1、检查更新接口，获取最新app版本以及下载链接

2、下载apk文件到Context.getCacheDir() app缓存目录下，方便清理

3、安装apk

3.1、配置安装apk的权限

<uses-permission android:name="android.permission.REQUEST_INSTALL_PACKAGES" />

3.2、在AndroidManifest的application中配置provider和meta-data

<provider
        android:name="androidx.core.content.FileProvider"
        android:authorities="com.zjw.touchscreen.fileProvider"
        android:exported="false"
        android:grantUriPermissions="true">
    <meta-data
            android:name="android.support.FILE_PROVIDER_PATHS"
            android:resource="@xml/file_paths" />
</provider>

3.1、实现安装代码

protected void installApk(File file) {
    Intent intent = new Intent();
    intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    intent.setAction(Intent.ACTION_VIEW);

    if (Build.VERSION.SDK_INT >= 24) {
        //注意getUriForFile的第二个参数和AndroidManifest中配置的android:authorities保持一致
        Uri apkUri = FileProvider.getUriForFile(this,"com.zjw.touchscreen.fileProvider", file);
        intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
        intent.setDataAndType(apkUri, "application/vnd.android.package-archive");
    } else {
        intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        intent.setDataAndType(Uri.fromFile(file), "application/vnd.android.package-archive");
    }
    this.startActivity(intent);
    android.os.Process.killProcess(android.os.Process.myPid());
}