Try this code, i use to display the screen specification:
this example tested on API 8 and you can easy understand Display Matrix ... hope this helps
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getWindow().setFlags( WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN );
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.activity_main);
TextView tv=(TextView) findViewById(R.id.tv);
TextView tv1=(TextView) findViewById(R.id.TextView01);
TextView tv2=(TextView) findViewById(R.id.TextView02);
TextView tv3=(TextView) findViewById(R.id.TextView03);
TextView tv4=(TextView) findViewById(R.id.TextView04);
TextView tv5=(TextView) findViewById(R.id.TextView05);
TextView tv6=(TextView) findViewById(R.id.TextView06);
TextView tv7=(TextView) findViewById(R.id.TextView07);
TextView tv8=(TextView) findViewById(R.id.TextView08);
TextView tv9=(TextView) findViewById(R.id.TextView09);
TextView tv10=(TextView) findViewById(R.id.TextView10);
TextView tv11=(TextView) findViewById(R.id.TextView11);
TextView tv12=(TextView) findViewById(R.id.TextView12);
DisplayMetrics metrics=new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(metrics);
float height=metrics.heightPixels/metrics.ydpi;
float width=metrics.widthPixels/metrics.xdpi;
tv.setText("The screen size is:"+Math.sqrt(height*height+width*width));
tv1.setText("The screen height:"+height);
tv2.setText("The screen width:"+metrics.densityDpi);
tv3.setText("The screen metrics.heightPixels:"+metrics.heightPixels);
tv4.setText("The screen metrics.xdpi:"+metrics.xdpi);
tv5.setText("The screen height:"+height);
tv6.setText("The screen width:"+metrics);
tv7.setText("The screen metrics.widthPixels:"+metrics.widthPixels);
tv8.setText("The screen metrics.ydpi:"+metrics.ydpi);
tv9.setText("The screen Math.pow x :"+Math.pow(metrics.widthPixels/metrics.xdpi,2));
tv10.setText("The screen Math.pow y :"+Math.pow(metrics.heightPixels/metrics.ydpi,2));
float x = (float) Math.pow(metrics.widthPixels/metrics.xdpi,2);
float y = (float) Math.pow(metrics.heightPixels/metrics.ydpi,2);
tv11.setText("The screen metrics.widthPixels:"+Math.sqrt(x+y));
}
}
activity_main.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity" >
<TextView
android:id="@+id/tv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/hello_world" />
<TextView
android:id="@+id/TextView01"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="@+id/tv"
android:layout_marginTop="20dp"
android:text="@string/hello_world" />
<TextView
android:id="@+id/TextView02"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="@+id/TextView01"
android:text="@string/hello_world" />
<TextView
android:id="@+id/TextView03"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="@+id/TextView02"
android:text="@string/hello_world" />
<TextView
android:id="@+id/TextView04"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="@+id/TextView03"
android:text="@string/hello_world" />
<TextView
android:id="@+id/TextView05"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="@+id/TextView04"
android:layout_marginTop="40dp"
android:text="@string/hello_world" />
<TextView
android:id="@+id/TextView06"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="@+id/TextView05"
android:text="@string/hello_world" />
<TextView
android:id="@+id/TextView07"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="@+id/TextView06"
android:text="@string/hello_world" />
<TextView
android:id="@+id/TextView08"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="@+id/TextView07"
android:text="@string/hello_world" />
<TextView
android:id="@+id/TextView09"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="@+id/TextView08"
android:layout_marginTop="63dp"
android:text="@string/hello_world" />
<TextView
android:id="@+id/TextView10"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="@+id/TextView09"
android:text="@string/hello_world" />
<TextView
android:id="@+id/TextView11"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="@+id/TextView10"
android:text="@string/hello_world" />
<TextView
android:id="@+id/TextView12"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="@+id/TextView11"
android:text="@string/hello_world" />
<ImageView
android:id="@+id/imageView1"
android:layout_width="10dp"
android:layout_height="158.77dp"
android:layout_alignParentRight="true"
android:layout_alignParentTop="true"
android:layout_toRightOf="@+id/tv"
android:adjustViewBounds="true"
android:scaleType="fitXY"
android:src="@drawable/inch1" />
</RelativeLayout>