I am using Android Studio to create a fullscreen app. And I used the FullScreenActivity template provided by Android Studio.
It can toggle full screen mode perfectly except that activity's content's top is offset upward by some pixels(similar to status bar's height) when return from full screen.
Here are screenshots of screen at different stages: before full screen, at full screen, and return from full screen. And as I've turns on the display of layout bounds setting, you can see the red rectangles which are view bounds.
Before full screen, the bounds are clear: action bar's bottom is overlapping content's top
At full screen
After return from full screen: action bar's bottom is not overlapping content's top, and here is the problem, it seems content's top get moved upward.
Why would this happen and how could I solved it? please give me a hand, thanks
FullScreenActivity.java
import android.annotation.SuppressLint;
import android.support.v7.app.ActionBar;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.os.Handler;
import android.view.MotionEvent;
import android.view.View;
/**
* An example full-screen activity that shows and hides the system UI (i.e.
* status bar and navigation/system bar) with user interaction.
*/
public class FullscreenActivity extends AppCompatActivity {
/**
* 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;
/**
* Some older devices needs a small delay between UI widget updates
* and a change of the status and navigation bar.
*/
private static final int UI_ANIMATION_DELAY = 300;
private final Handler mHideHandler = new Handler();
private View mContentView;
private final Runnable mHidePart2Runnable = new Runnable() {
@SuppressLint("InlinedApi")
@Override
public void run() {
// Delayed removal of status and navigation bar
// Note that some of these constants are new as of API 16 (Jelly Bean)
// and API 19 (KitKat). It is safe to use them, as they are inlined
// at compile-time and do nothing on earlier devices.
mContentView.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LOW_PROFILE
| View.SYSTEM_UI_FLAG_FULLSCREEN
| View.SYSTEM_UI_FLAG_LAYOUT_STABLE
| View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY
| View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
| View.SYSTEM_UI_FLAG_HIDE_NAVIGATION);
}
};
private View mControlsView;
private final Runnable mShowPart2Runnable = new Runnable() {
@Override
public void run() {
// Delayed display of UI elements
ActionBar actionBar = getSupportActionBar();
if (actionBar != null) {
actionBar.show();
}
mControlsView.setVisibility(View.VISIBLE);
}
};
private boolean mVisible;
private final Runnable mHideRunnable = new Runnable() {
@Override
public void run() {
hide();
}
};
/**
* 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.
*/
private final View.OnTouchListener mDelayHideTouchListener = new View.OnTouchListener() {
@Override
public boolean onTouch(View view, MotionEvent motionEvent) {
if (AUTO_HIDE) {
delayedHide(AUTO_HIDE_DELAY_MILLIS);
}
return false;
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_fullscreen);
mVisible = true;
mControlsView = findViewById(R.id.fullscreen_content_controls);
mContentView = findViewById(R.id.fullscreen_content);
// Set up the user interaction to manually show or hide the system UI.
mContentView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
toggle();
}
});
// 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);
}
private void toggle() {
if (mVisible) {
hide();
} else {
show();
}
}
private void hide() {
// Hide UI first
ActionBar actionBar = getSupportActionBar();
if (actionBar != null) {
actionBar.hide();
}
mControlsView.setVisibility(View.GONE);
mVisible = false;
// Schedule a runnable to remove the status and navigation bar after a delay
mHideHandler.removeCallbacks(mShowPart2Runnable);
mHideHandler.postDelayed(mHidePart2Runnable, UI_ANIMATION_DELAY);
}
@SuppressLint("InlinedApi")
private void show() {
// Show the system bar
mContentView.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
| View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION);
mVisible = true;
// Schedule a runnable to display UI elements after a delay
mHideHandler.removeCallbacks(mHidePart2Runnable);
mHideHandler.postDelayed(mShowPart2Runnable, UI_ANIMATION_DELAY);
}
/**
* 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);
}
}
activity_fullscreen.xml
<FrameLayout 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"
android:background="#0099cc"
tools:context=".FullscreenActivity">
<!-- The primary full-screen view. This can be replaced with whatever view
is needed to present your content, e.g. VideoView, SurfaceView,
TextureView, etc. -->
<TextView
android:id="@+id/fullscreen_content"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"
android:keepScreenOn="true"
android:text="@string/dummy_content"
android:textColor="#33b5e5"
android:textSize="50sp"
android:textStyle="bold" />
<!-- This FrameLayout insets its children based on system windows using
android:fitsSystemWindows. -->
<FrameLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true">
<LinearLayout
android:id="@+id/fullscreen_content_controls"
style="?metaButtonBarStyle"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom|center_horizontal"
android:background="@color/black_overlay"
android:orientation="horizontal"
tools:ignore="UselessParent">
<Button
android:id="@+id/dummy_button"
style="?metaButtonBarButtonStyle"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="@string/dummy_button" />
</LinearLayout>
</FrameLayout>
</FrameLayout>
manifest.xml
...
<application
android:name=".MyApplication"
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/AppTheme">
...
<activity
android:name=".FullscreenActivity"
android:configChanges="orientation|keyboardHidden|screenSize"
android:label="@string/title_activity_fullscreen"
android:theme="@style/FullscreenTheme"></activity>
...
</application>
...
