Create 0313.md

summary for 0313

Programming/basicStudy/0313.md

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+#03_13
+
+#Firebase
+
+firebase.google.com
+
+-  database - noSQL, node.js의 구조라고 보면 된다.
+key - value 의 형태
+비구조적인 계층형태
+
+```
+fir-test-66f76addclose
+ -  1
+    -  content: "내용"
+    -  ndate: "2017-03-13"
+    -  title: "제목"
+ -  2
+    -  content: "내용2"
+    -  ndate: "2017-03-14"
+    -  title: "제목2"
+```
+
+
+-  안드로이드 스튜디오 toos - firebase
+
+
+- realtime databse - save&retrieve - connect to firebase - add the realtime database to your app
+
+
+-  권한설정 ->
+firebase 웹페이지 콘솔에 들어가서 
+database - rules - learn more..
+
+
+
+>-----여기까지 database 쓰기위한 준비완료 -----
+
+
+## database 입력
+
+  -  HashMap
+
+```java
+package com.hyugnmin.android.firebaseone;
+
+import android.support.v7.app.AppCompatActivity;
+import android.os.Bundle;
+import android.view.View;
+import android.widget.Button;
+import android.widget.EditText;
+
+import com.google.firebase.database.DatabaseReference;
+import com.google.firebase.database.FirebaseDatabase;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class MainActivity extends AppCompatActivity {
+
+    Button btnSave;
+    EditText editText1, editText2;
+
+    // Write a message to the database
+    FirebaseDatabase database;
+    DatabaseReference bbsRef;
+
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_main);
+
+        database = FirebaseDatabase.getInstance();
+        bbsRef = database.getReference("bbs");
+
+
+        btnSave = (Button)findViewById(R.id.btnSave);
+        editText1 = (EditText)findViewById(R.id.editText);
+        editText2 = (EditText)findViewById(R.id.editText2);
+
+        btnSave.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View v) {
+                String title = editText1.getText().toString();
+                String content = editText2.getText().toString();
+
+                //bbs 레퍼런스(테이블)에 키를 생성
+                String key = bbsRef.push().getKey();
+                //입력될 레코드(키,값 세트)를 생성한다
+                Map<String, String> postValues = new HashMap<>();
+                postValues.put("title", title);
+                postValues.put("content", content);
+
+                //생성된 레코드를 데이터베이스에 입력
+//
+//                bbs - 키1 - title : 값
+//                            content : 값
+//                      키2 - title : 값
+//                            content : 값
+//
+
+                Map<String, Object> keyMap = new HashMap<>();
+                keyMap.put(key, postValues);
+                bbsRef.updateChildren(keyMap);
+
+            }
+        });
+
+    }
+}
+
+
+```
+  -  setValue 
+
+```java
+
+public class MainActivity extends AppCompatActivity {
+
+    Button btnSave;
+    EditText editText1, editText2;
+
+    // Write a message to the database
+    FirebaseDatabase database;
+    DatabaseReference bbsRef;
+
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_main);
+
+        database = FirebaseDatabase.getInstance();
+        bbsRef = database.getReference("bbs");
+
+
+        btnSave = (Button)findViewById(R.id.btnSave);
+        editText1 = (EditText)findViewById(R.id.editText);
+        editText2 = (EditText)findViewById(R.id.editText2);
+
+        btnSave.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View v) {
+                String title = editText1.getText().toString();
+                String content = editText2.getText().toString();
+
+                //bbs 레퍼런스(테이블)에 키를 생성
+                String key = bbsRef.push().getKey();
+                //입력될 레코드(키,값 세트)를 생성한다
+                Map<String, String> postValues = new HashMap<>();
+                postValues.put("title", title);
+                postValues.put("content", content);
+
+                //생성된 레코드를 데이터베이스에 입력
+//
+//                bbs - 키1 - title : 값
+//                            content : 값
+//                      키2 - title : 값
+//                            content : 값
+//
+                DatabaseReference keyRef = bbsRef.child(key);
+                keyRef.setValue(postValues);
+
+                DatabaseReference titleRef = bbsRef.child(key).child("title");
+                titleRef.setValue("제목입니다");
+                //트리구조를 child로 계속 타고 가서 ref를 가져와 수정할 수 있다.
+
+            }
+        });
+
+    }
+}
+
+```
+##  listView에 출력
+
+-  Main
+```java
+package com.hyugnmin.android.firebaseone;
+
+import android.support.v7.app.AppCompatActivity;
+import android.os.Bundle;
+import android.util.Log;
+import android.view.View;
+import android.widget.Button;
+import android.widget.EditText;
+import android.widget.ListView;
+
+import com.google.firebase.database.DataSnapshot;
+import com.google.firebase.database.DatabaseError;
+import com.google.firebase.database.DatabaseReference;
+import com.google.firebase.database.FirebaseDatabase;
+import com.google.firebase.database.ValueEventListener;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+public class MainActivity extends AppCompatActivity {
+
+    Button btnSave;
+    EditText editText1, editText2;
+
+    // Write a message to the database
+    FirebaseDatabase database;
+    DatabaseReference bbsRef;
+
+    ListView listView;
+    ListAdapter listAdapter;
+    List<Bbs> datas = new ArrayList<>();
+
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_main);
+
+        database = FirebaseDatabase.getInstance();
+        bbsRef = database.getReference("Bbs");
+
+        listView = (ListView)findViewById(R.id.listView);
+        listAdapter = new ListAdapter(datas, this);
+        listView.setAdapter(listAdapter);
+
+
+        btnSave = (Button)findViewById(R.id.btnSave);
+        editText1 = (EditText)findViewById(R.id.editText);
+        editText2 = (EditText)findViewById(R.id.editText2);
+
+        btnSave.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View v) {
+                String title = editText1.getText().toString();
+                String content = editText2.getText().toString();
+
+                //Bbs 레퍼런스(테이블)에 키를 생성
+                String key = bbsRef.push().getKey();
+                //입력될 레코드(키,값 세트)를 생성한다
+                Map<String, String> postValues = new HashMap<>();
+                postValues.put("title", title);
+                postValues.put("content", content);
+
+                //생성된 레코드를 데이터베이스에 입력
+//
+//                Bbs - 키1 - title : 값
+//                            content : 값
+//                      키2 - title : 값
+//                            content : 값
+//
+                DatabaseReference keyRef = bbsRef.child(key);
+                keyRef.setValue(postValues);
+//
+//                DatabaseReference titleRef = bbsRef.child(key).child("title");
+//                titleRef.setValue("제목입니다");
+//                //트리구조를 child로 계속 타고 가서 ref를 가져와 수정할 수 있다.
+
+            }
+        });
+
+        bbsRef.addValueEventListener(postListener);
+
+    }
+
+    ValueEventListener postListener = new ValueEventListener() {
+        @Override
+        public void onDataChange(DataSnapshot dataSnapshot) {
+            // Get Post object and use the values to update the UI
+//            Post post = dataSnapshot.getValue(Post.class);
+            // ...
+            Log.w("MainActivity", "data count = " + dataSnapshot.getChildrenCount());
+
+            datas.clear();
+
+            for(DataSnapshot snapshot : dataSnapshot.getChildren()) {
+                String key = snapshot.getKey();
+                Bbs bbs = snapshot.getValue(Bbs.class); //컨버팅
+                bbs.key = key;
+                datas.add(bbs);
+            }
+            listAdapter.notifyDataSetChanged();
+        }
+
+        @Override
+        public void onCancelled(DatabaseError databaseError) {
+            // Getting Post failed, log a message
+            Log.w("MainActivity", "loadpost : OnCancelled", databaseError.toException());
+            // ...
+        }
+    };
+}
+
+
+```
+
+- listAdapter
+
+```java
+package com.hyugnmin.android.firebaseone;
+
+import android.content.Context;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.BaseAdapter;
+import android.widget.TextView;
+
+import java.util.List;
+
+/**
+ * Created by besto on 2017-03-13.
+ */
+
+public class ListAdapter extends BaseAdapter {
+
+    List<Bbs> datas;
+    Context context;
+    LayoutInflater inflater;
+    View view;
+
+    public ListAdapter(List<Bbs> datas, Context context) {
+        this.datas = datas;
+        this.context = context;
+        this.inflater = (LayoutInflater)context.getSystemService(context.LAYOUT_INFLATER_SERVICE);
+    }
+
+    @Override
+    public int getCount() {
+        return datas.size();
+    }
+
+    @Override
+    public Object getItem(int position) {
+        return datas.get(position);
+    }
+
+    @Override
+    public long getItemId(int position) {
+        return position;
+    }
+
+    @Override
+    public View getView(int position, View convertView, ViewGroup parent) {
+        if(convertView == null)
+        convertView = inflater.inflate(R.layout.list_item, null);
+
+        TextView textTitle = (TextView)convertView.findViewById(R.id.textTitle);
+        TextView textContent= (TextView)convertView.findViewById(R.id.textContent);
+
+        Bbs bbs = datas.get(position);
+        textTitle.setText(bbs.title);
+        textContent.setText(bbs.content);
+
+        return convertView;
+    }
+}
+
+
+```
+
+-  Bbs
+
+```java
+
+package com.hyugnmin.android.firebaseone;
+
+/**
+ * Created by besto on 2017-03-13.
+ */
+
+public class Bbs {
+    public String key;
+    public String title;
+    public String content;
+
+    public String getTitle() {
+        return title;
+    }
+
+    public void setTitle(String title) {
+        this.title = title;
+    }
+
+    public String getContent() {
+        return content;
+    }
+
+    public void setContent(String content) {
+        this.content = content;
+    }
+}
+
+```
+
+