How to clear or hide an ImageView in Android

MainActivity.java

        ProgressBar mProgressBarScore;
      // onCreate
	mProgressBarScore = (ProgressBar)findViewById(R.id.progressBarScore);
	Resources res = getResources();
	mProgressBarScore.setProgressDrawable(res.getDrawable( R.drawable.my_progress));

res/layout/main.xml

       <ProgressBar
            android:id="@+id/progressBarScore"
            style="?android:attr/progressBarStyleHorizontal"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content" android:max="100"/>

res/drawable/my_progress.xml

    

        

        

                        android:startColor="#FF001A"

                android:centerColor="#ff5a5d5a"

                android:centerY="0.75"

                android:endColor="#FF001A"

                android:angle="270"

        />

    







    

        

            

                                android:startColor="#80ffd300"

                    android:centerColor="#80ffb600"

                    android:centerY="0.75"

                    android:endColor="#a0ffcb00"

                    android:angle="270"

            />

        

    



    android:id="@android:id/progress"

>

    

        

            

                            android:radius="10dip" />

                            android:startColor="#00ff00"

                android:centerColor="#80ffb600"

                android:centerY="0.75"

                android:endColor="#339900"

                android:angle="270" />

        

    

Problem in Android application:

E/AndroidRuntime(416): FATAL EXCEPTION: main
E/AndroidRuntime(416): java.lang.IndexOutOfBoundsException
E/AndroidRuntime(416): 	at java.util.Arrays$ArrayList.get(Arrays.java:75)
E/AndroidRuntime(416): 	at android.widget.ArrayAdapter.getItem(ArrayAdapter.java:298)
E/AndroidRuntime(416): 	at android.widget.ArrayAdapter.createViewFromResource(ArrayAdapter.java:351)
E/AndroidRuntime(416): 	at android.widget.ArrayAdapter.getView(ArrayAdapter.java:323)
E/AndroidRuntime(416): 	at android.widget.Spinner.makeAndAddView(Spinner.java:192)
E/AndroidRuntime(416): 	at android.widget.Spinner.layout(Spinner.java:151)
E/AndroidRuntime(416): 	at android.widget.Spinner.onLayout(Spinner.java:115)

Solution: check code for set and get selection

// Spinner _spin1 contain only  49 items 
// you can set max 48 ( range 0 - 48)
// 50 is IndexOutOfBoundsException
_spin1.setSelection(50);

Code with error:

ImageView imgV = (ImageView)findViewById(R.id.myView);
        imgV.setLayoutParams(new ViewGroup.LayoutParams(
        		ViewGroup.LayoutParams.WRAP_CONTENT,
        		0));

If you get error try this code:

        ViewGroup.LayoutParams layoutParams = imgV
				.getLayoutParams();
		layoutParams.height = 0;
		imgV.setLayoutParams(layoutParams);

java.lang.ClassCastException: android.view.ViewGroup$LayoutParams
at android.widget.LinearLayout.measureHorizontal(LinearLayout.java:659)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:311)
at android.view.View.measure(View.java:8313)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3138)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1017)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:386)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:309)
at android.view.View.measure(View.java:8313)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3138)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:250)
at android.view.View.measure(View.java:8313)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:531)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:309)
at android.view.View.measure(View.java:8313)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3138)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:250)
at android.view.View.measure(View.java:8313)

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)
{
    return (int) (px / Resources.getSystem().getDisplayMetrics().density);
}

Definition of ListView in layout main.xml file Android example

<ListView android:id="@+id/idListView"
        android:background="#7700CC00"
        android:layout_height="wrap_content"
        android:layout_width="fill_parent" /> 

Code in Main.java ListView example source code Java Android

public class Main extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        ListView mlistView = (ListView) findViewById(R.id.idListView);
        mlistView.setAdapter(new ArrayAdapter<String>(this,
                android.R.layout.simple_list_item_1, 
                new String[] {"Game", "Help", "Home site"}));
    
        mlistView.setOnItemClickListener(new OnItemClickListener() {
            public void onItemClick(AdapterView<?> parent, View view,
                int position, long id) {
              // When clicked, show a toast with the TextView text Game, Help, Home
              Toast.makeText(getApplicationContext(), ((TextView) view).getText(),
                  Toast.LENGTH_SHORT).show();
            }
          });
     }
}