我的项目有错误，它似乎来自我的代码的这一部分
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
json = sb.toString();
Log.e("JSON", json);
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
在此之后，我将字符串解析为 jsonobject
有人可以帮忙吗？
这是我的 logcat “错误”文件
02-05 17:46:27.286：E/Buffer 错误（527）：错误转换结果 java.lang.NullPointerException 02-05 17:46:27.286：E/JSON 解析器（527）：解析数据时出错 org.json.JSONException : 02-05 17:46:27.286 字符 0 处的输入结束：E/AndroidRuntime(527): FATAL EXCEPTION: main 02-05 17:46:27.286: E/AndroidRuntime(527): java.lang.NullPointerException 02 -05 17:46:27.286: E/AndroidRuntime(527): 在 com.example.androidhive.LoginActivity$1.onClick(LoginActivity.java:65) 02-05 17:46:27.286: E/AndroidRuntime(527): 在android.view.View.performClick(View.java:2408) 02-05 17:46:27.286: E/AndroidRuntime(527): 在 android.view.View$PerformClick.run(View.java:8816) 02-05 17:46:27.286: E/AndroidRuntime(527): 在 android.os.Handler.handleCallback(Handler.java:587) 02-05 17:46:27.286: E/AndroidRuntime(527): 在 android.os.Handler .dispatchMessage（处理程序.java：92) 02-05 17:46:27.286: E/AndroidRuntime(527): 在 android.os.Looper.loop(Looper.java:123) 02-05 17:46:27.286: E/AndroidRuntime(527): 在android.app.ActivityThread.main(ActivityThread.java:4627) 02-05 17:46:27.286: E/AndroidRuntime(527): at java.lang.reflect.Method.invokeNative(Native Method) 02-05 17:46 :27.286: E/AndroidRuntime(527): at java.lang.reflect.Method.invoke(Method.java:521) 02-05 17:46:27.286: E/AndroidRuntime(527): at com.android.internal。 os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868) 02-05 17:46:27.286: E/AndroidRuntime(527): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626) 02 -05 17:46:27.286：E/AndroidRuntime（527）：在 dalvik.system.NativeStart.main（本机方法）app.ActivityThread.main(ActivityThread.java:4627) 02-05 17:46:27.286: E/AndroidRuntime(527): 在 java.lang.reflect.Method.invokeNative(Native Method) 02-05 17:46:27.286 : E/AndroidRuntime(527): at java.lang.reflect.Method.invoke(Method.java:521) 02-05 17:46:27.286: E/AndroidRuntime(527): at com.android.internal.os。 ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868) 02-05 17:46:27.286: E/AndroidRuntime(527): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626) 02-05 17:46:27.286：E/AndroidRuntime（527）：在 dalvik.system.NativeStart.main（本机方法）app.ActivityThread.main(ActivityThread.java:4627) 02-05 17:46:27.286: E/AndroidRuntime(527): 在 java.lang.reflect.Method.invokeNative(Native Method) 02-05 17:46:27.286 : E/AndroidRuntime(527): at java.lang.reflect.Method.invoke(Method.java:521) 02-05 17:46:27.286: E/AndroidRuntime(527): at com.android.internal.os。 ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868) 02-05 17:46:27.286: E/AndroidRuntime(527): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626) 02-05 17:46:27.286：E/AndroidRuntime（527）：在 dalvik.system.NativeStart.main（本机方法）在 com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868) 02-05 17:46:27.286: E/AndroidRuntime(527): 在 com.android.internal.os.ZygoteInit.main( ZygoteInit.java:626) 02-05 17:46:27.286: E/AndroidRuntime(527): at dalvik.system.NativeStart.main(Native Method)在 com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868) 02-05 17:46:27.286: E/AndroidRuntime(527): 在 com.android.internal.os.ZygoteInit.main( ZygoteInit.java:626) 02-05 17:46:27.286: E/AndroidRuntime(527): at dalvik.system.NativeStart.main(Native Method)
这是我的 loginactivity.java
public class LoginActivity extends Activity {
Button btnLogin;
Button btnLinkToRegister;
EditText inputEmail;
EditText inputPassword;
TextView loginErrorMsg;
// JSON Response node names
private static String KEY_SUCCESS = "success";
private static String KEY_ERROR = "error";
private static String KEY_ERROR_MSG = "error_msg";
private static String KEY_UID = "uid";
private static String KEY_NAME = "name";
private static String KEY_EMAIL = "email";
private static String KEY_CREATED_AT = "created_at";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.login);
// Importing all assets like buttons, text fields
inputEmail = (EditText) findViewById(R.id.loginEmail);
inputPassword = (EditText) findViewById(R.id.loginPassword);
btnLogin = (Button) findViewById(R.id.btnLogin);
btnLinkToRegister = (Button) findViewById(R.id.btnLinkToRegisterScreen);
loginErrorMsg = (TextView) findViewById(R.id.login_error);
// Login button Click Event
btnLogin.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
String email = inputEmail.getText().toString();
String password = inputPassword.getText().toString();
UserFunctions userFunction = new UserFunctions();
Log.d("Button", "Login");
JSONObject json = userFunction.loginUser(email, password);
// check for login response
try {
if (json.getString(KEY_SUCCESS) != null) {
loginErrorMsg.setText("");
String res = json.getString(KEY_SUCCESS);
if(Integer.parseInt(res) == 1){
// user successfully logged in
// Store user details in SQLite Database
DatabaseHandler db = new DatabaseHandler(getApplicationContext());
JSONObject json_user = json.getJSONObject("user");
// Clear all previous data in database
userFunction.logoutUser(getApplicationContext());
db.addUser(json_user.getString(KEY_NAME), json_user.getString(KEY_EMAIL), json.getString(KEY_UID), json_user.getString(KEY_CREATED_AT));
// Launch Dashboard Screen
Intent dashboard = new Intent(getApplicationContext(), DashboardActivity.class);
// Close all views before launching Dashboard
dashboard.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(dashboard);
// Close Login Screen
finish();
}else{
// Error in login
loginErrorMsg.setText("Incorrect username/password");
}
}
} catch (JSONException e) {
e.printStackTrace();
}
}
});
// Link to Register Screen
btnLinkToRegister.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
Intent i = new Intent(getApplicationContext(),
RegisterActivity.class);
startActivity(i);
finish();
}
});
}
}
这是 loginuser 方法
public JSONObject loginUser(String email, String password){
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("tag", login_tag));
params.add(new BasicNameValuePair("email", email));
params.add(new BasicNameValuePair("password", password));
JSONObject json = jsonParser.getJSONFromUrl(loginURL, params);
// return json
Log.d("JSON", "issa");
return json;
}
这是 gestjsonfromurl
public JSONObject getJSONFromUrl(String url, List<NameValuePair> params) {
// Making HTTP request
try {
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
httpPost.setEntity(new UrlEncodedFormEntity(params));
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}