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Get Context Java Android example


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getContext() getApplicationContext() method Java Android example source






Context myContext_1 = ThisClassName.this; // to open a Dialog
Context myContext_2 = getContext();
Context myContext_3 = this.getContext();
Context myContext_4 = this;
Context myContext_5 = this.getApplicationContext ();


OnClickListener getImageBtnOnClick = new OnClickListener() {
public void onClick(View view) {
Context context = view.getContext();

}
};
// Toast
Toast.makeText(getApplicationContext(), "Context == getApplicationContext "
, Toast.LENGTH_SHORT).show();



// store Context in public class
public class MyActivity extends Activity {
public static Context myCnt = null;
...
protected void onCreate(Bundle icicle) {
...
myCnt = this;
MyStorage.setContext(myCnt);
// or
// MyStorage.setContext(this);

// cntxFromStorage == this
Context cntxFromStorage = MyStorage.getContext();
...
};
};

public class MyStorage
{
private static Context cntStorageContext = null;


public static Context getContext() {
return cntStorageContext;
}

public static void setContext(Context context) {
MyStorage.cntStorageContext = context;
}


};

class DataBaseHelper extends SQLiteOpenHelper {
// get MyActivity context
Context cnt = MyStorage.getContext();

}




397LW NO topic_id




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Physical pixel (px)
Density independent pixel (dp)
Dots per inch (dpi) .. physical pixels per inch
px = dp * (dpi / 160)

public static int dpToPx(int dp)
{
    return (int) (dp * Resources.getSystem().getDisplayMetrics().density);
}

public static int pxToDp(int px)
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Draw drawARGB() Android basic example | draw-drawargb-android-basic-example



public class MainActivity extends Activity {
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(new SampleView(this));
	}

	private static class SampleView extends View {

		// CONSTRUCTOR
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			super(context);
			setFocusable(true);

		}
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			//drawARGB (int a, int r, int g, int b)
//			a  alpha component (0..255) of the color to draw onto the canvas 
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R.java not generated - Android project in Eclipse issue | r-java-not-generating-android-project-in-eclipse-issue


If You create new xml file with prefix _ , for example _style.xml and You to clean project (Project->Clean), than package in folder project\gen will deleted with R.java class and new R.java not be created.

For to solving this problem You have to rename file without prefix _ as style.xml or name what You need and rebuild project.

If some ID cannot be resolved or is not a field get error occurence
You have to delete import android.R; in Activity.class if was inserted,
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int mCurrentPhotoIndex = 0;
   @Override
    protected void onSaveInstanceState(Bundle outState) {
        outState.putInt("photo_index", mCurrentPhotoIndex);
        super.onSaveInstanceState(outState);
    }

    @Override
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}
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xml example source code with image.


   <TableLayout android:layout_width="match_parent" android:id="@+id/idTableInRadioGroup" android:layout_height="wrap_content">
        <TableRow android:id="@+id/tableRow1" android:layout_width="wrap_content" android:layout_height="wrap_content">


<RadioGroup android:id="@+id/idRadio_group_1_column"
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            android:layout_marginLeft="20dp"
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 <RadioButton android:id="@+id/idRadio_1"
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            <RadioButton android:id="@+id/idRadio_2"
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            <RadioButton android:id="@+id/idRadio_3"
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        </RadioGroup>
<RadioGroup android:id="@+id/idRadio_group_2_column"
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            android:layout_height="wrap_content"
            android:layout_marginLeft="20dp"
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  <RadioButton android:id="@+id/idRadio_4"
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            <RadioButton android:id="@+id/idRadio_5"
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            <RadioButton android:id="@+id/idRadio_6"
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        </RadioGroup>
</TableRow>        
    </TableLayout>



two-column-radiogroup-menu


Editace: 2011-10-15 08:31:19
Počet článků v kategorii: 397
Url:get-context-java-android-example

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