什么是 versionCodeMajor?和 versionCode 有什么区别?

What is versionCodeMajor? And what is the difference with versionCode?

我刚发现 PackageInfo.versionCode is deprecated in Android Pie. They point you to use PackageInfo.getLongVersionCode()。这个新方法的 JavaDoc 是:

Return versionCode and versionCodeMajor combined together as a single long value. The versionCodeMajor is placed in the upper 32 bits.

但是 versionCodeMajor 是什么?我该如何使用它? versionCodeMajor和旧的versionCode有什么区别?

它的文档几乎什么都没说:

Internal major version code. This is essentially additional high bits for the base version code; it has no other meaning than that higher numbers are more recent. This is not a version number generally shown to the user, that is usually supplied with R.attr.versionName.

到目前为止,我发现使用 Android Studio 3.2.1 设置 versionCodeMajor 的唯一方法是通过 AndroidManifest.xml 并禁用 InstantRun.

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:versionCodeMajor="8" [...]

'因为在 build.gradle 文件中设置了它

android {
    compileSdkVersion 28
    defaultConfig {
        applicationId "com.example.xxx.myapplicationp"
        minSdkVersion 'P'
        targetSdkVersion 'P'
        versionCode 127
        //versionCodeMajor 8
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

Could not find method versionCodeMajor() for arguments

因此,在 AndroidManifest.xml 中设置了您选择的主要版本代码并禁用 InstantRun 然后您可以通过以下方式获得它:

static long getAppVersionCode(Context context) throws PackageManager.NameNotFoundException {
        PackageInfo pinfo = context.getPackageManager().getPackageInfo(context.getPackageName(), 0);
        long returnValue = Long.MAX_VALUE;
        //if (Build.VERSION.SDK_INT < Build.VERSION_CODES.P) {
        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.P
                && !"P".equals(Build.VERSION.CODENAME) /* This 'cause the dev preview */) {
            returnValue = pinfo.versionCode;
        } else {
            returnValue = pinfo.getLongVersionCode();
            Log.d("AAA", "Full long value: " + returnValue);
            Log.d("AAA", "Major Version Code (your chosen one) " + (returnValue >> 32)); // 8 in this scenario
            Log.d("AAA", "Version Code (your chosen one) " + (int)(returnValue & 0x00000000ffffffff)); // 127 in this scenario
        }
        return returnValue;
    }

或者您可以这样使用 PackageInfoCompat

static long getAppVersionCode(Context context) throws PackageManager.NameNotFoundException {
        PackageInfo pinfo = context.getPackageManager().getPackageInfo(context.getPackageName(), 0);
        long returnValue = Long.MAX_VALUE;
        returnValue = PackageInfoCompat.getLongVersionCode(pinfo);
        if (BuildConfig.DEBUG) {
            int majorCode = (int)(returnValue >> 32);
            int versionCode = (int)(returnValue & 0x00000000ffffffff); // or simply returnValue

            Log.d("AAA", "Full long value: " + returnValue);
            Log.d("AAA", "Major Version Code (your chosen one) " + majorCode); // 8 in this scenario
            Log.d("AAA", "Version Code (your chosen one) " + versionCode); // 127 in this scenario
        }
        return returnValue;
    }

这应该回答如何使用它或一种方法。

何时以及为何使用它...我想这取决于您...正如您指出的那样,文档没有告诉您为什么应该使用它。文档说你应该只向你的用户展示众所周知的版本号。

我猜他们在 versionCode 中添加了更多位,因为他们需要更多的数字来进行版本控制 ^^'

就是说,如果您没有在 AndroidManifest.xmlbuild.gradle 文件中设置 versionCodeMajor(当它处理它时),或者您将其设置为 0 则此值与旧的 versionNumber 弃用字段相同。

另一种获取版本名称和版本代码的方法是通过 BuildConfig

BuildConfig.VERSION_CODE
BuildConfig.VERSION_NAME