插入NewChidldActivity在MainActivity和FirstChildAcvitity之间，并将默认ChildActivity更改为NewChildActivity

Question

各位朋友，

谢谢大家的一贯支持。

我已经开发了一个具有登录功能的考试应用程序。

以前，该应用程序有3个活动(MainActivity、WelcomeScreenActivity和QuestionsAcvitity)。这个应用程序工作得很好。

但是，当用户从MainActivity登录时，WelcomeScreenActivity显示。但我需要在PROFILE_ACTIVITY和MainActivity之间插入另一个活动( WelcomeScreenActivity )，以便当用户成功登录时，应用程序将显示用户的PROFILEACTIVITY。

页面下面的图片

在新的 ProfileActivity之前使用以前的代码

MainActivity.java代码

@Override
        protected void onPostExecute(Void result){
            if (!responseData.equals( "User Not Found" )) {
                message = "Welcome";
                data = responseData;//store the user id from the server in data
                //Bundle bundle = new Bundle();//bundle the message and parse it to the next activity
                //bundle.putString("dispMsg", message);//bundle the message using the variable dispMsg
                //intent.putExtras(bundle);
                startActivity(intent);
                statusBar.setText(message);
            } else {
                message = responseData;//"Incorrect Username or Password. Try again!";
                statusBar.setText(message);
            }
            super.onPostExecute(result);
        }

DisplayWelcomeScreenActivity.java代码此活动在成功登录后显示。

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_display_welcome_screen);

    // Get the Intent that started this activity and extract the string
        intent = getIntent();
}

要从这个WelcomeActivity传递到下一个QuestionsActivity，下面的代码是在按钮单击()事件上执行的

public void courseClicked(View v) {

        String course = "";
        Intent intent = new Intent(this, CSS_342_Questions.class);
        int qNum = 0;

       switch (v.getId()){
           case R.id.buttonCSS342:
               course = "CSS 342";
               qNum=1;
               break;
           case R.id.buttonCSS352:
               course = "CSS 352";
               qNum=1;
               break;
           case R.id.buttonCSS354:
               course = "CSS 354";
               qNum=1;
               break;
           case R.id.buttonCSS356:
               course = "CSS 356";
               qNum=1;
               break;
           case R.id.buttonCSS381:
               course = "CSS 381";
               qNum=1;
               break;
           case R.id.buttonPCR362:
               course = "PCR 362";
               qNum=1;
               break;
       }
        Bundle bundle = new Bundle();
        bundle.putString("dispCode", course);
        bundle.putInt("qNum", qNum);
        //bundle.putString("dispMsg", "Welcome");
        intent.putExtras(bundle);

        startActivity(intent);
    }

使用下面的代码显示QuestionsActivity。

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_css_342__questions);

        // Get the Intent that started this activity and extract the string
        intent = getIntent();
        bundle = getIntent().getExtras();

        showCode = bundle.getString("dispCode");
        qNum = bundle.getInt("qNum");
}

下面的代码是Manifest xml，它将3项活动链接在一起以进行正确的导航。

AndroidManifest.XML代码

?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.examinationportal">

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

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.AppCompat.DayNight.DarkActionBar">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <activity android:name=".DisplayWelcomeScreen"
            android:label="@string/welcome_screen_title"
            android:parentActivityName=".MainActivity">

            <!-- The meta-data tag is required if you support API level 15 and lower -->
            <meta-data
                android:name="android.support.PARENT_ACTIVITY"
                android:value=".MainActivity" />

        </activity>

        <activity
            android:name=".CSS_342_Questions"
            android:allowTaskReparenting="true"
            android:label="@string/question_screen"
            android:parentActivityName=".DisplayWelcomeScreen">

            <!-- The meta-data tag is required if you support API level 15 and lower -->
            <meta-data
                android:name="android.support.PARENT_ACTIVITY"
                android:value=".DisplayWelcomeScreen" />
        </activity>
        <activity
            android:name=".RegisterUserActivity"
            android:label="@string/new_user_form"
            android:parentActivityName=".MainActivity">

            <!-- The meta-data tag is required if you support API level 15 and lower -->
            <meta-data
                android:name="android.support.PARENT_ACTIVITY"
                android:value=".MainActivity" />
        </activity>
    </application>

</manifest>

现在，我想在ProfileActivity和MainActivity之间插入一个新的活动( DisplayScreenActivity )。

我已经更改了下面的AndroidManifest xml代码。这个应用程序正在崩溃。LogCat显示应用程序在MainActivity.java中崩溃**StartActivity(intent)**的行；第153行

新活动后的代码

MainActivity代码仍然保持不变。

新的AndroidManifest.xml代码

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.examinationportal">

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

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.AppCompat.DayNight.DarkActionBar">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <activity android:name=".ProfileAcvitity"
            android:label="@string/student_profile"
            android:parentActivityName=".MainActivity">

            <!-- The meta-data tag is required if you support API level 15 and lower -->
            <meta-data
                android:name="android.support.PARENT_ACTIVITY"
                android:value=".MainActivity" />

        </activity>

        <activity
            android:name=".RegisterUserActivity"
            android:label="@string/new_user_form"
            android:parentActivityName=".MainActivity">

            <!-- The meta-data tag is required if you support API level 15 and lower -->
            <meta-data
                android:name="android.support.PARENT_ACTIVITY"
                android:value=".MainActivity" />
        </activity>
    </application>

</manifest>

新ProfileActivity.java码

public class ProfileAcvitity extends AppCompatActivity {
    public Intent intent;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_profile_acvitity);

        intent = getIntent();
    }

LOGCAT信息

04-25 13:53:33.680 14789-14789/com.example.examinationportal E/AndroidRuntime: FATAL EXCEPTION: main
                                                                               Process: com.example.examinationportal, PID: 14789
                                                                               android.content.ActivityNotFoundException: Unable to find explicit activity class {com.example.examinationportal/com.example.examinationportal.DisplayWelcomeScreen}; have you declared this activity in your AndroidManifest.xml?
                                                                                   at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:1805)
                                                                                   at android.app.Instrumentation.execStartActivity(Instrumentation.java:1523)
                                                                                   at android.app.Activity.startActivityForResult(Activity.java:4034)
                                                                                   at android.support.v4.app.BaseFragmentActivityJB.startActivityForResult(BaseFragmentActivityJB.java:50)
                                                                                   at android.support.v4.app.FragmentActivity.startActivityForResult(FragmentActivity.java:79)
                                                                                   at android.app.Activity.startActivityForResult(Activity.java:3986)
                                                                                   at android.support.v4.app.FragmentActivity.startActivityForResult(FragmentActivity.java:859)
                                                                                   at android.app.Activity.startActivity(Activity.java:4325)
                                                                                   at android.app.Activity.startActivity(Activity.java:4293)
                                                                                   at com.example.examinationportal.MainActivity$GetText.onPostExecute(MainActivity.java:153)
                                                                                   at com.example.examinationportal.MainActivity$GetText.onPostExecute(MainActivity.java:83)
                                                                                   at android.os.AsyncTask.finish(AsyncTask.java:651)
                                                                                   at android.os.AsyncTask.-wrap1(AsyncTask.java)
                                                                                   at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:668)
                                                                                   at android.os.Handler.dispatchMessage(Handler.java:111)
                                                                                   at android.os.Looper.loop(Looper.java:207)
                                                                                   at android.app.ActivityThread.main(ActivityThread.java:5763)
                                                                                   at java.lang.reflect.Method.invoke(Native Method)
                                                                                   at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:789)
                                                                                   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:679)

请帮我解决这个问题。

谢谢。

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Answer 1

<activity android:name=".DisplayWelcomeScreen"
            android:label="@string/student_welcome"
            android:parentActivityName=".MainActivity">

            <!-- The meta-data tag is required if you support API level 15 and lower -->
            <meta-data
                android:name="android.support.PARENT_ACTIVITY"
                android:value=".MainActivity" />

        </activity>

在AndroidManifest.xml文件中添加这些行将解决问题。