[英]OnItemClickListener is not firing
我正在制作一个具有要在ListView中显示的练习列表的应用程序。 我试图让用户从列表中选择一个项目以启动新活动,但是我的OnItemClickListener没有启动。 这是我的活动(不是listActivity,而是appCompatActivity):
ArrayList<Exercise> myExercises = new ArrayList<>();
AlertDialog.Builder alertDialogBuilder;
ArrayAdapter<Exercise> arrayAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_list);
refreshList();
Button newExButton = (Button) findViewById(R.id.newExButton);
arrayAdapter = new ArrayAdapter<Exercise>(
this,
android.R.layout.simple_list_item_1,
myExercises );
ListView lv = (ListView) findViewById(R.id.actList);
lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
System.out.println("listener heard");
// selected item
int selection = position;
startExercise(selection);
}
});
lv.setAdapter(arrayAdapter);
}
public void refreshList(){
setContentView(R.layout.activity_list);
ListView lv = (ListView) findViewById(R.id.actList);
lv.setChoiceMode(AbsListView.CHOICE_MODE_SINGLE);
lv.setAdapter(arrayAdapter);
}
public void startExercise(int selection){
Intent exIntent = new Intent(this, CommenceExercise.class);
Exercise chosenEx = myExercises.get(selection);
Bundle info = new Bundle();
info.putLong("duration", chosenEx.getTime());
info.putString("name", chosenEx.getName());
info.putString("description", chosenEx.getDescription());
exIntent.putExtras(info);
startActivity(exIntent);
}
该列表最初是空的,但是用户可以通过按下按钮来添加项目。 该按钮通过以下代码创建一个alertDialog:
public void addNewActivity(View view) {
//get prompts.xml view
LayoutInflater li = LayoutInflater.from(context);
View promptsView = li.inflate(R.layout.custom, null);
alertDialogBuilder = new AlertDialog.Builder(
context);
// set prompts.xml to alertdialog builder
alertDialogBuilder.setView(promptsView);
final EditText userInput = (EditText) promptsView
.findViewById(R.id.exNameInput);
final EditText durInput = (EditText) promptsView
.findViewById(R.id.exDurInput);
// set dialog message
alertDialogBuilder
.setCancelable(false)
.setPositiveButton("OK",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int id) {
long duration = 0;
String exName;
exName = userInput.getText().toString();
duration = Integer.valueOf(durInput.getText().toString());
myExercises.add(new Exercise(exName, duration));
// create new exercise with user input
refreshList();
}
})
.setNegativeButton("Cancel",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,int id) {
dialog.cancel();
}
});
// create alert dialog
AlertDialog alertDialog = alertDialogBuilder.create();
// show it
alertDialog.show();
}
}
这是我的xml:
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:descendantFocusability="blocksDescendants"
tools:context="com.example.mytimer.ListActivity">
<TextView
android:id="@+id/textView2"
android:layout_width="146dp"
android:layout_height="30dp"
android:layout_marginLeft="16dp"
android:layout_marginRight="16dp"
android:layout_marginTop="16dp"
android:text="Activities"
android:textAlignment="center"
android:textSize="24sp"
app:layout_constraintHorizontal_bias="0.502"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
android:layout_marginStart="16dp"
android:clickable="false"
android:layout_marginEnd="16dp" />
<Button
android:id="@+id/newExButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginEnd="16dp"
android:layout_marginLeft="16dp"
android:layout_marginRight="16dp"
android:layout_marginStart="16dp"
android:layout_marginTop="87dp"
android:onClick="addNewActivity"
android:text="New Exercise"
android:textSize="18sp"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toBottomOf="@+id/textView2" />
<ListView
android:id="@+id/actList"
android:layout_width="328dp"
android:layout_height="301dp"
android:layout_marginBottom="16dp"
android:layout_marginEnd="16dp"
android:layout_marginLeft="16dp"
android:layout_marginRight="16dp"
android:layout_marginStart="16dp"
android:layout_marginTop="16dp"
android:descendantFocusability="blocksDescendants"
android:focusable="false"
android:clickable="false"
android:focusableInTouchMode="false"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toBottomOf="@+id/newExButton"
app:layout_constraintVertical_bias="1.0">
<requestFocus/>
</ListView>
<TextView
android:id="@+id/debugText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="36dp"
android:text="TextView"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
android:clickable="false"
app:layout_constraintTop_toBottomOf="@+id/textView2" />
</android.support.constraint.ConstraintLayout>
当我点击添加到列表中的项目时,什么也没有发生。 我可以说OnItemClickListener没有被触发,因为从不打印System.out行。 我不知道为什么我不能让它工作。 任何帮助将不胜感激。 提前致谢。
我认为XML中的问题请设置ListView
clickable true
请对XML进行一些更改
<ListView
android:id="@+id/actList"
android:layout_width="328dp"
android:layout_height="301dp"
android:layout_marginBottom="16dp"
android:layout_marginEnd="16dp"
android:layout_marginLeft="16dp"
android:layout_marginRight="16dp"
android:layout_marginStart="16dp"
android:layout_marginTop="16dp"
android:descendantFocusability="blocksDescendants"
android:focusable="true" // change this
android:clickable="true" // change this
android:focusableInTouchMode="true" // change this
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toBottomOf="@+id/newExButton"
app:layout_constraintVertical_bias="1.0">
<requestFocus/>
</ListView>
真的很奇怪……您的代码应该可以正常工作……我建议您尝试在活动中实现,以包含lv.setClcickable(true)
和lv.setEnable(true)
:
public class MenuActivity extends AppCompatActivity implements
AdapterView.OnItemClickListener{
ArrayList<Exercise> myExercises = new ArrayList<>();
AlertDialog.Builder alertDialogBuilder;
ArrayAdapter<Exercise> arrayAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_list);
refreshList();
Button newExButton = (Button) findViewById(R.id.newExButton);
arrayAdapter = new ArrayAdapter<Exercise>(
this,
android.R.layout.simple_list_item_1,
myExercises );
ListView lv = (ListView) findViewById(R.id.actList);
lv.setClickable(true);
lv.setEnabled(true);
lv.setOnItemClickListener(new AdapterView.OnItemClickListener(){
public void onItemClick(AdapterView<?> parent, View view , int
position, long id)
{
startExercise(position);
}
lv.setAdapter(arrayAdapter);
}
public void refreshList(){
setContentView(R.layout.activity_list);
ListView lv = (ListView) findViewById(R.id.actList);
lv.setChoiceMode(AbsListView.CHOICE_MODE_SINGLE);
lv.setAdapter(arrayAdapter);
}
public void startExercise(int selection){
Intent exIntent = new Intent(this, CommenceExercise.class);
Exercise chosenEx = myExercises.get(selection);
Bundle info = new Bundle();
info.putLong("duration", chosenEx.getTime());
info.putString("name", chosenEx.getName());
info.putString("description", chosenEx.getDescription());
exIntent.putExtras(info);
startActivity(exIntent);
}
}
或将这三行添加到您的xml中
android:focusable="false"
android:focusableInTouchMode="false"
android:clickable="true
android:descendantFocusability="blocksDescendants"
如果有任何可聚焦的子视图,则始终将第一个单击作为焦点。我建议您使用带有Viewholder
Pattern的Custom ListView
来提高效率,或者使用Recyclerview
支持库,这将使您的滚动更加流畅并且不会创建额外的View对象...它将仅创建适合屏幕的视图对象
这是RecyclerView
的链接https://guides.codepath.com/android/using-the-recyclerview
将您的refreshList
方法更改为以下一种
public void refreshList(){
arrayAdapter.notifyDataSetChanged();
}
您正在做的是,再次给ListView
充气并为其设置新数据,而不是更新旧数据。 并且当您为ListView
分配新值时,您忘记设置onClickListener
。
会的
您需要从xml中删除以下listview属性:
android:descendantFocusability="blocksDescendants"
android:focusable="true"
android:clickable="true"
android:focusableInTouchMode="true"
另外,不需要refreshList()这实际上是一种不好的处理方式,而是在模型添加好之后(可能在单击肯定按钮时)在addNewActivity()中将该项目添加到arrayAdapter然后执行arrayAdapter.notifyDataSetChanged ()。
我希望这可以帮助你!
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.