Android 文本视图在片段中不可见？_Android_Android Fragments_Textview

Android 文本视图在片段中不可见？

android android-fragments

Android 文本视图在片段中不可见？,android,android-fragments,textview,Android,Android Fragments,Textview,在此基础上，我学习了如何在Android中使用Fragments在操作栏中创建选项卡。虽然标签显示得很好，但是代码>文本视图< /代码>应该出现在片段< /代码> s的中间。我看过其他与此相关的StackOverflow问题，但没有一个解决了我的问题 FragmentTab1.java: public class FragmentTab1 extends Fragment { final String TAG = "FRAGMENT_TAB_1"; public View on

在此基础上，我学习了如何在Android中使用

Fragment

s在

操作栏中创建选项卡。虽然标签显示得很好，但是<>代码>文本视图< /代码>应该出现在<代码>片段< /代码> s的中间。我看过其他与此相关的StackOverflow问题，但没有一个解决了我的问题
FragmentTab1.java:
public class FragmentTab1 extends Fragment {
    final String TAG = "FRAGMENT_TAB_1";

    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        View view = inflater.inflate(R.layout.tab, container, false);
        TextView textview = (TextView) view.findViewById(R.id.txtvwTab);
        textview.setText("one");

        Log.i(TAG, "textview's text: " + textview.getText());

        return view;
    }
}

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <TextView
        android:id="@+id/txtvwTab" 
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true" //added later
        android:textColor="@color/Black" //added later
        android:textSize="40sp" //added later
        android:alpha="1" //added later
        android:text="DEFAULT" //added later
        />

</RelativeLayout>

public class Main extends Activity {
    ActionBar.Tab tab1, tab2, tab3;

    Fragment fragmentTab1 = new FragmentTab1();
    Fragment fragmentTab2 = new FragmentTab2();
    Fragment fragmentTab3 = new FragmentTab3();

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        //Remove status bar
        View decorView = getWindow().getDecorView();
        // Hide the status bar.
        int uiOptions = View.SYSTEM_UI_FLAG_FULLSCREEN;
        decorView.setSystemUiVisibility(uiOptions);

        setContentView(R.layout.activity_main);

        ActionBar actionBar = getActionBar();
        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

        tab1 = actionBar.newTab().setText("1");
        tab2 = actionBar.newTab().setText("2");
        tab3 = actionBar.newTab().setText("3");

        tab1.setTabListener(new TabListener(fragmentTab1));
        tab2.setTabListener(new TabListener(fragmentTab2));
        tab3.setTabListener(new TabListener(fragmentTab3));

        actionBar.addTab(tab1);
        actionBar.addTab(tab2);
        actionBar.addTab(tab3);
    }

<android.support.v4.view.ViewPager xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/fragment_container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.novoloc.upup2.Main" />

public class TabListener implements ActionBar.TabListener {
    Fragment fragment;

    public TabListener(Fragment fragment) {
        this.fragment = fragment;
    }

    public void onTabSelected(Tab tab, FragmentTransaction ft) {
        ft.replace(R.id.fragment_container, fragment);
    }

    public void onTabUnselected(Tab tab, FragmentTransaction ft) {
        ft.remove(fragment);
    }

    public void onTabReselected(Tab tab, FragmentTransaction ft) {
        // nothing done here
    }
}

最奇怪的是，虽然TextView
不可见，但当我查看LogCat
时，它仍然显示“TextView的text:one”。显然，TextView
仍在创建中。根本没有错误消息
tab.xml:
public class FragmentTab1 extends Fragment {
    final String TAG = "FRAGMENT_TAB_1";

    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        View view = inflater.inflate(R.layout.tab, container, false);
        TextView textview = (TextView) view.findViewById(R.id.txtvwTab);
        textview.setText("one");

        Log.i(TAG, "textview's text: " + textview.getText());

        return view;
    }
}

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <TextView
        android:id="@+id/txtvwTab" 
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true" //added later
        android:textColor="@color/Black" //added later
        android:textSize="40sp" //added later
        android:alpha="1" //added later
        android:text="DEFAULT" //added later
        />

</RelativeLayout>

public class Main extends Activity {
    ActionBar.Tab tab1, tab2, tab3;

    Fragment fragmentTab1 = new FragmentTab1();
    Fragment fragmentTab2 = new FragmentTab2();
    Fragment fragmentTab3 = new FragmentTab3();

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        //Remove status bar
        View decorView = getWindow().getDecorView();
        // Hide the status bar.
        int uiOptions = View.SYSTEM_UI_FLAG_FULLSCREEN;
        decorView.setSystemUiVisibility(uiOptions);

        setContentView(R.layout.activity_main);

        ActionBar actionBar = getActionBar();
        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

        tab1 = actionBar.newTab().setText("1");
        tab2 = actionBar.newTab().setText("2");
        tab3 = actionBar.newTab().setText("3");

        tab1.setTabListener(new TabListener(fragmentTab1));
        tab2.setTabListener(new TabListener(fragmentTab2));
        tab3.setTabListener(new TabListener(fragmentTab3));

        actionBar.addTab(tab1);
        actionBar.addTab(tab2);
        actionBar.addTab(tab3);
    }

<android.support.v4.view.ViewPager xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/fragment_container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.novoloc.upup2.Main" />

public class TabListener implements ActionBar.TabListener {
    Fragment fragment;

    public TabListener(Fragment fragment) {
        this.fragment = fragment;
    }

    public void onTabSelected(Tab tab, FragmentTransaction ft) {
        ft.replace(R.id.fragment_container, fragment);
    }

    public void onTabUnselected(Tab tab, FragmentTransaction ft) {
        ft.remove(fragment);
    }

    public void onTabReselected(Tab tab, FragmentTransaction ft) {
        // nothing done here
    }
}

活动\u main.xml:
public class FragmentTab1 extends Fragment {
    final String TAG = "FRAGMENT_TAB_1";

    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        View view = inflater.inflate(R.layout.tab, container, false);
        TextView textview = (TextView) view.findViewById(R.id.txtvwTab);
        textview.setText("one");

        Log.i(TAG, "textview's text: " + textview.getText());

        return view;
    }
}

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <TextView
        android:id="@+id/txtvwTab" 
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true" //added later
        android:textColor="@color/Black" //added later
        android:textSize="40sp" //added later
        android:alpha="1" //added later
        android:text="DEFAULT" //added later
        />

</RelativeLayout>

public class Main extends Activity {
    ActionBar.Tab tab1, tab2, tab3;

    Fragment fragmentTab1 = new FragmentTab1();
    Fragment fragmentTab2 = new FragmentTab2();
    Fragment fragmentTab3 = new FragmentTab3();

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        //Remove status bar
        View decorView = getWindow().getDecorView();
        // Hide the status bar.
        int uiOptions = View.SYSTEM_UI_FLAG_FULLSCREEN;
        decorView.setSystemUiVisibility(uiOptions);

        setContentView(R.layout.activity_main);

        ActionBar actionBar = getActionBar();
        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

        tab1 = actionBar.newTab().setText("1");
        tab2 = actionBar.newTab().setText("2");
        tab3 = actionBar.newTab().setText("3");

        tab1.setTabListener(new TabListener(fragmentTab1));
        tab2.setTabListener(new TabListener(fragmentTab2));
        tab3.setTabListener(new TabListener(fragmentTab3));

        actionBar.addTab(tab1);
        actionBar.addTab(tab2);
        actionBar.addTab(tab3);
    }

<android.support.v4.view.ViewPager xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/fragment_container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.novoloc.upup2.Main" />

public class TabListener implements ActionBar.TabListener {
    Fragment fragment;

    public TabListener(Fragment fragment) {
        this.fragment = fragment;
    }

    public void onTabSelected(Tab tab, FragmentTransaction ft) {
        ft.replace(R.id.fragment_container, fragment);
    }

    public void onTabUnselected(Tab tab, FragmentTransaction ft) {
        ft.remove(fragment);
    }

    public void onTabReselected(Tab tab, FragmentTransaction ft) {
        // nothing done here
    }
}

我面临着类似的问题。但我发现textview在那里，但它隐藏在扩展工具栏/操作栏下（因为它包含tablayout）。给你的textview一个100dp或200dp的margintop，并给它一个背景色，你就能看到它在那里，但隐藏在actionBar下。或者你甚至可以通过向上滑动动作栏来收缩它，以显示你的文本视图
如何解决此问题，请参见以下问题：
一直为此头疼，终于找到了一个简单的解决办法。将您的ViewPager高度设置为绝对值，而不是android:layout\u height=“match\u parent”
或android:layout\u height=“wrap\u content”

尝试android:layout\u height=“300dp

或一些首选值

嘿，一次小的尝试，而不是

RelativeLayout

尝试

LinearLayout

，然后将

方向设置为垂直
，然后查看结果：-/也没有运气（这一定是高度和/或宽度的问题。为相对布局设置背景色，然后为textview设置对比色，查看它们是否绘制。还可以尝试在dp
中设置实心高度和宽度，请参见我已尝试将宽度设置为300dp，高度设置为150dp。我还将相对视图设置为显式白色。还是不走运。：（@color/Black的值是多少？我想知道这个映射到的任何颜色是否与您的背景色相同？