Java onClick在片段中不工作
基本上,我的片段布局中有listview。还有另一个名为item_todo.xml的布局,其中包含我的按钮。 单击“我的布局”中的“删除任务”按钮时,Java onClick在片段中不工作,java,android,android-fragments,onclick,onclicklistener,Java,Android,Android Fragments,Onclick,Onclicklistener,基本上,我的片段布局中有listview。还有另一个名为item_todo.xml的布局,其中包含我的按钮。 单击“我的布局”中的“删除任务”按钮时,onClick()不起作用。 如果你能帮我,那就太好了 <ListView android:id="@+id/list_todo" android:layout_width="wrap_content" android:layout_height="wra
onClick()
不起作用。
如果你能帮我,那就太好了
<ListView
android:id="@+id/list_todo"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_marginBottom="16dp"
android:layout_marginRight="16dp"
android:orientation="horizontal" >
<android.support.design.widget.FloatingActionButton
android:layout_width="50dp"
android:id="@+id/btnadd"
android:layout_height="50dp"
app:fabSize="normal"
android:clickable="true"
android:src="@drawable/red"
android:scaleType="center"
/>
</LinearLayout>
</RelativeLayout>
这是我今天的课
public class ToDoFragment extends Fragment {
private static final String TAG = "MainActivity";
private TaskDbHelper mHelper;
private ListView mTaskListView;
private ArrayAdapter<String> mAdapter;
Button myButton;
FloatingActionButton btnadd;
//Overriden method onCreateView
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_two, container, false);
mHelper = new TaskDbHelper(getActivity());
mTaskListView = (ListView) view.findViewById(R.id.list_todo);
//Floating action button
btnadd = (FloatingActionButton) view.findViewById(R.id.btnadd);
btnadd.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
final EditText taskEditText = new EditText(getActivity());
AlertDialog dialog = new AlertDialog.Builder(getActivity())
.setTitle("Add a new task")
.setMessage("What do you want to do next?")
.setView(taskEditText)
.setPositiveButton("Add", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
String task = String.valueOf(taskEditText.getText());
SQLiteDatabase db = mHelper.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(TaskContract.TaskEntry.COL_TASK_TITLE, task);
db.insertWithOnConflict(TaskContract.TaskEntry.TABLE,
null,
values,
SQLiteDatabase.CONFLICT_REPLACE);
db.close();
updateUI();
}
})
.setNegativeButton("Cancel", null)
.create();
dialog.show();
}
});
updateUI();
return view;
}
@Override
public void onActivityCreated(Bundle saved){
super.onActivityCreated(saved);
final LayoutInflater factory = getActivity().getLayoutInflater();
final View textEntryView = factory.inflate(R.layout.item_todo, null);
myButton = (Button) textEntryView.findViewById(R.id.task_delete);
myButton.setOnClickListener(new View.OnClickListener() {
// OnClick() Not Working !!
@Override
public void onClick(View view) {
deleteTask(view);
}
});
}
public void deleteTask(View view) {
View parent = (View) view.getParent();
TextView taskTextView = (TextView) parent.findViewById(R.id.task_title);
String task = String.valueOf(taskTextView.getText());
SQLiteDatabase db = mHelper.getWritableDatabase();
db.delete(TaskContract.TaskEntry.TABLE,
TaskContract.TaskEntry.COL_TASK_TITLE + " = ?",
new String[]{task});
db.close();
updateUI();
}
private void updateUI() {
ArrayList<String> taskList = new ArrayList<>();
SQLiteDatabase db = mHelper.getReadableDatabase();
Cursor cursor = db.query(TaskContract.TaskEntry.TABLE,
new String[]{TaskContract.TaskEntry._ID, TaskContract.TaskEntry.COL_TASK_TITLE},
null, null, null, null, null);
while (cursor.moveToNext()) {
int idx = cursor.getColumnIndex(TaskContract.TaskEntry.COL_TASK_TITLE);
taskList.add(cursor.getString(idx));
}
if (mAdapter == null) {
mAdapter = new ArrayAdapter<>(getActivity(),
R.layout.item_todo,
R.id.task_title,
taskList);
mTaskListView.setAdapter(mAdapter);
} else {
mAdapter.clear();
mAdapter.addAll(taskList);
mAdapter.notifyDataSetChanged();
}
cursor.close();
db.close();
}}
<ListView
android:id="@+id/list_todo"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_marginBottom="16dp"
android:layout_marginRight="16dp"
android:orientation="horizontal" >
<android.support.design.widget.FloatingActionButton
android:layout_width="50dp"
android:id="@+id/btnadd"
android:layout_height="50dp"
app:fabSize="normal"
android:clickable="true"
android:src="@drawable/red"
android:scaleType="center"
/>
</LinearLayout>
</RelativeLayout>
公共类ToDoFragment扩展了片段{
私有静态最终字符串TAG=“MainActivity”;
私人任务助手mHelper;
私有ListView mTaskListView;
私人ArrayaAdapter mAdapter;
按钮myButton;
浮动操作按钮btnadd;
//重写方法onCreateView
@凌驾
CreateView上的公共视图(布局、充气机、视图组容器、捆绑包保存状态){
视图=充气机。充气(R.layout.fragment\u two,容器,错误);
mHelper=新的TaskDbHelper(getActivity());
mTaskListView=(ListView)view.findViewById(R.id.list\u todo);
//浮动动作按钮
btnadd=(FloatingActionButton)view.findViewById(R.id.btnadd);
btnadd.setOnClickListener(新视图.OnClickListener(){
@凌驾
公共void onClick(视图v){
final EditText taskEditText=新的EditText(getActivity());
AlertDialog=新建AlertDialog.Builder(getActivity())
.setTitle(“添加新任务”)
.setMessage(“下一步要做什么?”)
.setView(任务编辑文本)
.setPositiveButton(“添加”,新建DialogInterface.OnClickListener(){
@凌驾
public void onClick(DialogInterface dialog,int which){
String task=String.valueOf(taskEditText.getText());
SQLiteDatabase db=mHelper.getWritableDatabase();
ContentValues=新的ContentValues();
value.put(TaskContract.TaskEntry.COL_TASK_TITLE,TASK);
db.insertWithOnConflict(TaskContract.TaskEntry.TABLE,
无效的
价值观
SQLiteDatabase.CONFLICT\u REPLACE);
db.close();
updateUI();
}
})
.setNegativeButton(“取消”,null)
.create();
dialog.show();
}
});
updateUI();
返回视图;
}
@凌驾
已创建活动上的公共无效(已保存捆绑){
super.onActivityCreated(保存);
最终LayoutFlater工厂=getActivity().GetLayoutFlater();
最终视图textEntryView=工厂。充气(R.layout.item_todo,null);
myButton=(Button)textEntryView.findViewById(R.id.task\u delete);
myButton.setOnClickListener(新视图.OnClickListener(){
//OnClick()不工作!!
@凌驾
公共void onClick(视图){
删除任务(视图);
}
});
}
公共void deleteTask(视图){
View parent=(View)View.getParent();
TextView taskTextView=(TextView)parent.findViewById(R.id.task_title);
String task=String.valueOf(taskTextView.getText());
SQLiteDatabase db=mHelper.getWritableDatabase();
db.delete(TaskContract.TaskEntry.TABLE、,
TaskContract.TaskEntry.COL_TASK_TITLE+“=?”,
新字符串[]{task});
db.close();
updateUI();
}
私有void updateUI(){
ArrayList taskList=新建ArrayList();
SQLiteDatabase db=mHelper.getReadableDatabase();
Cursor Cursor=db.query(TaskContract.TaskEntry.TABLE,
新字符串[]{TaskContract.TaskEntry.\u ID,TaskContract.TaskEntry.COL\u TASK\u TITLE},
空,空,空,空,空,空);
while(cursor.moveToNext()){
int idx=cursor.getColumnIndex(TaskContract.TaskEntry.COL\u TASK\u TITLE);
taskList.add(cursor.getString(idx));
}
if(mAdapter==null){
mAdapter=newarrayadapter(getActivity(),
R.layout.item_todo,
R.id.任务名称,
任务清单);
mTaskListView.setAdapter(mAdapter);
}否则{
mAdapter.clear();
mAdapter.addAll(任务列表);
mAdapter.notifyDataSetChanged();
}
cursor.close();
db.close();
}}
两段XML
<ListView
android:id="@+id/list_todo"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_marginBottom="16dp"
android:layout_marginRight="16dp"
android:orientation="horizontal" >
<android.support.design.widget.FloatingActionButton
android:layout_width="50dp"
android:id="@+id/btnadd"
android:layout_height="50dp"
app:fabSize="normal"
android:clickable="true"
android:src="@drawable/red"
android:scaleType="center"
/>
</LinearLayout>
</RelativeLayout>
item_todo XML
<ListView
android:id="@+id/list_todo"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_marginBottom="16dp"
android:layout_marginRight="16dp"
android:orientation="horizontal" >
<android.support.design.widget.FloatingActionButton
android:layout_width="50dp"
android:id="@+id/btnadd"
android:layout_height="50dp"
app:fabSize="normal"
android:clickable="true"
android:src="@drawable/red"
android:scaleType="center"
/>
</LinearLayout>
</RelativeLayout>
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="center_vertical">
<TextView
android:id="@+id/task_title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:text="Hello"
android:textSize="20sp" />
<Button
android:id="@+id/task_delete"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentEnd="true"
android:layout_alignParentRight="true"
android:text="Done" />
</RelativeLayout>
您在创建的活动中膨胀了一个新视图,但您从未使用过该视图<代码>我的按钮指其视图未被使用的按钮
<ListView
android:id="@+id/list_todo"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_marginBottom="16dp"
android:layout_marginRight="16dp"
android:orientation="horizontal" >
<android.support.design.widget.FloatingActionButton
android:layout_width="50dp"
android:id="@+id/btnadd"
android:layout_height="50dp"
app:fabSize="normal"
android:clickable="true"
android:src="@drawable/red"
android:scaleType="center"
/>
</LinearLayout>
</RelativeLayout>
编辑:
<ListView
android:id="@+id/list_todo"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_marginBottom="16dp"
android:layout_marginRight="16dp"
android:orientation="horizontal" >
<android.support.design.widget.FloatingActionButton
android:layout_width="50dp"
android:id="@+id/btnadd"
android:layout_height="50dp"
app:fabSize="normal"
android:clickable="true"
android:src="@drawable/red"
android:scaleType="center"
/>
</LinearLayout>
</RelativeLayout>
实现目标的方法有很多:
<ListView
android:id="@+id/list_todo"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_marginBottom="16dp"
android:layout_marginRight="16dp"
android:orientation="horizontal" >
<android.support.design.widget.FloatingActionButton
android:layout_width="50dp"
android:id="@+id/btnadd"
android:layout_height="50dp"
app:fabSize="normal"
android:clickable="true"
android:src="@drawable/red"
android:scaleType="center"
/>
</LinearLayout>
</RelativeLayout>
接口
<ListView
android:id="@+id/list_todo"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_marginBottom="16dp"
android:layout_marginRight="16dp"
android:orientation="horizontal" >
<android.support.design.widget.FloatingActionButton
android:layout_width="50dp"
android:id="@+id/btnadd"
android:layout_height="50dp"
app:fabSize="normal"
android:clickable="true"
android:src="@drawable/red"
android:scaleType="center"
/>
</LinearLayout>
</RelativeLayout>
您可以初始化一个接口并将其传递给fragment,这样无论何时在您的活动中发生什么事情(例如,单击按钮),您都可以理解
<ListView
android:id="@+id/list_todo"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_marginBottom="16dp"
android:layout_marginRight="16dp"
android:orientation="horizontal" >
<android.support.design.widget.FloatingActionButton
android:layout_width="50dp"
android:id="@+id/btnadd"
android:layout_height="50dp"
app:fabSize="normal"
android:clickable="true"
android:src="@drawable/red"
android:scaleType="center"
/>
</LinearLayout>
</RelativeLayout>
广播接收机
<ListView
android:id="@+id/list_todo"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_marginBottom="16dp"
android:layout_marginRight="16dp"
android:orientation="horizontal" >
<android.support.design.widget.FloatingActionButton
android:layout_width="50dp"
android:id="@+id/btnadd"
android:layout_height="50dp"
app:fabSize="normal"
android:clickable="true"
android:src="@drawable/red"
android:scaleType="center"
/>
</LinearLayout>
</RelativeLayout>
您可以在片段中注册本地广播接收器,当用户单击按钮时,您发送该广播,以便片段理解
<ListView
android:id="@+id/list_todo"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_marginBottom="16dp"
android:layout_marginRight="16dp"
android:orientation="horizontal" >
<android.support.design.widget.FloatingActionButton
android:layout_width="50dp"
android:id="@+id/btnadd"
android:layout_height="50dp"
app:fabSize="normal"
android:clickable="true"
android:src="@drawable/red"
android:scaleType="center"
/>
</LinearLayout>
</RelativeLayout>
我建议使用第二种方法,并使用库可以添加您得到的错误吗?您从未将膨胀的
texentryview
添加到您的片段中。@NeelaySrivastava没有这样的错误。只是当我用id=“task_delete”@VladMatvienko点击按钮时什么都没有发生,实际上,因为我的按钮位于不同的布局中,所以为了避免包含myButton.setOnClickListener的行中出现空指针错误,我插入了一个新视图。你能引导我走向正确的道路吗?通过膨胀视图,你不会显示它,只是创建它。所以你刚刚创建了一个
<ListView
android:id="@+id/list_todo"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_marginBottom="16dp"
android:layout_marginRight="16dp"
android:orientation="horizontal" >
<android.support.design.widget.FloatingActionButton
android:layout_width="50dp"
android:id="@+id/btnadd"
android:layout_height="50dp"
app:fabSize="normal"
android:clickable="true"
android:src="@drawable/red"
android:scaleType="center"
/>
</LinearLayout>
</RelativeLayout>