Question

我想知道如何编写操作栏中的后退按钮以恢复到之前的活动并完成刚刚显示的活动？

About.class

public class About extends FragmentActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.about);
        getActionBar().setDisplayHomeAsUpEnabled(true);
// Get tracker.
        Tracker t = ((AnalyticsTracker) getApplication()).getTracker(AnalyticsTracker.TrackerName.APP_TRACKER);

// Enable Display Features so you can see demographics in Google Analytics
        t.enableAdvertisingIdCollection(true);

// Set screen name.
        t.setScreenName("About");

// Send a screen view.
        t.send(new HitBuilders.AppViewBuilder().build());
        FragmentManager fragmentManager = getFragmentManager();
        android.app.FragmentTransaction fragmentTransaction =
                fragmentManager.beginTransaction();

        adView ls_fragment = new adView();
        fragmentTransaction.replace(android.R.id.content, ls_fragment);

        AdView mAdView = (AdView) findViewById(R.id.adView);
        AdRequest adRequest = new AdRequest.Builder().build();
        mAdView.loadAd(adRequest);

    }

}

关于页面的布局。 about.xml

<?xml version="1.0" encoding="utf-8"?>
    <RelativeLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:ads="http://schemas.android.com/apk/res-auto"
        xmlns:tools="http://schemas.android.com/tools"
        android:id = "@+id/content_frame"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@color/black"
        >


    <RelativeLayout
            android:background="@mipmap/home"
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <ImageView
                android:layout_width="200dp"
                android:layout_height="200dp"
                android:id="@+id/imageView"
                android:background="@mipmap/ic_launcher"
                android:layout_alignParentTop="true"
                android:layout_centerHorizontal="true" />

        <TextView
            android:layout_width="300dp"
            android:layout_height="250dp"
            android:id="@+id/textView9"
            android:gravity="center"
            android:textSize="16dp"
            android:text="@string/aboutText"
            android:background="@drawable/text"
            android:layout_below="@+id/imageView"
            android:layout_centerHorizontal="true" />

        <fragment
            android:layout_width="match_parent"
            android:layout_height="50dp"
            android:name="course.labs.converjz.adView"
            android:id="@+id/fragment"
            tools:layout="@layout/adview"
            android:layout_gravity="center|bottom"
            android:layout_alignWithParentIfMissing="false"
            android:layout_alignParentBottom="true"
            android:layout_alignParentStart="true" />

    </RelativeLayout>
</RelativeLayout>

创建操作栏并向其添加后退按钮的特定样式。 Styles.xml

 <style name= "MenuBar" parent="@style/AppBaseTheme">
        <item name = "android:homeAsUpIndicator">@mipmap/back</item>

</style>

后退按钮图像位于mipmap图标文件夹中。

Answer 1

试试这个

@Override
        public boolean onOptionsItemSelected(MenuItem item) {
                switch (item.getItemId()) {
                case android.R.id.home:
                       finish();
                   break;
                }
                return true;
        }

Answer 2

只需将getActionBar更改为getSupportActionBar 如图所示：

getSupportActionBar().setDisplayHomeAsUpEnabled(true);

如何编写操作栏上的后退按钮以返回上一个活动？

2 个答案: