Question

The answer to this question may be too advanced for me, but I would still like to give it a try. I am able to determine and set the value for the screen size within a method, but it does not have scope outside of that method. My question is, how do I give it scope inside the entire class? Also inside the entire project? Thanks. Here is what I am using to determine the screen size, but it only works inside a single method:

    DisplayMetrics metrics = this.getResources().getDisplayMetrics();
    int width = metrics.widthPixels;
    int height = metrics.heightPixels;

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Thanks!

Answer 1

My question is, how do I give it scope inside the entire class? Also inside the entire project?

If you only want to worry about setting those values once, extending the Application class would probably be a good start.

public class MyApplication extends Application {
    private Point mDimensions;

    @Override public void onCreate() {
        // this will only get run on app startup
        DisplayMetrics metrics = this.getResources().getDisplayMetrics();
        int width = metrics.widthPixels;
        int height = metrics.heightPixels;
        mDimensions = new Point(width, height);
    }

    public int getWidth() {
        return mDimensions.x;
    }

    public int getHeight() {
        return mDimensions.y;
    }
}

To access the getter methods, set the android:name attribute on the application tag in your project’s manifest:

<application android:name="com.myname.MyApplication" ... ></application>

You can then cast the result of any getApplication() and getApplicationContext() call to MyApplication and call the methods; e.g.

int width = ((MyApplication) getApplication()).getWidth(); 

Do note that since the width and height values are initialized only once, they will not change on screen orientation changes. If you want to take that into account too, a simple util method accepting a context instance (can be e.g. an Activity or Service) is probably a more straightforward solution.

public static Point getDimensions(Context context) {
    DisplayMetrics metrics = context.getResources().getDisplayMetrics();
    int width = metrics.widthPixels;
    int height = metrics.heightPixels;
    return new Point(width, height);
}