屏幕旋转到横向后，onCreate的活动无限调用

Question

我创建了一个包含自定义Toolbar和NavigationDrawer的Android应用。我使用Android API 22并在Nexus 5（Android 5.1.0）上进行了测试。当我在横向屏幕中启动应用程序（并且还将应用程序从纵向旋转到横向）时，应用程序始终显示无限闪烁。虽然，我旋转到肖像，它仍然闪烁。我运行调试器，发现Activity.onCreate总是被重复调用。

这是我的代码：

的AndroidManifest.xml

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

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/MyTheme.NoActionBar">
        <activity
            android:name=".activity.MainActivity"
            android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name=".activity.SettingsActivity"
            android:configChanges="locale"
            android:label="@string/settings"
            android:parentActivityName=".activity.MainActivity"
            android:theme="@style/MyTheme.Light">
            <meta-data
                android:name="android.support.PARENT_ACTIVITY"
                android:value=".activity.MainActivity" />
        </activity>
    </application>

</manifest>

MainActivity.java

package com.example.activity;

import android.content.Intent;
import android.content.res.Configuration;
import android.content.res.TypedArray;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.LinearLayout;
import android.widget.ListView;

import com.example.R;
import com.example.nav.NavDrawerItem;
import com.example.nav.NavDrawerListAdapter;
import com.example.util.VersionUtil;

import java.util.ArrayList;

public class MainActivity extends ActionBarActivity {

    private Toolbar mToolbar;
    private DrawerLayout mDrawerLayout;
    private LinearLayout mDrawerRoot;
    private ListView mDrawerList;
    private ActionBarDrawerToggle mDrawerToggle;
    private NavDrawerListAdapter mDrawerAdapter;

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

        mDrawerList = (ListView) findViewById(R.id.drawer_list);
        mToolbar = (Toolbar) findViewById(R.id.toolbar);
        mDrawerLayout = (DrawerLayout) findViewById(R.id.main_drawer_layout);
        mDrawerRoot = (LinearLayout) findViewById(R.id.drawer_root);

        initNavigationDrawer();
    }

    protected void initNavigationDrawer() {
        if (mToolbar != null) {
            setSupportActionBar(mToolbar);
        }

        mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout, mToolbar, R.string.drawer_open, R.string.drawer_close) {
            @Override
            public void onDrawerClosed(View drawerView) {
                super.onDrawerClosed(drawerView);
            }

            @Override
            public void onDrawerOpened(View drawerView) {
                super.onDrawerOpened(drawerView);
            }
        };
        mDrawerLayout.setDrawerListener(mDrawerToggle);


        String[] navMenuTitles = getResources().getStringArray(R.array.nav_drawer_items);
        TypedArray navMenuIcons = getResources().obtainTypedArray(R.array.nav_drawer_icons);
        TypedArray navMenuSelectedIcons = getResources().obtainTypedArray(R.array.nav_drawer_selected_icons);

        ArrayList<NavDrawerItem> navDrawerItems = new ArrayList<>();
        for (int i = 0, len = navMenuTitles.length; i < len; i++) {
            navDrawerItems.add(new NavDrawerItem(navMenuTitles[i], navMenuIcons.getResourceId(i, -1), navMenuSelectedIcons.getResourceId(i, -1), false));
        }

        // Recycle the typed array
        navMenuIcons.recycle();
        navMenuSelectedIcons.recycle();

        // setting the nav drawer list adapter
        mDrawerAdapter = new NavDrawerListAdapter(getApplicationContext(), navDrawerItems);
        mDrawerList.setAdapter(mDrawerAdapter);
        mDrawerList.setOnItemClickListener(new DrawerItemClickListener());
        mDrawerList.setChoiceMode(ListView.CHOICE_MODE_SINGLE);
        selectDrawerMenuItem(0);
    }

    @Override
    protected void onPostCreate(Bundle savedInstanceState) {
        super.onPostCreate(savedInstanceState);
        mDrawerToggle.syncState();
    }

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        mDrawerToggle.onConfigurationChanged(newConfig);
        setContentView(R.layout.activity_main);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        if (mDrawerToggle.onOptionsItemSelected(item)) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    @Override
    public void setTitle(CharSequence title) {
        if (mToolbar != null) {
            mToolbar.setTitle(title);
        } else {
            super.setTitle(title);
        }
    }

    private class DrawerItemClickListener implements ListView.OnItemClickListener {
        @Override
        public void onItemClick(AdapterView parent, View view, int position, long id) {
            selectDrawerMenuItem(position);
        }
    }

    private void selectDrawerMenuItem(int position) {
        switch (position) {
            case 3: // Settings
                showSettings();
                break;
            case 4: // Help and Feedback
                sendHelpAndFeedbackEmail();
                break;
            default:
                setSelectedNavItemMenu(position);
                break;
        }
        mDrawerLayout.closeDrawer(mDrawerRoot);
    }

    private void setSelectedNavItemMenu(int position) {
        for (int i = 0, size = mDrawerAdapter.getCount(); i < size; i++) {
            NavDrawerItem menuItem = (NavDrawerItem) mDrawerAdapter.getItem(i);
            menuItem.setSelected(i == position);
        }
        mDrawerList.setItemChecked(position, true);
    }

    private void showSettings() {
        Intent settingsIntent = new Intent(this, SettingsActivity.class);
        startActivity(settingsIntent);
    }

    private void sendHelpAndFeedbackEmail() {
        Intent emailIntent = new Intent(Intent.ACTION_SENDTO);
        emailIntent.setType("text/plain");

        String versionName = VersionUtil.getVersionName(this);
        int versionCode = VersionUtil.getVersionCode(this);
        emailIntent.putExtra(Intent.EXTRA_SUBJECT, String.format(getString(R.string.email_help_subject), getText(R.string.app_name), versionName, versionCode));

        emailIntent.setData(Uri.parse("mailto:" + getText(R.string.email_send_to)));
        emailIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        startActivity(Intent.createChooser(emailIntent, getText(R.string.email_chooser_title)));
    }
 }

为什么应用程序会闪烁？有没有解决这个问题的方法？ 感谢。

编辑＃1

这是来自Logcat：

...
03-22 22:50:51.716  31125-31125/com.example W/View﹕ requestLayout() improperly called by android.widget.ListView{654f6b5 VFED.VC. ......ID 0,75-912,1080 #7f0b0042 app:id/drawer_list} during layout: running second layout pass
03-22 22:50:51.821  31125-31125/com.example W/View﹕ requestLayout() improperly called by android.widget.ListView{3df1b0fa VFED.VC. ......ID 0,75-912,1080 #7f0b0042 app:id/drawer_list} during layout: running second layout pass
03-22 22:50:51.918  31125-31125/com.example W/View﹕ requestLayout() improperly called by android.widget.ListView{7b0a09b VFED.VC. ......ID 0,75-912,1080 #7f0b0042 app:id/drawer_list} during layout: running second layout pass
...

重复了这些错误。

编辑＃2

activity_main.xml中

<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/main_drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true">

    <!-- Your normal content view -->
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">

        <!-- We use a Toolbar so that our drawer can be displayed
             in front of the action bar -->
        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="?attr/colorPrimary"
            android:minHeight="?attr/actionBarSize"
            app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
            app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar" />

        <!-- The rest of your content view -->
        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:background="#fff">

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="Activity Content"
                android:textColor="#000" />
        </RelativeLayout>
    </LinearLayout>

    <!-- Your drawer view. This can be any view, LinearLayout
         is just an example. As we have set fitSystemWindows=true
         this will be displayed under the status bar. -->
    <LinearLayout
        android:id="@+id/drawer_root"
        android:layout_width="304dp"
        android:layout_height="match_parent"
        android:layout_gravity="left|start"
        android:fitsSystemWindows="true">

        <!-- Your drawer content -->
        <ListView
            android:id="@+id/drawer_list"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:background="@color/white"
            android:divider="@null"
            android:fastScrollEnabled="false"
            />
    </LinearLayout>
</android.support.v4.widget.DrawerLayout>

编辑＃3

NavDrawerListAdapter.java

import java.util.ArrayList;

import android.app.Activity;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;

import com.example.R;

/**
 * Created by edward on 01/03/2015.
 */
public class NavDrawerListAdapter extends BaseAdapter {

    private Context context;
    private ArrayList<NavDrawerItem> navDrawerItems;

    public NavDrawerListAdapter(Context context, ArrayList<NavDrawerItem> navDrawerItems) {
        this.context = context;
        this.navDrawerItems = navDrawerItems;
    }

    @Override
    public int getCount() {
        return navDrawerItems.size();
    }

    @Override
    public Object getItem(int position) {
        return navDrawerItems.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        if (convertView == null) {
            LayoutInflater mInflater = (LayoutInflater)
                    context.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
            convertView = mInflater.inflate(R.layout.nav_list_item, null);
        }

        ImageView imgIcon = (ImageView) convertView.findViewById(R.id.nav_icon);
        TextView txtTitle = (TextView) convertView.findViewById(R.id.nav_title);
        TextView txtCount = (TextView) convertView.findViewById(R.id.nav_counter);

        NavDrawerItem item = navDrawerItems.get(position);
        if (item.isSelected()) {
            imgIcon.setImageResource(navDrawerItems.get(position).getIconSelectedResId());
        } else {
            imgIcon.setImageResource(navDrawerItems.get(position).getIconResId());
        }
        txtTitle.setText(item.getTitle());

        if (navDrawerItems.get(position).isCounterVisible()) {
            txtCount.setVisibility(View.VISIBLE);
            txtCount.setText(navDrawerItems.get(position).getCount());
        } else {
            txtCount.setVisibility(View.GONE);
        }

        return convertView;
    }

}

nav_list_item.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/nav_background_selector"
    android:minHeight="?android:attr/listPreferredItemHeightSmall">

    <ImageView
        android:id="@+id/nav_icon"
        android:layout_width="@dimen/nav_icon_size"
        android:layout_height="@dimen/nav_icon_size"
        android:layout_alignParentLeft="true"
        android:layout_centerVertical="true"
        android:layout_marginLeft="16dp"
        android:layout_marginRight="24dp"
        android:src="@drawable/ic_launcher" />

    <TextView
        android:id="@+id/nav_title"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_centerVertical="true"
        android:layout_toRightOf="@id/nav_icon"
        android:gravity="center_vertical"
        android:paddingRight="40dp"
        android:textAppearance="?android:attr/textAppearanceSmall"
        android:textColor="@color/primary_text"
        android:textStyle="bold"/>

    <TextView
        android:id="@+id/nav_counter"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:layout_centerVertical="true"
        android:layout_marginRight="8dp"
        android:background="@color/primary_light"
        android:text="0"
        android:textColor="@color/primary_text" />
</RelativeLayout>

Answer 1

从setContentView(R.layout.activity_main);方法

中删除onConfigurationChanged()

如果您使用此功能，请将其删除

android:fastScrollEnabled="true"
 android:fastScrollAlwaysVisible="true"