方式一:
在AndroidManifest.xml配置文件中为对应的Activity设置
android:theme="@android:style/Theme.Light.NoTitleBar.Fullscreen"

方式二:
在代码中onCreate()方法中设置
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.main);