运行如下(注:目标> 3.0)
Running the following (note: target > 3.0)
ActionBar actionBar = getActionBar();
在Android版本< 3.0(SDK 11)的结果是的NoSuchMethodError
。
有几种方法来解决这个问题,包括反射和类懒加载。但是,以下似乎在所有我测试过的设备上班(2.3.6,3.0,3.1,4.0):
There are several ways to get around this, including reflection and class lazy loading. However, the following seems to work across all the devices I've tested (2.3.6, 3.0, 3.1, 4.0):
boolean hasActionBar = android.os.Build.VERSION.SDK_INT >= 11;
if (hasActionBar) {
ActionBar actionBar = getActionBar();
} else {
// create custom actionbar
}
注意 SDK_INT
参数静态最后
,这似乎可以解释为什么这个工作的。
Note the SDK_INT
parameter is static final
, which appears to be why this works.
这是对付兼容性的有效方法是什么?
Is this a valid way to deal with compatibility?
它看起来像这样的作品由于JIT编译器。这code未能在SDK< 2.1,支持这一理论。无论如何,这可能不是一个可靠的方法,以避免反光。
It looks like this works due to the JIT compiler. This code fails on SDK < 2.1, which supports this theory. Regardless, this probably isn't a reliable way to avoid reflection.