Question

我只是提问，我认为只是:) 我无法在Retrofit中从我的CallBack方法启动新的Activity，我遇到的问题就像

“android.util.AndroidRuntimeException：从Activity上下文外部调用startActivity（）需要FLAG_ACTIVITY_NEW_TASK标志。这真的是你想要的吗？”

    sign_in_button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            String userEmail = email.getText().toString();
            String userPassword = password.getText().toString();

            final LoginService loginService = RetrofitClient.createService(LoginService.class, userEmail, userPassword);
            loginService.basicLogin(new Callback<User>() {
                @Override
                public void success(User user, Response response) {
                    Toast.makeText(getApplicationContext(),"You are Logged", Toast.LENGTH_SHORT).show();

                    Intent intent = new Intent(getApplicationContext(), BetweenActivity.class);
                    startActivity(intent);





                }

                @Override
                public void failure(RetrofitError error) {
                    Toast.makeText(getApplicationContext(),"Something went wrong", Toast.LENGTH_SHORT).show();

                }
            });

这是我的日志：

致命的例外：主要处理：com.example.bunzlau.retrofit，PID：18138 java.lang.RuntimeException：无法启动活动ComponentInfo {com.example.bunzlau.retrofit / com.example.bunzlau.retrofit.BetweenActivity}：java.lang.NullPointerException：尝试调用虚拟方法'android.view.View android。 widget.Button.findViewById（int）'在空对象引用上在android.app.ActivityThread.performLaunchActivity（ActivityThread.java:3253）在android.app.ActivityThread.handleLaunchActivity（ActivityThread.java:3349）在android.app.ActivityThread.access $ 1100（ActivityThread.java:221）在android.app.ActivityThread $ H.handleMessage（ActivityThread.java:1794）在android.os.Handler.dispatchMessage（Handler.java:102）在android.os.Looper.loop（Looper.java:158）在android.app.ActivityThread.main（ActivityThread.java:7225） at java.lang.reflect.Method.invoke（Native Method）在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:1230）在com.android.internal.os.ZygoteInit.main（ZygoteInit.java:1120）引起：java.lang.NullPointerException：尝试在空对象引用上调用虚方法'android.view.View android.widget.Button.findViewById（int）' 在com.example.bunzlau.retrofit.BetweenActivity.onCreate（BetweenActivity.java:18）在android.app.Activity.performCreate（Activity.java:6876）在android.app.Instrumentation.callActivityOnCreate（Instrumentation.java:1135）在android.app.ActivityThread.performLaunchActivity（ActivityThread.java:3206）在android.app.ActivityThread.handleLaunchActivity（ActivityThread.java:3349）在android.app.ActivityThread.access $ 1100（ActivityThread.java:221）在android.app.ActivityThread $ H.handleMessage（ActivityThread.java:1794）在android.os.Handler.dispatchMessage（Handler.java:102）在android.os.Looper.loop（Looper.java:158）在android.app.ActivityThread.main（ActivityThread.java:7225） at java.lang.reflect.Method.invoke（Native Method）在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:1230）在com.android.internal.os.ZygoteInit.main（ZygoteInit.java:1120）

Answer 1

您从Callback范围内调用startActivity（），而不是活动范围。您需要获取当前活动的参考，并使用它来启动下一个活动。

private Context context = this;

sign_in_button.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        String userEmail = email.getText().toString();
        String userPassword = password.getText().toString();

        final LoginService loginService = RetrofitClient.createService(LoginService.class, userEmail, userPassword);
        loginService.basicLogin(new Callback<User>() {
            @Override
            public void success(User user, Response response) {
                Toast.makeText(getApplicationContext(),"You are Logged", Toast.LENGTH_SHORT).show();

                Intent intent = new Intent(getApplicationContext(), BetweenActivity.class);
                context.startActivity(intent);





            }

            @Override
            public void failure(RetrofitError error) {
                Toast.makeText(getApplicationContext(),"Something went wrong", Toast.LENGTH_SHORT).show();

            }
        });

改造1.9如何从回调中开始新的活动

1 个答案: