Actually i read the answers but i am in a confused state of what to do now.I am using Eclipse and i get the errors in the lines--
setContentView(R.layout.activity_main);
Clickhere=(Button)findViewById(R.id.button1);
getMenuInflater().inflate(R.menu.main,menu);
Here is the following code:-
package com.example.vaish;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
public class MainActivity extends Activity {
Button Clickhere;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Clickhere=(Button)findViewById(R.id.button1);
Clickhere.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
Intent i=new Intent(getApplicationContext(),MainActivity1.class);
startActivity(i);
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main,menu);
return true;
}
}
XML file:
<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/happy"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<TextView
android:id="#+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="" />
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:text="Clickhere" />
</RelativeLayout>
please help!!!
i need to get the errors cleared off.
Try cleaning your project, If R.java is still not build, there can be errors in your project. You can check exact errors in Problems tab as shown in below image:
Resolve the errors, then clean and build your project.
#Vaishnavi this is not an Error.
Means it is the Error in your XML file...Check XML File First.
Otherwise Try to Clean Your Project OR Build Your Project Properly.
That will solved Your Problem.
Don't Forget (R.) error will never Solve untill you will Remove Your Error from XML File.
Hope this will help you...(:
if setContentView(R.layout.activity_main); is line of code which cause of application crash it means you have written incorrect tags or syntax error.
What is your XML Layout code?
``
<TextView
android:id="#+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="" />
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:text="Clickhere" />
``
Add this import statement
import <your.package.name>.R;
For instance
import com.shivam.cleaner.R;
Related
When I look at my code in the editor, nothing seems to be a problem. However, when I run the code on my phone and try to go from one activity to another which features a floating action button, the floating action button cannot find the view by Id despite the ID being exactly the same in both java and XML.
My Java:
package com.test.app.app2_test1;
import android.support.design.widget.FloatingActionButton;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
public class TermsOfUse extends AppCompatActivity {
FloatingActionButton mFloatingActionButton;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.terms_of_use);
mFloatingActionButton = (FloatingActionButton) mFloatingActionButton.findViewById(R.id.terms_back_fab);
mFloatingActionButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
onBackPressed();
}
});
}
}
My XML:
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
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"
tools:context="com.test.app.app2_test1.TermsOfUse"
android:background="#color/backdrop">
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginBottom="44dp"
android:orientation="vertical">
</ScrollView>
<View
android:layout_gravity="bottom"
android:layout_width="match_parent"
android:layout_height="44dp"
android:background="#color/colorPrimary"
android:elevation="4dp"/>
<android.support.design.widget.FloatingActionButton
android:id="#+id/terms_back_fab"
android:layout_gravity="bottom"
android:layout_width="56dp"
android:layout_height="56dp"
android:layout_margin="16dp"
android:src="#drawable/ic_arrow_back"
app:pressedTranslationZ="12dp"/>
</android.support.design.widget.CoordinatorLayout>
The message that I get in my console is the following:
Attempt to invoke virtual method 'android.view.View android.support.design.widget.FloatingActionButton.findViewById(int)' on a null object reference
Any help would be appreciated.
You are treating a view as a child of its own!
Replace:
mFloatingActionButton = (FloatingActionButton) mFloatingActionButton.findViewById(R.id.terms_back_fab);
With:
mFloatingActionButton = (FloatingActionButton)findViewById(R.id.terms_back_fab);
I am trying to make a simple Planner app so I have an XML file with a ListView on it, and another XML file with an EditText and a sumbit button on it, and of course my Java files. I have done a ton of research but I can't find a working method to make it when I press the button, it adds the EditText stuff to the ListView as an item. Here is my code:
activity_main.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"
tools:context=".MainActivity" >
<ListView
android:layout_width="300dp"
android:layout_height="fill_parent"
android:id="#+id/event_list"
android:layout_alignParentStart="true"
android:layout_toStartOf="#+id/datePicker" />
<DatePicker
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/datePicker"
android:layout_alignParentTop="true"
android:layout_alignParentEnd="true" />
<CalendarView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/calendarView"
android:layout_alignBottom="#+id/datePicker"
android:layout_alignParentEnd="true" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="New Event"
android:id="#+id/button"
android:layout_centerVertical="true"
android:layout_alignEnd="#+id/datePicker"
android:layout_toEndOf="#+id/event_list"
android:background="#android:color/holo_blue_light"
android:onClick="newEvent"
android:textSize="20dp"
android:textColor="#android:color/white" />
</RelativeLayout>
new_plan.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:weightSum="1">
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/event_name"
android:hint="Event Name"
android:inputType="textCapWords"/>
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/event_date"
android:hint="Event Date" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Save"
android:id="#+id/button2"
android:layout_gravity="center_horizontal"
android:background="#android:color/holo_blue_light"
android:textSize="20dp"
android:textColor="#android:color/white" />
</LinearLayout>
MakePlan.java
package com.kass.planner;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
public class MakePlan extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.new_plan);
}
}
MainActivity.java
package com.kass.planner;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import java.util.ArrayList;
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void newEvent(View v){
Intent i = new Intent(this, MakePlan.class);
startActivity(i);}}
Please help, thank you.
Take a look on this google developers project. It's for animations but i think it also have the solution to your question.
https://developer.android.com/training/animation/layout.html
You should append data to the collection of items linked to your ListView via your adapter and notify your adapter that your data has changed. This illustration assumes that you have a List of String objects.
EditText editText = ...
List<String> list = ...
YourAdapter adapter = ...
ListView listView = ...
You must have done something like this to setup your listView.
listView.setAdapter(new YourAdapter(list, this));
Now on button click you should get the String in EditText, add it to your List and finally notify the adapter that your data has changed in order to update your ListView for e.g.
void OnButtonClick(View view){
String strToAdd = editText.getText().toString();
list.add(strToAdd);
adapter.notifyDataSetChanged();
}
I am developing my first andoid app and want to post some data to my php webservice. I have the following signup.xml form
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/signup_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context=".MainActivity">
<TextView
android:id="#+id/header"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/textView6"
android:layout_centerHorizontal="true"
android:layout_marginTop="20dp"
android:text="Please Register To Get Started"
android:textSize="20sp" />
.
.
.
<Button
android:id="#+id/signupbutton"
style="#android:style/Widget.Material.Button.Borderless"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/phone"
android:layout_centerHorizontal="true"
android:layout_marginTop="20dp"
android:background="#drawable/rg_bg"
android:text="Signup"
android:textColor="#ffffff"
android:textSize="20sp"
android:onClick="send" />
</RelativeLayout>
This is the corresponding code for the signup.java file
package com.example.abhi.myapplication2;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Button;
import android.widget.EditText;
public class signup extends ActionBarActivity {
EditText username,pass,cpass,mail,phn;
String uname,password,confirmpass,email;
int phone=0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.login);
username = (EditText)findViewById(R.id.username);
pass = (EditText)findViewById(R.id.password);
cpass = (EditText)findViewById(R.id.comfirmpass);
mail = (EditText)findViewById(R.id.email);
phn = (EditText)findViewById(R.id.phone);
Button signup = (Button)findViewById(R.id.signupbutton);
public void send(View v)
{
//Some code will go here
}
}
I am reading tutorials and trying to code now the tutorial says that for the signup button to work I need to create the public void send(View V) but this line throws an error - Cannot Resolve Symbol View
Why is this error coming up, and in the situation above where all I want to do is post some data to my php backend when user clicks on the signup button what should be the correct way of solving this situation?
Try import android.view.View;
IDE usually takes care of imports though, are you not using Android Studio or Eclipse?
I'm becoming mad because of this problem. I've searched a lot through the internet but no one is experiencing this problem like in my case.
What i'm doing is trying to debug a simple android app with my phone and Eclipse with ADT, composed by a TextView and a Button.
The button should write something in the TextView but actually I left the "Send" function empty.
Everytime i press that button, the app closes and in the Eclipse debug log there is an "IllegalStateException" error, related to a function called "ZygoteInit$MethodAndArgsCaller.run(), on line: 745
This is my code:
Main Activiy.java
package com.android_test.examples;
import com.example.android_test.R;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.TextView;
import android.widget.Button;
public class MainActivity extends Activity
{
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
#Override
public boolean onCreateOptionsMenu(Menu menu)
{
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
protected void Send()
{
}
}
and activity_main.xml:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/txt"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<requestFocus />
<Button
android:id="#+id/btnok"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_marginBottom="24dp"
android:onClick="Send()"
android:text="Invia" />
<EditText
android:id="#+id/txt"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_marginTop="104dp"
android:layout_toLeftOf="#+id/btnok"
android:ems="10" />
</RelativeLayout>
I'm really becoming mad because of this, please someone help me
Change protected void Send() {}
with
public void Send(View view) {}
and remove the brackets from the onClick property:
android:onClick="Send"
Change to
public void Send(View v)
{
}
and change
android:onClick="Send()"
to
android:onClick="Send"
http://developer.android.com/reference/android/view/View.html#attr_android:onClick
android:onClick
Name of the method in this View's context to invoke when the view is
clicked. This name must correspond to a public method that takes
exactly one parameter of type View. For instance, if you specify
android:onClick="sayHello", you must declare a public void
sayHello(View v) method of your context (typically, your Activity).
Please have a look at the following code
game_activity.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:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context=".Game" >
//Please note the GUI Has been removed
<include layout="#layout/common_status_bar"/>
</RelativeLayout>
Game.java
package game.games;
import android.os.Bundle;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.View.OnTouchListener;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;
import java.util.ArrayList;
import java.util.Collections;
public class Game extends Activity {
private ImageView goToLanguageSelection;
private ImageView goToInternet;
private Button giveUp;
private LayoutInflater layoutInflater;
private View commonView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_game);
layoutInflater= (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
commonView = layoutInflater.inflate(R.layout.common_status_bar, null);
//Intializing instance variables
goToLanguageSelection = (ImageView)commonView.findViewById(R.id.backToLanguageSelectionButton);
goToInternet = (ImageView)commonView.findViewById(R.id.internetButton);
giveUp = (Button)commonView.findViewById(R.id.giveUpButton);
flag = getIntent().getBooleanExtra("LANGUAGE", true);
//Add listeners
goToLanguageSelection.setOnClickListener(goToLanguageSelectionClicked);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.game, menu);
return true;
}
//Will get activated when the ThunderBolt image is clicked
private OnClickListener goToLanguageSelectionClicked = new OnClickListener()
{
#Override
public void onClick(View v)
{
// TODO Auto-generated method stub
Intent intent = new Intent(getBaseContext(),LanguageSelector.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);
}
};
}
common_status_bar.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:background="#373734"
android:orientation="horizontal" >
<ImageView
android:id="#+id/backToLanguageSelectionButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:paddingBottom="5dp"
android:layout_marginLeft="10dp"
android:layout_marginRight="15dp"
android:paddingTop="5dp"
android:src="#drawable/thunderbolt" />
<ImageView
android:id="#+id/internetButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:paddingBottom="5dp"
android:paddingTop="5dp"
android:src="#drawable/globe_small_2" />
<ImageView
android:id="#+id/justForFun"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:paddingBottom="5dp"
android:paddingTop="5dp" />
<Button
android:id="#+id/giveUpButton"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="right"
android:paddingTop="5dp"
android:paddingBottom="5dp"
android:text="Button" />
</LinearLayout>
Here, the common_status_bar.xml is a common layout. I have added this layout to game_activity.xml by <include layout="#layout/common_status_bar"/>.
It displays everything fine, no issue. But the case is I can't make any of it's elements to work. I have attached a OnClickListener to the first element of it, the goToLanguageSelection but it is not responding to the Click. I tested this by adding the click event to all other buttons, images as well (one at a time) and I got the same result. It is not responding to user click, or whatever.
Why this button and images in separate layout do not respond to the user events?
The commonView should not be created again.
If you want keep a reference of the common_status_bar.xml, you can give name it by an id, like the code below:
<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:paddingBottom="10dp"
android:paddingLeft="10dp"
android:paddingRight="10dp"
android:paddingTop="10dp" >
<include
android:id="#+id/common_status_bar"
layout="#layout/common_status_bar" />
</RelativeLayout>
Then, change this code:
commonView = layoutInflater.inflate(R.layout.common_status_bar, null);
to:
commonView = findViewById(R.id.common_status_bar);