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標題: android SharedPreferences存儲數據 [打印本頁]

作者: 2313536951 時間: 2020-12-17 21:09
標題: android SharedPreferences存儲數據
MainActivity.java:
package com.example.android9;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {
private SharedPreferences preferences = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);//加載布局文件
      //獲取ui控件
      Button btn_set=findViewById(R.id.btn_set);
      //按鈕點擊事件
      btn_set.setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View v) {
            //創建意圖
            Intent intent = new Intent(MainActivity.this, MainActivity2.class);
            startActivity(intent);//開啟意圖
         }
      });
}
//重寫onStart（）函數
@Override
protected void onStart() {
      super.onStart();//繼承
      //指定該SharedPreferences數據只能被本應用程序讀寫
      preferences = getSharedPreferences("crazyit", Context.MODE_PRIVATE);
      //讀取字符數據
      String user = preferences.getString("user", "");
      //獲取textview控件
      TextView tx = findViewById(R.id.tx);
      //設置顯示內容
      tx.setText("歡迎 " + user + " 來到我的家園");
}
}package com.example.android9;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {
private SharedPreferences preferences = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);//加載布局文件
      //獲取ui控件
      Button btn_set=findViewById(R.id.btn_set);
      //按鈕點擊事件
      btn_set.setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View v) {
            //創建意圖
            Intent intent = new Intent(MainActivity.this, MainActivity2.class);
            startActivity(intent);//開啟意圖
         }
      });
}
//重寫onStart（）函數
@Override
protected void onStart() {
      super.onStart();//繼承
      //指定該SharedPreferences數據只能被本應用程序讀寫
      preferences = getSharedPreferences("crazyit", Context.MODE_PRIVATE);
      //讀取字符數據
      String user = preferences.getString("user", "");
      //獲取textview控件
      TextView tx = findViewById(R.id.tx);
      //設置顯示內容
      tx.setText("歡迎 " + user + " 來到我的家園");
}
}
MainActivity2.java:
package com.example.android9;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Context;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class MainActivity2 extends AppCompatActivity {
private SharedPreferences preferences = null;
private SharedPreferences.Editor editor = null;

@Override
protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      //加載布局文件
      setContentView(R.layout.activity_main2);
      //利用SharedPreferences讀取數據并顯示
      preferences = getSharedPreferences("crazyit", Context.MODE_PRIVATE);
      //獲取haredPreferences.Editor對象，嘗試寫數據
      editor = preferences.edit();
      //為“確定”按鈕綁定監聽器
      Button btn_ok = findViewById(R.id.btn);
      final EditText tv = findViewById(R.id.tv);
      btn_ok.setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View v) {
            String user = tv.getText().toString();
            editor.putString("user", user);
            editor.apply();
            finish();
         }
      });
}
}
activity_main.xml:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity" >

<TextView
      android:id="@+id/tx"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_marginStart="43dp"
      android:layout_marginLeft="43dp"
      android:layout_marginTop="31dp"
      android:textSize="22dp"
      android:text="歡迎  來到我的家園" />
<Button
      android:id="@+id/btn_set"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_below="@id/tx"
      android:layout_marginLeft="130dp"
      android:textSize="22dp"
      android:text="參數設置"/>
</RelativeLayout>
activity_main2.xml:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity2">
<TextView
      android:id="@+id/tx2"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="請輸入用戶名："
      android:textSize="28dp" />

<EditText
      android:id="@+id/tv"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_below="@+id/tx2"
      android:inputType="text"
      android:ems="9"
      android:textColorHighlight="@color/colorAccent"
      android:textSize="28dp" />
<Button
      android:id="@+id/btn"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_below="@id/tv"
      android:textSize="28dp"
      android:layout_marginLeft="100dp"
      android:text="確定"/>

</RelativeLayout>

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