Java 安卓静态按钮监听器
基本上,我正在尝试为我的fragment_home_屏幕活动设置一些按钮侦听器。我一直遇到的唯一问题是,如何获得用于实例化按钮的正确视图。你看,视图在一个静态类中,所以当我试图设置按钮侦听器时,任何内部调用都必须是静态对象 到目前为止,我的应用程序有一个滑动抽屉和一个起始片段 我想从侦听器中调用一个非静态方法。有没有办法解决这个问题,或者有可能的解决办法 [在中间向下滚动到onCreateView方法以查看问题]Java 安卓静态按钮监听器,java,android,static,Java,Android,Static,基本上,我正在尝试为我的fragment_home_屏幕活动设置一些按钮侦听器。我一直遇到的唯一问题是,如何获得用于实例化按钮的正确视图。你看,视图在一个静态类中,所以当我试图设置按钮侦听器时,任何内部调用都必须是静态对象 到目前为止,我的应用程序有一个滑动抽屉和一个起始片段 我想从侦听器中调用一个非静态方法。有没有办法解决这个问题,或者有可能的解决办法 [在中间向下滚动到onCreateView方法以查看问题] public class HomeScreen extends Activity
public class HomeScreen extends Activity
implements NavigationDrawerFragment.NavigationDrawerCallbacks {
private BluetoothSocket mmSocket;
private BluetoothAdapter mBluetoothAdapter;
private BluetoothDevice mmDevice;
private UUID MY_UUID;
private final String NAME = "Acceptor";
private NavigationDrawerFragment mNavigationDrawerFragment;
private CharSequence mTitle;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home_screen);
mNavigationDrawerFragment = (NavigationDrawerFragment)
getFragmentManager().findFragmentById(R.id.navigation_drawer);
mTitle = getTitle();
// Set up the drawer.
mNavigationDrawerFragment.setUp(
R.id.navigation_drawer,
(DrawerLayout) findViewById(R.id.drawer_layout));
startUpBluetooth();
}
@Override
public void onNavigationDrawerItemSelected(int position) {
// update the main content by replacing fragments
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.container, PlaceholderFragment.newInstance(position + 1))
.commit();
}
public void onSectionAttached(int number) {
switch (number) {
case 1:
mTitle = getString(R.string.title_section1);
break;
case 2:
mTitle = getString(R.string.title_section2);
break;
case 3:
mTitle = getString(R.string.title_section3);
break;
case 4:
mTitle = getString(R.string.title_section4);
break;
case 5:
mTitle = getString(R.string.title_section5);
break;
}
}
public void restoreActionBar() {
ActionBar actionBar = getActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
actionBar.setDisplayShowTitleEnabled(true);
actionBar.setTitle(mTitle);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
if (!mNavigationDrawerFragment.isDrawerOpen()) {
getMenuInflater().inflate(R.menu.home_screen, menu);
restoreActionBar();
return true;
}
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
public static class PlaceholderFragment extends Fragment {
/
private static final String ARG_SECTION_NUMBER = "section_number";
public static PlaceholderFragment newInstance(int sectionNumber) {
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_home_screen, container, false);
try {
Button acceptButton = (Button) rootView.findViewById(R.id.acceptButton);
Button connectedButton = (Button) rootView.findViewById(R.id.connectedButton);
Button connectButton = (Button) rootView.findViewById(R.id.connectButton);
acceptButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
// ***problem is here***
AcceptThread a = new AcceptThread();
a.run();
}
});
connectedButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
ConnectedThread cc = new ConnectedThread();
cc.run();
}
});
connectButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
ConnectThread con = new ConnectThread();
con.run();
}
});
}
catch(Exception e1 ){
errorToast("We have a button problem: "+e1.toString());
}
return rootView;
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
((HomeScreen) activity).onSectionAttached(
getArguments().getInt(ARG_SECTION_NUMBER));
}
}
public class ConnectThread extends Thread {
public ConnectThread() {
...
}
public void run() {
...
}
public void cancel() {
...
}
}
public class ConnectedThread extends Thread {
private final InputStream mmInStream;
private final OutputStream mmOutStream;
public ConnectedThread() {
...
}
public void run() {
...
}
public void write(byte[] bytes) {
...
}
public void cancel() {
...
}
}
//this class is in the same file
public class AcceptThread extends Thread {
private final BluetoothServerSocket mmServerSocket;
public AcceptThread() {
...
}
public void run() {
...
}
public void cancel() {
....
}
}
}
以下是XML:
Fragment_home_screen.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
tools:context=".HomeScreen$PlaceholderFragment">
<TextView android:id="@+id/largeText" android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Connected Thread"
android:id="@+id/acceptButton"
android:layout_centerVertical="true"
android:layout_alignParentStart="true"
android:layout_alignEnd="@+id/connectButton" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Connect Thread"
android:id="@+id/connectedButton"
android:layout_below="@+id/acceptButton"
android:layout_alignEnd="@+id/acceptButton"
android:layout_toEndOf="@+id/largeText"
android:layout_alignParentStart="true" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Accept Thread"
android:id="@+id/connectButton"
android:layout_above="@+id/acceptButton"
android:layout_alignParentEnd="true"
android:layout_toEndOf="@+id/largeText" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Large Text"
android:id="@+id/textView"
android:layout_alignEnd="@+id/connectButton"
android:layout_above="@+id/connectButton"
android:layout_toEndOf="@+id/largeText"
android:layout_below="@+id/largeText" />
Fragment\u home\u screen.xml
Activity\u home\u screen.xml
我想从侦听器中调用一个非静态方法。是
有没有办法解决这个问题,或者可能的解决方案
要访问AcceptThread
和ConnectedThread
类:
选项1。使两个类都静态
,因为我们只能访问静态范围内的静态方法和类
选项2。从占位符片段
类中删除静态
同时更改newInstance
方法:
public PlaceholderFragment newInstance(int sectionNumber) {
return fragment;
}
并在FragmentManager中添加时使用new获取Placeholder Fragment类的对象:
fragmentManager.beginTransaction()
.replace(R.id.container,new PlaceholderFragment.newInstance(
position + 1))
.commit();
第二个选项很简单,不必使所有类都是静态的,只需从
占位符片段类中删除静态,我不确定静态类是否是最好的方法
以下几点建议可以简化此过程:
使占位符片段不是静态的李>
使用常规构造函数实例化片段:PlaceholderFragment()
李>
使用setArguments(Bundle extras)
方法传递位置
基本上,做newInstance
代码在外部执行的任何操作
或…
为片段创建新的构造函数:
public PlaceholderFragment(int sectionNumber) {
this();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
setArguments(args);
}
决不能重写默认构造函数。Android使用它在需要时重新创建片段
创建此新构造函数将允许您执行以下操作:
@Override
public void onNavigationDrawerItemSelected(int position) {
// update the main content by replacing fragments
FragmentManager fm = getFragmentManager();
fm.beginTransaction().replace(R.id.container,
new PlaceholderFragment(position + 1)).commit();
}
问题是,我不希望线程是静态的,因为这样,它们使用的所有全局变量都必须是静态的,然后最终强制整个java文件是静态的。您知道可能的解决方法吗?当我从PlacehodlerFragment中删除static时,我会遇到一系列错误,导致导航抽屉上的ReitemSelected(int位置)
无法正常运行。特别是在PlaceholderFragment.newInstance(位置+1)
部分。@Greg:再次查看我的答案,我做了一个评论,认为它有效(因为IntelliJ在清理项目之前没有显示任何错误)。我的onNavigationDrawerItemSelected(int位置)
方法似乎有问题。特别是在占位符片段.newInstance(位置+1)
部分。错误是:非静态方法“newInstance(Int)”不能从静态上下文引用
是的,我意识到了这一点。没问题。但是看看我的答案。通过创建新构造函数,您将不会使用静态方法newInstance(int)
。相反,您使用的是完全非静态的构造函数。但无论如何,很高兴你的问题解决了
@Override
public void onNavigationDrawerItemSelected(int position) {
// update the main content by replacing fragments
FragmentManager fm = getFragmentManager();
fm.beginTransaction().replace(R.id.container,
new PlaceholderFragment(position + 1)).commit();
}