I am learning to make android apps and I have a problem with my hello world programs buttons.
Here's my code:
package com.Norwood.helloandroid; import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
import android.view.View;
import android.widget.Toast;
public class MainActivity extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
TextView tv = new TextView(this);
tv.setText("Hello, Android.");
setContentView(tv);
}
public void onclick01(View View)
{
Toast.makeText(this, "Will change in 1.2", Toast.LENGTH_SHORT).show();
}
public void onclick02(View View)
{
Toast.makeText(this, "Will change in 1.2", Toast.LENGTH_SHORT).show();
}
}
And my 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"
tools:context=".MainActivity" >
<TextView
android:id="#+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:text="#string/hello_world"
android:textSize="60sp" />
<Button
android:id="#+id/Button01"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:minHeight="92sp"
android:onClick="onclick01"
android:text="#string/ChangeCoulour"
android:textSize="22sp" />
<Button
android:id="#+id/Button02"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentBottom="true"
android:minHeight="92sp"
android:onClick="onclick02"
android:text="#string/Change_Text_Colour"
android:textSize="22sp" />
</RelativeLayout>
But when I run the app both on the emulator and on my android the buttons don't show up.
And they show up in the graphical layout of the XML file.
Thanks
Collin N.
try:
setContentView(R.layout.yourXml)
You cannot do it your way because you must set your view to your xml first. have setContentview on the line after onCreate
TextView tv = new TextView(this);
tv.setText("Hello, Android.");
setContentView(tv);//wrong
reply to comment:
Like this:
public class MainActivity extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.YOUR_XML_FILE_NAME);
TextView tv = new TextView(this);
tv.setText("Hello, Android.");
}
Related
When trying to run our app, we consistently have errors with conflicting fragments not letting us run the activity. Here's a screencast of the problem I am facing
As you can see, the app itself contains a multitude of problems, but my primary focus is getting the clicker to respond on the click. Here is the class page for the clicker activity:
package com.example.android.Chapsnat;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class ContactsFragment extends AppCompatActivity {
Button btnClick;
Button btnReset;
TextView txtCount;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.fragment_contacts);
btnClick = (Button)findViewById(R.id.buttonClick);
btnReset = (Button)findViewById(R.id.buttonReset);
txtCount = (TextView)findViewById(R.id.textViewCount);
btnClick.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
String countValue = txtCount.getText().toString();
int intCountValue = Integer.parseInt(countValue);
intCountValue++;
txtCount.setText(String.valueOf(intCountValue));
} });
btnReset.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
txtCount.setText(String.valueOf(0));
}
});
}
}
And this is the xml page it is being built in, which is also a fragment:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/fragment_contacts"
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="com.example.android.Chapsnat.ContactsFragment">
<TextView
android:id="#+id/textViewCount"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="66dp"
android:text="0"
android:textColor="#android:color/holo_purple"
android:textSize="40sp" />
<Button
android:text="Click"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/buttonClick"
android:layout_below="#+id/textViewCount"
android:layout_centerHorizontal="true"
android:layout_marginTop="79dp" />
<Button
android:text="Reset"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="171dp"
android:id="#+id/buttonReset"
android:layout_below="#+id/textViewCount"
android:layout_alignStart="#+id/buttonClick" />
</RelativeLayout>
Is there any way you can help? If so please let me know.
package com.me.trial;
import android.app.Activity;
import android.os.Bundle;
import android.view.View.OnClickListener;
import android.widget.ImageView;
public class TrialActivity extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
ImageView img = (ImageView)findViewById(R.id.imageView1);
img.setClickable(true);
OnClickListener l;
}
private void hasBeenClicked(<method invoked when the user has clicked>){
}
}
<?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" >
<LinearLayout
android:id="#+id/linearLayout1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
<RelativeLayout
android:id="#+id/relativeLayout1"
android:layout_width="match_parent"
android:layout_height="wrap_content" >
<TextView
android:id="#+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_marginLeft="56dp"
android:text="Large Text"
android:textAppearance="?android:attr/textAppearanceLarge" />
<EditText
android:id="#+id/editText1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/textView1"
android:layout_alignRight="#+id/textView1"
android:layout_below="#+id/textView1"
android:layout_marginTop="64dp" >
<requestFocus />
</EditText>
<ImageView
android:id="#+id/imageView1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:scaleType="fitEnd"
android:tag="Employee name"
android:src="#drawable/img18" />
</RelativeLayout>
</LinearLayout>
</LinearLayout>
I need the application to pass some string value associated to it to be passed into the text as soon as the user clicks on the image.How do i use the click Listeners in android to achieve the following task.
It is not necessary to fill in the code snippet that i have given.Any new ideas regarding the design are most welcome.
U can set text as Tag to the Image so that u can get that text onClick event. Tag can be set either in XML or dynamically.
public class TrialActivity extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
ImageView img = (ImageView)findViewById(R.id.imageView1);
img.setTag("YOur text");
img.setClickable(true);
img.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View arg0) {
String urText= arg0.getTag().toString();
EditText edt = (EditText)findViewById(R.id.editText1);
edt.setText(urText);
}
});
}
}
This code demonstrates how to achieve your requirement dynamically.
This is a simple shell app that will display number of files in data/app folder when button is clicked the textviews are aligned as they should be, but when the button is clicked the textview that displays the number of files is moved down one line. Why?
Here is the code and the main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/RelativeLayout1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_marginBottom="32dp"
android:text="Button" />
<TextView
android:id="#+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="#+id/textView2"
android:text="#string/user_apps" />
<TextView
android:id="#+id/tv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_below="#+id/textView2"
android:text="0" />
</RelativeLayout>
code:
package rs.test.rootapp;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class RootAppActivity extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
final Button button=(Button) findViewById(R.id.button1);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
String command[]={"su", "-c","ls /data/app | wc -l"};
Shell shell = new Shell();
String text = shell.sendShellCommand(command);
setNewTextInTextView(text);
}
});
}
public void setNewTextInTextView(String text){
//TextView tv= new TextView (this);
//tv.setText(text);
//setContentView(tv);
TextView tv =(TextView) findViewById(R.id.tv);
tv.setText(text);
}
}
Screenshots:
set the text in textview after done the trimming operation on it,may be this will work, try it
tv.setText(text.trim());
With looking very quickly it seems like the return from the command is coming with the text.. Try and replace the new line in text before setting the text in the TextView.
I'm very new with android development. I'm trying to develop an application, I decided to try out the code below but I keep getting errors when I try to open it on the emulator. please can anyone tell me what I'm doing wrong?
package hajara.android.MyRecipes;
import android.app.Activity;
import android.os.Bundle;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class MyRecipesActivity extends Activity {
Button btn;
TextView t1, t2;
EditText e;
#Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
setContentView(R.layout.main);
t1 = (TextView)findViewById(R.id.text1);
t2 = (TextView)findViewById(R.id.text2);
e = (EditText)findViewById(R.id.edit1);
btn=(Button)findViewById(R.id.button1);
btn.setOnClickListener((OnClickListener) this);
}
}
My main.xml file is
<?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" >
<TextView
android:id="#+id/text1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Enter a string:"
/>
<EditText android:id="#+id/edit1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:cursorVisible="true"
android:editable="true"
android:singleLine="true"
/>
<Button android:id="#+id/button1"
android:text="OK"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
<TextView
android:id="#+id/text2"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text=""
/>
</LinearLayout>
Your onClick listener is done incorrectly. I find it easier to simply create a method such as:
public void buttonOnClick(View v) {
// Do something
}
and within your XML layout file (ie. main.xml) invoke the onClick attribute:
<Button
...
android:onClick="buttonOnClick"
...
/>
I think you haven't Declared button Properly.
btn.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// Your Code Goes here
}
});
And Hope you have Declared your Activity in Manifest File.
i want to have a set of buttons and the focus on buttons should change periodically first i want to try it with 2 buttons.this is my main.xml file.
<?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/number_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_weight="0.72"
android:focusable="true"
android:gravity="center"
android:text="#string/number"
android:textSize="10pt" android:clickable="true"
android:focusableInTouchMode="true"/>
<Button
android:text="#string/contact"
android:textSize="10pt"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/contact_button"
android:layout_weight="1" android:layout_gravity="center"
android:focusable="true" android:gravity="center"
android:focusableInTouchMode="true"/>
</LinearLayout>
in the source code i have used FOCUS_LEFT,RIGHT and all other options ,but i am getting a run time exception. the orientation is set as vertical in linear layout.Please help me to sort out this problem, if anybody know how to set the timer option as well post it here
here is the code
package com.example.helloandroid;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
public class HelloandroidActivity extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Object o=null;
// o.toString();
// TextView tv = new TextView(this);
// tv.setText("Hello Andriod");
setContentView(R.layout.main);
Button mybtn= (Button)findViewById(R.id.number_button);
mybtn.requestFocus();
try
{
Button mybtn2= (Button)mybtn.focusSearch(View.FOCUS_DOWN);
mybtn2.requestFocus();
}
catch(Exception e)
{
Log.e("focus change","focus failed",e);
}
}
}
The problem is that you is finding a control in mybtn. Inside your activity you should call focusSearch in Activity context. Try this:
Button mybtn2 = (Button) focusSearch(View.FOCUS_DOWN);
if (mybtn2 != null)
mybtn2.requestFocus();