Hoping to get into android app development so I'm doing some basic tutorials just now.
Just trying to get comfortable with the basics at the moment, one of which is using the Typeface class.
package org.me.myandroidstuff;
import android.os.Bundle;
import android.app.Activity;
import android.graphics.Typeface;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
public class HelloWorldActivity extends Activity implements OnClickListener
{
private View mainView;
private TextView tbox1;
private Button exitButton;
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mainView=(View)findViewById(R.id.mainView);
mainView.setBackgroundColor(getResources().getColor(R.color.silver));
tbox1 = (TextView)findViewById(R.id.textBox1);
tbox1.setTypeface(Typeface.MONOSPACE);
}
}
The line
tbox1 = (TextView)findViewById(R.id.textBox1);
Has a red cross beside it (I'm using eclipse) with the error
tbox1 cannot be resolved
Its been a while since i have used java, but as i aware the following code
create a new TextView object called tbox1
Assigns the tbox1 object the id specified in the xml for the TextView tag in an external main.xml
Then tbox1 executes the setTypeFace() method on itself?
Obviously I'm going wrong somewhere, any ideas? Something really simple no doubt...
You can't inform us about one error and neglect the others. Look at your code.
Besides what user370305 said, you have other problems. Namely, your Activity, according to the contract, implements OnClickListener but does not override the necessary onClick(View v) method. You must add it for the contract to be met.
So your code should look like:
package org.me.myandroidstuff;
import android.app.Activity;
import android.graphics.Typeface;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
public class HelloWorldActivity extends Activity implements OnClickListener {
private View mainView;
private TextView tbox1;
private Button exitButton;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mainView=(View)findViewById(R.id.mainView);
mainView.setBackgroundColor(getResources().getColor(R.color.silver));
tbox1 = (TextView)findViewById(R.id.textBox1);
tbox1.setTypeface(Typeface.MONOSPACE);
}
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
}
}
Remember, you can't talk about errors until you fix every other that might cause other errors to be falsely reported.
First try to set setContentView(R.layout.yourlayoutfilename); in onCreate().
1.) Delete line super.onCreate(savedInstanceState);
2.) Retype super.onCreate(savedInstanceState);
3.) Clean the Project
4.) Build the Project
Related
In the line txtPass=(EditText) findViewById(R.id.txtPass); it says casting 'findViewByld(...)' to 'EditText' is redundant. How do I fix this?
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.Button;
import android.widget.Toast;
import androidx.appcompat.app.AppCompatActivity;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
public class datainsert extends AppCompatActivity {
EditText txtPass, txtName, txtNum, txtEmail;
Button btnLogin, btnSignUp;
DatabaseReference reff;
Member member;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.signup);
txtPass=(EditText) findViewById(R.id.txtPass);
txtName=(EditText)findViewById(R.id.txtName);
txtNum=(EditText)findViewById(R.id.txtNum);
txtEmail=(EditText)findViewById(R.id.txtEmail);
btnLogin=(Button)findViewById(R.id.btnLogin);
btnSignUp=(Button)findViewById(R.id.btnSignUp);
reff= FirebaseDatabase.getInstance().getReference().child("Member");
member=new Member();
btnSignUp.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Float agea=Float.parseFloat(txtPass.getText().toString().trim());
Float hit= Float.parseFloat(txtName.getText().toString().trim());
Float dsa= Float.parseFloat(txtEmail.getText().toString().trim());
Long phn=Long.parseLong(txtNum.getText().toString().trim());
member.setName(txtName.getText().toString().trim());
member.setEmail(txtEmail.getText().toString().trim());
member.setHt(dsa);
member.setHm(hit);
member.setPh(phn);
member.setHt(agea);
reff.push().setValue(member);
Toast.makeText(datainsert.this,"data inserted sucessfully",Toast.LENGTH_LONG).show();
}
});
}
}```
Just remove the cast to remove the warning:
txtPass = findViewById(R.id.txtPass);
Java figured out what you wanted from findViewById, so there's no need to cast it. The message is not really an error (the existing code will compile and run just fine), so there's no harm in leaving it in. It's considered better style to remove redundancies.
Replace these lines
txtPass=(EditText) findViewById(R.id.txtPass);
txtName=(EditText)findViewById(R.id.txtName);
txtNum=(EditText)findViewById(R.id.txtNum);
txtEmail=(EditText)findViewById(R.id.txtEmail);
with these
txtPass=findViewById(R.id.txtPass);
txtName=findViewById(R.id.txtName);
txtNum=findViewById(R.id.txtNum);
txtEmail=findViewById(R.id.txtEmail);
Both the View Type and actual view are same i.e EditText so typecasting is not required in this case you can directly assign the values
To more know about TypeCasting Check this
Why do we always type cast in Android/Java?
I am trying to build a very simple Android app, with just instantiating one class, but for some reason it fails and doesn't build, I am probably making some fundamental mistake but am unable to figure out what it is.
package algon.app;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import anroid.widget.TextView;
import android.graphics.drawable.Drawable;
import android.content.Context;
public class AlgonActivity extends Activity
{
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
TextView t = new TextView(Context context);
setContentView(R.layout.main);
}
}
It just doesn't want to instantiate the TextView class, I can't understand why actually.
Thank you for response in advance
TextView t = new TextView(Context context);
should be:
TextView t = new TextView(this);
So I'm fairly new to Java coding and I'm trying to create a simple code to have an edit text value act as a url for an intent internet command. I'm using this in Eclipse and ADT. The following is my java code.
import android.widget.EditText;
import android.widget.Button;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View.OnClickListener;
import android.view.View;
import android.content.Intent;
import android.net.Uri;
public class MainActivity extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button button2 = (Button) findViewById(R.id.button2);
button2.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
EditText UR_L=(EditText) findViewById(R.id.ur_l);
String sUR_L= new String(UR_L.getText().toString());
Intent brwsrintnt = new Intent(Intent.ACTION_VIEW, Uri.parse(sUR_L));
startActivity(brwsrintnt);
}
});
In my layout I have a 2 buttons and an edit box but the edit box reflects a missing input type error. I have no idea how to fix this and I've looked many places.
Thanks,
David
I think your problem might be that the EditText is never intialized until you have already hit the button, so when you go to get text from it, it doesn't know the user has already entered something. Try moving
EditText UR_L=(EditText) findViewById(R.id.ur_l);
to just before you set the OnClickListener and see if anything changes
I wanted to navigate to a new page when clicking a button. Below are my both activities I have created. I am using eclipse and I am getting an error saying The method onClick(View) of type new View.OnClickListener(){} must override a superclass method on the main activity.
This is my main activity.
package com.example.grammer;
import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.support.v4.app.NavUtils;
public class MainActivity extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button grammerButton = (Button)findViewById(R.id.grammar);
grammerButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent intent = new Intent(MainActivity.this, Grammer.class);
startActivity(intent);
}
});
}
}
This is my second activity.
package com.example.grammer;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.support.v4.app.NavUtils;
import android.annotation.TargetApi;
import android.os.Build;
public class Grammer extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_grammer);
Button grammerButton = (Button) findViewById(R.id.grammar);
grammerButton.setOnClickListener(new View.OnClickListener() {
// #Override
public void onClick(View view) {
finish();
}
});
}
}
Removing the #override will remove the error, but then app is not working as intended.
Check this
OnClickListener() must override a superclass method?
Uncheck "Enable project specific settings", click "Configure Workspace Settings..." and change "Compiler Compliance Level" to 1.6 or above
Have this import statement
import android.view.View.OnClickListener;
There is no need to remove #Override Annotation.
Also calling finish() is not necessary. The hardware back button does the job.
When you press back button in Grammar Activity your current activity is popped from the back stack and the previous activity in the back stack takes focus. So there is no need to call finish() on button click.
http://developer.android.com/guide/components/tasks-and-back-stack.html
Also if you have a Button with id grammar in activity_grammer.xml it is ok.
Make sure you have a button with id grammar in activity_grammer.xml
You can read the topic id
http://developer.android.com/guide/topics/ui/declaring-layout.html
An ID need not be unique throughout the entire tree, but it should be unique within the part of the tree you are searching.
Change "Compiler Compliance Level" to 1.6. of java from project properties.
Place this code::
Just replace then name of layout and button id by your
import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class MainActivity extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.alayout);
Button grammerButton = (Button)findViewById(R.id.aId);
grammerButton.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View view) {
Intent intent = new Intent(MainActivity.this, Grammer.class);
startActivity(intent);
}
});
}
}
Just replace then name of layout and button id by your
import android.os.Bundle;
import android.app.Activity;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class Grammer extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.blayout);
Button grammerButton = (Button) findViewById(R.id.aId);
grammerButton.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View view) {
finish();
}
});
}
}
You are suppose to import the ViewClickListener namespace in your code.
Just Press ctrl + shift + O and it will add the relevant and missing namespaces in your project.
All you need is to import the library for OnClickListener. Just press ctrl + Shift + O in your eclipse and it will import the import android.view.View.OnClickListener file for you.
Try this..
First, You havn't import OnClickListener
import android.view.View.OnClickListener;
and second one
Button grammerButton = (Button) findViewById(R.id.grammar);
you are giving same name for both Button Ids in different layouts. Make sure you have a button with id grammar in activity_grammer.xml present are not.
I used samples from similar code to make this, unfortunately I'm not to sure what I did wrong.
The purpose of this app is to output text entered in a field to a TextView, where I changed the color, when a button is pressed.
package edu.wmich.project3
import android.os.Bundle;
import android.app.Activity;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.view.View.OnClickListener;
public class Main extends Activity {
String txtResult;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button text =(Button) findViewById(R.id.btnColor0);
final TextView result = ((TextView) findViewById(R.id.txtResult));
text.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
txtResult= getText(R.id.txtField0).toString();
result.setText(txtResult);
}
});
}
}
txtResult = (findViewById(R.id.txtField0)).toString();
will solve...
the problem is that you're using the method getText() from the Activity which has nothing to do with the TextField you're dealing with.
...what is the type of view of R.id.txtField0? I guess with this you can take it from here.