findViewById in onCreate returns NULL when using Fragment

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Call findViewById from onCreateView


public class MainActivity extends ActionBarActivity {

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

		if (savedInstanceState == null) {
			getSupportFragmentManager().beginTransaction()
					.add(R.id.containerMoje, new PlaceholderFragment()).commit();
		}
		
	}


	/**
	 * A placeholder fragment containing a simple view.
	 */
	public static class PlaceholderFragment extends Fragment {
		public PlaceholderFragment() {
		}

		@Override
		public View onCreateView(LayoutInflater inflater, ViewGroup container,
				Bundle savedInstanceState) {
			View rootView = inflater.inflate(R.layout.fragment_main, container,
					false);
			if (container == null) {
		        return null;
		    }


			 TextView mText;
			mText = (TextView)rootView.findViewById(R.id.idText);
			mText.setText("Hello from fragment_main");

			return rootView;
		}
	}
}

res\layout
activity_main.xml


<FrameLayout xmlns:android="//schemas.android.com/apk/res/android"
    xmlns:tools="//schemas.android.com/tools"
    android:id="@+id/containerMoje"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="cz.okhelp.autoskola.MainActivity"
    tools:ignore="MergeRootFrame" />

fragment_main.xml


<RelativeLayout xmlns:android="//schemas.android.com/apk/res/android"
    xmlns:tools="//schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="cz.okhelp.autoskola.MainActivity$PlaceholderFragment" >

    <TextView
        android:id="@+id/idText"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />

</RelativeLayout>

397LW NO topic_id

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Get the color of a specific pixel Java Android example | get-the-color-of-a-specific-pixel-java-android-example


             ImputStream      is = this.getResources().openRawResource(R.drawable.colors);
             Bitmap    mBitmap2 = BitmapFactory.decodeStream(is);
        
         int  w = mBitmap2.getWidth();
         int  h = mBitmap2.getHeight();
//  int x , y have to be smaller as w , h 
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372

ListView set the item as checked to be highlighted | listview-set-the-item-as-checked-to-be-highlighted

Important: Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB

int layout = Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB ?

				android.R.layout.simple_list_item_activated_1 :

android.R.layout.simple_list_item_1;





 getListView().setChoiceMode(ListView.CHOICE_MODE_SINGLE);

        getListView().setItemChecked(position, true);

Example of usage:



public void updateList() {
		Context ctx = getActivity();
		Notes notes = new Notes(ctx);

		String[] from = { Notes.COLUMN_TITLE };
		int[] to = { android.R.id.text1 };
		int layout = Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB ?
				android.R.layout.simple_list_item_activated_1 : android.R.layout.simple_list_item_1;
		ListAdapter adapter = new SimpleCursorAdapter(ctx,
				layout, notes.getNotes(), from,
				to, 0);

		setListAdapter(adapter);

		notes.close();
	}

/..................
@Override
    public void onListItemClick(ListView l, View v, int position, long id) {
        
        // Set the item as checked to be highlighted when in two-pane layout
        getListView().setChoiceMode(ListView.CHOICE_MODE_SINGLE);
        getListView().setItemChecked(position, true);
     
    }

139

drawBitmap createBitmap by array of colours Android example | drawbitmap-createbitmap-draw-bitmap-by-array-of-colours-android-example

public static Bitmap createBitmap (int[] colors, int offset, int stride, int width, int height, Bitmap.Config config)
public void drawBitmap (Bitmap bitmap, float left, float top, Paint paint)


//  //www.apache.org/licenses/LICENSE-2.0
public class MainActivity extends Activity {
	    private static final int WIDTH = 50;
	    private static final int HEIGHT = 50;
	    private static final int STRIDE = 64;   // must be >= WIDTH
	    
	    private static int[] createColors() {
	        int[] colors = new int[STRIDE * HEIGHT];
	        for (int y = 0; y < HEIGHT; y++) {
	            for (int x = 0; x < WIDTH; x++) {
	                int r = x * 255 / (WIDTH - 1);
	                int g = y * 255 / (HEIGHT - 1);
	                int b = 255 - Math.min(r, g);
	                int a = Math.max(r, g);
	                colors[y * STRIDE + x] = (a << 24) | (r << 16) | (g << 8) | b;
	            }
	        }
	        return colors;
	    }
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(new SampleView(this));
	}

	private static class SampleView extends View {

		// CONSTRUCTOR
		public SampleView(Context context) {
			super(context);
			setFocusable(true);

		}
		@Override
		protected void onDraw(Canvas canvas) {
			Paint paint = new Paint();
			
			canvas.drawColor(Color.GREEN);

            int[] mColors = createColors();
            int[] colors = mColors;

           
            Bitmap bitmap = Bitmap.createBitmap(colors, 0, STRIDE, WIDTH, HEIGHT,
                    Bitmap.Config.RGB_565);
                      
			canvas.drawBitmap(bitmap, 50,20, paint); 
		}

	}
}

Show keyboard in WebView Android example | webview-keyboard

Show keyboard if WebView input have focus Android apps development example source code.


WebView webview;

//in onCreate

	webview = (WebView) findViewById(R.id.idWebviewPda);
	webview.getSettings().setJavaScriptEnabled(true);
	webview.loadUrl("//android.okhelp.cz");
	
	webview.requestFocus(View.FOCUS_DOWN);
    webview.setOnTouchListener(new View.OnTouchListener() {
        @Override
        public boolean onTouch(View v, MotionEvent event) {
            switch (event.getAction()) {
                case MotionEvent.ACTION_DOWN:
                case MotionEvent.ACTION_UP:
                    if (!v.hasFocus()) {
                        v.requestFocus();
                    }
                    break;
            }
            return false;
        }
    });

Editace: 2014-07-12 13:48:55
Počet článků v kategorii: 397
Url:findviewbyid-in-oncreate-returns-null-when-using-fragment

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