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因此，我正在構建一個使用android SDK和firebase作爲後端的簡單待辦應用程序，並且一切似乎都起作用，因爲數據將添加到我的Firebase存儲中，移動設備以及數據也會被刪除，但數據只會從Firebase存儲中刪除，並不會從移動設備/屏幕上刪除，因此我如何從活動中刪除數據。Android ListView當數據在firebase被刪除時刪除
這裏是MainActivity.java
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
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 com.firebase.client.ChildEventListener;
import com.firebase.client.DataSnapshot;
import com.firebase.client.Firebase;
import com.firebase.client.FirebaseError;
import com.firebase.client.ValueEventListener;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
// Get ListView object from xml
final ListView listView = (ListView)findViewById(R.id.listView);
// Create a new Adapter
final ArrayAdapter<String> adapter = new ArrayAdapter<>(this,
android.R.layout.simple_list_item_1, android.R.id.text1);
// Assign adapter to ListView
listView.setAdapter(adapter);
// Use Firebase to populate the list.
Firebase.setAndroidContext(this);
new Firebase("https://MY-FIREBASE-APP.firebaseio.com/todoItems")
.addChildEventListener(new ChildEventListener() {
@Override
public void onChildAdded(DataSnapshot dataSnapshot, String s) {
adapter.add((String)dataSnapshot.child("text").getValue());
}
@Override
public void onChildChanged(DataSnapshot dataSnapshot, String s) {
adapter.remove((String)dataSnapshot.child("text").getValue());
}
@Override
public void onChildRemoved(DataSnapshot dataSnapshot) {
}
@Override
public void onChildMoved(DataSnapshot dataSnapshot, String s) {
}
@Override
public void onCancelled(FirebaseError firebaseError) {
}
});
// Add items via the Button and EditText at the bottom of the window.
final EditText text = (EditText)findViewById(R.id.todoText);
final Button btn = (Button)findViewById(R.id.addButton);
btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
new Firebase("https://MY-FIREBASE-APP.firebaseio.com/todoItems")
.push()
.child("text")
.setValue(text.getText().toString());
}
});
// Delete items when clicked
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, final int position, long id) {
AlertDialog.Builder adb=new AlertDialog.Builder(MainActivity.this);
adb.setTitle("Delete?");
adb.setMessage("Are you sure you want to delete " + position);
adb.setNegativeButton("Cancel", null);
adb.setPositiveButton("Ok", new AlertDialog.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
adapter.notifyDataSetChanged();
}
});
adb.show();
new Firebase("https://MY-FIREBASE-APP.firebaseio.com/todoItems")
.orderByChild("text")
.equalTo((String) listView.getItemAtPosition(position))
.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
if(dataSnapshot.hasChildren()){
DataSnapshot firstChild = dataSnapshot.getChildren().iterator().next();
firstChild.getRef().removeValue();
}
}
@Override
public void onCancelled(FirebaseError firebaseError) {}
});
}
});
}
}
的MY-火力-APP ==已經改變了我的火力點的應用程序的名字，我只是把一個佔位符那裏。
需要幫助:)
'notifyDataSetChanged（）'？ –