Android API 21是指Android系统的第21个版本,它引入了许多新的特性和改进。在这个版本中,使用异步GET请求可能会遇到一些问题。下面是一个完善且全面的答案:
问题:Android API 21 async GET请求不工作
答案:
在Android API 21中,异步GET请求可能会遇到一些问题。这可能是由于以下原因导致的:
<uses-permission android:name="android.permission.INTERNET" />
ConnectivityManager connectivityManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();
if (networkInfo != null && networkInfo.isConnected()) {
// 网络连接正常
} else {
// 网络连接异常
}
private class MyAsyncTask extends AsyncTask<Void, Void, String> {
@Override
protected String doInBackground(Void... params) {
try {
URL url = new URL("http://example.com/api");
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("GET");
connection.connect();
int responseCode = connection.getResponseCode();
if (responseCode == HttpURLConnection.HTTP_OK) {
InputStream inputStream = connection.getInputStream();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
StringBuilder stringBuilder = new StringBuilder();
String line;
while ((line = bufferedReader.readLine()) != null) {
stringBuilder.append(line);
}
bufferedReader.close();
inputStream.close();
return stringBuilder.toString();
}
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(String result) {
if (result != null) {
// 处理请求结果
} else {
// 请求失败
}
}
}
// 执行异步任务
new MyAsyncTask().execute();
private class MyAsyncTask extends AsyncTask<Void, Void, String> {
@Override
protected String doInBackground(Void... params) {
try {
URL url = new URL("https://example.com/api");
HttpsURLConnection connection = (HttpsURLConnection) url.openConnection();
connection.setSSLSocketFactory(getSSLSocketFactory());
connection.setHostnameVerifier(getHostnameVerifier());
connection.setRequestMethod("GET");
connection.connect();
int responseCode = connection.getResponseCode();
if (responseCode == HttpsURLConnection.HTTP_OK) {
InputStream inputStream = connection.getInputStream();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
StringBuilder stringBuilder = new StringBuilder();
String line;
while ((line = bufferedReader.readLine()) != null) {
stringBuilder.append(line);
}
bufferedReader.close();
inputStream.close();
return stringBuilder.toString();
}
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(String result) {
if (result != null) {
// 处理请求结果
} else {
// 请求失败
}
}
private SSLSocketFactory getSSLSocketFactory() {
try {
TrustManager[] trustAllCerts = new TrustManager[]{new X509TrustManager() {
@Override
public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException {
}
@Override
public void checkServerTrusted(X509Certificate[] chain, String authType) throws CertificateException {
}
@Override
public X509Certificate[] getAcceptedIssuers() {
return new X509Certificate[0];
}
}};
SSLContext sslContext = SSLContext.getInstance("TLS");
sslContext.init(null, trustAllCerts, new SecureRandom());
return sslContext.getSocketFactory();
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
private HostnameVerifier getHostnameVerifier() {
return new HostnameVerifier() {
@Override
public boolean verify(String hostname, SSLSession session) {
return true;
}
};
}
}
// 执行异步任务
new MyAsyncTask().execute();
以上是针对Android API 21异步GET请求不工作的一些可能解决方案。如果问题仍然存在,请进一步检查日志和调试代码以确定具体原因。另外,建议使用最新的Android API版本,并参考官方文档和开发者社区获取更多帮助和支持。
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