我正在应用为我的开发团队,我想补充的应用程序版本编辑所有登录与火力实时数据库的用户,我使用的代码访问火力地堡实时数据库值
appIdEndPoint = mDatabase.child("users").child(user.getUid()).child("app").child("id");
appVersionEndPoint = mDatabase.child("users").child(user.getUid()).child("app").child("latest_version");
uid_text.setText("User firebase ID: " + user.getUid());
appIdEndPoint.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
appDetails address = dataSnapshot.getValue(appDetails.class);
if (address.getID().equals("")){
appIdEndPoint.setValue(getRandom(1000, 9999));
}
appid_text.setText("App ID: " + address.getID());
appid_edittext.setText(address.getID());
}
@Override
public void onCancelled(DatabaseError databaseError) {
Log.d("AppID", databaseError.getMessage());
Toast.makeText(AppDetailsEditor.this, "Failed to fetch data from database", Toast.LENGTH_LONG);
finish();
}
});
appVersionEndPoint.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
appDetails address = dataSnapshot.getValue(appDetails.class);
if (address.getVersion().equals("")){
appVersionEndPoint.setValue("Waiting for developers input");
}
appversion_text.setText("App version: " + address.getVersion());
appversion_edittext.setText(address.getVersion());
}
@Override
public void onCancelled(DatabaseError databaseError) {
Log.d("AppVersion", databaseError.getMessage());
Toast.makeText(AppDetailsEditor.this, "Failed to fetch data from database", Toast.LENGTH_LONG);
finish();
}
});
我试图用“ String appID = dataSnapshot.getValue()。toString();“但它产生java.lang.NullPointerException错误。请有人编辑我的代码来获取数据库值? 这里是 “appDetails.java” 类:
public class appDetails {
public String ID = "";
public String version = "";
public appDetails(){
}
public appDetails(String ID, String version){
this.ID = ID;
this.version = version;
}
public String getID(){
return ID;
}
public String getVersion(){
return version;
}
}
编辑:
代码显示上面也产生错误显示java.lang.NullPointerException
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