问题
Some Java library methods like DecimalFormat.setRoundingMode have a @since 1.6 entry in their documentation.
/**
...
* @since 1.6
*/
public void setRoundingMode(RoundingMode roundingMode) {
...
}
When I tried to use this method compiled under Android 4.2.2 and JDK 1.6 with my android:minSdkVersion set to 7 as shown,
myNumberFormat.setRoundingMode(RoundingMode.DOWN);
Android Lint underlined setRoundingMode in red for me and told me that
Call requires API level 9 (current min is 7): java.text.NumberFormat#setRoundingMode
How and why can the Android API restrict which Java library methods I can and cannot use? I cleaned my project and the Lint error disappeared. My project compiled with no errors and ran on a device running Android 2.2.3 (API 8).
My program crashed with:
05-09 11:32:38.436: E/AndroidRuntime(2074): Caused by: java.lang.NoSuchMethodError: java.text.NumberFormat.setRoundingMode
The Android documentation confirms that setRoundingMode, copySign, and others were added in API level 9. Does that mean that devices running Android OS level 8 and below are specifically compiled/built with JDK 1.5?
And I can understand that. But is it impossible for the Android Support Library (or anything else) to allow us to use these methods?
Related to Rounding Half Up with Decimal Format in Android
来源：https://stackoverflow.com/questions/16471345/compatibility-for-java-library-methods-that-require-android-api-level-9