详解Android app自动更新总结（已适配9.0）

 <uses-permission android:name="android.permission.internet"/>
 <uses-permission android:name="android.permission.read_external_storage"/>
 <uses-permission android:name="android.permission.write_external_storage"/>
 <uses-permission android:name="android.permission.request_install_packages" />
  <provider
   android:name="androidx.core.content.fileprovider"
   android:authorities="com.fengzhi.wuyemanagement.fileprovider"
   android:granturipermissions="true"
   android:exported="false">
   <meta-data
    android:name="android.support.file_provider_paths"
    android:resource="@xml/file_paths" />
  </provider>

<paths>
 <external-path path="." name="external_storage_root" />
</paths>

 implementation "com.lzy.net:okgo:3.0.4"//okgo 网络请求
 implementation 'com.google.code.gson:gson:2.8.2'//gson
 implementation "org.permissionsdispatcher:permissionsdispatcher:4.3.1"//权限
 annotationprocessor "org.permissionsdispatcher:permissionsdispatcher-processor:4.3.1"//权限

 private int version;
 /* 更新进度条 */
 private progressbar mprogress;
 private alertdialog mdownloaddialog;
 
--------------------------------------------------------------------------------------------------------------------
 
 //点击按钮，检查权限，，，检查更新的方法
 @needspermission({manifest.permission.read_external_storage,
   manifest.permission.write_external_storage,
   manifest.permission.request_install_packages})
 protected void checkupdate() {
  showloadingdialog("检测更新中...");
  version = appupdateutil.getappversioncode(this);//检查当前版本号
//  调用方法，，，接口的具体实现，接收传过来的参数，再调自己的方法，
  requestappupdate(version, new datarequestlistener<updateappbean>() {
   @override
   public void success(updateappbean data) {
//    返回的json，getstatus为0时，去下载apk文件,这里是下载apk文件的方法
    updateapp(data.getdata().getapk_url());
   }

   @override
   public void fail(string msg) {
//    返回的json，getstatus为1时，提示："已是最新版本！"
    stoast(msg);
    dismissloadingdialog();
   }
  });
 }

 //检查版本号，第一次请求(post)，，，updateappbean根据服务器返回生成
 private void requestappupdate(int version, final datarequestlistener<updateappbean> listener) {
  okgo.<string>post(const.host_url + const.updateapp).params("version", version).execute(new stringcallback() {
   @override
   public void onsuccess(response<string> response) {
    gson gson = new gson();
    updateappbean updateappbean = gson.fromjson(response.body(), updateappbean.class);
    if (updateappbean.getstatus() == 0) {
     listener.success(updateappbean);
    } else {
     listener.fail(updateappbean.getmsg());
    }
   }

   @override
   public void onerror(response<string> response) {
    listener.fail("服务器连接失败");
    dismissloadingdialog();
   }
  });
 }

 //如果有新版本，提示有新的版本，然后下载apk文件
 private void updateapp(string apk_url) {
  dismissloadingdialog();
  dialogutils.getinstance().showdialog(this, "发现新的版本，是否下载更新？",
    new dialogutils.dialoglistener() {
   @override
   public void positivebutton() {
    downloadapp(apk_url);
   }
  });
 }

 //下载apk文件并跳转(第二次请求，get)
 private void downloadapp(string apk_url) {
  okgo.<file>get(apk_url).tag(this).execute(new filecallback() {
   @override
   public void onsuccess(response<file> response) {
    string filepath = response.body().getabsolutepath();
    intent intent = intentutil.getinstallappintent(mcontext, filepath);
//    测试过这里必须用startactivity，不能用stratactivityforresult
    mcontext.startactivity(intent);
    dismissloadingdialog();
    mdownloaddialog.dismiss();
    mdownloaddialog=null;
   }

   @override
   public void downloadprogress(progress progress) {
//      showdownloaddialog();
//      mprogress.setprogress((int) (progress.fraction * 100));
    if (mdownloaddialog == null) {
     // 构造软件下载对话框
     alertdialog.builder builder = new alertdialog.builder(mcontext);
     builder.settitle("正在更新");
     // 给下载对话框增加进度条
     final layoutinflater inflater = layoutinflater.from(mcontext);
     view v = inflater.inflate(r.layout.item_progress, null);
     mprogress = (progressbar) v.findviewbyid(r.id.update_progress);
     builder.setview(v);
     mdownloaddialog = builder.create();
     mdownloaddialog.setcancelable(false);
     mdownloaddialog.show();
    }
    mprogress.setprogress((int) (progress.fraction * 100));
   }
  });
 }

public interface datarequestlistener<t> {
 //请求成功
 void success(t data);
 //请求失败
 void fail(string msg);
}

 /**
  * 获取app版本码
  *
  * @param context 上下文
  * @return app版本码
  */
 public static int getappversioncode(context context) {
  return getappversioncode(context, context.getpackagename());
 }

public class intentutil {

 /**
  * 获取安装app(支持7.0)的意图
  *
  * @param context
  * @param filepath
  * @return
  */
 public static intent getinstallappintent(context context, string filepath) {
  //apk文件的本地路径
  file apkfile = new file(filepath);
  if (!apkfile.exists()) {
   return null;
  }
  intent intent = new intent(intent.action_view);
  uri contenturi = fileutil.geturiforfile(context, apkfile);
  intent.setflags(intent.flag_activity_new_task);
  if (build.version.sdk_int >= build.version_codes.n) {
   intent.addflags(intent.flag_grant_read_uri_permission | intent.flag_grant_write_uri_permission);
  }
  intent.setdataandtype(contenturi, "application/vnd.android.package-archive");
  return intent;
 }

 /**
  * 将文件转换成uri(支持7.0)
  *
  * @param mcontext
  * @param file
  * @return
  */
 public static uri geturiforfile(context mcontext, file file) {
  uri fileuri = null;
  if (build.version.sdk_int >= 24) {
   fileuri = fileprovider.geturiforfile(mcontext, mcontext.getpackagename() + ".fileprovider", file);
  } else {
   fileuri = uri.fromfile(file);
  }
  return fileuri;
 }