我遇到的问题是，我items上的新ArrayList（在另一个Activity中创建并通过Intent发送到主要活动中）替换旧的Main Activity而不是添加，所以我始终只显示一个项目。这是我的public class AssetsOverview extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener {
protected List<Transaction> myTransactions = new ArrayList<Transaction>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_assets_overview);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fabplus = (FloatingActionButton) findViewById(R.id.fabAdd);
fabplus.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
startActivity(new Intent(AssetsOverview.this, AddMoneyTransaction.class));
}
});
FloatingActionButton fabminus = (FloatingActionButton) findViewById(R.id.fabRemove);
fabminus.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
startActivity(new Intent(AssetsOverview.this, RemoveMoneyTransaction.class));
}
});
FloatingActionButton fabhint = (FloatingActionButton) findViewById(R.id.fabHint);
fabhint.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
startActivity(new Intent(AssetsOverview.this, HintMoneyTransaction.class));
}
});
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.setDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
//transaction list
populateTransactionList();
populateListView();
//set a value to the balance variable
float startBalance = 0;
//calculate and set current (actual) balance
TextView balance_view = (TextView) findViewById(R.id.balance_view);
balance_view.setText(startBalance + " $");
}
//populated transaction list
protected void populateTransactionList() {
myTransactions.add(new Transaction(78,98,"halo"));
}
//populated list view
private void populateListView() {
ArrayAdapter<Transaction> adapter = new LastTransactionsListAdapter();
ListView list = (ListView) findViewById(R.id.last_transactions_listView);
list.setAdapter(adapter);
}
private class LastTransactionsListAdapter extends ArrayAdapter<Transaction>{
public LastTransactionsListAdapter(){
super(AssetsOverview.this, R.layout.transaction_list_view, myTransactions);
}
@Override
public View getView(int position, View convertView, ViewGroup parent){
//make sure there is a view to work with (may null)
View itemView = convertView;
if (itemView == null){
itemView = getLayoutInflater().inflate(R.layout.transaction_list_view, parent, false);
}
if(getIntent().getExtras() !=null) {
Intent depositIntent = getIntent();
Transaction deposit = depositIntent.getParcelableExtra("data");
assert false;
Float newVal = deposit.getValue();
String newDes = deposit.getDescription();
Integer newDat = deposit.getTransaction_Date();
//find a transaction to work with
Transaction currentTransaction = myTransactions.get(position);
// fill the view:
// value
TextView valueView = (TextView) itemView.findViewById(R.id.transactionValueView);
valueView.setText(newVal + "$");
// date
TextView dateView = (TextView) itemView.findViewById(R.id.transactionDateView);
dateView.setText(newDat + "");
// description
TextView descriptionView = (TextView) itemView.findViewById(R.id.transactionDesciptionView);
descriptionView.setText(newDes);
}
return itemView;
}
}
@Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
super.onBackPressed();
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.assets_overview, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
// Handle navigation view item clicks here.
int id = item.getItemId();
if (id == R.id.nav_camera) {
// Handle the camera action
} else if (id == R.id.nav_gallery) {
} else if (id == R.id.nav_slideshow) {
} else if (id == R.id.nav_manage) {
} else if (id == R.id.nav_share) {
} else if (id == R.id.nav_send) {
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
：
Activity这是我public class AddMoneyTransaction extends AppCompatActivity implements View.OnClickListener {
Button addDepositButton;
EditText depositInput, depositInputDate, depositInputNote;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add_money_transaction);
//setup the Button and EditText
addDepositButton = (Button)findViewById(R.id.addDepositButton);
depositInput = (EditText) findViewById(R.id.depositInput);
depositInputDate = (EditText) findViewById(R.id.depositInputDate);
depositInputNote = (EditText) findViewById(R.id.depositInputNote);
//get the onClickListener
addDepositButton.setOnClickListener(this);
}
@Override
public void onClick(View view) {
Intent depositIntent = new Intent(AddMoneyTransaction.this, AssetsOverview.class);
Transaction deposit = new Transaction(100, 16, "random comment");
deposit.setValue(Float.parseFloat(depositInput.getText().toString()));
deposit.setTransaction_Date(Integer.parseInt(depositInputDate.getText().toString()));
deposit.setDescription(depositInputNote.getText().toString());
depositIntent.putExtra("data",deposit);
startActivity(depositIntent);
}
我添加新项目的地方：
private Socket _tcpWorkSocket;
private byte[] _tcpWorkBuffer;
private byte[] _tcpReceiveBuffer;
public void BeginTcpReceive() {
if (!Connected)
return;
_tcpWorkBuffer = new byte[BufferSize]; // 1024
_tcpWorkSocket.BeginReceive(_tcpWorkBuffer, 0, BufferSize, 0, new AsyncCallback(TcpReadCallback), this);
}
private void TcpReadCallback(IAsyncResult ar) {
try {
if (!Connected)
return;
int readBytes = _tcpWorkSocket.EndReceive(ar);
if (readBytes > 0) {
byte[] buffer = new byte[readBytes];
Array.Copy(_tcpWorkBuffer, 0, buffer, 0, readBytes);
if (User != null)
User.SessionTimerReset();
Proccess_Buffer(buffer);
}
BeginTcpReceive();
}
catch(SocketException ex) {
Close(false);
}
catch (Exception ex) {
Logger.LogError("{0}: {1}\n{2}", ex.GetType(), ex.Message, ex.StackTrace);
Close(false);
}
}
private void Proccess_Buffer(byte[] buffer) {
if (!Receiving) {
Receiving = true;
_tcpPacketLength = BitConverter.ToUInt16(buffer, 0);
_tcpBytesNeeded = _tcpPacketLength;
_tcpCurIndex = 0;
_tcpReceiveBuffer = new byte[_tcpPacketLength];
}
int origSize = buffer.Length;
int copyLength = _tcpBytesNeeded;
if (_tcpBytesNeeded > BufferSize)
copyLength = BufferSize;
Array.Copy(buffer, 0, _tcpReceiveBuffer, _tcpCurIndex, copyLength);
_tcpCurIndex += buffer.Length;
_tcpBytesNeeded -= buffer.Length;
if (_tcpBytesNeeded <= 0) {
Receiving = false;
ProcessReceiveBuffer(_tcpReceiveBuffer, Protocal.Tcp);
}
if (origSize > buffer.Length) {
// next packet, incase 2 messages are sent in the same packet.
byte[] nextBuffer = new byte[buffer.Length - origSize ];
if (nextBuffer.Length > 1) {
Array.Copy(buffer, origSize , nextBuffer, 0, nextBuffer.Length);
Proccess_Buffer(nextBuffer);
}
else {
Logger.LogError("Next buffer length split!");
}
}
}
我知道很多代码，但经过数小时的故障排除后，我无法弄清楚正确的解决方案是什么。哦，我在谷歌上找不到任何东西......
答案 0 :(得分：1)
问题在于您的getView()方法。您的代码正在执行以下操作：
使用对具有一个项目（new Transaction(78,98,"halo")）的列表的引用来创建适配器，这意味着将仅为位置0调用getView()方法。
然后，在getView()内，您从intent获取事务对象，并更改新值的项值。没有提到要添加的项目。
您需要更改以下内容：
AssetOverview.onCreate()而不是在适配器adapter.notifyDatasetChanged() Transaction current = getItem(position) AssetOverview.onDestroy()方法中将其设置为null，以避免内存泄漏。