在Android中以编程方式添加视图

Question

Is it possible to add views to a different layout than the one called in setContentView() in the OnCreate()?

Im trying to use Zylincs ViewPager (found at http://www.zylinc.com/blog-reader/items/viewpager-page-indicator.html ) and I have that part setup and working great.

What this leaves me with is 4 layouts. 1 is main.xml, and the other three are main_pg0.xml, main_pg1.xml, and main_pg3.xml

The three pages are where the content of each "page" is where main.xml contains the page viewer.

In the onCreate im using setContentView(main.xml).

What im trying to do now is be able to add textViews programically to some of the pages.

What I have right now is:

LayoutInflater factory = getLayoutInflater();

View layout = factory.inflate(R.layout.main_pg0, null);
View linearLayout = layout.findViewById(R.id.linearLayout);

TextView valueTV = new TextView(this);
valueTV.setText("hallo hallo");
valueTV.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.WRAP_CONTENT));

((LinearLayout) linearLayout).addView(valueTV);

This is as far as I've been able to get, which does not add the textview at all.

----EDIT----

Hoping to clarify a little more what im trying to do Heres my code

Main.java

public class Main extends FragmentActivity implements PageInfoProvider {
  public GlobalVars globalVars;

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

    globalVars = (GlobalVars) getApplicationContext();

    MyPagerAdapter adapter = new MyPagerAdapter();
    ViewPager myPager = (ViewPager) findViewById(R.id.viewpager);
    myPager.setAdapter(adapter);
    myPager.setCurrentItem(0);

    ViewPagerIndicator indicator = (ViewPagerIndicator) findViewById(R.id.indicator);
    myPager.setOnPageChangeListener(indicator);

    indicator.init(0, adapter.getCount(), this);

    Resources res = getResources();
    Drawable prev = res.getDrawable(R.drawable.indicator_prev_arrow);
    Drawable next = res.getDrawable(R.drawable.indicator_next_arrow);

    indicator.setArrows(prev, next);
  }

  private class MyPagerAdapter extends PagerAdapter {

    public int getCount() {
      return 3;
    }

    public Object instantiateItem(View collection, int position) {

      LayoutInflater inflater = (LayoutInflater) collection.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);

      int resId = 0;
      switch (position) {
      case 0:
        resId = R.layout.main_pg0;
        LoadVehicles();
        break;
      case 1:
        resId = R.layout.main_pg1;
        break;
      case 2:
        resId = R.layout.main_pg2;
        break;
      }

      View view = inflater.inflate(resId, null);
      ((ViewPager) collection).addView(view, 0);

      return view;
    }

    @Override
    public void destroyItem(View arg0, int arg1, Object arg2) {
      ((ViewPager) arg0).removeView((View) arg2);

    }

    @Override
    public void finishUpdate(View arg0) {
      // TODO Auto-generated method stub
    }

    @Override
    public boolean isViewFromObject(View arg0, Object arg1) {
      return arg0 == ((View) arg1);
    }

    @Override
    public void restoreState(Parcelable arg0, ClassLoader arg1) {
      // TODO Auto-generated method stub

    }

    @Override
    public Parcelable saveState() {
      // TODO Auto-generated method stub
      return null;
    }

    @Override
    public void startUpdate(View arg0) {
      // TODO Auto-generated method stub

    }

  }

  public String getTitle(int position) {
    String title = "--Untitled--";
    switch (position) {
    case 0:
      title = "Page 0";
      break;
    case 1:
      title = "Page 1";
      break;
    case 2:
      title = "Page 2";
      break;
    }
    return title;
  }
}

main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  android:orientation="vertical" >
  <com.zylinc.view.ViewPagerIndicator
    android:id="@+id/indicator"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="#EAEAEA"
    android:paddingBottom="8dp"
    android:paddingLeft="5dp"
    android:paddingRight="5dp"
    android:paddingTop="8dp" />
  <RelativeLayout
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:background="#ffeaeaea" >
    <View
      android:layout_width="fill_parent"
      android:layout_height="1dp"
      android:layout_alignBottom="@+id/current"
      android:background="#C5C5C5" />
    <ImageView
      android:id="@+id/current"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_alignParentTop="true"
      android:layout_centerInParent="true"
      android:src="@drawable/indicator_current" />
  </RelativeLayout>
  <android.support.v4.view.ViewPager
    android:id="@+android:id/viewpager"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" />
</LinearLayout>

main_pg0.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  android:background="#FFFFFF"
  android:orientation="vertical"
  android:id="@+id/linearLayout" >
  <TextView
      android:layout_width="fill_parent"
      android:layout_height="wrap_content"
      android:layout_marginLeft="5dp"
      android:text="main_pg0.xml"
      android:textColor="#0C0C0C"
      android:textSize="18sp" />

</LinearLayout>

What im trying to do is add a text view programmatically to main_pg0.xml ONLY, while leaving the other 2 pages alone

Answer 1

You have to add view in main view which is inflated layout.So just add one line.

LayoutInflater factory = getLayoutInflater();

View layout = factory.inflate(R.layout.main_pg0, null);
View linearLayout = layout.findViewById(R.id.linearLayout);

TextView valueTV = new TextView(this);
valueTV.setText("hallo hallo");
valueTV.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.WRAP_CONTENT));

((LinearLayout) linearLayout).addView(valueTV);
layout.addView(linearLayout);

Answer 2

You haven't explicitly mentioned whether you're feeding Fragment s to the ViewPager , but since you're working from the Zylinc implementation, I'm going to assume you are. As a matter of fact, I'll just use the provided example code to show you the idea.

The key to understanding how to realise what you're after is to get that the pages in the ViewPager are self-contained units in the form of Fragment s. They are reusable, have their own life cycle, and can handle their own layouts. Hence, if you want to make runtime modifications to the layout of the pages, you will want to do this inside the Fragment (s) that make up these pages.

The following method can be found in the example code's ItemFragment class. I've simply added the TextView from your own code snippet to it. For demonstration purposes, I did hide the ListView that used to fill up all the space in the date_fragment.xml layout file.

@Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View v = inflater.inflate(R.layout.date_fragment, container, false);
    View tv = v.findViewById(R.id.text);
    ((TextView)tv).setText(readableDateFormat.format(date));

    // changes below
    TextView valueTV = new TextView(getActivity());
    valueTV.setText("hallo hallo");
    valueTV.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT,LayoutParams.WRAP_CONTENT));
    ((ViewGroup)v).addView(valueTV);

    return v;
}

That will give you the "hallo hallo" text (you're a Dutchie? ;)) directly underneath the date in the page:

By the way, you might want to consider switching to Jake's ViewPagerIndicator . Although I haven't closely looked at the one you're currently using, Jake's seems more flexible to me and cleaner to work with. Up to you of course.

---

Edit: Okay, so you're not actually using fragments in the ViewPager , but are rather feeding it the layouts. That's fine, although it'll probably become harder to manage when the pages get more complex. Anyways, key to changing the page's layouts at runtime is still to do it whenever you build/inflate it. When using fragments, that would be in the overridden method, as shown above. In your case, however, you'll need to do it directly in instantiateItem(...) .

I didn't actually type this out in an IDE, so please mind and minor syntactical errors.

public Object instantiateItem(View collection, int position) {

    LayoutInflater inflater = (LayoutInflater) collection.getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);

    View view = null;
    switch (position) {
    case 0:
        view = inflater.inflate(R.layout.main_pg0, null);
        TextView valueTV = new TextView(getActivity());
        valueTV.setText("hallo hallo");
        valueTV.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT,LayoutParams.WRAP_CONTENT));
        ((ViewGroup)view).addView(valueTV);
        break;
    case 1:
        view = inflater.inflate(R.layout.main_pg1, null);
        // or perhaps better for readability: build the layout in a different method, passing in the root
        buildSecondPageLayout(view);
        break;
    case 2:
        view = inflater.inflate(R.layout.main_pg2, null);
        buildThirdPageLayout(view);
        break;
    }

    return view;
}