什么可能导致失败的反弹类型？ [英] What could be causing the failed bounce to type?

问题描述

我正在使用Firebase，并试图通过我的Android应用程序显示来自Firebase的数据。然而，当我运行的应用程序，它崩溃，logcat说未能反弹类型。我在Java类中模拟了JSON结构的属性。

这是MainActivity：

  @Override 
保护无效的onCreate（Bundle savedInstanceState）{
 super.onCreate（savedInstanceState）; 
 setContentView（R.layout.activity_main）; 
 Firebase.setAndroidContext（this）; 
 Firebase ref =新的Firebase（https://fbandg.firebaseio.com/）; 
 android.R.layout.simple_list_item_1，android.R.id.text1）; 
 final TextView textbox =（TextView）findViewById（R.id.textbox）; 
 Firebase.setAndroidContext（this）; 
 ValueEventListener newCon = ref.addValueEventListener（new ValueEventListener（）{
 @Override 
 public void onDataChange（DataSnapshot dataSnapshot）{
 fObject obj = dataSnapshot.getValue（fObject.class）; //第49行
 textbox.setText（obj.toString（））; 
 
 $ b @Override 
 public void onCancelled（FirebaseError firebaseError）{
 
} 
}）; 
  

这是我创建的Java类：

  public class fObject 
 {
 String newCond; 
 public String getCondition（）
 {
 return newCond; 
 
 
 code 
 $ b 
产生的错误如下：
  firebase.client.DataSnapshot.getValue（DataSnapshot.java:183）
 com.example.elish_000.myfirstapp.MainActivity $ 1.onDataChange （MainActivity.java:49）
  
 
 
解决方案
 / b> 
 
 
  @Override 
保护无效的onCreate（Bundle savedInstanceState）{
 
 super.onCreate（savedInstanceState ）; 
 setContentView（R.layout.activity_main）; 
 Firebase.setAndroidContext（this）; 
 Firebase ref =新的Firebase（https://fbandg.firebaseio.com）; 
 final TextView textbox =（TextView）findViewById（R.id.textbox）; 
 ref.addValueEventListener（new ValueEventListener（）{
 @Override 
 public void onDataChange（DataSnapshot dataSnapshot）{
 
 fObject fobject = new fObject（）; 
 fobject.setNewCondition（dataSnapshot.child（condition）。getValue（）。toString（））; 
 textbox.setText（fobject.getNewCondition（））; 
} 
 
 @Override 
 public void onCancelled（FirebaseError firebaseError）{
 
 
}）; 
  
修改您的fObject类，
 
 
  public class fObject 
 {
 String newCond; 
 public String getNewCond（）
 {
 return newCond; 
} 
 
 public void setNewCond（String cond）
 {
 newCond = cond; 
} 
} 
  
 
I am using Firebase, and I am trying to show data from Firebase through my Android app. Yet, when I run the app, it crashes and logcat says "failed to bounce to type". I mimicked the properties of the JSON structure in a java class.



Here is the MainActivity: 
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Firebase.setAndroidContext(this);
    Firebase ref = new Firebase("https://fbandg.firebaseio.com/");
    android.R.layout.simple_list_item_1, android.R.id.text1);
    final TextView textbox = (TextView) findViewById(R.id.textbox);
    Firebase.setAndroidContext(this);
    ValueEventListener newCon = ref.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            fObject obj = dataSnapshot.getValue(fObject.class); //Line 49
            textbox.setText(obj.toString());
        }

        @Override
        public void onCancelled(FirebaseError firebaseError) {

        }
    });
Here is the Java class I created:
public class fObject
{
    String newCond;
    public String getCondition()
    {
        return newCond;
    }
}
The errors produced are the following:
firebase.client.DataSnapshot.getValue(DataSnapshot.java:183)
com.example.elish_000.myfirstapp.MainActivity$1.onDataChange(MainActivity.java:49)

解决方案
Try this,
@Override
protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Firebase.setAndroidContext(this);
Firebase ref = new Firebase("https://fbandg.firebaseio.com");
final TextView textbox = (TextView) findViewById(R.id.textbox);
ref.addValueEventListener(new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {

        fObject fobject = new fObject();
        fobject.setNewCondition(dataSnapshot.child("condition").getValue().toString());
        textbox.setText(fobject.getNewCondition());
    }

    @Override
    public void onCancelled(FirebaseError firebaseError) {

    }
});
modify your fObject class,
public class fObject
{
    String newCond;
    public String getNewCond()
    {
        return newCond;
    }

    public void setNewCond(String cond)
    {
        newCond = cond;
    }
}


                        
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