问题描述
嘿,我刚刚将我的应用升级到AppCompat v22.1.0,并遇到了此异常
Hey I've just upgraded my app to AppCompat v22.1.0 and got this exception
Caused by: java.lang.IllegalArgumentException: AppCompat does not support the current theme features
at android.support.v7.app.AppCompatDelegateImplV7.ensureSubDecor(AppCompatDelegateImplV7.java:360)
at android.support.v7.app.AppCompatDelegateImplV7.setContentView(AppCompatDelegateImplV7.java:246)
at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:106)
我找到了。此处
问题仍然没有解决,因为我在 ConnectionWifiEditActivity
类中的super.onCreate之后调用setContentView。
Still the problem wasn't solved because I was calling the setContentView after super.onCreate, in the ConnectionWifiEditActivity
Class.
当我更改此设置时,它引发 NullPointerException
我该如何解决?
When I changed this it throws NullPointerException
How Can I Solve this?
Caused by: java.lang.NullPointerException
at Client.Activity.connection.ConnectionEditActivity.onResume(ConnectionEditActivity.java:46)
at Client.Activity.connection.ConnectionWifiEditActivity.onResume(ConnectionWifiEditActivity.java:81)
ConnectionWifiEditActivity
public class ConnectionWifiEditActivity extends ConnectionEditActivity implements OnClickListener
{
private ConnectionWifi connection;
private EditText host;
private EditText port;
Button scan;
ListView lv;
private Toolbar mToolbar;
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
this.setContentView(R.layout.connectionwifiedit);
lv = (ListView) findViewById(android.R.id.list);
this.connection = (ConnectionWifi) connectionParam;
mToolbar = (Toolbar) findViewById(R.id.toolbar_actionbar);
setSupportActionBar(mToolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
this.host = (EditText) this.findViewById(R.id.host);
this.port = (EditText) this.findViewById(R.id.port);
SnackbarManager.show(
Snackbar.with(getApplicationContext()) // context
.type(SnackbarType.MULTI_LINE) // Set is as a multi-line snackbar
.text(R.string.tip) // text to be displayed
.duration(Snackbar.SnackbarDuration.LENGTH_INDEFINITE)
, this);
}
public void Save(View v){
this.finish();
}
@Override
public void onClick(View v)
{
}
protected void onResume()
{
super.onResume();
this.host.setText(this.connection.getHost());
this.port.setText(Integer.toString(this.connection.getPort()));
}
protected void onPause()
{
super.onPause();
this.connection.setHost(this.host.getText().toString());
this.connection.setPort(Integer.parseInt(this.port.getText().toString()));
}}
ConnectionEditActivity
public static Connection connectionParam;
private Connection connection;
private EditText name;
private EditText password;
public class ConnectionEditActivity extends AppCompatActivity implements OnClickListener
{
public static Connection connectionParam;
private Connection connection;
private Button save;
private EditText name;
private EditText password;
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
this.connection = connectionParam;
this.name = (EditText) this.findViewById(R.id.name);
this.password = (EditText) this.findViewById(R.id.password);
}
protected void onResume()
{
super.onResume();
this.name.setText(this.connection.getName());
this.password.setText(this.connection.getPassword());
}
protected void onPause()
{
super.onPause();
this.connection.setName(this.name.getText().toString());
this.connection.setPassword(this.password.getText().toString());
}
public void onClick(View v)
{
if (v == this.save)
{
this.finish();
}
}
}
连接
public abstract class Connection implements Comparable<Connection>, Serializable
{
private static final long serialVersionUID = 1L;
public static final int TYPE_COUNT = 2;
public static final int WIFI = 0;
public static final int BLUETOOTH = 1;
private String name;
private String password;
public Connection()
{
this.name = "";
this.password = RemoteItConnection.DEFAULT_PASSWORD;
}
public static Connection load(SharedPreferences preferences, ConnectionList list, int position)
{
Connection connection = null;
int type = preferences.getInt("connection_" + position + "_type", -1);
switch (type)
{
case WIFI:
connection = ConnectionWifi.load(preferences, position);
break;
case BLUETOOTH:
connection = ConnectionBluetooth.load(preferences, position);
break;
}
connection.name = preferences.getString("connection_" + position + "_name", null);
connection.password = preferences.getString("connection_" + position + "_password", null);
return connection;
}
public void save(Editor editor, int position)
{
editor.putString("connection_" + position + "_name", this.name);
editor.putString("connection_" + position + "_password", this.password);
}
public abstract RemoteItConnection connect(RemoteIt application) throws IOException;
public abstract void edit(Context context);
protected void edit(Context context, Intent intent)
{
ConnectionEditActivity.connectionParam = this;
context.startActivity(intent);
}
public String getName()
{
return name;
}
public void setName(String name)
{
this.name = name;
}
public String getPassword()
{
return password;
}
public void setPassword(String password)
{
this.password = password;
}
public int compareTo(Connection c)
{
return this.name.compareTo(c.name);
}
}
推荐答案
自要在super方法中获取一些ui元素,必须找到一种在超类中定义布局的方法。这是因为您按照其他答案中的说明获得了NPE。
Since you want to get some ui elements in the super method, you have to find a way to define the layout in the superclass. It is the reason because you are getting an NPE as described in the other answers.
您可以使用 setContentView()$ c $在超类中,c>使用一种方法返回要使用的布局。
You can use the setContentView()
in the superclass, using a method to return the layout to use.
通过这种方式,您可以在子类中覆盖布局,从而覆盖方法。
In this way you can override the layout in the sub class, overriding the method.
例如,您可以使用类似 setContentView(getLayoutId())的东西:
For example you can use something like setContentView(getLayoutId()):
public class ConnectionEditActivity extends AppCompatActivity {
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(getLayoutId()); //pay attention here...
this.connection = connectionParam;
this.name = (EditText) this.findViewById(R.id.name);
this.password = (EditText) this.findViewById(R.id.password);
}
protected int getLayoutId(){
//....
}
}
您可以在其他活动中覆盖它,从而避免使用 setContentView
And you can override it in other activity, where you can avoid the setContentView
method.
public class ConnectionWifiEditActivity extends ConnectionEditActivity{
@Override
protected int getLayoutId(){
return R.layout.connectionwifiedit;
}
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
//setContentView(); //comment this line
//..
}
}
这篇关于使用AppCompat v22.1.0时如何在super.onCreate之前设置ContentView?的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!