ActionBar Up导航不适用于API 15 [英] ActionBar Up Navigation not working on API 15

问题描述

我已经为ActionBar实现了Up导航，但是在APi低于16的APi上却遇到了麻烦.

I have implemented the Up navigation for my ActionBar, but I'm having trouble with it on APi's lower than 16.

在运行4.0.4(API 15)的测试设备上，我可以点击ActionBar中的向上"图标，但是它不会转到清单中定义的父活动.

On a test device, running 4.0.4 (API 15) I can tap the Up icon in the ActionBar, but it doesnt go to the parent activity, which I have defined in the manifest.

清单:

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

<uses-sdk
    android:minSdkVersion="11"
    android:targetSdkVersion="19" />

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

<application
    android:allowBackup="true"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >
    <meta-data
        android:name="com.google.android.gms.version"
        android:value="@integer/google_play_services_version" />
    <meta-data
        android:name="com.google.android.maps.v2.API_KEY"
        android:value="" />

    <activity
        android:name=".Home"
        android:label="@string/app_name"
        android:screenOrientation="portrait" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity
        android:name=".Buildings"
        android:label="@string/title_activity_buildings"
        android:parentActivityName=".Home"
        android:screenOrientation="portrait" >
        <meta-data
            android:name="android.support.PARENT_ACTIVITY"
            android:value=".Home" />
    </activity>
    <activity
        android:name=".Map"
        android:label="@string/title_activity_map"
        android:parentActivityName=".Home"
        android:screenOrientation="portrait" >
        <meta-data
            android:name="android.support.PARENT_ACTIVITY"
            android:value=".Home" />
    </activity>
    <activity
        android:name=".Timeline"
        android:label="@string/title_activity_timeline"
        android:parentActivityName=".Home"
        android:screenOrientation="portrait" >
        <meta-data
            android:name="android.support.PARENT_ACTIVITY"
            android:value=".Home" />
    </activity>
    <activity
        android:name=".About"
        android:label="@string/title_activity_about"
        android:parentActivityName=".Home"
        android:screenOrientation="portrait" >
        <meta-data
            android:name="android.support.PARENT_ACTIVITY"
            android:value=".Home" />
    </activity>
</application>

我了解到android:parentActivityName适用于API 16+，并且在运行4.4.4的另一台设备上运行良好.

I understand that android:parentActivityName is for API 16+, and that works fine on another device running 4.4.4.

我了解到我需要元数据标记，因此可以看到，我在其中添加了这些标记，但是根本无法正常工作.

I read that I needed the meta-data tags, so you can see, I added those in, but it simply won't work.

我还添加了对支持库v7的依赖.

I have added the dependency for support library v7 as well.

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'com.google.android.gms:play-services:6.1.+'
    compile "com.android.support:appcompat-v7:21.0.+"
}

我的Building.class在onCreate中具有以下内容:

My Building.class has the following in onCreate:

getActionBar().setDisplayHomeAsUpEnabled(true);

我的印象是我的活动很好，不扩展了ActionBarActivity，因为这是针对11以下的API的，我没有这样做.

I am under the impression my activity is fine not extending ActionBarActivity, as that is for APIs below 11, which I am not doing.

推荐答案

使用以下代码:

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
    // Respond to the action bar's Up/Home button
    case android.R.id.home:
        NavUtils.navigateUpFromSameTask(this);
        return true;
    }
    return super.onOptionsItemSelected(item);
}

参考文档:

当您在API 16+中使用android:parentActivityName时，系统会读取此属性以确定当用户按下操作栏中的向上"按钮时应该启动哪个活动.但是，当使用支持库的meta-data时，必须覆盖onOptionsItemSelected，然后可以使用NavUtils API导航到相应的父级.

when you use android:parentActivityName in API 16+ the system reads this attribute to determine which activity should be started when the user presses the Up button in the action bar. But when you use meta-data of support library, you have to override onOptionsItemSelected then you can navigate Up to the appropriate parent using the NavUtils APIs.

这篇关于ActionBar Up导航不适用于API 15的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！