之前让我的应用程序完美地，现在它已经不断崩溃，因为我试图添加额外的，但功能几乎相同。通过额外的功能，我的意思是编辑文本，旋转器等。这非常令人沮丧，因为它显然是非常小的似乎是问题。
我的LogCat显示我的Property类的第114行出现错误，但是，我无法理解为什么这会出现问题，因为它在实现添加功能之前不会影响应用程序。
LogCat
02-26 21:19:20.424 9478-9478/com.example.benchalmers.myapplication E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.benchalmers.myapplication, PID: 9478
com.google.firebase.database.DatabaseException: Class com.example.benchalmers.myapplication.Property does not define a no-argument constructor. If you are using ProGuard, make sure these constructors are not stripped.
at com.google.android.gms.internal.zzelx.zze(Unknown Source:51)
at com.google.android.gms.internal.zzelw.zzb(Unknown Source:772)
at com.google.android.gms.internal.zzelw.zza(Unknown Source:0)
at com.google.firebase.database.DataSnapshot.getValue(Unknown Source:10)
at com.example.benchalmers.myapplication.PropertyActivity$4.onDataChange(PropertyActivity.java:114)
at com.google.android.gms.internal.zzegf.zza(Unknown Source:13)
at com.google.android.gms.internal.zzeia.zzbyc(Unknown Source:2)
at com.google.android.gms.internal.zzeig.run(Unknown Source:65)
at android.os.Handler.handleCallback(Handler.java:790)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6494)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
02-26 21:19:20.425 9478-9478/com.example.benchalmers.myapplication E/UncaughtException: com.google.firebase.database.DatabaseException: Class com.example.benchalmers.myapplication.Property does not define a no-argument constructor. If you are using ProGuard, make sure these constructors are not stripped.
at com.google.android.gms.internal.zzelx.zze(Unknown Source:51)
at com.google.android.gms.internal.zzelw.zzb(Unknown Source:772)
at com.google.android.gms.internal.zzelw.zza(Unknown Source:0)
at com.google.firebase.database.DataSnapshot.getValue(Unknown Source:10)
at com.example.benchalmers.myapplication.PropertyActivity$4.onDataChange(PropertyActivity.java:114)
at com.google.android.gms.internal.zzegf.zza(Unknown Source:13)
at com.google.android.gms.internal.zzeia.zzbyc(Unknown Source:2)
at com.google.android.gms.internal.zzeig.run(Unknown Source:65)
at android.os.Handler.handleCallback(Handler.java:790)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6494)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
在进行这些更改之前，我能够完美地添加，更新和删除记录，没有任何打嗝。这就是让我相信我遇到的问题很容易解决的原因。
当屏幕加载1秒后，它几乎立即崩溃。
我对变量名等做了一些小改动，认为这可能有所帮助，但无济于事。
对此的任何帮助将不胜感激。我是Android的新手，还有Stack！第一篇文章！
PropertyActivity.java
package com.example.benchalmers.myapplication;
import android.content.Intent;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;
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.List;
public class PropertyActivity extends AppCompatActivity {
public static final String PROPERTY_NAME = "propertyname";
public static final String PROPERTY_ID = "propertyid";
EditText editTextProperty;
EditText editTextPostcode;
EditText editTextBedrooms;
EditText editTextBathrooms;
Button buttonAddProperty;
Spinner spinnerFuel;
Spinner spinnerStatus;
Spinner spinnerEPC;
DatabaseReference databaseProperties;
ListView listViewProperties;
List<Property> propertyList;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_property);
databaseProperties = FirebaseDatabase.getInstance().getReference("properties");
editTextProperty = (EditText) findViewById(R.id.editTextProperty);
editTextPostcode = (EditText) findViewById(R.id.editTextPostcode);
editTextBedrooms = (EditText) findViewById(R.id.editTextBedrooms);
editTextBathrooms = (EditText) findViewById(R.id.editTextBathrooms);
buttonAddProperty = (Button) findViewById(R.id.buttonAddProperty);
spinnerStatus = (Spinner) findViewById(R.id.spinnerStatus);
spinnerEPC = (Spinner) findViewById(R.id.spinnerEPC);
spinnerFuel = (Spinner) findViewById(R.id.spinnerFuel);
listViewProperties = (ListView) findViewById(R.id.listViewProperties);
propertyList = new ArrayList<>();
buttonAddProperty.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
addProperty();
}
});
listViewProperties.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> adapterView, View view, int position, long id) {
Property property = propertyList.get(position);
Intent intent = new Intent(getApplicationContext(), AddTenantsActivity.class);
intent.putExtra(PROPERTY_ID, property.getPropertyId());
intent.putExtra(PROPERTY_NAME, property.getPropertyAddress());
startActivity(intent);
}
});
listViewProperties.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
@Override
public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
Property property = propertyList.get(position);
showUpdateDialog(property.getPropertyId(), property.getPropertyAddress(), property.getPropertyPostcode(), property.getPropertyBedrooms(), property.getPropertyBathrooms(), property.getPropertyStatus(), property.getPropertyEPC(), property.getPropertyFuel());
return false;
}
});
}
@Override
protected void onStart() {
super.onStart();
databaseProperties.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
propertyList.clear();
for(DataSnapshot propertySnapshot : dataSnapshot.getChildren()){
Property property = propertySnapshot.getValue(Property.class);
propertyList.add(property);
}
PropertyList adapter = new PropertyList (PropertyActivity.this, propertyList);
listViewProperties.setAdapter(adapter);
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
private void showUpdateDialog(final String id, String propertyAddress, String propertyPostcode, String propertyBedrooms, String propertyBathrooms, String propertyStatus, final String propertyId, String propertyName) {
AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(this);
LayoutInflater inflater = getLayoutInflater();
final View dialogView = inflater.inflate(R.layout.update_dialog, null);
dialogBuilder.setView(dialogView);
final EditText editTextName = (EditText) dialogView.findViewById(R.id.editTextName);
final Button buttonUpdate = (Button) dialogView.findViewById(R.id.buttonUpdate);
final Spinner spinnerFuel = (Spinner) dialogView.findViewById(R.id.spinnerFuel);
final Button buttonDelete = (Button) dialogView.findViewById(R.id.buttonDelete);
dialogBuilder.setTitle("Updating Property " + propertyName);
final AlertDialog alertDialog = dialogBuilder.create();
alertDialog.show();
buttonUpdate.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String name = editTextName.getText().toString().trim();
String postcode = editTextPostcode.getText().toString().trim();
String bedrooms = editTextBedrooms.getText().toString().trim();
String bathrooms = editTextBathrooms.getText().toString().trim();
String status = spinnerStatus.getSelectedItem().toString();
String epc = spinnerEPC.getSelectedItem().toString();
String fuel = spinnerFuel.getSelectedItem().toString();
if(TextUtils.isEmpty(name)){
editTextName.setError("Name Required");
return;
}
updateProperty(propertyId, status, postcode, bedrooms, bathrooms, id, name, epc, fuel);
alertDialog.dismiss();
}
});
buttonDelete.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
deleteProperty(propertyId);
}
});
}
private void deleteProperty(String propertyId) {
DatabaseReference drProperty = FirebaseDatabase.getInstance().getReference("properties").child(propertyId);
DatabaseReference drTenants = FirebaseDatabase.getInstance().getReference("tenants").child(propertyId);
drProperty.removeValue();
drTenants.removeValue();
Toast.makeText(this, "Property has been deleted", Toast.LENGTH_LONG).show();
}
private boolean updateProperty(String propertyId, String status, String postcode, String bedrooms, String bathrooms, String id, String name, String epc, String fuel){
DatabaseReference databaseReference = FirebaseDatabase.getInstance().getReference("properties").child(id);
Property property = new Property (id, name, postcode, bedrooms, bathrooms, status, epc, fuel);
databaseReference.setValue(property);
Toast.makeText(this, "Property Updated Successfully", Toast.LENGTH_LONG).show();
return true;
}
private void addProperty(){
String address = editTextProperty.getText().toString().trim();
String postcode = editTextPostcode.getText().toString().trim();
String bedrooms = editTextBedrooms.getText().toString().trim();
String bathrooms = editTextBathrooms.getText().toString().trim();
String status = spinnerStatus.getSelectedItem().toString();
String epc = spinnerEPC.getSelectedItem().toString();
String fuel = spinnerFuel.getSelectedItem().toString();
if(!TextUtils.isEmpty(address)){
String id = databaseProperties.push().getKey();
Property property = new Property (id, address, postcode, bedrooms, bathrooms, status, epc, fuel);
databaseProperties.child(id).setValue(property);
Toast.makeText(this, "Property Added", Toast.LENGTH_LONG).show();
}else {
Toast.makeText(this, "You must enter a property", Toast.LENGTH_LONG).show();
}
}
}
Property.java
package com.example.benchalmers.myapplication;
/**
* Created by benchalmers on 21/02/2018.
*/
public class Property {
String propertyId;
String propertyAddress;
String propertyPostcode;
String propertyFuel;
String propertyBedrooms;
String propertyBathrooms;
String propertyEPC;
String propertyStatus;
public Property(String id, String address, String postcode, String bedrooms, String bathrooms, String status, String epc, String fuel ) {
this.propertyId = propertyId;
this.propertyAddress = propertyAddress;
this.propertyPostcode = postcode;
this.propertyFuel = propertyFuel;
this.propertyBedrooms = bedrooms;
this.propertyBathrooms = bathrooms;
this.propertyEPC = epc;
this.propertyStatus = status;
}
public String getPropertyId() {
return propertyId;
}
public String getPropertyAddress() {
return propertyAddress;
}
public String getPropertyPostcode() {
return propertyPostcode;
}
public String getPropertyFuel() {
return propertyFuel;
}
public String getPropertyBedrooms() {
return propertyBedrooms;
}
public String getPropertyBathrooms() {
return propertyBathrooms;
}
public String getPropertyEPC() {
return propertyEPC;
}
public String getPropertyStatus() {
return propertyStatus;
}
}
PropertyList.java
package com.example.benchalmers.myapplication;
import android.app.Activity;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;
import java.util.List;
public class PropertyList extends ArrayAdapter<Property> {
private Activity context;
private List<Property> propertyList;
public PropertyList(Activity context, List<Property> propertyList) {
super(context, R.layout.property_list_layout, propertyList);
this.context = context;
this.propertyList = propertyList;
}
@NonNull
@Override
public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
LayoutInflater inflater = context.getLayoutInflater();
View listViewItem = inflater.inflate(R.layout.property_list_layout, null, true);
TextView textViewProperty = (TextView) listViewItem.findViewById(R.id.textViewProperty);
TextView textViewPostcode = (TextView) listViewItem.findViewById(R.id.textViewPostcode);
TextView textViewBedrooms = (TextView) listViewItem.findViewById(R.id.textViewBedrooms);
TextView textViewBathrooms = (TextView) listViewItem.findViewById(R.id.textViewBathrooms);
TextView textViewStatus = (TextView) listViewItem.findViewById(R.id.textViewStatus);
TextView textViewEPC = (TextView) listViewItem.findViewById(R.id.textViewEPC);
TextView textViewFuel = (TextView) listViewItem.findViewById(R.id.textViewFuel);
Property property = propertyList.get(position);
textViewProperty.setText(property.getPropertyAddress());
textViewPostcode.setText(property.getPropertyPostcode());
textViewBedrooms.setText(property.getPropertyBedrooms());
textViewBathrooms.setText(property.getPropertyBathrooms());
textViewStatus.setText(property.getPropertyStatus());
textViewEPC.setText(property.getPropertyEPC());
textViewFuel.setText(property.getPropertyFuel());
return listViewItem;
}
}
答案 0 :(得分：0)
Firebase需要Property类中的无参数构造函数，以便您可以使用getValue(Property.class)。因此，将此构造函数添加到Property类：
public Property() {}