版本更新逻辑

1、联网，从远程服务器获取最新的版本，然后跟本地的版本号比对，如果远程的版本号大于本地的版本号，弹出对话框，有新版本，如果相等，已经是最新版本，不需要更新，本地版本号不可能比远程版本好大，

1、立刻升级
点击立刻升级，把最新的apk下载下来，然后提示更新安装。
2、稍后再说
点击稍后再说，立即进入主界面。

3、版本名、版本号
1、versionCode：给程序员看的
2、versionName：给用户看的
3、版本名规则：eg。6.1.3
1、6.1.C：小版本更新，修改了小bug，做一些微调
2、6.B.3：中等版本更新，更改了比较重要的bug，添加新功能
3、A.1.3：大版本更新，很重要的更新，里程碑意义的更新。

实战
D:\Software-tools\Tomcat\webapps\ROOT\update.txt
里面新建文本update模拟远程版本，在update文本里面写上json格式的数据:

{"remoteVesion":"2"}  //版本号为：2

访问成功：

异常处理的原则

1、如果有统一的解决方案，就在方法内部try catch掉
2、如果每次调用处理异常的方式都不同，就直接往外抛（谁调用，谁处理）

版本更新demo

SplashActivity

public class SplashActivity extends Activity {

    private static final String TAG = "SplashActivity";
    
    private static final int REQUEST_CODE = 100;
    //错误码
    protected static final int NET_ERROR = 1001;

    protected static final int NET_KEEP = 1002;
    
    private TextView tv_version;
    private ProgressDialog progressDialog;
    
    Handler mHandler = new Handler(){
        public void handleMessage(android.os.Message msg) {
            switch (msg.what) {
            case NET_ERROR:
                Toast.makeText(getApplicationContext(), "网络错误！", Toast.LENGTH_SHORT).show();
                enterHome();
                break;
            case NET_KEEP:
                Toast.makeText(getApplicationContext(), "服务器正在维护！", Toast.LENGTH_SHORT).show();
                enterHome();
                break;

            default:
                break;
            }
            
        };
    };
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_splash);

        tv_version = (TextView) findViewById(R.id.splash_tv_version);
        // 设置版本名
        initVersionName();
        //版本更新
        updateVersion();
    }

    private void updateVersion() {
        final String url = "http://192.168.39.50:8080/update.txt";
        //1.访问服务器，获取最新版本信息
        new Thread(new Runnable() {
            
            @Override
            public void run() {
                 //01. 定义okhttp
//              OkHttpClient okHttpClient_get = new OkHttpClient();
                //设置连接超时时间
                OkHttpClient okHttpClient_get = new OkHttpClient.Builder().connectTimeout(3, TimeUnit.SECONDS).build();
                //02.请求体
                Request request = new Request.Builder()
                    .get()//get请求方式
                    .url(url)//网址
                    .build();
                    
                //03.执行okhttp
                Response response;
                try {
                    response = okHttpClient_get.newCall(request).execute();
                    
                    /**
                     * 打印数据,注意一次请求，一次响应，读取一次就没了，要注释掉
                     */
//                  System.out.println(response.body().string());
                    String json = response.body().string();
                    //001.解析
                    //{"remoteVesion":"2","desc":"1.添加了摇一摇的功能\n2.优化了用户的体验","apkUrl":"http://192.168.39.50:8080/safenet.apk"}
                    JSONObject jsonObject = new JSONObject(json);
                    
                    int remoteVesion = jsonObject.getInt("remoteVesion");
                    String desc = jsonObject.getString("desc");
                    String url = jsonObject.getString("apkUrl");
                    
                    final UpdateInfo updateInfo = new UpdateInfo();
                    updateInfo.remoteVesion = remoteVesion;
                    updateInfo.desc = desc;
                    updateInfo.apkUrl = url;
                    
                    //2.判断最新版本与本地是否一致
                    int localVersion = PackageUtil.getVersionCode(getApplicationContext());
                    if (remoteVesion > localVersion) {
                        //3.弹出提示dialog
                        //不能在子线程中更新UI
                        runOnUiThread(new Runnable() {
                            
                            @Override
                            public void run() {
                                showUpdateDialog(updateInfo);
                            }
                        });
                        
                    }else{
                        //跳转到主页 
                        enterHome();
                    }
                } catch (IOException e) {
                    Message message = mHandler.obtainMessage();
                    message.what = NET_ERROR;
                    message.sendToTarget();
                    
                    e.printStackTrace();
                } catch (JSONException e) {
                    Message message = mHandler.obtainMessage();
                    message.what = NET_KEEP;
                    message.sendToTarget();
                    
                    e.printStackTrace();
                }
                
            }
        }).start();
        
    }
    //进入主页
    protected void enterHome() {
        mHandler.postDelayed(new Runnable() {
            
            @Override
            public void run() {
                Intent intent = new Intent(SplashActivity.this, HomeActivity.class);
                startActivity(intent);  
            }
        }, 2000);
        
    }

    private void showUpdateDialog(final UpdateInfo info) {
        AlertDialog.Builder builder = new Builder(SplashActivity.this);
        builder.setTitle("版本更新提示");
        builder.setCancelable(false);//点击旁边不能消失
        builder.setMessage(info.desc);
        
        //4.是否升级
        builder.setPositiveButton("立刻升级", new OnClickListener() {
            
            @Override
            public void onClick(DialogInterface dialog, int which) {
                
                downApk(info);
            }
        });
        builder.setNegativeButton("稍后再说", new OnClickListener() {
            
            @Override
            public void onClick(DialogInterface dialog, int which) {
                //回到主页
                enterHome();
                
            }
        });
        builder.show();
    }

    protected void downApk(UpdateInfo info) {
        //5.下载最新APK
        if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
            
            progressDialog = new ProgressDialog(this);
            progressDialog.setCancelable(false);
            progressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
            progressDialog.show();
            
            new Thread(new DownTask(info.apkUrl)).start();
        }else{
            //回到主页
            Toast.makeText(this, "没有SD卡！", Toast.LENGTH_SHORT).show();
            enterHome();
        }
    
    }
    
    class DownTask implements Runnable{
        
        String mUrl;
        
        public DownTask(String apkUrl) {
            this.mUrl = apkUrl;
        }

        @Override
        public void run() {
            InputStream is = null;
            FileOutputStream fos = null;
            try {
                Response response = HttpUtil.get(mUrl);
                is = response.body().byteStream();
                
                long contentLength = response.body().contentLength();
                //01.设置进度条最大值
                progressDialog.setMax((int) contentLength);
                //路径：mnt/sdcard/
                File file = new File(Environment.getExternalStorageDirectory(), "safe.apk");
                fos = new FileOutputStream(file);
                
                byte[] buffer = new byte[1024];
                
                int len = -1;
                
                int progress = 0;
                while((len = is.read(buffer)) != -1){
                    fos.write(buffer, 0, len);
                    
//                  SystemClock.sleep(10);
                    progress += len;
                    //02.设置进度
                    progressDialog.setProgress(progress);
                }
                
                fos.flush();
                //03.进度条消失
                progressDialog.dismiss();
                //6.提示用户安装 
                installApk(file);
            } catch (IOException e) {
                Message message = mHandler.obtainMessage();
                message.what = NET_ERROR;
                message.sendToTarget();
                e.printStackTrace();
            } finally{
                closeIo(fos);
                closeIo(is);
//              closeIo2(fos,is);
            }
        }
        
    }
    
    public void closeIo(Closeable io){
        if (io != null) {
            try {
                io.close();
                io = null;
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
    
    public void installApk(File file) {
//       <intent-filter>
//         <action android:name="android.intent.action.VIEW" />
//         <category android:name="android.intent.category.DEFAULT" />
//         <data android:scheme="content" />
//         <data android:scheme="file" />
//         <data android:mimeType="application/vnd.android.package-archive" />
//     </intent-filter>
        //7.安装APK
        Intent intent = new Intent();
        intent.addCategory("android.intent.category.DEFAULT");
        intent.setAction("android.intent.action.VIEW");
        //获取文件的uri
        Uri data = Uri.fromFile(file);
        intent.setDataAndType(data, "application/vnd.android.package-archive");
//      startActivity(intent);
        startActivityForResult(intent, REQUEST_CODE);
        
    }
    
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == REQUEST_CODE) {
            //系统默认的用户行为只有两种：yes no
            switch (resultCode) {
            case Activity.RESULT_OK:
                //***被覆盖安装了，所以不会出日志
                Log.d(TAG, "RESULT_OK");
                break;
            case Activity.RESULT_CANCELED:
                Log.d(TAG, "RESULT_CANCELED");
                //进入到主页
                enterHome();
                break;

            default:
                break;
            }
            
        }
    }

    public void closeIo2(Closeable... io){
        for (int i = 0; i < io.length; i++) {
            if(io[i] != null){
                try {
                    io[i].close();
                    io[i] = null;
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    private void initVersionName() {

        // PackageManager pm = this.getPackageManager();
        // /**
        // * flags:标志位，0标志包的基本信息
        // */
        // try {
        // PackageInfo info = pm.getPackageInfo(getPackageName(), 0);
        // String versionName = info.versionName;
        //
        // tv_version.setText(versionName);
        // } catch (NameNotFoundException e) {
        // e.printStackTrace();
        // }
        
        String versionName = PackageUtil.getVersionName(this);
        tv_version.setText(versionName);

    }
}

UpdateInfo

public class UpdateInfo {
    
    public int remoteVesion;//远程版本号
    public String desc;//版本描述
    public String apkUrl;//apk的下载地址
}

HttpUtil

public class HttpUtil {
    
    public static Response get(String url) throws IOException{
         //01. 定义okhttp
        OkHttpClient okHttpClient_get = new OkHttpClient();
        //02.请求体
        Request request = new Request.Builder()
            .get()//get请求方式
            .url(url)//网址
            .build();
            
        //03.执行okhttp
        Response response = okHttpClient_get.newCall(request).execute();
        
        return response;
    }       
}

public class PackageUtil {
    
    public static String getVersionName(Context context){
        
        PackageManager pm = context.getPackageManager();
        /**
         * flags:标志位，0标志包的基本信息
         */
        try {
            PackageInfo info = pm.getPackageInfo(context.getPackageName(), 0);
            String versionName = info.versionName;
            return versionName;
        } catch (NameNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return "未知版本名";
    }
    
    public static int getVersionCode(Context context){
        
        PackageManager pm = context.getPackageManager();
        /**
         * flags:标志位，0标志包的基本信息
         */
        try {
            PackageInfo info = pm.getPackageInfo(context.getPackageName(), 0);
            int versionCode = info.versionCode;
            
            return versionCode;
        } catch (NameNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return 1;
    }
}