android做到一定程度，需要考虑缓存的问题，不信可以掏出手机看看淘宝等一些app是否无网的情况下还可以浏览，不过大部分app并没有考虑到这些问题，解决Android的缓存有哪些方法呢
1.IO流读写文件
2.数据库
3.LruCache和DiskLruCache
个人比较喜欢sd卡文件读写的方式，原因自己可以去分析。
（1）权限
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /> <uses-permission android:name="android.permission.INTERNET"></uses-permission> <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"></uses-permission> <!-- 在SDCard中创建与删除文件权限 --> <uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/> <!-- 往SDCard写入数据权限 --> <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
（2）判断网络连接的状态，有什么用呢？自己想
if (isNetworkAvailable(MainActivity.this)) { Toast.makeText(getApplicationContext(), "当前有可用网络！", Toast.LENGTH_LONG).show(); } else { Toast.makeText(getApplicationContext(), "当前wu可用网络！", Toast.LENGTH_LONG).show(); } public boolean isNetworkAvailable(Activity activity) { Context context = activity.getApplicationContext(); // 获取手机所有连接管理对象（包括对wi-fi,net等连接的管理） ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE); if (connectivityManager == null) { return false; } else { // 获取NetworkInfo对象 NetworkInfo[] networkInfo = connectivityManager.getAllNetworkInfo(); if (networkInfo != null && networkInfo.length > 0) { for (int i = 0; i < networkInfo.length; i++) { System.out.println(i + "===状态===" + networkInfo[i].getState()); System.out.println(i + "===类型===" + networkInfo[i].getTypeName()); // 判断当前网络状态是否为连接状态 if (networkInfo[i].getState() == NetworkInfo.State.CONNECTED) { return true; } } } } return false; }
（3）端口写入数据
if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){ File sdCardDir = Environment.getExternalStorageDirectory();//获取SDCard目录 File saveFile = new File(sdCardDir, "itcast.txt"); FileOutputStream outStream = new FileOutputStream(saveFile); outStream.write(result.getBytes()); outStream.close(); }
（4）读取数据
File sdCardDir = Environment.getExternalStorageDirectory();//获取SDCard目录 File saveFile1 = new File(sdCardDir, "itcast.txt"); BufferedReader br = null; try { br = new BufferedReader(new FileReader(saveFile1)); String readline = ""; StringBuffer sb = new StringBuffer(); while ((readline = br.readLine()) != null) { System.out.println("readline:" + readline); sb.append(readline); } String str = sb.toString();
(5)部分完整demo1
if (isNetworkAvailable(MainActivity.this)) { Toast.makeText(getApplicationContext(), "当前有可用网络！", Toast.LENGTH_LONG).show(); } else { Toast.makeText(getApplicationContext(), "当前wu可用网络！", Toast.LENGTH_LONG).show(); File sdCardDir = Environment.getExternalStorageDirectory();//获取SDCard目录 File saveFile1 = new File(sdCardDir, "itcast.txt"); BufferedReader br = null; try { br = new BufferedReader(new FileReader(saveFile1)); String readline = ""; StringBuffer sb = new StringBuffer(); while ((readline = br.readLine()) != null) { System.out.println("readline:" + readline); sb.append(readline); } String str = sb.toString(); JSONObject jsonObject = new JSONObject(str); JSONArray jsonArray = jsonObject.getJSONArray("data"); for (int i = 0; i < jsonArray.length(); i++) { JSONObject object = jsonArray.getJSONObject(i); String title = object.getString("name"); String content = object.getString("description"); String url = object.getString("picSmall"); domainBean newsInfo = new domainBean(title, content, url); //String path = Environment.getExternalStorageDirectory() + "/" + name; //ObjectOutputStream out =new ObjectOutputStream(new FileOutputStream(path)); //out.writeObject(newsInfo); list.add(newsInfo); //新建适配器 beanAdapter = new BeanAdapter(list, MainActivity.this); //配置适配器 xListView.setAdapter(beanAdapter); br.close(); } } catch (IOException e) { e.printStackTrace(); } catch (JSONException e) { e.printStackTrace(); } }
(6)部分完整demo2
public String logoutPost(String URL){ String result = ""; try { String data = URLEncoder.encode("UTF-8"); // + "&password=" + URLEncoder.encode(password, "UTF-8");//传递的数据 URL url = new URL(URL); //2、url.openConnection()打开网络链接 HttpURLConnection conn = (HttpURLConnection) url.openConnection(); //3、设置请求的方式 conn.setRequestMethod("POST"); conn.setDoInput(true);//发送POST请求必须设置允许输出 conn.setDoOutput(true);//发送POST请求必须设置允许输入 conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded"); conn.setRequestProperty("Charset", "utf-8"); conn.setRequestProperty("Content-Length", String.valueOf(data.getBytes().length)); //5、获取输出流 OutputStream os = conn.getOutputStream(); os.write(data.getBytes()); os.flush(); BufferedReader in=new BufferedReader(new InputStreamReader(conn.getInputStream())); String line; while((line=in.readLine())!=null){result+="\n"+line;} if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){ File sdCardDir = Environment.getExternalStorageDirectory();//获取SDCard目录 File saveFile = new File(sdCardDir, "itcast.txt"); FileOutputStream outStream = new FileOutputStream(saveFile); outStream.write(result.getBytes()); outStream.close(); } } catch (UnsupportedEncodingException e) { e.printStackTrace(); } catch (ProtocolException e) { e.printStackTrace(); } catch (MalformedURLException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } return result; }
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。