[ Android Stubio ] 連線Firebase之Realtime Database 實時數據庫與新增修改刪除的方法

一、Firebase 之 Save and retrieve data 說明

1. Connect your app to Firebase 將您的應用程序連接到Firebase


2. Add the Realtime Database to your app 將實時數據庫添加到您的應用程序

3. Configure Firebase Database Rules 配置Firebase數據庫規則

4. Write to your database 寫入數據庫

FirebaseDatabase database = FirebaseDatabase.getInstance();
DatabaseReference myRef = database.getReference("message");

myRef.setValue("Hello, World!");

5. Read from your database 從數據庫中讀取

 @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        // This method is called once with the initial value and again
        // whenever data at this location is updated.
        String value = dataSnapshot.getValue(String.class);
        Log.d(TAG, "Value is: " + value);
    }

    @Override
    public void onCancelled(DatabaseError error) {
        // Failed to read value
        Log.w(TAG, "Failed to read value.", error.toException());
    }
});

6. Optional：Configure ProGuard 可選：配置ProGuard

# Add this global rule
-keepattributes Signature

# This rule will properly ProGuard all the model classes in
# the package com.yourcompany.models. Modify to fit the structure
# of your app.
-keepclassmembers class com.yourcompany.models.** {
  *;
}

7. Prepare for Launch 準備發射

8. Next Steps


二、語法說明：
1. 屬性：
getParent 得到父
getRoot 獲得根
getRepo()：獲取回購
getSpec 獲得規格 
getRef 獲得參考

setPriority 優先權 

setValue(值,priority 優先權);

addValueEventListener 添加值事件監聽器addChildEventListener 添加子事件監聽器addListenerForSingleValueEvent();為單值事件添加偵聽器

orderByPriority 優先順序 

push 推

2. 讀取資料的方法：

for (DataSnapshot ds : dataSnapshot.getChildren()) {
//=====
}

三、影片教學：