1、通过一个Data.java实例类，可以实现全局数据保存，这里就不多说了，学Java的都知道。

2、Android特有的Application，是应用的入口，运行贯穿整个app运行过程，可以在这个类中定义全局变量

public class baseApplication extends Application {
		
	private float screenWidth;
	private float screenHeight;
	
	
	public float getScreenWidth() {
		return screenWidth;
	}
	public void setScreenWidth(float screenWidth) {
		this.screenWidth = screenWidth;
	}
	public float getScreenHeight() {
		return screenHeight;
	}
	public void setScreenHeight(float screenHeight) {
		this.screenHeight = screenHeight;
	}
	
	
}

        
        baseApplication b=(baseApplication) getApplicationContext();
        float width=b.getScreenWidth();
        float height=b.getScreenHeight();