Good day everyone,
I'm learning Android development and I try to build some dynamic lists for my application. And I'm stuck... like for 4 hours already.
I have two layouts:
1. main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="#+id/action_buttons"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:gravity="center"
>
<Button
android:id="#+id/button_count"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/button_calculate" />
<Button
android:id="#+id/button_add"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_toRightOf="#+id/button_count"
android:text="#string/button_add" />
</LinearLayout>
<ScrollView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_below="#+id/action_buttons"
>
<LinearLayout
android:id="#+id/action_list"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
</LinearLayout>
</ScrollView>
</RelativeLayout>
action_list_item.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/action_list_item_root"
android:layout_width="fill_parent"
android:layout_height="wrap_content" >
<EditText
android:id="#+id/action_list_item_edittext_drinkName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="#+id/action_list_item_button_remove"
android:layout_alignParentTop="true"
android:layout_toRightOf="#+id/action_list_item_title"
android:padding="10dp" />
<EditText
android:id="#+id/action_list_item_edittext_drinkPercent"
android:text="40"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_toLeftOf="#+id/action_list_item_edittext_drinkAmount"
android:inputType="number"
android:padding="10dp"/>
<EditText
android:id="#+id/action_list_item_edittext_drinkAmount"
android:text="0.0"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_toLeftOf="#+id/action_list_item_button_remove"
android:layout_alignBottom="#+id/action_list_item_button_remove"
android:inputType="numberDecimal"
android:width="50dp"
android:padding="10dp" />
<Button
android:id="#+id/action_list_item_button_remove"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:text="#string/action_list_item_button_remove" />
And code that creates dynamic list:
public class MainActivity extends Activity {
LinearLayout actionList = null;
private Button btnAdd;
private Button btnCalculate;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
initActivityElements();
}
private void initActivityElements() {
initAddButton();
initCalculateButton();
}
private void initCalculateButton() {
btnCalculate = (Button) findViewById(R.id.button_count);
btnCalculate.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
TextView amount = (TextView) findViewById(R.id.action_list_item_edittext_drinkAmount);
//this retrives TextView value from first list
Toast.makeText(getApplicationContext(), amount.getText().toString(),
Toast.LENGTH_SHORT)
.show();
}
});
}
private void initAddButton() {
actionList = (LinearLayout) findViewById(R.id.action_list);
btnAdd = (Button) findViewById(R.id.button_add);
btnAdd.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
RelativeLayout listItem = (RelativeLayout) View.inflate(
MainActivity.this, R.layout.action_list_item, null);
TextView name = (TextView) listItem
.findViewById(R.id.action_list_item_edittext_drinkName);
name.setText("Here is the Title " + actionList.getChildCount());
listItem.findViewById(R.id.action_list_item_button_remove)
.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
actionList.removeView((View) v.getParent());
}
});
actionList.addView(listItem);
}
});
}
My problem is that I need to get all data from TextView boxes (Amount, Percent), but I can retrive that data only from first item of a list (look at onClickListener for btnCalculate) and can't figure out how to do it, but tried to add 'unique ids' for view (but that brakes layout, badly), tried setting Tags but again with no luck.
Maybe anyone can give a tip? I bet there is some easy way to do it, but I'm failing to find it and google is no help here.
Thanks
I'm not really sure what exactly you are trying to do but it sounds like you are trying to take in information and populate it into a view. I would recommend having a static text box that takes in your information and builds that into a listview. A good example of how to do that is located here http://developer.android.com/resources/tutorials/notepad/notepad-ex1.html.
Related
I am trying to create a custom dialog class with a custom layout, but, for reasons unknown to be, I am getting a null pointer exception when trying to access the buttons for the layout. Here is the XML for the dialog:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/enableTopRelativeLayout"
android:layout_width="460dp"
android:layout_height="wrap_content"
android:background="#drawable/dialog_background"
android:paddingBottom="15dp"
android:paddingLeft="15dp"
android:paddingRight="15dp"
android:paddingTop="15dp" >
<ImageView
android:id="#+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_centerVertical="true"
android:src="#drawable/ic_launcher" />
<RelativeLayout
android:id="#+id/enableInnerRelativeLayout"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_toRightOf="#id/imageView1" >
<TextView
android:id="#+id/enableMessage"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerInParent="false"
android:paddingBottom="10dp"
android:text="Start service?"
android:textAppearance="?android:attr/textAppearanceMedium" />
<TextView
android:id="#+id/enableStrut"
android:layout_width="25dp"
android:layout_height="wrap_content"
android:layout_below="#id/enableMessage"
android:layout_centerHorizontal="true"
android:text=" " />
<Button
android:id="#+id/noenable"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#id/enableMessage"
android:layout_toLeftOf="#id/enableStrut"
android:background="#drawable/button_background"
android:text="No"
android:textColorLink="#color/color2"
android:textStyle="bold" />
<Button
android:id="#+id/enable"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#id/enableMessage"
android:layout_toRightOf="#id/enableStrut"
android:background="#drawable/button_background"
android:text="Yes"
android:textColorLink="#color/color2"
android:textStyle="bold" />
</RelativeLayout>
Here is the code for the class:
public class DialogStartService extends Dialog implements android.view.View.OnClickListener{
public Button yes;
public Button no;
public TextView tv;
public DialogStartService(Context context) {
super(context);
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.start_service_layout);
getWindow().setBackgroundDrawable(new ColorDrawable(android.graphics.Color.TRANSPARENT));
tv = (TextView) findViewById(R.id.enableMessage);
yes = (Button) findViewById(R.id.enable);
no = (Button) findViewById(R.id.noenable);
yes.setOnClickListener(this);
no.setOnClickListener(this);
}
#Override
public void onClick(View v) {
dismiss();
}
}
I instantiate the dialog with this code:
DialogStartService enableDialog = new DialogStartService(this);
Button enable = (Button) enableDialog.findViewById(R.id.enable);
enable.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// Do stuff
}
});
Button noenable = (Button) enableDialog.findViewById(R.id.noenable);
noenable.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// Do stuff
}
});
enableDialog.show();
The stack trace indicates the NPE occurs on this line:
enable.setOnClickListener(new OnClickListener() {
My question for the experts is... why is this code causing a NPE, and what is the best way to fix it? Thank you for any input you have.
According to documentation of findViewById() method:
Finds a child view with the given identifier. Returns null if the specified child view does not exist or the dialog has not yet been fully created (for example, via show() or create()).
In your code you call findViewById() before show() - that's why Button enable is null.
I'm new to Android, and am currently using a ViewFlipper. I'd like to know if it's possible to use only one ImageView? That way I can just create an Arraylist of my images. I think using multiple ImageViews is not a good practice since I have 50+ images.
public void initContent() {
imageArrayList = new ArrayList<Integer>();
imageArrayList.add(R.drawable.pig2);
imageArrayList.add(R.drawable.pig3);
imageArrayList.add(R.drawable.pig4);
imageArrayList.add(R.drawable.pig5);
imageArrayList.add(R.drawable.pig6);
imageArrayList.add(R.drawable.pig7);
imageArrayList.add(R.drawable.pig8);
imageArrayList.add(R.drawable.pig9);
imageArrayList.add(R.drawable.pig10);
imageArrayList.add(R.drawable.pig11);
imageArrayList.add(R.drawable.pig12);
imageArrayList.add(R.drawable.pig13);
imageArrayList.add(R.drawable.pig14);
imageArrayList.add(R.drawable.pig24);
imageArrayList.add(R.drawable.pig25);
imageArrayList.add(R.drawable.theend);
MainActivity.java
public class MainActivity extends Activity {
ViewFlipper viewFlipper;
Button Next;
private Integer images[] = {R.drawable.ic_launcher,
R.drawable.ic_no_image, R.drawable.calendar52};
ImageView imageView1;
private int currImage = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
viewFlipper = (ViewFlipper) findViewById(R.id.ViewFlipper01);
Next = (Button) findViewById(R.id.Next);
imageView1 = (ImageView) findViewById(R.id.imageView1);
Next.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
currImage++;
if (currImage == 3) {
currImage = 0;
}
final ImageView imageView = (ImageView) findViewById(R.id.imageView1);
imageView.setImageResource(images[currImage]);
viewFlipper.showNext();
}
});
}
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/LinearLayout01"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<RelativeLayout
android:id="#+id/RelativeLayout02"
android:layout_width="wrap_content"
android:layout_height="wrap_content" >
<ViewFlipper
android:id="#+id/ViewFlipper01"
android:layout_width="fill_parent"
android:layout_height="400dp" >
<RelativeLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#4B0082" >
<ImageView
android:id="#+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="117dp"
android:src="#drawable/ic_launcher" />
</RelativeLayout>
</ViewFlipper>
</RelativeLayout>
<RelativeLayout
android:id="#+id/RelativeLayout03"
android:layout_width="fill_parent"
android:layout_height="match_parent"
android:background="#000000"
android:gravity="center" >
<Button
android:id="#+id/Next"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_marginBottom="5dp"
android:layout_marginRight="20dp"
android:text="Next" />
</RelativeLayout>
</LinearLayout>
Yes. Use the frame animation, delete your arraylist. Here is some sample code: Link
I am displaying a listview programmiclly using the following codes:
Below is how the listview is displayed programmatically:
messagesList = (ListView) findViewById(R.id.listMessages);
messageAdapter = new MessageAdapter(this);
I would want to limit the list to 25 items, and where it is not infinite.
Below is the layout.
<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:background="#drawable/white_wallpaper"
>
<ListView
android:id="#+id/listMessages"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_above="#+id/divider"
android:divider="#null"
android:dividerHeight="0dp"
android:inputType="text|textNoSuggestions"
android:padding="0dip"
android:stackFromBottom="true"
android:transcriptMode="alwaysScroll"
tools:listitem="#layout/message_left" />
<RelativeLayout
android:id="#+id/divider"
android:layout_width="fill_parent"
android:layout_height="1dip"
android:background="#color/off_white"
android:layout_above="#+id/relSendMessage" />
<RelativeLayout
android:id="#+id/relSendMessage"
android:layout_width="wrap_content"
android:layout_height="48dp"
android:background="#ddd"
android:paddingLeft="10dp"
android:layout_alignParentBottom="true">
<EditText
android:id="#+id/messageBodyField"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignBottom="#+id/sendButton"
android:layout_alignTop="#+id/sendButton"
android:layout_marginBottom="-4dp"
android:layout_marginRight="10dp"
android:inputType="text|textNoSuggestions"
android:layout_toLeftOf="#+id/sendButton"
android:background="#android:color/white"
android:hint="#string/message_elipses"
android:textColor="#000000"
android:textColorLink="#adefda"
android:textSize="14sp" />
<Button
android:id="#+id/sendButton"
android:layout_width="72dp"
android:layout_height="match_parent"
android:layout_alignParentRight="true"
android:layout_margin="4dp"
android:background="#drawable/button_send" />
</RelativeLayout>
<Button
android:id="#+id/iSchedule"
android:layout_width="120dp"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_alignParentTop="true"
android:alpha="0.7"
android:background="#C11B17"
android:text="Schedule"
android:textColor="#f2f2f2"
android:textSize="20sp"
android:textStyle="bold"
android:typeface="serif" />
</RelativeLayout>
I have been suggested the following, but I am not sure how to integrate it within the above code:
#Override
public int getCount() {
return 25;
}
Thanks in advance, and for any clarification, let me know.
Update
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.messaging);
feedBack = new FeedbackDialog(this, "ID");
final TextView iSchedule = (TextView) this.findViewById(R.id.iSchedule);
iSchedule.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
MessagingActivity1.this.startActivity(new Intent(MessagingActivity1.this, ScheduleMatchOptionActivity.class));
}
});
Parse.initialize(this, "ID", "ID");
bindService(new Intent(this, MessageService.class), serviceConnection,
BIND_AUTO_CREATE);
Intent intent = getIntent();
recipientId = intent.getStringExtra("RECIPIENT_ID");
currentUserId = ParseUser.getCurrentUser().getObjectId();
messageAdapter = new MessageAdapter(this);
#Override
public int getCount() {
messagesList.setAdapter(messageAdapter);
return 25;
}
messagesList = (ListView) findViewById(R.id.listMessages);
populateMessageHistory();
messageBodyField = (EditText) findViewById(R.id.messageBodyField);
findViewById(R.id.sendButton).setOnClickListener(
new View.OnClickListener() {
#Override
public void onClick(View view) {
sendMessage();
}
});
}
However, I receive the following error
in the live #override it says Syntax error on token(s), misplaced construct(s)
in the public int get count "Syntax error on token(s), misplaced construct(s)"
In the return 25 - Void methods cannot return a value
You want to use that code (or similar) to override the default getCount method in ListAdapter: http://developer.android.com/reference/android/widget/ListAdapter.html
You can check an example in: http://www.vogella.com/tutorials/AndroidListView/article.html#listview_listviewexample
Hey you want to get list with limit, you have two option
1. You set array list size,
2. You can set, when you get data put for loop and set limit
So I have simple listview with a list item that contains a textview, and two imageviews.
I want both of the imageviews to act as buttons. Unfortunately, I can't even get one of them to work. The list view loads but then the app crashes when either image is touched. Here is the xml for the listitem:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal" android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#drawable/bg_card">
<TextView
android:layout_width="wrap_content" android:layout_height="wrap_content"
android:textColor="#color/Black"
android:id="#+id/name"
android:textSize="20sp"
android:padding="16dp">
</TextView>
<LinearLayout
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="match_parent"
android:layout_gravity="right"
android:gravity="right">
<ImageView
android:layout_width="40dp"
android:layout_height="fill_parent"
android:id="#+id/email"
android:clickable="true"
android:src="#drawable/ic_action_email"
android:layout_margin="8dp"/>
<View
android:layout_width="2dp"
android:layout_height="match_parent"
android:background="#color/LightGrey" />
<ImageView
android:layout_width="40dp"
android:layout_height="fill_parent"
android:id="#+id/internet"
android:clickable="true"
android:layout_margin="8dp"
android:src="#drawable/ic_action_web_site" />
</LinearLayout>
</LinearLayout>
Here is the layout with the listview:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<ListView
android:id="#+id/lvDepartments"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:divider="#android:color/transparent"
android:dividerHeight="8dp"
android:padding="8dp"
android:smoothScrollbar="true"
android:scrollbarStyle="insideOverlay"
android:listSelector="#color/Navy"/>
</LinearLayout>
Here is the related java code:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.staff_layout);
staffmemberlist = (ListView)findViewById(R.id.lvDepartments);
ArrayAdapter<String> arrayAdapter =new ArrayAdapter<String> (getApplicationContext(),R.layout.emailbrowsingcard,R.id.name, d);
staffmemberlist.setAdapter(arrayAdapter);
mailbutton=(ImageView)findViewById(R.id.email);
mailbutton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Toast.makeText(getApplicationContext(),
"This line would appear on clicking this icon",
Toast.LENGTH_LONG).show();
}
});
}
this isnt going to work because the ImageView is in the item list so you should consider doing..
mailButton = (ImageView) row.findViewById(R.id.email);
where row is the item list. remember the ImageView isn't in staff_layout, it is in your item_layout.
to make it works you need to move this block:
mailbutton=(ImageView)findViewById(R.id.email);
mailbutton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Toast.makeText(getApplicationContext(),
"This line would appear on clicking this icon",
Toast.LENGTH_LONG).show();
}
});
to the getView() in your adapter class. and let the View get findViewById or have an instance of the item_layout view in order to reach the buttons.
you should use a custom adapter for that and in custom adapter use findViewById for finding imageviews and setting listener
this is a good tutorial: http://www.vogella.com/articles/AndroidListView/article.html
I'm a beginner in android and making my first app. Here, I had taken 3 textViews and a button named Add. When I click on this button, I need to show the content of 2 textViews on third textView. I used eventListener and buttonClick event but it doesn't work. Please guide me with the code of Add button.
First create the xml as below:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_height="fill_parent"
android:layout_width="fill_parent"
android:layout_gravity="center_horizontal"
android:orientation="horizontal"
android:layout_weight="1"
android:id="#+id/singleEmployee"
android:background="#ffffff">
<TextView
android:text="TextView"
android:id="#+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
<TextView
android:text="TextView"
android:id="#+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
<TextView
android:text="TextView"
android:id="#+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
<Button
android:text="Button"
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
</LinearLayout>
And then use this Java code to done your desire action:
public class MainActivity extends Activity {
/** Called when the activity is first created. */
TextView tv1,tv2,tv3;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.testing);
tv1 = findViewById(R.id.textView1);
tv2 = findViewById(R.id.textView2);
tv3 = findViewById(R.id.textView3);
tv1.setText("Hello");
tv2.setText("World");
Button add = findViewById(R.id.button1);
add.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
tv3.setText("");
String tvValue1 = tv1.getText().toString();
String tvValue2 = tv2.getText().toString();
tv3.setText("Value of First Text is: "+tvValue1+".And the value of second TextView is: "+tvValue2);
}
});
}