Question

登录成功后，我试图打开Mainactivity

E/flutter (14457): [ERROR:flutter/shell/common/shell.cc(188)] Dart Error: Unhandled exception:
E/flutter (14457): Looking up a deactivated widget's ancestor is unsafe.
E/flutter (14457): At this point the state of the widget's element tree is no longer stable. To safely refer to a widget's ancestor in its dispose() method, save a reference to the ancestor by calling inheritFromWidgetOfExactType() in the widget's didChangeDependencies() method.

来自PHP的“消息”：“已成功登录”和“错误的详细信息”

如果我更改：

protected void onPostExecute(JSONObject result) {
    try {
        if (result != null) {
            Toast.makeText(getApplicationContext(),result.getString("message"),Toast.LENGTH_LONG).show();
        } else {
            Toast.makeText(getApplicationContext(), "Unable to retrieve any data from server", Toast.LENGTH_LONG).show();
        }
    } catch (JSONException e) {
        e.printStackTrace();
}

无论登录成功还是失败，都输入MainActivity 有人帮我

Answer 1

根据您的代码，当结果对象不为null时，您将输入MainActivity。您应该添加更多条件来输入MainActivity，例如：

if (result != null && result.getString("result").equals("success"))

Answer 2

您只是在检查if( [CONST1, CONST2].some(x=>path.match(x)) ) {...};是否为空。您应该通过修改代码来检查登录的确切状态。

result

即使{message“的值为空，使用if (result != null && result.optString("message", "failed").equals("Successfully logged in"))也可以。

注意：：您可以根据JSON结构修改代码。

Answer 3

将if条件替换为以下条件。

  if (result != null && result.getString("message").contains("Successfully logged in"))

Answer 4

protected void onPostExecute(JSONObject result) {
        try {
            if (result.length() != 0) {
                Toast.makeText(getApplicationContext(), result.getString("message"), Toast.LENGTH_LONG).show();
                        Intent i = new Intent(getApplicationContext(), MainActivity.class);
                      startActivity(i);

            } else {
                Toast.makeText(getApplicationContext(), "Unable to retrieve any data from server", Toast.LENGTH_LONG).show();
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }
    }

使用PHP Massage成功登录后如何打开Mainactivity？

4 个答案: