通过okhttp3下载文件实现APP版本更新

原文：https://blog.csdn.net/qq_34261214/article/details/77124729

概况

思路是这样的,首先在服务器上把已经签名打包的apk放上去,还有一份TXT文件，文件上写着相关的版本号，然后客户端通过对比版本号决定是否下载文件。下载后就打开安装界面安装。

第一步

把已经签名打包apk和txt文件放上到服务器上，版本号要和txt文件上的描述一致。Android Studio的版本号除了在manifests上，写上code和name(code是面向开发者，name就是用户所看到的版本号），那么我要更新的是2.0版本，那么我应该写2.0，并且要把访问网络和写入数据权限写上

还要在build.gradle(Module:app）上更改版本号，如果是用eclipse开发就不需要这一步

TXT文件的内容如下，第一行是版本号，第二行版本描述，第三行是apk的下载链接

第二步

服务器端已经完成，接下来是代码的实现。
我这里采用okhttp3+mvp模式实现下载文件，如果有对这种模式不清楚的可以看在MVP模式下使用OkHttp3和初试OkHttp3实现登录功能

Model层有更新版本描述实例UpdateInfo和Okhttp3的get和post方法
首先在Presenter上有查询版本号和下载apk这两个方法，这两个都是使用Get请求
在View上就需要有一个对应一个触发更新的按钮，显示最新版本的Toast,显示并询问是否更新的Dialog,和显示进度的ProgressDialog，一个跳转到安装界面的操作

Model层

首先要有updateInfo,一个版本信息的实例

public class UpdateInfo

{

        private String version;

        private String description;

        private String url;

        public String getVersion()

        {

                return version;

        }

        public void setVersion(String version)

        {

                this.version = version;

        }

        public String getDescription()

        {

                return description;

        }

        public void setDescription(String description)

        {

                this.description = description;

        }

        public String getUrl()

        {

                return url;

        }

        public void setUrl(String url)

        {

                this.url = url;

        }

}

另一个是Modle，包装着okhttp3的post和get方法，这里只需要get请求



    /**

     * get请求

     * @param address

     * @param callback

     */

    public void get(String address, okhttp3.Callback callback)

    {

        OkHttpClient client = new OkHttpClient();

        FormBody.Builder builder = new FormBody.Builder();

        FormBody body = builder.build();

        Request request = new Request.Builder()

                .url(address)

                .build();

        client.newCall(request).enqueue(callback);

    }

Presenter层

检查是否需要更新

 public void updateAPK() {

        model = Model.getInstance();

        model.get("TXT文件的url",new okhttp3.Callback(){

            @Override

            public void onFailure(Call call, IOException e) {

            }

            @Override

            public void onResponse(Call call, Response response) throws IOException {

                String responseBody = response.body().string();

                StringBuffer sb = new StringBuffer();

                BufferedReader reader = null;

                UpdateInfo updateInfo = new UpdateInfo();

                Log.d("版本", "onResponse: "+responseBody);

                reader = new BufferedReader(new StringReader(responseBody));

                  updateInfo.setVersion(reader.readLine());//把版本信息读出来

                  updateInfo.setDescription(reader.readLine());

                  updateInfo.setUrl(reader.readLine());

                  String new_version = updateInfo.getVersion();

                  Log.d("版本", "onResponse: "+updateInfo.getVersion());

                  Log.d("版本描述", "onResponse: "+updateInfo.getDescription());

                  Log.d("更新链接", "onResponse: "+updateInfo.getUrl());

                String now_version = "";

                try {

                    PackageManager packageManager = context.getPackageManager();

                    PackageInfo packageInfo = packageManager.getPackageInfo(context.getPackageName(),0);

                    now_version = packageInfo.versionName;//获取原版本号

                } catch (PackageManager.NameNotFoundException e) {

                    e.printStackTrace();

                }

                if(new_version.equals(now_version)){

                    view.showError("");

                    Log.d("版本号是", "onResponse: "+now_version);

                }else{

                    view.showUpdateDialog(updateInfo);

                }

            }

        });

    }

下载apk

    public void downFile(final String url) {

        Log.d("SettingPresenter", "downFile: ");

        model = Model.getInstance();

        model.get(url,new okhttp3.Callback(){

            @Override

            public void onFailure(Call call, IOException e) {

                view.downFial();

            }

            @Override

            public void onResponse(Call call, Response response) throws IOException {

                InputStream is = null;//输入流

                FileOutputStream fos = null;//输出流

                try {

                    is = response.body().byteStream();//获取输入流

                    long total = response.body().contentLength();//获取文件大小

                    view.setMax(total);//为progressDialog设置大小

                    if(is != null){

                        Log.d("SettingPresenter", "onResponse: 不为空");

                        File file = new File(Environment.getExternalStorageDirectory(),"Earn.apk");// 设置路径

                        fos = new FileOutputStream(file);

                        byte[] buf = new byte[1024];

                        int ch = -1;

                        int process = 0;

                        while ((ch = is.read(buf)) != -1) {

                            fos.write(buf, 0, ch);

                            process += ch;

                            view.downLoading(process);       //这里就是关键的实时更新进度了！

                        }

                    }

                    fos.flush();

                    // 下载完成

                    if(fos != null){

                        fos.close();

                    }

                    view.downSuccess();

                } catch (Exception e) {

                    view.downFial();

                    Log.d("SettingPresenter",e.toString());

                } finally {

                    try {

                        if (is != null)

                            is.close();

                    } catch (IOException e) {

                    }

                    try {

                        if (fos != null)

                            fos.close();

                    } catch (IOException e) {

                    }

                }

            }

            //private void down() {

               // progressDialog.cancel();

           // }

        });

    }

View层

这一层注意的东西很多，例如Android6.0以上等需要在这里设置一下权限，还有Dialog注意关闭，否则出现窗口泄露问题。话不多说，直接上代码

public class MainActivity extends AppCompatActivity {

    //下载进度

    private ProgressDialog progressDialog;

    private Button button;

    private SettingPresenter presenter;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        presenter = new SettingPresenter(this,this);

        button = (Button) findViewById(R.id.button);

        button.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View v) {

                if (Build.VERSION.SDK_INT >= 23) {//如果是6.0以上的

                    int REQUEST_CODE_CONTACT = 101;

                    String[] permissions = {Manifest.permission.WRITE_EXTERNAL_STORAGE};

                    //验证是否许可权限

                    for (String str : permissions) {

                        if (MainActivity.this.checkSelfPermission(str) != PackageManager.PERMISSION_GRANTED) {

                            //申请权限

                            MainActivity.this.requestPermissions(permissions, REQUEST_CODE_CONTACT);

                            return;

                        }

                    }

                }

                presenter.updateAPK();

            }

        });

    }

//显示更新错误

    public void showError(final String msg) {

        runOnUiThread(new Runnable() {

            @Override

            public void run() {

                Toast.makeText(MainActivity.this, msg, Toast.LENGTH_SHORT).show();

            }

        });

    }

//显示进度条

    public void showUpdateDialog(final UpdateInfo updateInfo) {

        runOnUiThread(new Runnable() {

            @Override

            public void run() {

                AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);

                builder.setIcon(android.R.drawable.ic_dialog_info);

                builder.setTitle("请升级APP至版本" + updateInfo.getVersion());

                builder.setMessage(updateInfo.getDescription());

                builder.setCancelable(false);

                builder.setPositiveButton("确定", new DialogInterface.OnClickListener() {

                    @Override

                    public void onClick(DialogInterface dialog, int which) {

                        if (Environment.getExternalStorageState().equals(

                                Environment.MEDIA_MOUNTED)) {

                            downFile(updateInfo.getUrl());

                        } else {

                            Toast.makeText(MainActivity.this,"SD卡不可用，请插入SD卡",Toast.LENGTH_LONG).show();

                        }

                    }

                });

                builder.setNegativeButton("取消", new DialogInterface.OnClickListener() {

                    @Override

                    public void onClick(DialogInterface dialog, int which) {

                    }

                });

                builder.create().show();

            }

        });

    }

//下载apk操作

   public void downFile(final String url) {

        progressDialog = new ProgressDialog(MainActivity.this);    //进度条，在下载的时候实时更新进度，提高用户友好度

        progressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);

        progressDialog.setTitle("正在下载");

        progressDialog.setMessage("请稍候...");

        progressDialog.setProgress(0);

        progressDialog.show();

        presenter.downFile(url);

        Log.d("SettingActivity", "downFile: ");

    }

    /**

     * 进度条实时更新

     * @param i

     */

    public void downLoading(final int i) {

        runOnUiThread(new Runnable() {

            @Override

            public void run() {

                progressDialog.setProgress(i);

            }

        });

    }

    /**

     * 下载成功

     */

    public void downSuccess() {

        runOnUiThread(new Runnable() {

            @Override

            public void run() {

                if (progressDialog != null && progressDialog.isShowing())

                {

                    progressDialog.dismiss();

                }

                AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);

                builder.setIcon(android.R.drawable.ic_dialog_info);

                builder.setTitle("下载完成");

                builder.setMessage("是否安装");

                builder.setCancelable(false);

                builder.setPositiveButton("确定", new DialogInterface.OnClickListener() {

                    @Override

                    public void onClick(DialogInterface dialog, int which) {

                        Intent intent = new Intent(Intent.ACTION_VIEW);

                        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) { //aandroid N的权限问题

                            intent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);

                            Uri contentUri = FileProvider.getUriForFile(MainActivity.this, "对应的包名.fileprovider", new File(Environment.getExternalStorageDirectory(), "软件名.apk"));//注意修改

                            intent.setDataAndType(contentUri, "application/vnd.android.package-archive");

                        } else {

                            intent.setDataAndType(Uri.fromFile(new File(Environment.getExternalStorageDirectory(), "软件名.apk")), "application/vnd.android.package-archive");

                            intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

                        }

                        startActivity(intent);

                    }

                });

                builder.setNegativeButton("取消", new DialogInterface.OnClickListener() {

                    @Override

                    public void onClick(DialogInterface dialog, int which) {

                    }

                });

                builder.create().show();

            }

        });

    }

    /**

     * 下载失败

     */

    public void downFial() {

        runOnUiThread(new Runnable() {

            @Override

            public void run() {

                progressDialog.cancel();

                Toast.makeText(MainActivity.this,"更新失败",Toast.LENGTH_LONG).show();

            }

        });

    }

    public void setMax(final long total) {

        runOnUiThread(new Runnable() {

            @Override

            public void run() {

                progressDialog.setMax((int) total);

            }

        });

    }

}

注意：在跳转到安装界面时，android 6.0即android N以上的需要设置权限。

首先在Manifests加上

  <provider

            android:name="android.support.v4.content.FileProvider"

            android:authorities="对应的包名.fileprovider"

            android:grantUriPermissions="true"

            android:exported="false"

            >

            <meta-data

                android:name="android.support.FILE_PROVIDER_PATHS"

                android:resource="@xml/file_paths" />

        </provider>

然后在res中创建xml包，存放file_paths.xml文件

<?xml version="1.0" encoding="utf-8"?>

<paths>

    <external-path path="Android/data/com.earn/" name="files_root" />

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

</paths>

文章所用Demo这里下载