Get Screen Size Pixels per Inch Android example
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The exact physical pixels per inch of the screen
Get size of pixel
Get DPI
Get count of pixels per inch
Get size of pixel
Get DPI
Get count of pixels per inch
float mXDpi;
float mYDpi;
DisplayMetrics metrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(metrics);
mXDpi = metrics.xdpi; // The exact physical pixels per inch of the screen in the X dimension.
mYDpi = metrics.ydpi;
float mMetersToPixelsX = mXDpi / 0.0254f; // 1 inch == 0.0254 metre
float mMetersToPixelsY = mYDpi / 0.0254f;
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Další témata ....(Topics)
RelativeLayout like parent, child Srollview is centered horizontal.
Second RelativeLayout in SrollView have gravity center, every child will centered horizontally and vertically.
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>
While cycle Java basic example with array of strings.
MainClass.java
MainClass.java
public class MainClass {
public static void main(String[] arg) {
String[] arrayOfString = { "Hello", "people", "hello", "world!" };
int i = 0;
while ( i < arrayOfString.length ){
System.out.println(arrayOfString[i]);
i++;
}
}
}
Activities launcher
public class MainActivity extends ListActivity {
private class Sample {
private CharSequence title;
private Class<? extends Activity> activityClass;
public Sample(int titleResId, Class<? extends Activity> activityClass) {
this.activityClass = activityClass;
this.title = getResources().getString(titleResId);
}
@Override
public String toString() {
return title.toString();
}
}
private static Sample[] mSamples;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Instantiate the list of samples.
mSamples = new Sample[]{
new Sample(R.string.title_first_app, FirstActivity.class),
new Sample(R.string.title_second_app, SecondActivity.class),
new Sample(R.string.title_third_app, ThirdActivity.class),
};
setListAdapter(new ArrayAdapter<Sample>(this,
android.R.layout.simple_list_item_1,
android.R.id.text1,
mSamples));
}
@Override
protected void onListItemClick(ListView listView, View view, int position, long id) {
// Launch the sample associated with this list position.
startActivity(new Intent(MainActivity.this, mSamples[position].activityClass));
}
}
Try add to AndroidManifest.xml configChanges for your Activity
android:configChanges="keyboardHidden|orientation|screenSize"
android:configChanges="keyboardHidden|orientation|screenSize"
<activity android:name=".MainActivity"
android:label="@string/app_name"
android:configChanges="keyboardHidden|orientation|screenSize"
>
AlertDialog like MessageBox by WinApi:
If error: Unable to add window -- token null is not for an application
try change get Context.
If error: Unable to add window -- token null is not for an application
try change get Context.
// you can put this text into some function body or case in switch statement
new AlertDialog.Builder(this)
.setMessage("Hello boys!!!")
.setPositiveButton("OK", null)
.show();
Context context = getApplicationContext();
AlertDialog.Builder builder = new AlertDialog.Builder(context);
builder.setTitle("Select font size");
final CharSequence[] chsSize= { "Small", "Medium", "Large"};
builder.setSingleChoiceItems(chsSize, 0 /*sel.item*/,
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int item) {
Toast.makeText(context, "Hello from dialog!!!", Toast.LENGTH_SHORT).show();
dialog.dismiss();
}
});
AlertDialog alert = builder.create();
alert.show();
Editace: 2013-12-09 13:06:15
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Url:get-screen-pixels-android-example
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