如何修复“呼叫需要API级别11”与Android活动？ [英] How to fix "Call requires API level 11" with Android Activity?

问题描述

我刚刚开始做Android开发，
或以上的 http://developer.android.com/training/basics/firstapp/starting-activity.html 教程，
和一件事情会阻止我：
I有两个类，都是使用Android Activity创建向导创建的：

I'm just starting to do Android development, more-or-less following the http://developer.android.com/training/basics/firstapp/starting-activity.html tutorial, and one thing keeps bugging me: I have two classes, both created using the "Android Activity" creation wizard:

public class PlacesActivity extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_places);
        // I manually commented out the following line to get it to compile.
        // getActionBar().setDisplayHomeAsUpEnabled(true);
    }
    // ... other methods
}

和

public class ShowOnePlace extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_show_one_place);
        getActionBar().setDisplayHomeAsUpEnabled(true);
    }
    // ... other methods
}

Eclipse不断给我以下错误：

Eclipse kept giving me the following errors:

调用需要API级别11（当前最小为8）：
android.app。活动＃getActionBar

Call requires API level 11 (current min is 8): android.app.Activity#getActionBar

调用需要API级别11（当前
分钟为8）：android.app.ActionBar＃setDisplayHomeAsUpEnabled

Call requires API level 11 (current min is 8): android.app.ActionBar#setDisplayHomeAsUpEnabled

，直到我注释掉一个的行（如上所示）。
现在，应用程序似乎在我的Android设备
上编译并运行，没有错误。 （嗯，至少没有 错误）

until I commented out one of the lines (as shown above). Now the application seems to compile and run on my Android device without errors. (Well, at least without that error).

所以：

• 为什么 getActionBar（）。setDisplayHomeAsUpEnabled（true）; 在一个类中给出错误，但是完全相同的行不是错误 - 甚至不一个警告 - 在另一个类？


• Android Activity创建向导中有一个错误，不知何故 getActionBar（）。setDisplayHomeAsUpEnabled（true） ; 语句在一个活动中是错误的，但在另一个活动中是完美的？


• Eclipse Lint中可能有一个错误，并且该声明实际上可以在两个活动（或者两个活动中可能是错误的）？


• 我该怎么办才能解决这个问题，而不会将minSdkVersion =8更改为minSdkVersion =11？我的印象是，android-support-v4.jar文件是一个运行在版本8设备上的兼容性库，用于处理在版本11设备中本机处理的东西。


• 什么是当我看到这个错误的时候，真的很正确吗？

• Why is getActionBar().setDisplayHomeAsUpEnabled(true); give that error in one class, but that exact same line is not an error -- not even a warning -- in the other class?
• Is there a bug in the "Android Activity" creation wizard, and somehow that getActionBar().setDisplayHomeAsUpEnabled(true); statement is wrong in one activity, but perfectly fine in the other?
• Is maybe there a bug in Eclipse Lint, and that statement is actually OK in both activities (or perhaps wrong in both activities)?
• What do I have to do so that I can fix this without changing minSdkVersion="8" to minSdkVersion="11"? I was under the impression that the "android-support-v4.jar" file was a compatibility library that ran on version 8 devices to handle stuff that's handled natively in version 11 devices.
• What's really the Right Thing to Do when I see this error?

推荐答案

使用 getSupportActionBar（）而不是 getActionBar（）。这将提供API低于11的 ActionBar 功能。

Use getSupportActionBar() instead of getActionBar(). That will provide ActionBar features on API levels below 11.

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