在Android中，可以使用HttpClient或者HttpURLConnection來調用API接口。

使用HttpClient調用API接口的步驟如下：

1. 創建HttpClient實例：

HttpClient httpClient = new DefaultHttpClient();

2. 創建HttpGet或者HttpPost請求：

HttpGet httpGet = new HttpGet(url);
HttpPost httpPost = new HttpPost(url);

3. 設置請求參數（可選）：

List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("param1", value1));
params.add(new BasicNameValuePair("param2", value2));
httpPost.setEntity(new UrlEncodedFormEntity(params));

4. 發送請求并獲取響應：

HttpResponse response = httpClient.execute(httpGet); // 或者httpClient.execute(httpPost);
HttpEntity entity = response.getEntity();
String responseString = EntityUtils.toString(entity);

使用HttpURLConnection調用API接口的步驟如下：

1. 創建URL對象：

URL url = new URL(apiUrl);

2. 打開連接并設置請求方法：

HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("GET"); // 或者"POST"

3. 設置請求參數（可選）：

String params = "param1=value1&param2=value2";
connection.setDoOutput(true);
DataOutputStream outputStream = new DataOutputStream(connection.getOutputStream());
outputStream.writeBytes(params);
outputStream.flush();
outputStream.close();

4. 發送請求并獲取響應：

int responseCode = connection.getResponseCode();
InputStream inputStream;
if (responseCode == HttpURLConnection.HTTP_OK) {
inputStream = connection.getInputStream();
} else {
inputStream = connection.getErrorStream();
}
BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
String line;
StringBuilder responseString = new StringBuilder();
while ((line = reader.readLine()) != null) {
responseString.append(line);
}
reader.close();

以上是簡單的調用API接口的示例，實際使用中可能需要根據具體情況進行適當的修改和處理。另外，記得在AndroidManifest.xml文件中添加網絡權限：

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