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Android에서 Firebase 데이터를 설정하는 방법을 배우는 중입니다. 데이터베이스에 쓸 수 있지만 읽을 수 없어 다시 내 응용 프로그램에 표시 할 수 없습니다. 내 응용 프로그램은 매우 간단합니다 (단지 현재 하나의 기본 화면이 있습니다). 나는 배움으로써 데이터가 페이지에 어떻게 표시되는지는 신경 쓰지 않습니다. 지금은 텍스트보기로 표시하려고합니다. 나는 응용 프로그램을 실행하면Firebase로 Android에서 데이터를 검색하는 데 문제가 있음
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
tools:context=".MainActivity">
<TextView
android:id="@+id/sampleTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/hello_world"/>
</LinearLayout>
, 그것은 충돌 :
package com.example.ispotrachel.myapplication;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.TextView;
import com.firebase.client.DataSnapshot;
import com.firebase.client.Firebase;
import com.firebase.client.FirebaseError;
import com.firebase.client.ValueEventListener;
import java.util.HashMap;
import java.util.Map;
public class MainActivity extends ActionBarActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Firebase.setAndroidContext(this);
Firebase ref = new Firebase("https://blistering-torch-9015.firebaseio.com");
class User {
private int birthYear;
private String fullName;
public User() {
}
public User(String fullName, int birthYear) {
this.fullName = fullName;
this.birthYear = birthYear;
}
public long getBirthYear() {
return birthYear;
}
public String getFullName() {
return fullName;
}
}
User user1 = new User("Name 1", 1982);
User user2 = new User("Name 2", 1972);
Firebase usersRef = ref.child("users");
Map<String, User> users = new HashMap<String, User>();
users.put("user1", user1);
users.put("user 2", user2);
usersRef.setValue(users);
Firebase postRef = ref.child("posts");
Map<String, String> post1 = new HashMap<String, String>();
post1.put("author", "user1");
post1.put("title", "Announcing COBOL, a New Programming Language");
postRef.push().setValue(post1);
Map<String, String> post2 = new HashMap<String, String>();
post2.put("author", "user2");
post2.put("title", "The Turing Machine");
postRef.push().setValue(post2);
ref.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot arg0) {
//System.out.println(arg0.getValue());
TextView textViewSample = (TextView) findViewById(R.id.sampleTextView);
textViewSample.setText(arg0.getValue(String.class));
}
@Override
public void onCancelled(FirebaseError firebaseError) {
System.out.println("the read failed");
}
});
}}
여기 내 activity_main.xml입니다 :
은 여기 내 주 활동 자바입니다. 여기에 로그 캣 오류 메시지는 다음과 같습니다
12-27 12:15:02.678 1895-1895/com.example.ispotrachel.myapplication I/art﹕ Not late enabling -Xcheck:jni (already on)
12-27 12:15:02.946 1895-1907/com.example.ispotrachel.myapplication I/art﹕ Background sticky concurrent mark sweep GC freed 3867(286KB) AllocSpace objects, 0(0B) LOS objects, 11% free, 1009KB/1135KB, paused 2.595ms total 117.910ms
12-27 12:15:03.317 1895-1926/com.example.ispotrachel.myapplication D/OpenGLRenderer﹕ Render dirty regions requested: true
12-27 12:15:03.320 1895-1895/com.example.ispotrachel.myapplication D/﹕ HostConnection::get() New Host Connection established 0xa6667e80, tid 1895
12-27 12:15:03.327 1895-1895/com.example.ispotrachel.myapplication D/Atlas﹕ Validating map...
12-27 12:15:03.391 1895-1926/com.example.ispotrachel.myapplication D/﹕ HostConnection::get() New Host Connection established 0xa66ef3b0, tid 1926
12-27 12:15:03.405 1895-1926/com.example.ispotrachel.myapplication I/OpenGLRenderer﹕ Initialized EGL, version 1.4
12-27 12:15:03.422 1895-1926/com.example.ispotrachel.myapplication D/OpenGLRenderer﹕ Enabling debug mode 0
12-27 12:15:03.439 1895-1926/com.example.ispotrachel.myapplication W/EGL_emulation﹕ eglSurfaceAttrib not implemented
12-27 12:15:03.439 1895-1926/com.example.ispotrachel.myapplication W/OpenGLRenderer﹕ Failed to set EGL_SWAP_BEHAVIOR on surface 0xa66b7880, error=EGL_SUCCESS
12-27 12:15:07.474 1895-1926/com.example.ispotrachel.myapplication W/EGL_emulation﹕ eglSurfaceAttrib not implemented
12-27 12:15:07.474 1895-1926/com.example.ispotrachel.myapplication W/OpenGLRenderer﹕ Failed to set EGL_SWAP_BEHAVIOR on surface 0xa66b7880, error=EGL_SUCCESS
12-27 12:15:13.993 1895-1895/com.example.ispotrachel.myapplication D/AndroidRuntime﹕ Shutting down VM
--------- beginning of crash
12-27 12:15:13.993 1895-1895/com.example.ispotrachel.myapplication E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.example.ispotrachel.myapplication, PID: 1895 com.firebase.client.FirebaseException: Failed to bounce to type
at com.firebase.client.DataSnapshot.getValue(DataSnapshot.java:196)
at com.example.ispotrachel.myapplication.MainActivity$1.onDataChange(MainActivity.java:79)
at com.firebase.client.core.ValueEventRegistration$1.run(ValueEventRegistration.java:48)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
Caused by: com.fasterxml.jackson.databind.JsonMappingException: Can not deserialize instance of java.lang.String out of START_OBJECT token
at [Source: [email protected]; line: 1, column: 1]
at com.fasterxml.jackson.databind.DeserializationContext.mappingException(DeserializationContext.java:575)
at com.fasterxml.jackson.databind.deser.std.StringDeserializer.deserialize(StringDeserializer.java:46)
at com.fasterxml.jackson.databind.deser.std.StringDeserializer.deserialize(StringDeserializer.java:11)
at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:2888)
at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2034)
at com.firebase.client.DataSnapshot.getValue(DataSnapshot.java:192)
at com.example.ispotrachel.myapplication.MainActivity$1.onDataChange(MainActivity.java:79)
at com.firebase.client.core.ValueEventRegistration$1.run(ValueEventRegistration.java:48)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)device not found
오류 메시지가 있습니까? – emecas
일하는 대신에 어떤 일이 발생합니까? (예 : 오류 메시지) –
@ispotrachel : 아래에있는 편집 링크를 클릭하여 질문에 스택 추적을 추가하십시오. 그렇게하면 더 쉽게 읽을 수있는 형식으로 서식을 지정할 수 있습니다. –