Android determine screen orientation at runtime

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清酒与你
清酒与你 2021-02-01 05:41

Here\'s a pseudo code to detect screen rotate event, and decide to retain or changes the screen orientation.

public boolean onOrientationChanges(orientation) {
          


        
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  • 2021-02-01 05:46

    Another solution to determine screen orientation:

    public boolean isLandscape() {
        return Resources.getSystem().getDisplayMetrics().widthPixels - Resources.getSystem().getDisplayMetrics().heightPixels > 0;
    }
    
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  • 2021-02-01 05:49

    You need a Display instance firstly:

    Display display = ((WindowManager) getSystemService(WINDOW_SERVICE)).getDefaultDisplay();
    

    Then orientation may be called like this:

    int orientation = display.getOrientation();
    

    Check orientation as your way and use this to change orientation:

    setRequestedOrientation (ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
    

    I hope it helps.

    Update:

    Okay, let's say you've an oAllow var which is Boolean and default value is False.

    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        Display display = ((WindowManager) getSystemService(WINDOW_SERVICE)).getDefaultDisplay();
        int orientation = display.getOrientation(); 
        switch(orientation) {
            case Configuration.ORIENTATION_PORTRAIT:
                if(!oAllow) {
                        setRequestedOrientation (ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
                }
                break;
            case Configuration.ORIENTATION_LANDSCAPE:
                if(!oAllow) {
                        setRequestedOrientation (ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
                }
                break;
        }
    }
    

    You can add more choices.

    I didn't try this sample, but at least tells you some clues about how to solve. Tell me if you got any error.

    UPDATE

    getOrientation() is already deprecated see here. Instead Use getRotation(). To check if the device is in landscape mode you can do something like this:

    Display display = ((WindowManager) getSystemService(WINDOW_SERVICE))
            .getDefaultDisplay();
    
    int orientation = display.getRotation();
    
    if (orientation == Surface.ROTATION_90
            || orientation == Surface.ROTATION_270) {
        // TODO: add logic for landscape mode here            
    }
    
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  • 2021-02-01 05:54
    if (this.getWindow().getWindowManager().getDefaultDisplay()
        .getOrientation() == ActivityInfo.SCREEN_ORIENTATION_PORTRAIT) {
      // portrait mode
    } else if (this.getWindow().getWindowManager().getDefaultDisplay()
               .getOrientation() == ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE) {
      // landscape
    }
    
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  • 2021-02-01 05:56

    Try running

    getResources().getConfiguration().orientation
    

    From your context object to figure out what is the screen orientation at runtime, the possible values are documented here

    In order to catch the orientation change event you can find the answer in the Android Dev Guide: Handling the Configuration Change Yourself

    From the guide :

    For example, the following manifest code declares an activity that handles both the screen orientation change and keyboard availability change:

    <activity android:name=".MyActivity"
    android:configChanges="orientation|keyboardHidden"
    android:label="@string/app_name">

    Now, when one of these configurations change, MyActivity does not restart. Instead, the MyActivity receives a call to onConfigurationChanged(). This method is passed a Configuration object that specifies the new device configuration. By reading fields in the Configuration, you can determine the new configuration and make appropriate changes by updating the resources used in your interface. At the time this method is called, your activity's Resources object is updated to return resources based on the new configuration, so you can easily reset elements of your UI without the system restarting your activity.

    ...

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  • 2021-02-01 06:06

    Check your android screen orientation at Runtime:

    ListView listView = (ListView) findViewById(R.id.listView1);
    if (getResources().getConfiguration().orientation == ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE) {
        //do work for landscape screen mode.
        listView.setPadding(0, 5, 0, 1);
    } else if (getResources().getConfiguration().orientation == ActivityInfo.SCREEN_ORIENTATION_PORTRAIT) {
        //Do work for portrait screen mode.
        listView.setPadding(1, 10, 1, 10);
    }
    
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  • 2021-02-01 06:11

    You don't need to intercept the event and then override it. Just use:

    // Allow rotation
    setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_USER);
    // Lock rotation (to Landscape)
    setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_USER_LANDSCAPE);
    

    Points to note here are, if on Jellybean and above this will allow a 180 degree rotation when locked. Also when unlocked this only allows rotation if the user's master settings is to allow rotation. You can forbid 180 degree rotations and override the master settings and allow rotation, and much much more, so check out the options in ActivityInfo

    In addition, if you have pre-set that there is to be no rotation, then your activity will not be destroyed and then restarted, just for you to set the orientation back which will again cause the activity to be restarted; Thus setting what you want in advance can be much more efficient.

    Pre Jellybean use ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE -- no 180 degree rotation with this.

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