I surdenly noticed that My project starts throwing error anytime I try to access a resources that is a button. It underlines R.id.button. I dont understand why. I even deleted the last xml that I created but problem persist.
This is an example of my xml file
<?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="match_parent"
android:background="#drawable/layoutborder"
android:orientation="vertical" >
<TextView
android:id="#+id/chat"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:text="#string/stepone"
android:textAppearance="?android:attr/textAppearanceMedium"
android:textColor="#color/wine" />
<ImageView
android:id="#+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:src="#drawable/ai" />
<Button
android:id="#+id/drugdetails"
style="#style/smallButtonStyleBlackpearl"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="20dp"
android:layout_marginRight="20dp"
android:layout_marginTop="10dp"
android:text="#string/nextbut" />
</LinearLayout>
My Java code
package com.example.rhemahealthcare;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import com.actionbarsherlock.app.SherlockActivity;
import com.example.rhemahealthcare.R;
public class SteponeActivity extends SherlockActivity{
#Override
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.steponeactivity);
final Button button = (Button)findViewById(R.id.button1);
button.setOnClickListener(new OnClickListener(){
#Override
public void onClick(View v){
// TODO Auto-generated method stub
Intent intent = new Intent(SteponeActivity.this,SteptwoActivity.class);
startActivity(intent);
}
});
}
}
i think you change any button1 id buy clicking right click and choose edit id. this option changes all the ids with that name in all the layouts.
As #Aleks G gussed it right in the comment, you don't have any button with id as button1 in your xml file. You've mentioned it :
final Button button = (Button)findViewById(R.id.button1);
Use the appropriate ID or put one in your layout file.
I have figured out the problem. My button ids were automatically change to button1 so they did not reference their previous ids that I gave to them. Thanks alot
Related
so I was working on some basics of android when I stumbled upon this. I am trying to implement a listview(having its layout stored in file eachrow.XML)and a button on my app such that when the user clicks one button "schoollife", the listview automatically imports layout stored from other file "eachrow2.XML".
the layout of eachrow.xml consists of buttons only, while the layout of eachrow2.xml consists of buttons.
Everything seems to work fine, the user clicking the button imports the other layout , but the problem starts when user tries to click buttons from the second layout. in the error logs, it is stating that the button 'subject' causing a null pointer exception
eachrow.xml:
eachrow2.xml:
===========codes========
eachrow2.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="match_parent"
android:orientation="horizontal">
<Button
android:id="#+id/subjectbutton"
android:layout_width="wrap_content"
android:layout_height="100dp"
android:padding="1dp"
android:layout_margin="1dp"
android:textAllCaps="false"
android:background="#color/colorPrimary"
android:textColor="#color/white"
/>
<TextView
android:id="#+id/marksbox"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
android:textSize="20dp"
android:text="click the button to show marks of each subject"
android:textAlignment="center"
/>
</LinearLayout>
mainactivity.java:
package com.example.ansh.reportcard;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;
import java.util.HashMap;
public class MainActivity extends AppCompatActivity implements View.OnClickListener{
private ListView l;
private String[] d_myself;
private ArrayAdapter adp;
private HashMap<String,String> d_school;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
l=(ListView)findViewById(R.id.a_list);
d_myself= new String[]{"something"
};
d_school=new HashMap<>();
d_school.put("A","B");
Button B_myself= (Button)findViewById(R.id.myself);
B_myself.setOnClickListener(this);
Button B_school=(Button)findViewById(R.id.school);
B_school.setOnClickListener(this);
Button subject=(Button)findViewById(R.id.subjectbutton);
subject.setOnClickListener(this);
}
#Override
public void onClick(View view) {
if(view.getId()==R.id.myself){
adp=new ArrayAdapter(MainActivity.this,R.layout.eachrow,R.id.textView,d_myself);
l.setAdapter(adp);
}
if (view.getId()==R.id.school){
adp=new ArrayAdapter(MainActivity.this,R.layout.eachrow2,R.id.subjectbutton,d_school.keySet().toArray());
l.setAdapter(adp);
}
if (view.getId()==R.id.subjectbutton){
Button tmp=(Button)view;
CharSequence x=tmp.getText();
TextView t= (TextView) findViewById(R.id.marksbox);
t.setText(d_school.get(x.toString()));
}
}
}
According to my understanding to your question, You declaring the Button from the xml file activity_main.xml, Instead you should find it from the eachrow2.xml file.
The subjectbutton is in the eachrow2.xml so you need to find the view from this file only instead activity_main.xml.
I am new to android programming and there are a few things I don't quite know how to do yet. I am doing a course on udemy and was trying to put together everything I have learned up to a certain point.
What I am trying to do is have the user click on a button (i have 12) and have it bring up a textField where they can enter two numbers. I just want to be able to get the user's two numbers and i'm pretty sure I can figure out the rest ( I hope). I just don't understand how to go about doing this.
Any help would be much appreciated. Basically all I want to do is to be able to have the user click on one of the 12 buttons and be asked to enter two values, then take those values and perform a calculation on it.
Your xml could be like this:
<?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="match_parent"
android:orientation="vertical" >
<Button android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="#+id/b_ok"
android:text="Click Me"/>
<EditText android:layout_width="fill_parent"
android:layout_height="match_parent"
android:visibility="invisible"
android:id="#+id/et_showme"/>
</LinearLayout>
and your activity could be like this:
package com.william.kinaan.welcomeback;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
public class Test1 extends Activity implements OnClickListener {
private Button b_ok;
private EditText et_showme;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.test1);
initialize();
}
private void initialize() {
this.b_ok = (Button) findViewById(R.id.b_ok);
this.b_ok.setOnClickListener(this);
this.et_showme = (EditText) findViewById(R.id.et_showme);
}
#Override
public void onClick(View v) {
this.et_showme.setVisibility(View.VISIBLE);
}
}
Create an Activity that has 2 EditTexts
When user click a button the Activity is started and user can enter the Numbers
Try this.
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:paddingLeft="16dp"
android:paddingRight="16dp" >
<EditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/tv_id"
android:visibility="invisible"
android:text="sample text"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="click"
android:id="#+id/click"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true" />
</RelativeLayout>
And in your activity, you can do like this.
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_test);
Button button = (Button) findViewById(R.id.click);
final EditText text = (EditText) findViewById(R.id.tv_id);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
text.setVisibility(View.VISIBLE);
}
});
}
I have created a simple xml with one button and one edittext.
Upon clicking the button, i can get into the CallLog page.
Is it possible to display the selected numbers into my EditText, after i click on any numbers in my CallLog??
XML:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:baselineAligned="true"
android:orientation="horizontal" >
<EditText
android:id="#+id/edittext"
android:layout_width="172dp"
android:layout_height="wrap_content"
android:layout_weight="0.29"
android:hint="CONTACT NUMBER" >
<requestFocus />
</EditText>
<Button
android:id="#+id/btn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="CALL LOG" />
</LinearLayout>
Coding:
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
public class CallLogRetrieveActivity extends Activity {
Button myCallLogBtn;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
myCallLogBtn=(Button)findViewById(R.id.btn);
myCallLogBtn.setOnClickListener(new Button.OnClickListener(){
public void onClick(View v) {
Intent myIntent=new Intent();
myIntent.setAction(Intent.ACTION_CALL_BUTTON);
startActivity(myIntent);
}});
}
}
You should start reading manual and tutorial first, not asking here about elementary things that you'd simply know after doing RTFM. So "yes, you can". But now please do your homework, by reading "android call log tutorial" googled materials. Nobody here is going that for you.
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
public class ProjectActivity extends Activity{
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button tut1 = (Button) findViewById(R.id.tutorial1);
tut1.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
startActivity(new Intent("android.intent.action.TUTORIALONE"));
}
});
}
}
Followed a youtube tutorial but i am
Getting an error in this line:
setContentView(R.layout.main);
"Button cannot be resolved to a type"
I'm new to android dev so im confused. Help!
move your cursor to "button" in your code and select "Import button(android.widget)"..
use this in your xml :
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<Button
android:id="#+id/tutorial1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button" >
</Button>
</LinearLayout>
Do you have a Button definied in you main.xml layout?
Something like:
<Button android:text="Click me" android:id="#+id/tutorial1"
android:layout_width="wrap_content" android:layout_height="wrap_content"/>
Had you added follwoing in your root layout:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" />
Try below steps:
1. Remove the import android.R (may have been accidentally imported)
2. clean the project
3. build the project again
Move your cursor to "button" in your code and press ALT + Enter
I bold at which you have to press alt + enter
Button tut1 = **(Button)** findViewById(R.id.tutorial1);
I'm trying to get a simple onClick to fire from an ImageButton - it seems like a simple enough task, but I'm obviously missing something here.
Here is my java file:
package com.jlbeard.android.testapp;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ImageButton;
import android.widget.Toast;
public class testapp extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
//handle the button press
ImageButton mainButton = (ImageButton) findViewById(R.id.mainButton);
mainButton.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
//show message
Toast.makeText(testapp.this, "Button Pressed", Toast.LENGTH_LONG);
}
});
}
}
Here is my layout file:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<ImageView
android:id="#+id/whereToEat"
android:src="#drawable/where_to_eat"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_marginTop="8px"
/>
<ImageButton
android:id="#+id/mainButton"
android:src="#drawable/main_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:background="#null"
android:clickable="true"
android:onClick="mainButtonClick"
/>
</RelativeLayout>
It seems to me that I'm missing something simple... but can't seem to figure it out. Thanks!
You didn't run show() method on Toast object. Very common mistake :-)
You also might have a problem due to the manifest setting onClick
android:onClick="mainButtonClick"
If mainButtonClick exists on post 1.5 devices it may be called instead, overriding the one you're setting in code
In my case, the imageButton was displayed behind a list. Because the list was empty, the ImageButton was seen but onClick was never fired.
Adding android:elevation="5dp" in the screen xml solve my problem
Note that if I use Button instead of ImageButton, elevation is not required.