Force Screen On - dont use WakeLock - use getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON) - Android sample

RelativeLayout like parent, child Srollview is centered horizontal.
Second RelativeLayout in SrollView have gravity center, every child will centered horizontally and vertically.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="//schemas.android.com/apk/res/android"
    android:layout_width="match_parent" android:layout_height="match_parent"
    android:gravity="center_horizontal">

    <ScrollView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/scrollView2" >

        <RelativeLayout
            android:layout_width="320dp"
            android:layout_height="wrap_content"
            android:background="#e6f825"
            android:gravity="center">

            <Button
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="New Button"
                android:id="@+id/button" />
        </RelativeLayout>
    </ScrollView>

</RelativeLayout>

Check

• is sett debug mode on device?


• enabled debugging over USB?


• is device right connected?


• have you downloaded and instaled drivers for your device on PC?


• For Windows //developer.android.com/sdk/win-usb.html


• try disconnect and connect USB cable


• try do restart Android Studio

android:background="@android:color/transparent"

<LinearLayout
    android:baselineAligned="false"
    android:background="@android:color/transparent"
    android:id="@+id/linearLayout1"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal"
   >
<LinearLayout>
////////////////////////////
LinearLayout  mLinearLayout1 = (LinearLayout)findViewById(R.id.linearLayout1);
mLinearLayout1.setBackgroundColor(Color.TRANSPARENT);

Draw the trajectory of shot.

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

		}
	       private static void makePath(Path p) {
	            p.moveTo(10, 0);
	            p.cubicTo(100, -50, 200, 150, 300, 0);
	        }
		@Override
		protected void onDraw(Canvas canvas) {

			canvas.drawColor(Color.CYAN);
			Paint p = new Paint();
			// smooths
			p.setAntiAlias(true);
			p.setColor(Color.RED);
			p.setStyle(Paint.Style.STROKE); 
			p.setStrokeWidth(5);
			// opacity
			//p.setAlpha(0x80);
 
			p.setColor(Color.BLACK);
			Path mPath = new Path();
            makePath(mPath);
			canvas.drawPath(mPath, p); //(rectF, 90, 45, true, p);
		}

	}
}

Check your xml files in Eclipse Graphical Editor and fix problems.



Check project setup, right click on project, select properties, Java build path and
select correct Android version etc.


Right click on project, Android Tools, Fix Project Properties

Menu Eclipse select Project ->Clean.