I installed Android Studio and created an Activity in it with the FullScreen theme. This Activity has a bunch of code and the util folder with classes. Where is this all from?

Here is the class:

 ** * An example full-screen activity that shows and hides the system UI (ie * status bar and navigation/system bar) with user interaction. * * @see SystemUiHider */ public class SelectDictionary extends Activity { /** * Whether or not the system UI should be auto-hidden after * {@link #AUTO_HIDE_DELAY_MILLIS} milliseconds. */ private static final boolean AUTO_HIDE = true; /** * If {@link #AUTO_HIDE} is set, the number of milliseconds to wait after * user interaction before hiding the system UI. */ private static final int AUTO_HIDE_DELAY_MILLIS = 3000; /** * If set, will toggle the system UI visibility upon interaction. Otherwise, * will show the system UI visibility upon interaction. */ private static final boolean TOGGLE_ON_CLICK = true; /** * The flags to pass to {@link SystemUiHider#getInstance}. */ private static final int HIDER_FLAGS = SystemUiHider.FLAG_HIDE_NAVIGATION; /** * The instance of the {@link SystemUiHider} for this activity. */ private SystemUiHider mSystemUiHider; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_select_dictionary); final View controlsView = findViewById(R.id.fullscreen_content_controls); final View contentView = findViewById(R.id.fullscreen_content); // Set up an instance of SystemUiHider to control the system UI for // this activity. mSystemUiHider = SystemUiHider.getInstance(this, contentView, HIDER_FLAGS); mSystemUiHider.setup(); mSystemUiHider .setOnVisibilityChangeListener(new SystemUiHider.OnVisibilityChangeListener() { // Cached values. int mControlsHeight; int mShortAnimTime; @Override @TargetApi(Build.VERSION_CODES.HONEYCOMB_MR2) public void onVisibilityChange(boolean visible) { if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB_MR2) { // If the ViewPropertyAnimator API is available // (Honeycomb MR2 and later), use it to animate the // in-layout UI controls at the bottom of the // screen. if (mControlsHeight == 0) { mControlsHeight = controlsView.getHeight(); } if (mShortAnimTime == 0) { mShortAnimTime = getResources().getInteger( android.R.integer.config_shortAnimTime); } controlsView.animate() .translationY(visible ? 0 : mControlsHeight) .setDuration(mShortAnimTime); } else { // If the ViewPropertyAnimator APIs aren't // available, simply show or hide the in-layout UI // controls. controlsView.setVisibility(visible ? View.VISIBLE : View.GONE); } if (visible && AUTO_HIDE) { // Schedule a hide(). delayedHide(AUTO_HIDE_DELAY_MILLIS); } } }); // Set up the user interaction to manually show or hide the system UI. contentView.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { if (TOGGLE_ON_CLICK) { mSystemUiHider.toggle(); } else { mSystemUiHider.show(); } } }); // Upon interacting with UI controls, delay any scheduled hide() // operations to prevent the jarring behavior of controls going away // while interacting with the UI. findViewById(R.id.dummy_button).setOnTouchListener(mDelayHideTouchListener); } @Override protected void onPostCreate(Bundle savedInstanceState) { super.onPostCreate(savedInstanceState); // Trigger the initial hide() shortly after the activity has been // created, to briefly hint to the user that UI controls // are available. delayedHide(100); } /** * Touch listener to use for in-layout UI controls to delay hiding the * system UI. This is to prevent the jarring behavior of controls going away * while interacting with activity UI. */ View.OnTouchListener mDelayHideTouchListener = new View.OnTouchListener() { @Override public boolean onTouch(View view, MotionEvent motionEvent) { if (AUTO_HIDE) { delayedHide(AUTO_HIDE_DELAY_MILLIS); } return false; } }; Handler mHideHandler = new Handler(); Runnable mHideRunnable = new Runnable() { @Override public void run() { mSystemUiHider.hide(); } }; /** * Schedules a call to hide() in [delay] milliseconds, canceling any * previously scheduled calls. */ private void delayedHide(int delayMillis) { mHideHandler.removeCallbacks(mHideRunnable); mHideHandler.postDelayed(mHideRunnable, delayMillis); } }

    1 answer 1

    This is just a template, its purpose is to reduce the number of the same “scribbling” when implementing a certain functionality, in this case full-screen activation.

    The purpose of this "extra" heap of code is written in the first line - a full-screen activation template that hides and shows system elements (such as the statusbar and navigation / systembar) with user interaction.

    If you think that you are implementing the full-screen mode better or you do not need such functionality, select the BlankActivity template, there is a minimum “extra” code and write everything yourself as you see fit.

    Also, you can completely remove everything that was in the template or only "superfluous" from your point of view and do it your way.

    "Excess" all this seems obvious to you because your ideas about the implementation of the half-screen activator differ from the idea of ​​this implementation among Google engineers.

    • Thank. After Eclipse It's unusual to see this .. :) - user189127