I'm trying to use droidParts, specifically the DI part. I'm testing 2 injections, InjectResource and InjectView, but the second one doesn;t seem to be working.
I have a simple default layout with a textView:
<TextView
android:id="#+id/text1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:text="#string/hello_world"
tools:context=".MainActivity" />
and here's my sample code:
import org.droidparts.annotation.inject.InjectResource;
import org.droidparts.annotation.inject.InjectView;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.widget.TextView;
public class MainActivity extends org.droidparts.activity.Activity {
#InjectView(R.id.text1) private TextView txtView;
#InjectResource(R.string.app_name) private String appName;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Log.v("testLog", appName);
txtView.setText("Test");
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
}
The InjectResource works properly and logs the String, but when it gets to the setText("Test"); line I get a nullPointerException. Is there anything else that needs to be done to use InjectView?
The content view needs to be set in preInject() as onCreate() is called right after the injection has been performed. And Views can't be found without layout information.
So the code should look like this:
#Override
public void onPreInject() {
setContentView(R.layout.activity_main);
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
txtView.setText("Test");
}
Related
I have two buttons on my main Activity, which both should lead to another activity, but when I run the code it is showing an error.
MainActivity.java is this:
package com.assignment2.courier;
import static android.icu.lang.UCharacter.GraphemeClusterBreak.V;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
public void second (View v){
Intent i = new Intent(this, adelivery.class);
startActivity(i);
}
}
}
This is the button code in activity_main.xml
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentStart="true"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:layout_marginStart="85dp"
android:layout_marginBottom="234dp"
android:onClick="second"
android:text="Arrange Delivery"
android:textSize="20sp" />
Error:
Failed to compile values file
What is the problem here?
The problem here is that the second function is inside the onCreate
You need to adapt the code as follows:
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void second (View v){
Intent i = new Intent(this, adelivery.class);
startActivity(i);
}
}
You should move second method out of the onCreate method; this is the problem in your code.
Please bear with me on this I'm new to android programming. I was trying to show an image on a button click in android but unfortunately my emulator is not showing the required output. Here is my layout.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: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" >
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/textView1"
android:layout_below="#+id/textView1"
android:layout_marginTop="14dp"
android:text="Button" />
</RelativeLayout>
main_activity.java
package com.example.app1;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.widget.Button;
import android.widget.ImageView;
import android.view.View;
import android.view.View.OnClickListener;
public class MainActivity extends Activity {
Button button;
ImageView image;
#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;
}
public void addListenerOnButton() {
button = (Button) findViewById(R.id.button1);
button.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View arg0) {
image.setImageResource(R.drawable.optimus);
}
});
}
}
I have included the image file under /res/drawable-mdpi. When I try running on emulator it does not show image on button click. Is there any problem with the code?
In your onCreate() method write this please :
Button theButton = (Button)findViewById(R.id.button1);
theButton.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
theButton.setBackgroundResource(R.drawable.optimus);
}
Assuming that you have an ImageView called imageView1,
You have to assign it, before using it.
So change this:
#Override
public void onClick(View arg0)
{
image.setImageResource(R.drawable.optimus);
}
to this
#Override
public void onClick(View arg0)
{
image = (ImageView) findViewById(R.id.imageView1);
image.setImageResource(R.drawable.optimus);
}
You have to write onclick method like this code and also you need to call addListenerOnButton method in the onCreate() method
package com.example.app1;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.widget.Button;
import android.widget.ImageView;
import android.view.View;
import android.view.View.OnClickListener;
public class MainActivity extends Activity {
Button button;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
addListenerOnButton();
}
#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;
}
public void addListenerOnButton() {
button = (Button) findViewById(R.id.button1);
button.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View arg0) {
button.setBackgroundResource(R.drawable.optimus);
}
});
}
}
Try This:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/background" <!-- you're adding this here -->
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" >
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/textView1"
android:layout_below="#+id/textView1"
android:layout_marginTop="14dp"
android:onClick="showImage" <!-- you're adding this here -->
android:text="Button" />
</RelativeLayout>
Then in the .java file...
Package com.example.app1;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.widget.Button;
import android.widget.ImageView;
import android.view.View;
import android.view.View.OnClickListener;
public class MainActivity extends Activity {
Button button;
ImageView image;
#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;
}
public void showImage(View view) {
RelativeLayout background = (RelativeLayout) findViewById(R.id.background);
background.setBackgroundResource(R.drawable.optimus);
} /* This is a whole new section of code to replace the onClick listener */
}
Since you're already using the XML Layouts, try to use the built in onClick listener whenever possible. You can do this by naming a function in your .java file called yourFunctionName with a single argument of (View view).
Then, in your XML, you need to point to it by adding android:onClick="yourFunctionName" for the view that needs the onClick method.
Lastly, you never had the image you were referring to actually pointing to anything. You simply said that the object "image" now used "R.drawable.optimus" but that Image was never used! So instead, I just pointed to placing it in the background of your RelativeView. If instead you wanted it in a separate image, you'll have to add an ImageView to the XML file and set the background resource for the ImageView the same way.
Best of luck on learning Android!
package mine.app;
import android.app.Activity;
import android.graphics.Color;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
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;
}
public void changeBackgroundColor(View view) {
setContentView(R.layout.color_list);
}
public void setBackgroundRed(View view) {
findViewById(R.layout.activity_main).setBackgroundColor(Color.RED);
setContentView(R.layout.activity_main);
}
}
When the app runs it creates a button that runs changeBackgroundColor. It then shows a button that runs setBackgroundRed which crashes the app.
Create a method in your MainActivity something like....
public void setActivityBackgroundColor(int color) {
View view = this.getWindow().getDecorView();
view.setBackgroundColor(color);
}
then call this function from your OnClickListener passing in colour whatever you want.
Change Your onCreate as Following
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
getWindow().setBackgroundDrawableResource(R.color.blue);// specify background drawable resource or background color resource here
}
calculated.java: (this has to command to show the calculated.xml layout)
public class Calculated extends Activity {
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.calculated);
}
}
older:
main class:
package com.barth.appie;
import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.EditText;
public class MainActivity extends Activity {
Button button1;
String text;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
addListenerOnButton();
}
public void addListenerOnButton() {
button1 = (Button) findViewById(R.id.buttoncalculate);
button1.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
EditText editText = (EditText)findViewById(R.id.editText1);
String text = editText.getText().toString();
Intent myIntent = new Intent(view.getContext(), Calculated.class);
startActivityForResult(myIntent, 0);
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
}
calculated.xml: (this is what it has to show after the button press)
<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/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_marginTop="42dp"
android:text="#string/text"
android:textAppearance="?android:attr/textAppearanceLarge" />
</RelativeLayout>
Furthermore I have <string name="text">Value</string> at strings.xml, and in the other class called calculated.class, I have it so that it outputs the calculated.xml ( which works fine)
What I want: I want to display text in calculated.xml, which is a string made in main.class, and i want the string to be the text filled in textfield called "editText1"
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.EditText;
public class MainActivity extends Activity {
Button button1;
String text;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
addListenerOnButton();
}
public void addListenerOnButton() {
button1 = (Button) findViewById(R.id.buttoncalculate);
button1.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
EditText editText = (EditText)findViewById(R.id.editText1);
String text = editText.getText().toString();
Intent myIntent = new Intent(view.getContext(),Calculated.class);
myIntent.putExtra("mytext",text);
startActivity(myIntent);
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
}
Calculated.java
public class Calculated extends Activity {
TextView mTextview;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.calculated);
mTextview = (TextView)findViewById(R.id.textView1);
mTextview.setText(getIntent().getStringExtra("mytext"));
}
calculated.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" >
<TextView
android:id="#+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_marginTop="42dp"
android:textAppearance="?android:attr/textAppearanceLarge" />
</RelativeLayout>
To send the data from one activity to another activity
MainActivity.java is first activity from where you want to send data to another activity.
Intent myIntent = new Intent(view.getContext(), Calculated.class);
myIntent.putExtra("text", text);
startActivity(myIntent);
Calculated.java is second activity which receive the intent data whatever you pass from MainActivity.java
String text = myIntent.getStringExtra("text");
TextView textView = (TextView)findViewById(R.id.textView1);
textView.setText(text);
I am trying to create a very simple help page in my app. The layout xml for the page contains only a textview that displays the help info. In the Eclipse layout view, the layout looks perfect... however, when i try to load it in the emulator (via an OptionsMenu) it comes up as a blank black screen. What am I doing wrong??
Here is the Code:
//This is my Help page code
package com.soapbox.servicerec;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.MenuItem;
public class HelpPage extends Activity {
private static final int INSERT_ID = Menu.FIRST;
private static final int ACTIVITY_CREATE=0;
protected void onCreate(){
setContentView(R.layout.help_page);
setTitle(R.string.help_title);
}
public boolean onCreateOptionsMenu(Menu menu) {
super.onCreateOptionsMenu(menu);
menu.add(0, INSERT_ID, 0, R.string.menu_insert);
return true;
}
public boolean onMenuItemSelected(int featureId, MenuItem item) {
switch(item.getItemId()) {
case INSERT_ID:
createNote();
return true;
}
return super.onMenuItemSelected(featureId, item);
}
private void createNote() {
Intent i = new Intent(this, NoteEdit.class);
startActivityForResult(i, ACTIVITY_CREATE);
}
}
AND the layout 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"
android:background="#android:color/white">
<TextView android:textSize="16px" android:textColor="#android:color/black" android:layout_height="fill_parent"
android:layout_width="fill_parent" android:gravity="center_horizontal" android:paddingLeft="10px"
android:paddingRight="10px" android:text="#string/help_text"/>
</LinearLayout>
You must have your onCreate() function defined as ::
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.help_page);
setTitle(R.string.help_title);
}
Your onCreate method signature is wrong.
notice the difference below
your method protected void onCreate()
proper way #Override public void onCreate(Bundle savedInstanceState)
The #Override notation is optional, but very useful because it ensure the method signature matches one from a parent class, helping prevent these situations.