app自动更新(android)

检查更新的时候，通过指定的URL获取服务器端版本信息。比较版本，如果更新，访问服务器端返回的apk的URL地址，下载，安装。各种 Makert 也是通过类似的机制实现的。原理搞清楚了，代码就相当简单了。

获取apk的VesionName，即AndroidManifest.xml中定义的android:versionName

public String getVesionName(Context context) {
String versionName = null;
try {
versionName = context.getPackageManager().getPackageInfo("net.vpntunnel", 0).versionName;
} catch (NameNotFoundException e) {
Log.e(TAG, e.getMessage());
}
return versionName;
}

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更新以及安装程序需要的权限，在AndroidManifest.xml中添加

<uses-permission android:name="android.permission.INTERNET"></uses-permission>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"></uses-permission>
<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"></uses-permission>
<uses-permission android:name="android.permission.INSTALL_PACKAGES"></uses-permission>

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获取apk的versionCode，即AndroidManifest.xml中定义的android:versionCode

public int getVersionCode(Context context) {
int versionCode = 0;
try {
versionCode = context.getPackageManager().getPackageInfo("net.vpntunnel", 0).versionCode;
} catch (NameNotFoundException e) {
Log.e(TAG, e.getMessage());
}
return versionCode;
}

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服务器端version.JSON，包含apk路径以及版本信息

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获取远程服务器的版本信息

private void getRemoteJSON(string host) throws ClientProtocolException, IOException, JSONException {
String url = String.format("http://%s/%s", host, VER_JSON);
StringBuilder sb = new StringBuilder();
HttpClient client = new DefaultHttpClient();
HttpParams httpParams = client.getParams();
HttpConnectionParams.setConnectionTimeout(httpParams, 3000);
HttpConnectionParams.setSoTimeout(httpParams, 5000);
HttpResponse response = client.execute(new HttpGet(url));
HttpEntity entity = response.getEntity();
if (entity != null) {
BufferedReader reader = new BufferedReader(new InputStreamReader(entity.getContent(), "UTF-8"), 8192);
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
reader.close();
}
JSONObject object = (JSONObject) new JSONTokener(sb.toString()).nextValue();
this.apkFullName = object.getString("ApkFullName");
this.versionName = object.getString("VersionName");
this.versionCode = Integer.valueOf(object.getInt("VersionCode"));
}

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发现更新的提醒窗口，通过AlertDialog实现

private void shoVersionUpdate(String newVersion, final String updateURL) {
String message = String.format("%s: %s, %s", mContext.getString(R.string.found_newversion), newVersion, mContext.getString(R.string.need_update));
AlertDialog dialog = new AlertDialog.Builder(mContext).setTitle(mContext.getString(R.string.alertdialog_title)).setMessage(message)
// update
.setPositiveButton(mContext.getString(R.string.alertdialog_update_button), new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
pBar = new ProgressDialog(mContext);
pBar.setTitle(mContext.getString(R.string.progressdialog_title));
pBar.setMessage(mContext.getString(R.string.progressdialog_message));
pBar.setProgressStyle(ProgressDialog.STYLE_SPINNER);
dialog.dismiss();
downFile(updateURL);
}
// cancel
}).setNegativeButton(mContext.getString(R.string.alertdialog_cancel_button), new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
dialog.dismiss();
}
}).create();
dialog.show();
}

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下载新版的apk文件，存放地址可以放到SD卡中。通过Environment.getExternalStorageDirectory()获取SD卡中的路径

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安装更新

private void installUpdate() {
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setDataAndType(Uri.fromFile(new File(UPDATE_DIR, updateFileName)), "application/vnd.android.package-archive");
mContext.startActivity(intent);
}

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至此更新需要函数就完成了

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