Question

我正在关注谷歌Android教程，以基本了解如何创建应用程序，但我无法弄清楚如何在操作菜单上实现选项卡式菜单栏。接下来，第一组教程，我可以创建一个基本的输入表单，并将输入的文本加载到一个新的活动。然后我尝试创建一个新按钮并将其链接到下面本教程中的活动。我是谷歌的一个例子

的精确副本

https://developer.android.com/training/implementing-navigation/lateral.html

这是我的清单文件。我有原始的主要活动，它只是一个输入表单和包含操作栏标签菜单的演示活动

    <activity
        android:name=".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=".DisplayMessageActivity"
        android:label="@string/title_activity_display_message"
        android:parentActivityName=".MainActivity" >
        <meta-data
            android:name="android.support.PARENT_ACTIVITY"
            android:value="com.francismitra.myapplication.MainActivity" />
    </activity>
    <activity
        android:name=".DemoActivity"
        android:label="@string/demo_fragment" />
    <activity
        android:name=".CollectionDemoActivity"
        android:label="@string/demo_collection" />
    <activity

我通过以下方式从主要活动启动演示活动（这总是会导致应用程序关闭）

public void openDemo(View view) {
    Intent intent = new Intent(this, DemoActivity.class);
    startActivity(intent);
}

DemoActivity.java文件是来自android开发人员示例的精确副本 - 我只是更新了包名称。 CollectionDemoActivity也是一个精确的副本。我已经确认附加到openDemo的按钮通过设置测试活动来工作，并且启动正常。应用程序仅关闭我尝试打开DemoActivity。

有人可以解释为什么我无法打开此特定活动吗？我试图实现一个设计，其中主要活动没有操作栏标签，另一个活动可以从具有操作栏标签的主要活动中访问

public class DemoActivity extends FragmentActivity implements ActionBar.TabListener {

AppSectionsPagerAdapter mAppSectionsPagerAdapter;
ViewPager mViewPager;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.article_view);

    // Create the adapter that will return a fragment for each of the three primary sections
    // of the app.
    mAppSectionsPagerAdapter = new AppSectionsPagerAdapter(getSupportFragmentManager());

    // Set up the action bar.
    final ActionBar actionBar = getActionBar();

    // Specify that the Home/Up button should not be enabled, since there is no hierarchical
    // parent.
    actionBar.setHomeButtonEnabled(false);

    // Specify that we will be displaying tabs in the action bar.
    actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

    // Set up the ViewPager, attaching the adapter and setting up a listener for when the
    // user swipes between sections.
    mViewPager = (ViewPager) findViewById(R.id.pager);
    mViewPager.setAdapter(mAppSectionsPagerAdapter);
    mViewPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
        @Override
        public void onPageSelected(int position) {
            // When swiping between different app sections, select the corresponding tab.
            // We can also use ActionBar.Tab#select() to do this if we have a reference to the
            // Tab.
            actionBar.setSelectedNavigationItem(position);
        }
    });

    // For each of the sections in the app, add a tab to the action bar.
    for (int i = 0; i < mAppSectionsPagerAdapter.getCount(); i++) {
        // Create a tab with text corresponding to the page title defined by the adapter.
        // Also specify this Activity object, which implements the TabListener interface, as the
        // listener for when this tab is selected.
        actionBar.addTab(
                actionBar.newTab()
                        .setText(mAppSectionsPagerAdapter.getPageTitle(i))
                        .setTabListener(this));
    }
}'

   /**
 * A fragment that launches other parts of the demo application.
 */
public static class LaunchpadSectionFragment extends Fragment {

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment_section_launchpad, container, false);

        // Demonstration of a collection-browsing activity.
        rootView.findViewById(R.id.demo_collection_button)
                .setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View view) {
                        Intent intent = new Intent(getActivity(), CollectionDemoActivity.class);
                        startActivity(intent);
                    }
                });

        // Demonstration of navigating to external activities.
        rootView.findViewById(R.id.demo_external_activity)
                .setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View view) {
                        // Create an intent that asks the user to pick a photo, but using
                        // FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET, ensures that relaunching
                        // the application from the device home screen does not return
                        // to the external activity.
                        Intent externalActivityIntent = new Intent(Intent.ACTION_PICK);
                        externalActivityIntent.setType("image/*");
                        externalActivityIntent.addFlags(
                                Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET);
                        startActivity(externalActivityIntent);
                    }
                });

        return rootView;
    }
}

/**
 * A dummy fragment representing a section of the app, but that simply displays dummy text.
 */
public static class DummySectionFragment extends Fragment {

    public static final String ARG_SECTION_NUMBER = "section_number";

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment_section_dummy, container, false);
        Bundle args = getArguments();
        ((TextView) rootView.findViewById(android.R.id.text1)).setText(
                getString(R.string.dummy_section_text, args.getInt(ARG_SECTION_NUMBER)));
        return rootView;
    }
}
}

}

以下是我的日志：

ddmlib: Broken pipe
java.io.IOException: Broken pipe
    at sun.nio.ch.FileDispatcherImpl.write0(Native Method)
    at sun.nio.ch.SocketDispatcher.write(SocketDispatcher.java:47)
    at sun.nio.ch.IOUtil.writeFromNativeBuffer(IOUtil.java:93)
    at sun.nio.ch.IOUtil.write(IOUtil.java:65)
    at sun.nio.ch.SocketChannelImpl.write(SocketChannelImpl.java:487)
    at com.android.ddmlib.JdwpPacket.writeAndConsume(JdwpPacket.java:213)
    at com.android.ddmlib.Client.sendAndConsume(Client.java:675)
    at com.android.ddmlib.HandleHeap.sendREAQ(HandleHeap.java:342)
    at com.android.ddmlib.Client.requestAllocationStatus(Client.java:521)
    at com.android.ddmlib.DeviceMonitor.createClient(DeviceMonitor.java:847)
    at com.android.ddmlib.DeviceMonitor.openClient(DeviceMonitor.java:815)
    at com.android.ddmlib.DeviceMonitor.processIncomingJdwpData(DeviceMonitor.java:775)
    at com.android.ddmlib.DeviceMonitor.deviceClientMonitorLoop(DeviceMonitor.java:664)
    at com.android.ddmlib.DeviceMonitor.access$100(DeviceMonitor.java:46)
    at com.android.ddmlib.DeviceMonitor$3.run(DeviceMonitor.java:592)

Answer 1

试试这个，

public void openDemo(View view) {
Intent intent = new Intent(MainActivity.this, DemoActivity.class);
startActivity(intent);

}

删除/评论导致崩溃的其他功能点击链接： Check this link

Answer 2

看起来您与测试设备失去了联系。尝试拔下插头或

adb kill-server adb start-server

Android无法从MainActivity

2 个答案: