R cannot be resolved to a variable

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="//schemas.android.com/apk/res/android"
    package="cz.okhelp.admob"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk android:minSdkVersion="13"
        android:targetSdkVersion="16"/>

    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    
   

    <application android:icon="@drawable/ic_launcher" android:label="@string/app_name">
       <meta-data 
        android:value="a14d932xxxxxxxx" 
        android:name="ADMOB_PUBLISHER_ID" />
        <activity android:name=".AdmobActivity"
                  android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

<activity android:name="com.google.ads.AdActivity"
 android:configChanges="keyboard|keyboardHidden|orientation|screenLayout|uiMode|screenSize|smallestScreenSize" />
</application>
</manifest>

		@Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
     			AdViw adView = new AdView(this, AdSize.BANNER, "a14d932xxxxxxxxx");//MY_AD_UNIT_ID
    			LinearLayout layout = (LinearLayout)findViewById(R.id.idReklamaLayout);
				// Add the adView to it
    			layout.addView(adView);
				// Initiate a generic request to load it with an ad
				AdRequest adRequest = new AdRequest();
    			//adRequest.setTesting(true);
    			adRequest.setGender(AdRequest.Gender.MALE);
    			adView.loadAd(adRequest);
    }

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="//schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >
    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/hello" />
<LinearLayout xmlns:android="//schemas.android.com/apk/res/android"
android:id="@+id/idReklamaLayout"
android:orientation="vertical"
android:gravity="center"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="3" />

</LinearLayout>

Android Studio ADB restart mobile device from USB every time if RUN of DEBUG button pressed

1. Restart Eclipse


2. Clean project and rebuild


3. Create a new project and try it if the problem persists, if no move copy project to other folder, delete project from workspace , create new project same name and copy java, xml etc. files to new project


4. Close Eclipse, backup folder c:\Users\myName\workspace\.metadata and delete it. Restart Eclipse try again import project to workspace



5. Re-installing the Android Developer Tools



6. Re-installing Eclipse - rename old folder with Android to Android_old, create new folder C:\Program Files\Android and copy new Eclipse with sdk into new folder



7. Created a new project importing from the file system



8. Created a new project from subversion

		Drawable dr = getResources().getDrawable(R.drawable.algebra);
		int h = dr.getIntrinsicHeight();
		int w = dr.getIntrinsicWidth();

		Bitmap ball = BitmapFactory.decodeResource(getResources(), R.drawable.algebra);
		int _nWidth = ball.getWidth();
		int _nHeight = ball.getHeight();

////www.apache.org/licenses/LICENSE-2.0
        private Paint mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        private ColorMatrix mCM = new ColorMatrix();
        private Bitmap mBitmap;
        private float mSaturation;
        private float mAngle;
//..........
mBitmap = BitmapFactory.decodeResource(context.getResources(),
                                                   R.drawable.my_image);
//..........
        private static void setContrastScaleOnly(ColorMatrix cm, float contrast) {
            float scale = contrast + 1.f;
               float translate = (-.5f * scale + .5f) * 255.f;
            cm.set(new float[] {
                   scale, 0, 0, 0, 0,
                   0, scale, 0, 0, 0,
                   0, 0, scale, 0, 0,
                   0, 0, 0, 1, 0 });
        }
       private static void setContrast(ColorMatrix cm, float contrast) {
            float scale = contrast + 1.f;
               float translate = (-.5f * scale + .5f) * 255.f;
            cm.set(new float[] {
                   scale, 0, 0, 0, translate,
                   0, scale, 0, 0, translate,
                   0, 0, scale, 0, translate,
                   0, 0, 0, 1, 0 });
        }
        
        private static void setContrastTranslateOnly(ColorMatrix cm, float contrast) {
            float scale = contrast + 1.f;
               float translate = (-.5f * scale + .5f) * 255.f;
            cm.set(new float[] {
                   1, 0, 0, 0, translate,
                   0, 1, 0, 0, translate,
                   0, 0, 1, 0, translate,
                   0, 0, 0, 1, 0 });
        }

       @Override protected void onDraw(Canvas canvas) {
            Paint paint = mPaint;
            float x = 20;
            float y = 20;
            
            canvas.drawColor(Color.WHITE);
            
            paint.setColorFilter(null);
            canvas.drawBitmap(mBitmap, x, y, paint);
            
            ColorMatrix cm = new ColorMatrix();
            
            mAngle += 2;
            if (mAngle > 180) {
                mAngle = 0;
            }
            
            //convert our animated angle [-180...180] to a contrast value of [-1..1]
            float contrast = mAngle / 180.f;
            
            setContrast(cm, contrast);
            paint.setColorFilter(new ColorMatrixColorFilter(cm));
            canvas.drawBitmap(mBitmap, x + mBitmap.getWidth() + 10, y, paint);
            
            setContrastScaleOnly(cm, contrast);
            paint.setColorFilter(new ColorMatrixColorFilter(cm));
            canvas.drawBitmap(mBitmap, x, y + mBitmap.getHeight() + 10, paint);
            
            setContrastTranslateOnly(cm, contrast);
            paint.setColorFilter(new ColorMatrixColorFilter(cm));
            canvas.drawBitmap(mBitmap, x, y + 2*(mBitmap.getHeight() + 10),
                              paint);
            
            invalidate();
        }
    }