As part of my attempt to create a memory game, I have placed 12 image buttons on my layout with id names imageButton1...imageButton12. I wrote an algrorithm to create an array called cards[12] with random values to represent which card (card1..card6) is behind each imageButton, so for example if cards[5]=4 then the card behind imageButton6 is card4.
Now, i'm trying to tell the program to show the appropraite card when clicking the imageButton using the array. I'm very new to android studio and as I understood I first need to use OnClickListener on all the buttons, so I done it using a loop. This is my code so far:
public class Memory extends AppCompatActivity implements OnClickListener{
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_memory);
int i;
int[] cards = new int[12];
// Algorithm here
for(i=1;i<=12;i++) {
String name = "imageButton" + i;
int resID = getResources().getIdentifier(name, "id", "com.amir.supermemory");
ImageButton btn = (ImageButton) findViewById(resID);
btn.setOnClickListener(this);
}
Now comes the onClick function, which performs the action of switching the appropraite image when clicked. The problem is I can't manage to pass the array cards[] which I created before into the function (it says "cannot resolve symbol 'cards'"), how do I do that?
public void onClick(View v) {
switch (v.getId()) {
case R.id.imageButton1:
ImageButton b = (ImageButton) findViewById(R.id.imageButton1);
String name = "card" + cards[0]; //cards is shown in red
int resID = getResources().getIdentifier(name, "drawable", "com.amir.supermemory");
b.setImageResource(resID);
break;
//copy paste forr all imageButtons
}
}
Any help is appreciated, thank you!
Because you are declaring your cards array locally in your OnCreate() you cannot access it in another method.
All you need to do is declare your cards array globally.
public class Memory extends AppCompatActivity implements OnClickListener{
int[] cards;
#Override
protected void onCreate(Bundle savedInstanceState) {
int i;
cards = new int[12];
...
}
You have declared cards[] as a local variable inside the onCreate method. Please declare it outside and try.
public class Memory extends AppCompatActivity implements OnClickListener{
int[] cards = new int[12];
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_memory);
int i;
// Algorithm here
for(i=1;i<=12;i++) {
String name = "imageButton" + i;
int resID = getResources().getIdentifier(name, "id", "com.amir.supermemory");
ImageButton btn = (ImageButton) findViewById(resID);
btn.setOnClickListener(this);
}
Related
Learning how to produce random numbers from arrays. The code will pick a random string during the onCreate method, but when the button is clicked there is no change to the string. Am I messing up the scope of my variables somehow? I really do not know what it wrong.
public class MainActivity extends AppCompatActivity {
String[] qArray; //initialize qArray
private static final Random rgen = new Random(); //sets the new Random method to the keyword rgen
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
qArray = getResources().getStringArray(R.array.qArray); //grabs string array in the XML file
String q = qArray[rgen.nextInt(qArray.length)];//generates a random index of qArray to set to q
TextView question = (TextView) findViewById(R.id.question); //sets the TextView to "question"
question.setText(q); //sets the text in "question" to q
}
public void onClick(View view){
Button button = (Button) view.findViewById(R.id.button_click);
button.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View view){
/*This should do the same thing as onCreate but each time
the button is pressed. I think the error is here.*/
String q = qArray[rgen.nextInt(qArray.length)];
TextView question = (TextView) findViewById(R.id.question);
question.setText(q);
}
});
}
}
First of all you haven't set click listener on button properly you made onClick method which is never called . Also you are getting the references of view multiple times you should do it like this.
public class MainActivity extends AppCompatActivity {
String[] qArray; //initialize qArray
private static final Random rgen = new Random(); //sets the new Random method to the keyword rgen
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
qArray = getResources().getStringArray(R.array.qArray); //grabs string array in the XML file
String q = qArray[rgen.nextInt(qArray.length)];//generates a random index of qArray to set to q
TextView question = (TextView) findViewById(R.id.question); //sets the TextView to "question"
question.setText(q); //sets the text in "question" to q
Button button = (Button) view.findViewById(R.id.button_click);
button.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View view){
/*This should do the same thing as onCreate but each time
the button is pressed. I think the error is here.*/
String q = qArray[rgen.nextInt(qArray.length)];
question.setText(q);
}
});
}
}
You either need to set the onClickListener in xml (in which case you don't need to set the listener in code), or you need to set the listener in onCreate. Right now its being set in a function named onClick, which is never called.
First, you never set the onClickListeren. You have a method which adds one, but you never call it. Move the code in the onClick method to your onCreate method. This will probably fix your problem.
If not, don't make your Random final and add this to your #Override onClick():
rgen = new Random(System.currentTimeMillis());
This will use a different seed every time
In my Activity I have one ImageView
XML Code:
<!-- FOTO LATERAL! -->
<ImageView
android:id="#+id/simbolo_raca"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
/>
<Button
android:id="#+id/button_save"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Ok. Seguinte Pergunta"
android:layout_gravity="right"
android:gravity="right"
android:paddingRight="30dip">
</LinearLayout>
This is the Activity:
public class QuestionarioActivityRaca extends Activity{
ImageView simbolo;
int position;
Button B_Save;
List<Drawable> List_imagens = new ArrayList<Drawable>();
#Override
public void onCreate(Bundle savedInstanceState) {
simbolo = (ImageView) findViewById(R.id.simbolo_raca);
B_Save = (Button) findViewById(R.id.button_save);
position = 0;
List_imagens.add(getResources().getDrawable(R.drawable.p1));
List_imagens.add(getResources().getDrawable(R.drawable.p2));
List_imagens.add(getResources().getDrawable(R.drawable.p3));
List_imagens.add(getResources().getDrawable(R.drawable.p4));
loadNewImage(position);
B_Save.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
loadNewImage(position);
position++;
}
});
}
// I Use this method to load the Image
public loadNewImage(int Page)
{
new Thread(new Runnable(){
#Override
public void run(){
simbolo.post(new Runnable(){
#Override
public void run()
{
simbolo.setImageDrawable(List_imagens.get(Page));
}
});
}
}).start();
}
The first time I call this method, (position = 0) the image doesnt loads. After that, the image is loading correctly.
How I have to do to load the image the first time?
(I can not load the image in the XML using android:src="#drawable/x") because the image could be different anytime.
EDITED!
There are a number of issues with the code sample you posted.
like writing int with a capital I.
Int position;
Not sending in a parameter with your method in the onClick:
public void onClick(View v) {
loadNewImage();
}
And several more in both your XML and code.
Is there a spesific reason you want to run a new thread every time for this task?
If you really need a thread, you have to declare your int as final in the method.
However, you should get your desired result with the code-sample below.
You have to modify your onClick to send the appropriate int for whatever drawable you want to use.
Good luck.
public class testactivity extends ActionBarActivity {
ImageView simbolo;
int position;
Button B_Save;
List<Drawable> List_imagens = new ArrayList<>();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_testactivity);
simbolo = (ImageView) findViewById(R.id.simbolo_raca);
B_Save = (Button) findViewById(R.id.button_save);
position = 0;
List_imagens.add(getResources().getDrawable(R.drawable.ic_drawer));
List_imagens.add(getResources().getDrawable(R.drawable.ic_check));
List_imagens.add(getResources().getDrawable(R.drawable.ic_action_add_package));
List_imagens.add(getResources().getDrawable(R.drawable.ic_action_exception));
loadNewImage(position);
final Random rand = new Random();
B_Save.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
loadNewImage(rand.nextInt(4));
}
});
}
public void loadNewImage(final int page)
{
simbolo.setImageDrawable(List_imagens.get(page));
}
}
first of all before the button gets clicked you call this function to load the initial image with loadNewImage(position); when the button is clicked you call this function loadNewImage(); i am guessing it works when the button is clicked because this loadNewImage(); method is ok and loadNewImage(int page); is not ok, because they are two different function.
Solving your problem if you want an integer object use Integer position or else go with int position and please let go of the thread. now your code will work
For my own practice I am a creating an array of 3 buttons in the instance field and i would like all of them to have setOnClickListeners,which allow each button to change the BackGround Color of a text View.Can any person please guide me towards the right direction.Here is my code:
public class MainActivity extends Activity {
Button b = {(Button)findViewById(R.id.button1),
(Button)findViewById(R.id.button2),
(Button)findViewById(R.id.button3),};
TextView tv;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tv = (TextView) findViewById(R.id.textView1);
for(int i=0; i < b.length;i++){
b[i].setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
if(butt[0].isPressed()){
tv.setBackgroundColor(Color.BLACK);
}
if(b[1].isPressed()){
tv.setBackgroundColor(Color.BLUE);
}
if(b[2].isPressed()){
tv.setBackgroundColor(Color.RED);
}
}
});
}
}
}
You aren't declaring an Array for your Buttons. I'm not sure what this would do or if it would even compile but I wouldn't think so
Button b = {(Button)findViewById(R.id.button1),
(Button)findViewById(R.id.button2),
(Button)findViewById(R.id.button3),};
Change it to
Button[] b = {(Button)findViewById(R.id.button1),
(Button)findViewById(R.id.button2),
(Button)findViewById(R.id.button3),};
Also, this code has to go after setcontentView() or you will get a NPE since your Buttons exist in your layout and your layout doesn't exist until you inflate it by calling setContentView().
You can declare your Array before onCreate() but you can't initialize them until you inflate your layout
So you can do something like this
public class MainActivity extends Activity {
Button[] b = new Button[3]; //initialize as an array
TextView tv;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
b = {(Button)findViewById(R.id.button1),
(Button)findViewById(R.id.button2),
(Button)findViewById(R.id.button3),}; //add buttons AFTER calling setContentView()
...
Edit Since #pragnani deleted his answer I will edit with a bit of it that is a good idea
You can simplify your logic by choosing which Button was clicked with a switch by doing something like below in your for loop
b[i].setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) { / v is the button that was clicked
switch (v.getId()) //so we get its id here
{
case (R.id.button1):
tv.setBackgroundColor(Color.BLACK);
break;
case (R.id.button2):
tv.setBackgroundColor(Color.BLUE);
break;
case (R.id.button3):
tv.setBackgroundColor(Color.RED);
break;
}
Can't work out a way to make an array of buttons in android.
This is the code I have tried but I'm getting a java.lang.NullPointerException.
private Button[] button = {(Button) findViewById(R.id.cGuess1),
(Button) findViewById(R.id.cGuess2),(Button)
findViewById(R.id.cGuess3),(Button) findViewById(R.id.cGuess4)};
Is this even possible?
EDIT:
Sorry everyone. Just realised my mistake!
I was trying to declare the array for my whole class and trying to get the views from the ids before onCreate so there was no setContentView(R.layout.game);
Sorry.
Since no one else posted actual code for a solution, here's a working snippet.
Button[] myButtons = null;
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
myButtons = new Button[]
{
(Button)findViewById(R.id.button1),
(Button)findViewById(R.id.button2),
(Button)findViewById(R.id.button3),
};
}
Just a guess as full code is not available here, have you called setContentView() before creating array.
Could you try
final Button[] button = {(Button) findViewById(R.id.cGuess1),
(Button) findViewById(R.id.cGuess2),(Button)
findViewById(R.id.cGuess3),(Button) findViewById(R.id.cGuess4)};
One of your buttons may be null. And putting a private keyword does not allow me to create the array. Also see that Firstly you are setting the cententView for your activity and then accessing these buttons.
public class main2 extends Activity{
final int[] button = {R.id.button1,R.id.button2,R.id.button3,R.id.button4,R.id.button5,
R.id.button6,R.id.button7,R.id.button8,R.id.button9,R.id.button10};
Button[] bt = new Button[button.length];
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.sign);
for(int i=0;i<button.length;i++){
final Context context = this;
final int b = i;
bt[b]= (Button) findViewById(button[b]);
Typeface font = Typeface.createFromAsset(getAssets(), "Angkor.ttf");
bt[b].setTypeface(font);
bt[b].setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
Intent myIntent = new Intent(context,r1.class);
startActivity(myIntent);
}
});
}
}
}
It's hard to explain in the title. Basically as far as I can tell the submit button is taking the name and placing it in the array like I want. What I need now is for the Play(done) Button to transfer the user and the data to the next class (which I believe is coded correctly) and I need it to start a game. The game which you will see in the second class (get the data from the previous) I need it to display the names from the names array 1 at a time and randomly assign them a task to do from the tasks array.
Currently the app is force closing after I click the play button. I'm linking both classes cause I'm pretty sure the problem is in the second class. Thanks for your help ahead of time.
Class1
public class Class1 extends Activity
{
int players=0;
String names[];
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.class1);
final EditText input = (EditText) findViewById(R.id.nameinput);
final ArrayList<String> names = new ArrayList<String>();
Button submitButton = (Button) findViewById(R.id.submit_btn);
submitButton.setOnClickListener(new View.OnClickListener()
{
public void onClick(View submit1)
{
players++;
for(int i=0; i < 6; i++)
{
names.add(input.getText().toString());
input.setText("");
}
}
});
Button doneButton = (Button) findViewById(R.id.done_btn);
doneButton.setOnClickListener(new View.OnClickListener()
{
public void onClick(View done1)
{
Intent done = new Intent(Class1.this, Game.class);
Bundle bundle = new Bundle();
bundle.putStringArrayList("arrayKey", names);
done.putExtra("players", players);
//done.putExtra("names", names[players]);
startActivity(done);
}
});
}
Game Class
public class Game extends Activity
{
int players, counter=0, score, ptasks,rindex;
String[] names, tasks;
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.game);
Bundle bundle = this.getIntent().getExtras();
String[] names = bundle.getStringArray("arrayKey");
Intent game = getIntent();
players = game.getIntExtra("players", 1);
//names = game.getStringArrayExtra("names");
Random generator = new Random();
tasks[0]= "";
tasks[1]= "";
tasks[2]= "";
tasks[3]= "";
tasks[4]= "";
tasks[5]= "";
tasks[6]= "";
tasks[7]= "";
tasks[8]= "";
tasks[9]= "";
while (counter <5)
{
for (int i = 0; i < players; i++)
{
TextView name1 = (TextView) findViewById(R.id.pname);
name1.setText( names[i]+":");
ptasks = 10;
rindex = generator.nextInt(ptasks);
TextView task = (TextView) findViewById(R.id.task);
task.setText( tasks[rindex]);
}
Button failButton = (Button) findViewById(R.id.fail_btn);
failButton.setOnClickListener(new View.OnClickListener()
{
public void onClick(View failed)
{
}
});
Button notButton = (Button) findViewById(R.id.notbad_btn);
notButton.setOnClickListener(new View.OnClickListener()
{
public void onClick(View notbad)
{
}
});
Button champButton = (Button) findViewById(R.id.champ_btn);
champButton.setOnClickListener(new View.OnClickListener()
{
public void onClick(View champp)
{
}
});
counter++;
}
}
Thought I should also mention that these buttons on the 2nd page I would like to assign a score to whichever name array person is up and keep track until the final round where it will display the winner. If anyone has any idea how to make that work.
Have you made sure to include the Game activity as an Application Node in your AndroidManifest?
If not, open your manifest to the application tab, on the bottom hit Add, and add an Activity of the name .Game
Without this, that intent never gets received by the other class.
You've already been told that you use non-initialized arrays here: EditText and using buttons to submit them. But also you're trying to get array extra, however you don't put it inside intent. And you're using uninitialized tasks array in Game class.