android - 从 ViewPager 中的 FragmentActivity 获取 Fragment 中 TextView 的 id

Question

我正在使用带有 3 个 Fragments 的 ViewPager，我想在第三页中更改 TextView 的文本。

在该页面中，我有一个 Button，当按下它时，转到 SD 图像以选择一个。完成后，返回页面并希望使用该图像的路径更新 TextView。问题是，当我尝试从 FragmentActivity 访问那个 TextView 时，它是空的。

这是我的代码

SherlockFragmentActivity:

public class TabsFacturasActivity extends SherlockFragmentActivity {

    protected MyApplication myApplication;
    private static final int FILE_SELECT_CODE = 0;

    private MyAdapter mAdapter;
    private ViewPager mPager;
    private PageIndicator mIndicator;
    private TextView textViewImg;

    private int lecturas = 0;
    private SimpleDateFormat dateFormat = new SimpleDateFormat("dd/MM/yyyy"); 
    private boolean adjunto = false;
    private String filePath;
    private boolean esLecturaAT = false;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.fragment_pager);

        // Get the application instance
        myApplication = (MyApplication)getApplication();

        //Need to get that view
        textViewImg = (TextView) findViewById(R.id.textViewUrlImgLectura);

        //Creamos la lista
        LinkedList<String> direcciones = new LinkedList<String>();
        ArrayList<TuplaCupsWS> dirs = myApplication.getUsuarioActual().getCups();
        for(int dir = 0; dir < myApplication.getUsuarioActual().getCups().size(); dir++) {
            direcciones.add(new String(dirs.get(dir).getDireccion()));
        }

        int tab = getIntent().getIntExtra("tab", 0);

        mAdapter = new MyAdapter(getSupportFragmentManager());

        mPager = (ViewPager)findViewById(R.id.pager);
        mPager.setAdapter(mAdapter);
        mPager.setCurrentItem(tab);

        mIndicator = (TitlePageIndicator)findViewById(R.id.indicator);
        mIndicator.setViewPager(mPager);

        getSupportActionBar().setDisplayShowTitleEnabled(false);
        getSupportActionBar().setIcon(R.drawable.logo_factorenergia_peque);

        /** Create an array adapter to populate dropdownlist */
        ArrayAdapter<String> adapter = new ArrayAdapter<String>(
                getBaseContext(), android.R.layout.simple_spinner_dropdown_item, direcciones);

        /** Enabling dropdown list navigation for the action bar */
        getSupportActionBar().setNavigationMode(ActionBar.NAVIGATION_MODE_LIST);

        /** Defining Navigation listener */
        OnNavigationListener navigationListener = new OnNavigationListener() {

            @Override
            public boolean onNavigationItemSelected(int itemPosition, long itemId) {
                return false;
            }
        };

        /** Setting dropdown items and item navigation listener for the actionbar */
        getSupportActionBar().setListNavigationCallbacks(adapter, 
                (com.actionbarsherlock.app.ActionBar.OnNavigationListener) 
                navigationListener);
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        switch (requestCode) {
            case FILE_SELECT_CODE:
            if (resultCode == RESULT_OK) {
                adjunto = true;
                // Get the Uri of the selected file 
                Uri uri = data.getData();
                // Get the path
                String path = "";
                try {
                    path = MyUtility.getPath(this, uri);
                } catch (URISyntaxException e) {
                    myApplication.throwException(this);
                    e.printStackTrace();
                }
                String imgName = path.split("/")[path.split("/").length-1];
                textViewImg.setText(imgName); //Here textViewImg is null
                filePath = path;
            }
            break;
        }
        super.onActivityResult(requestCode, resultCode, data);
    }

    //Method executed when Button is pressed
    public void examinar(View view) {
        mostrarFileChooser();       
    }

    private void mostrarFileChooser() {     
        Intent intent = new Intent(Intent.ACTION_PICK);
        intent.setType("image/*");

        try {
            startActivityForResult(intent, FILE_SELECT_CODE);
        } catch (android.content.ActivityNotFoundException ex) {
        }
    }

    private static class MyAdapter extends FragmentPagerAdapter {

        private String[] titles = { "VER FACTURAS", "VER CONSUMO", "INTRODUCIR LECTURA" };

        public MyAdapter(FragmentManager fragmentManager) {
            super(fragmentManager);
        }

        @Override
        public CharSequence getPageTitle(int position) {
            return titles[position];
        }

        @Override
        public Fragment getItem(int position) {
            switch (position) {
            case 0: // Fragment # 0
                return new FacturasActivity();
            case 1: // Fragment # 1
                return new ConsumoActivity();
            case 2:// Fragment # 2
                return new LecturaActivity();
            }
            //return new MyFragment();
            return null;
        }

        @Override
        public int getCount() {
            return titles.length;
        }
    }

}

fragment_pager.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical"
    tools:context=".TabsFacturasActivity" >

    <com.viewpagerindicator.TitlePageIndicator
        android:id="@+id/indicator"
        android:padding="10dip"
        android:layout_height="wrap_content"
        android:layout_width="fill_parent" />

    <android.support.v4.view.ViewPager
        android:id="@+id/pager"
        android:layout_width="fill_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:background="#1184A4E8" />

</LinearLayout>

Answer 1

您无法从 fragment activity 访问 TextView ，因为它位于 fragment 而您的 fragment activity layout 没有任何 带有此 id 的 TextView 。您必须从您的 third fragment 在其 layout 中使用它的地方访问 TextView 。然后从您的 fragment Activity 访问该对象。

在你的 fragment 中做这样的事情

TextView mTextView;
mTextView = (TextView)getView().findViewById(R.id.your_text_view);

像这样创建一个函数

public void changeText(String mText)
{
mTextView.setText(mText);
}

在您的 Activity 结果中

//Do not create new object each time you set text. Use the same fragment object which you use for view pager.
        Your_Fragment mFragment;
         protected void onActivityResult(int requestCode, int resultCode, Intent data) {
                switch (requestCode) {
                    case FILE_SELECT_CODE:
                    if (resultCode == RESULT_OK) {

    //Set text from here
                mFragment.changeText(imgName);

               }