BasicCallResult(String message, boolean ok) {
		super();
		this.message = message;
		this.ok = ok;
	}

}

傳遞下載相關信息..

public class RequestFileInfo {
		public String fileUrl;
		public String saveFilePath;
		public String saveFileName;

	}

  

    

今天更新到這裏,有什麼問題,請指出,謝謝.