java - ViewStub 没有膨胀并且布局保持空白 - Android

Question

我正在研究您启动 Navigation Drawer Activity 时生成的示例代码。在 Android 工作室中。我想做的是以编程方式更改包含的 View ，我的研究表明 ViewStub 是做到这一点的最佳方式。但是我无法让它工作。对于有问题的主要布局，涉及 3 个文件:

activity_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:openDrawer="start">

    <include
        layout="@layout/app_bar_main"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

    <android.support.design.widget.NavigationView
        android:id="@+id/nav_view"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        android:fitsSystemWindows="true"
        app:headerLayout="@layout/nav_header_main"
        app:menu="@menu/activity_main_drawer" />

</android.support.v4.widget.DrawerLayout>

app_bar_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:context="com.MY_APP.android.MainActivity">

    <android.support.design.widget.AppBarLayout
        android:layout_height="wrap_content"
        android:layout_width="match_parent"
        android:theme="@style/AppTheme.AppBarOverlay">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="?attr/colorPrimary"
            app:popupTheme="@style/AppTheme.PopupOverlay" />

    </android.support.design.widget.AppBarLayout>

    <ViewStub
        android:id="@+id/main_content"
        android:inflatedId="@id/main_content"
        android:layout="@layout/content_main"
        android:layout_height="match_parent"
        android:layout_width="match_parent"/>

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/fab"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom|end"
        android:layout_margin="@dimen/fab_margin"
        android:src="@android:drawable/ic_dialog_email" />

</android.support.design.widget.CoordinatorLayout>

content_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:showIn="@layout/app_bar_main"
    tools:context="com.MY_APP.android.MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/content_textview"
        android:text="//TODO Main Feed"/>
</RelativeLayout>

以下是我的 MainActivity.java。似乎什么都没有发生，并且 content_main 似乎从未出现过。这可能是可见性问题吗？

package com.myapp.android;


import android.app.Dialog;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.design.widget.NavigationView;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.MenuItem;
import android.view.ViewStub;
import android.widget.Toast;

import com.facebook.FacebookSdk;
import com.facebook.login.LoginManager;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GooglePlayServicesUtil;

import org.json.JSONException;
import org.json.JSONObject;

import java.util.ArrayList;

public class MainActivity
        extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener {


    NetworkHelpers NetworkHelper = new NetworkHelpers();
    SharedPreferences sharedpreferences;

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        //Check if user is connected
        if(!NetworkHelper.checkConnectivity(this)){
            NetworkHelper.showNotConnectedAlert(this);
        }

        //Check for Google Play Services
        checkGooglePlayServicesAvailable();

        //Get User Info From Database
        sharedpreferences = getSharedPreferences("com.myapp.android.prefs", Context.MODE_PRIVATE);
        String login_token = sharedpreferences.getString("login_token", "");
        String first_name = sharedpreferences.getString("first_name", "");
        String last_name = sharedpreferences.getString("last_name", "");
        String email = sharedpreferences.getString("email", "");


        if (login_token.isEmpty()){
            //Start LoginActivity
            Intent intent = new Intent(this, LoginActivity.class);
            intent.addFlags(Intent.FLAG_ACTIVITY_NO_ANIMATION);
            finish();
            startActivity(intent);
        }else{
            //Update user info
            ArrayList<String> params = new ArrayList<String>();
            params.add(login_token);
            new getUserInfo().execute(params);
        }

        //Create View
        super.onCreate(savedInstanceState);
        setContentView(com.myapp.android.R.layout.activity_main);

        //Set Toolbar and Navigation Drawer
        Toolbar toolbar = (Toolbar) findViewById(com.myapp.android.R.id.toolbar);
        setSupportActionBar(toolbar);
        DrawerLayout drawer = (DrawerLayout) findViewById(com.myapp.android.R.id.drawer_layout);
        ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
            this, drawer, toolbar, com.myapp.android.R.string.navigation_drawer_open, com.myapp.android.R.string.navigation_drawer_close);
        drawer.setDrawerListener(toggle);
        toggle.syncState();
        NavigationView navigationView = (NavigationView) findViewById(com.myapp.android.R.id.nav_view);
        navigationView.setNavigationItemSelectedListener(this);

        ViewStub stub = (ViewStub) findViewById(R.id.main_content);
        stub.setLayoutResource(R.layout.content_main);
        stub.inflate();

    }

    @Override
    public void onBackPressed() {
        DrawerLayout drawer = (DrawerLayout) findViewById(com.myapp.android.R.id.drawer_layout);
        if (drawer.isDrawerOpen(GravityCompat.START)) {
            drawer.closeDrawer(GravityCompat.START);
        } else {
            super.onBackPressed();
        }
    }

    @SuppressWarnings("StatementWithEmptyBody")
    @Override
    public boolean onNavigationItemSelected(MenuItem item) {
        int id = item.getItemId();

        if (id == R.id.nav_home) {
            // Start Home Screen
        } else if (id == R.id.nav_videos) {
            // Start Videos Screen
        } else if (id == R.id.nav_photos) {
            // Start Photos Screen
        } else if (id == R.id.nav_galleries) {
            // Start Galleries Screen
        } else if (id == R.id.nav_map) {
            // Start Map Screen
        } else if (id == com.myapp.android.R.id.nav_share) {
            //Open share app dialog
            Intent intent = new Intent(Intent.ACTION_SEND);
            intent.setType("text/plain");
            intent.putExtra(Intent.EXTRA_SUBJECT, "My App");
            intent.putExtra(Intent.EXTRA_TEXT, "Check out My App: http://myapp.com/app");
            Intent chooser = Intent.createChooser(intent, "Tell a friend about My App");
            startActivity(chooser);
        } else if (id == com.myapp.android.R.id.nav_logout){
            logout();
        }

        DrawerLayout drawer = (DrawerLayout) findViewById(com.myapp.android.R.id.drawer_layout);
        drawer.closeDrawer(GravityCompat.START);
        return true;
    }

    //AsyncTask to get user info from api
    class getUserInfo extends AsyncTask<ArrayList<String>, Void, String> {
        @Override
        protected String doInBackground(ArrayList<String>... params) {
            String token = params[0].get(0);
            String response = HttpRequest.post("http://api.myapp.com/users/get-info/").send("api_key=API_KEY&token="+token).body();
            return response;
        }

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
        }

        @Override
        protected void onPostExecute(String result) {
            try {
                // Do JSON Stuff
                JSONObject jsonobject = new JSONObject(result);
                String status = jsonobject.get("status").toString();
                String message = jsonobject.get("message").toString();
                JSONObject userinfo = jsonobject.getJSONObject("user_info");

                //Set up user variables
                String first_name = userinfo.get("first_name").toString();
                String last_name = userinfo.get("last_name").toString();
                String email = userinfo.get("email").toString();
                String display_name = userinfo.get("display_name").toString();
                String about = userinfo.get("about").toString();
                String newsletter = userinfo.get("newsletter").toString();


                if (status.equals("success")){
                    updateSharedPreferences(first_name, last_name, email, display_name, about, newsletter);
                }else if (status.equals("error")){
                    logout();
                } else{
                    logout();
                }

            } catch (JSONException e) {
                Toast.makeText(getApplicationContext(),"An unknown error occurred.", Toast.LENGTH_SHORT).show();
                logout();
            }
        }
    }

    private boolean checkGooglePlayServicesAvailable() {
        final int status = GooglePlayServicesUtil.isGooglePlayServicesAvailable(getApplicationContext());
        if (status == ConnectionResult.SUCCESS) {
            return true;
        }

        if (GooglePlayServicesUtil.isUserRecoverableError(status)) {
            final Dialog errorDialog = GooglePlayServicesUtil.getErrorDialog(status, this, 1);
            if (errorDialog != null)
            {
                errorDialog.show();
            }
        }
        return false;
    }

    private void updateSharedPreferences(String first_name, String last_name, String email, String display_name, String about, String newsletter){
        //Put user info into sharedpreferences
        SharedPreferences sharedpreferences = getSharedPreferences("com.myapp.android.prefs", Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = sharedpreferences.edit();
        editor.putString("first_name", first_name);
        editor.putString("last_name", last_name);
        editor.putString("email", email);
        editor.putString("display_name", display_name);
        editor.putString("about", about);
        editor.putString("newsletter", newsletter);
        editor.commit();
    }

    private void logout(){
        //Logout of Facebook
        FacebookSdk.sdkInitialize(this);
        LoginManager.getInstance().logOut();

        //Unset shared preferences login token
        SharedPreferences sharedpreferences = getSharedPreferences("com.myapp.android.prefs", Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = sharedpreferences.edit();
        editor.putString("login_token", "");
        editor.putString("facebook_token", "");
        editor.putString("google_token", "");
        editor.commit();

        //Open login screen
        Intent intent = new Intent(getApplicationContext(), LoginActivity.class);
        finish();
        startActivity(intent);
    }
}

Answer 1

我遇到了同样的问题。似乎当您动态膨胀 StubView , 行为与您仅使用 <include> 时不同。标记以包含另一个 xml 布局。在这种情况下，在膨胀后替换 StubView 的内容未位于 AppBar 下方布局，但正好位于它的后面。

解决此问题的一种方法是移动RelativeLayout 以使其包裹StubView。因此，需要进行以下更改:

app_bar_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:context="com.MY_APP.android.MainActivity">

    <android.support.design.widget.AppBarLayout
        android:layout_height="wrap_content"
        android:layout_width="match_parent"
        android:theme="@style/AppTheme.AppBarOverlay">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="?attr/colorPrimary"
            app:popupTheme="@style/AppTheme.PopupOverlay" />

    </android.support.design.widget.AppBarLayout>

    <!-- Changed Content -->

    <RelativeLayout
       android:layout_width="match_parent"
       android:layout_height="match_parent"
       android:paddingLeft="@dimen/activity_horizontal_margin"
       android:paddingRight="@dimen/activity_horizontal_margin"
       android:paddingTop="@dimen/activity_vertical_margin"
       android:paddingBottom="@dimen/activity_vertical_margin"
       app:layout_behavior="@string/appbar_scrolling_view_behavior"
       tools:showIn="@layout/app_bar_main"
       tools:context="com.MY_APP.android.MainActivity">

        <ViewStub
            android:id="@+id/main_content"
            android:inflatedId="@id/main_content"
            android:layout="@layout/content_main"
            android:layout_height="match_parent"
            android:layout_width="match_parent"/>

    </RelativeLayout>

    <!-- Changed Content -->

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/fab"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom|end"
        android:layout_margin="@dimen/fab_margin"
        android:src="@android:drawable/ic_dialog_email" />

</android.support.design.widget.CoordinatorLayout>

content_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<TextView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/content_textview"
    android:text="//TODO Main Feed"/>