Shulou(Shulou.com)06/02 Report--

This article mainly introduces "what is the method of Android development file storage". In the daily operation, I believe that many people have doubts about the method of Android development file storage. Xiaobian consulted all kinds of materials and sorted out simple and easy-to-use operation methods. I hope it will be helpful to answer the doubts of "what is the method of Android development file storage?" Next, please follow the editor to study!

Android's file storage, which is stored in the way of Ihammer O stream, like java, also has a SharePreferences storage method of Android's own.

Let's look at an example:

Use the SharePreferences O-stream storage method and the QQ storage method to store the QQ account number and password. When you enter the page again, the account password stored in the file is displayed on it.

Activity_main.xml

MainActivity.java

Package com.example.saveqq;import androidx.appcompat.app.AppCompatActivity;import android.os.Bundle;import android.text.TextUtils;import android.view.View;import android.widget.Button;import android.widget.EditText;import android.widget.Toast;import java.util.Map;public class MainActivity extends AppCompatActivity implements View.OnClickListener {private EditText user; private EditText password; private Button button; @ Override protected void onCreate (Bundle savedInstanceState) {super.onCreate (savedInstanceState) SetContentView (R.layout.activity_main); / / 1. Initialize view initView (); / / 2. If the user has saved the information, write back the data / / SharedPreferences O-stream method Map userInfo = FileSaveQQ.getUserInfo (this); / / SharedPreferences method / * Map userInfo = SpSaveQQ.getUserInfo (this); * / if ((userInfographic null)) {user.setText (userInfo.get ("user")); password.setText (userInfo.get ("password")) }} private void initView () {/ / initialization of the control user = (EditText) findViewById (R.id.et_number); password = (EditText) findViewById (R.id.et_password); button = (Button) findViewById (R.id.btn_login); / / 2. Set button click event button.setOnClickListener (this);} @ Override public void onClick (View v) {/ / 1. Click to get the account password String s_user = user.getText (). ToString (). Trim (); String s_password = password.getText (). ToString (). Trim (); / / 2. Check whether the username and password are empty if (TextUtils.isEmpty (s_user)) {Toast.makeText (this, "Please enter QQ account", Toast.LENGTH_LONG). Show (); return;} if (TextUtils.isEmpty (s_password)) {Toast.makeText (this, "Please enter QQ password", Toast.LENGTH_LONG). Show (); return } Toast.makeText (this, "login succeeded", Toast.LENGTH_LONG). Show (); / / 3. Boolean isSaveSuccess = FileSaveQQ.saveUserInfo (this,s_user,s_password) for saving user information / / SharedPreferences method / * boolean isSaveSuccess = SpSaveQQ.saveUserInfo (this,s_user,s_password); * / if (isSaveSuccess) {Toast.makeText (this, "saved successfully", Toast.LENGTH_LONG). Show () } else {Toast.makeText (this, "Save failed", Toast.LENGTH_LONG) .show ();}

Using the iUnistream method

FileSaveQQ.java

Package com.example.saveqq;import android.content.Context;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import java.util.HashMap;import java.util.Map;public class FileSaveQQ {/ / Save QQ account and password to data.txt public static boolean saveUserInfo (Context context,String user,String password) {try {/ / 1. Get the file output stream FileOutputStream fos = context.openFileOutput ("data.txt", context.MODE_APPEND); / / 2. Write the data to the file fos.write ((user+ ":" + password). GetBytes ()); fos.close (); return true;} catch (IOException e) {e.printStackTrace (); return false;}} public static Map getUserInfo (Context context) {String content = "" Try {FileInputStream fis = context.openFileInput ("data,txt"); byte [] buffer = new byte [fis.available ()]; fis.read (buffer); Map userMap = new HashMap (); content = new String (buffer); String [] infos = content.split (":"); userMap.put ("user", infos [0]) UserMap.put ("password", infos [1]); fis.close (); return userMap;} catch (IOException e) {return null;}

Using the method of SharedPreferences

SpSaveQQ.java

Package com.example.saveqq;import android.annotation.SuppressLint;import android.content.Context;import android.content.SharedPreferences;import java.util.HashMap;import java.util.Map;// saves QQ account and password to data.xml public class SpSaveQQ {public static boolean saveUserInfo (Context context,String username,String password) {SharedPreferences sp = context.getSharedPreferences ("data", context.MODE_PRIVATE); SharedPreferences.Editor editor = sp.edit (); editor.putString ("username", username) Editor.putString ("password", password); editor.commit (); return true;} / / obtain the stored QQ account and password public static Map getUserInfo (Context context) {SharedPreferences sp = context.getSharedPreferences ("data", context.MODE_PRIVATE); String username = sp.getString ("username", ""); String password = sp.getString ("password", "") Map userMap = new HashMap (); userMap.put ("username", username); userMap.put ("password", password); return userMap;}}

Run the screenshot:

Re-enter the page:

At this point, the study on "what is the method of Android development file storage" is over. I hope to be able to solve your doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.