Android下載apk文件並安裝

在Andrdoid程序中常常會有一個版本更新的功能,它的實現非常簡單,就是講新版本的apk文件上傳到服務器,然後修改服務器中的版本號,這樣當用戶點擊版本更新的時候就可以下載新版本的apk文件了,下面說一下是如何下載並安裝apk文件的:

public class UpdateActivity extends AppCompatActivity {
    private Button button1;
    private static String URL_STRING = "";//下載文件的地址
    private static int down = 0;//狀態碼
    File file;
    private Handler handler = new Handler() {

        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);

            switch (msg.what) {
                case 1:
                    button1.setText("點擊安裝");
                    down = 1;
                    break;
                case 2:
                    down = 2;
                    button1.setText("打開");
                    break;
            }
        }

    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_update);

        String apk = getIntent().getStringExtra("apk");
        String path = "http://59.110.12.225:8080/szcb.admin";
        URL_STRING = path + apk;
        //調用手機中的瀏覽器下載
//        Uri uri = Uri.parse(path+apk);
//        Intent intent = new Intent(Intent.ACTION_VIEW, uri);
//        startActivity(intent);

        button1 = (Button) findViewById(R.id.button1);
        button1.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // 下載apk
                if (down == 0) {
                    downFile(URL_STRING);
                    button1.setText("正在下載");
                    // 安裝APK
                } else if (down == 1) {
                    installApk();
                    // 打開apk
                } else if (down == 2) {
                    openApk(UpdateActivity.this, URL_STRING);
                }

            }
        });

    }

    // 接收到安裝完成apk的廣播
    BroadcastReceiver broadcastReceiver = new BroadcastReceiver() {

        @Override
        public void onReceive(Context context, Intent intent) {

            System.out.println("接收到安裝完成apk的廣播");

            Message message = handler.obtainMessage();
            message.what = 2;
            handler.sendMessage(message);
        }
    };

    /**
     * 後臺在下面一個Apk 下載完成後返回下載好的文件
     *
     * @param httpUrl
     * @return
     */
    private File downFile(final String httpUrl) {

        new Thread(new Runnable() {

            @Override
            public void run() {
                try {
                    URL url = new URL(httpUrl);
                    HttpURLConnection connection = (HttpURLConnection) url.openConnection();
                    connection.setRequestMethod("GET");
                    connection.setConnectTimeout(5000);
                    FileOutputStream fileOutputStream = null;
                    InputStream inputStream;
                    if (connection.getResponseCode() == 200) {
                        inputStream = connection.getInputStream();

                        if (inputStream != null) {
                            file = getFile(httpUrl);
                            fileOutputStream = new FileOutputStream(file);
                            byte[] buffer = new byte[1024];
                            int length = 0;

                            while ((length = inputStream.read(buffer)) != -1) {
                                fileOutputStream.write(buffer, 0, length);
                            }
                            fileOutputStream.close();
                            fileOutputStream.flush();
                        }
                        inputStream.close();
                    }


                    //Log.e("Mr.Kang", "run: "+"下載完成");
                    // 往handler發送一條消息 更改button的text屬性
                    Message message = handler.obtainMessage();
                    message.what = 1;
                    handler.sendMessage(message);
                } catch (MalformedURLException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }).start();
        return file;
    }

    /**
     * 安裝APK
     */
    private void installApk() {
        Intent intent = new Intent(Intent.ACTION_VIEW);
        intent.setDataAndType(Uri.fromFile(file), "application/vnd.android.package-archive");
        startActivity(intent);
    }

    @Override
    protected void onStart() {
        super.onStart();
        IntentFilter intentFilter = new IntentFilter();
        intentFilter.addAction(Intent.ACTION_PACKAGE_ADDED);
        intentFilter.addDataScheme("package");
        // 註冊一個廣播
        registerReceiver(broadcastReceiver, intentFilter);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        // 解除廣播
        unregisterReceiver(broadcastReceiver);
    }

    /**
     * 打開已經安裝好的apk
     */
    private void openApk(Context context, String url) {
        PackageManager manager = context.getPackageManager();
        // 這裏的是你下載好的文件路徑
        PackageInfo info = manager.getPackageArchiveInfo(Environment.getExternalStorageDirectory().getAbsolutePath() + getFilePath(url), PackageManager.GET_ACTIVITIES);
        if (info != null) {
            Intent intent = manager.getLaunchIntentForPackage(info.applicationInfo.packageName);
            startActivity(intent);
        }
    }

    /**
     * 根據傳過來url創建文件
     */
    private File getFile(String url) {
        File files = new File(Environment.getExternalStorageDirectory().getAbsoluteFile(), getFilePath(url));
        return files;
    }

    /**
     * 截取出url後面的apk的文件名    
     * @param url    
     * @return
     */
    private String getFilePath(String url) {
        return url.substring(url.lastIndexOf("/"), url.length());
    }
}