I'm new to android development. I've noticed some similar questions but none of them really answered my question well enough that I could figure it out, or else they relied upon depreciated functions.
So far, I've created my main class. I want to open to a screen where the user inputs two numbers for the row and column length of a matrix they want to reduce
public class MainActivity extends AppCompatActivity {
public int numberOfRows;
public int numberOfColumns;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void setRows(View v3) {
EditText editTextRow = (EditText) findViewById(R.id.editText2);
if ("".equals(editTextRow.getText())) {
}
else {
numberOfRows = Integer.parseInt(editTextRow.getText().toString());
}
}
public void setColumns(View v2) {
EditText editTextCol = (EditText) findViewById(R.id.editText3);
if ("".equals(editTextCol.getText())) {
numberOfRows = Integer.parseInt(editTextCol.getText().toString());
}
}
public void reduce(View view){
if(numberOfRows != 0 && numberOfColumns != 0) {
}
else {
Intent intent = new Intent(this, ReduceMatrix.class);
Bundle bundle = new Bundle();
bundle.putInt("rows", numberOfRows);
bundle.putInt("cols", numberOfColumns);
intent.putExtras(bundle);
startActivity(intent);
}
}
}
I'm having trouble coming up with the next activity, where I want to dynamically create a matrix of editText...
public class ReduceMatrix extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_reduce_matrix);
Intent passedIntent = getIntent();
Bundle extras = passedIntent.getExtras();
int rowNum = extras.getInt("rows");
int colNum = extras.getInt("cols");
Could anyone explain how to go about doing this? I was thinking some sort of for loop, but I have a really hard time with the android layout. Should I be using tableLayout? or gridview? Whenever I have something like
layout = new LinearLayout(this);
It tells me that my qualifier must be in an expression?
You need to add it programmatically. Here's my solution :
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Intent passedIntent = getIntent();
Bundle extras = passedIntent.getExtras();
EditText[][] editTexts = new EditText[rowNum][colNum];
GridLayout gridLayout = new GridLayout(this);
//define how many rows and columns to be used in the layout
gridLayout.setRowCount(rowNum);
gridLayout.setColumnCount(colNum);
for (int i = 0; i < rowNum; i++) {
for (int j = 0; j < colNum; j++) {
editTexts[i][j] = new EditText(this);
setPos(editTexts[i][j], i, j);
gridLayout.addView(editTexts[i][j]);
}
}
setContentView(gridLayout);
}
//putting the edit text according to row and column index
private void setPos(EditText editText, int row, int column) {
GridLayout.LayoutParams param =new GridLayout.LayoutParams();
param.width = 100;
param.height = 100;
param.setGravity(Gravity.CENTER);
param.rowSpec = GridLayout.spec(row);
param.columnSpec = GridLayout.spec(column);
editText.setLayoutParams(param);
}
This will enable you to add EditText(s) dynamically.
Related
I made a TableLayout 3x3 in "Activity A"(Chose a Table Layout, because I thought it suits my needs)
7 of the 9 cells are clickable and open "Activity B" which is a custom number picker I made.
I used an intent to pass an array and other data to activiy B
The idea of my number picker is to set a value in the cell I just clicked in Activiy A(I wanted something like the calendarDatePicker)
In "Activity B" I have a method to update the values from "Activity A" and finish() "Activity B" when an image View is clicked wich works very fine except that it does not set the value for the clicked Text View
How can I set the TextValue from another activity when the TextValue is contained in a Table Layout?
I don't use intent, because honestly I don't know how to handle it when the "Activity B" is closed.
I mean where in "Activity A" should I handle this intent from "Activity B"
Using the debugger I found out that trying to set the text using the TextView Id does not works as it shows a "null" object in the debugger.
Activiy A
package com.example.racu.threebythree;
public class threebythree extends AppCompatActivity {
public static ArrayList<Integer> ColumnA = new ArrayList<Integer>();
public static ArrayList<Integer> ColumnB = new ArrayList<Integer>();
public static ArrayList<Integer> ColumnC = new ArrayList<Integer>();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_three_by_three);
for (int i = 1; i < 28; i++) {
if (i > 0 && i < 10)
ColumnA.add(i);
if (i > 10 && i < 19)
ColumnB.add(i);
if (i > 19 && i < 28)
ColumnC.add(i);
}
}
public void openNumberPicker(View v) {
// I used this to "guess" the location of the cell in the table layout as I could not find a way to do it.
String cellName = v.getResources().getResourceName(v.getId());
String cellLetter = cellName.substring(cellName.lastIndexOf("/") + 1);
// Send intent
Intent intent = new Intent(this, NumberPicker.class);
intent.putExtra("Id", (cellLetter.substring(0, 1) + cellLetter.substring(2)).toUpperCase());
switch (cellLetter.substring(0, 1)) {
case ("a"):
intent.putIntegerArrayListExtra("Column", ColumnA);
break;
case ("b"):
intent.putIntegerArrayListExtra("Column", ColumnB);
break;
case ("c"):
intent.putIntegerArrayListExtra("Column", ColumnC);
break;
}
intent.putExtra("Cell ID", v.getId());
startActivity(intent);
}
}
Avtivity B
package com.example.racu.threebythree;
public class NumberPicker extends AppCompatActivity {
GridView numberPicker;
ArrayList<Integer> numbersToDisplay;
TextView viewToDisplay;
ImageView ok, cancel;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_number_picker);
numberPicker = (GridView) findViewById(R.id.arrayNumbers);
viewToDisplay = (TextView) findViewById(R.id.number_to_select);
ok = (ImageView) findViewById(R.id.add_number_to_card);
ok.setClickable(false);
Intent intent = getIntent();
String idFromIntent = intent.getStringExtra("Id");
numbersToDisplay = intent.getIntegerArrayListExtra("Letter");
TextView numberPosition = (TextView) findViewById(R.id.numberPosition);
numberPosition.setText(idFromIntent);
final TextView chosenNumber = (TextView) findViewById(R.id.chosenNumber);
ArrayAdapter<Integer> adapter = new ArrayAdapter<Integer>(this, R.layout.number_for_picker, numbersToDisplay);
numberPicker.setAdapter(adapter);
numberPicker.setOnItemClickListener(new AdapterView.OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View v, int position, long id) {
chosenNumber.setText(((TextView) v).getText());
ok.setImageResource(R.drawable.ok_blue);
ok.setClickable(true);
}
});
}
public void updateThreByThree(View v) {
Intent intent = getIntent();
int currentCell = intent.getIntExtra("Cell ID", 0);
String idFromIntent = intent.getStringExtra("Id").substring(0, 1);
TextView chosenNumber = (TextView) findViewById(R.id.chosenNumber);
// Here I try to Set the text to the cell in Activity A, using its R.id, but in the debugger I get a null reference, therefore my app crashes
TextView currentCellToEdit = (TextView) findViewById(currentCell);
currentCellToEdit.setText(chosenNumber.getText());
int temp = Integer.parseInt(chosenNumber.getText().toString());
switch (idFromIntent) {
case "A":
threebythree.ColumnA.remove(Integer.valueOf(temp));
break;
case "B":
threebythree.ColumnB.remove(Integer.valueOf(temp));
break;
case "C":
threebythree.ColumnC.remove(Integer.valueOf(temp));
break;
}
finish();
}
public void cancel(View view) {
finish();
}
}
Thanks to Pavan for the hint I found two more very helpful post here and this one was EXACTLY what I was looking for.
Like that ( make sure you give the TableLayout an id ):
TableLayout tl = (TableLayout)findViewById( R.id.tableLayout );
TextView tv = (TextView)tl.findViewById( R.id.textView );
My app is crashing at the end of the array in bluestacks. I have no idea why.
When I click the next button at the end of the array, the app crashes. I also tested it on my phone, same result. The rest of the app functions as intended.
From what I know "i %= image_elements.length;" is supposed to be the function that loops the array.
I am pretty sure this is where the crash is coming from.
i++;
element.setImageResource(image_elements[i]);
name.setImageResource(image_names[i]);
i %= image_elements.length;
Full code below
public class Practice extends MainMenuActivity {
int i = 0;
final int[] image_elements = {
R.drawable.spr_elements_0,
R.drawable.spr_elements_1,
[...]
R.drawable.spr_elements_86,
R.drawable.spr_elements_87,
};
final int[] image_names = {
R.drawable.spr_name_0,
R.drawable.spr_name_1,
[...]
R.drawable.spr_name_86,
R.drawable.spr_name_87,
};
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.practice);
final ImageView element = (ImageView) findViewById(R.id.element);
final ImageView name = (ImageView) findViewById(R.id.name);
Button nextButton = (Button) findViewById(R.id.buttonNext);
nextButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
i++;
element.setImageResource(image_elements[i]);
name.setImageResource(image_names[i]);
i %= image_elements.length;
}
});
}
public void backButton(View view) {
Intent z = new Intent(this, MainMenuActivity.class);
startActivity(z);
}
}
You'll need to rearrange your code from this:
i++;
element.setImageResource(image_elements[i]);
name.setImageResource(image_names[i]);
i %= image_elements.length;
to this:
i++;
i %= image_elements.length;
element.setImageResource(image_elements[i]);
name.setImageResource(image_names[i]);
What happens otherwise is that the index is incremented beyond the boundaries of the array, and that is corrected afterwards with the modulus operator. You'll need to the the correction before you use the index.
i %= image_elements.length in this particular case, is essentially the same as
if( i == image_elements.length ) {
i = 0;
}
Arrays indices go from 0 to length-1.
You could get rid of the arrays entirely by looking up the resources by name, such as this:
final static int MAX_ELEMENTS = 88; // this includes 0..87
private int index = 0;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.practice);
final ImageView element = (ImageView) findViewById(R.id.element);
final ImageView name = (ImageView) findViewById(R.id.name);
final Resources res = this.getResources();
final String pkgName = this.getPackageName();
Button nextButton = (Button) findViewById(R.id.buttonNext);
nextButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
final int imgId = res.getIdentifier( "spr_elements_" + index, "drawable", pkgName );
final int nameId = res.getIdentifier( "spr_name_" + index, "drawable", pkgName );
element.setImageResource( imgId );
name.setImageResource( nameId );
index = (index+1) % MAX_ELEMENTS;
}
});
}
I am new to Android. I am showing Text in the TextView on Button click Randomly. On 1st Textview the Heading and on 2nd the explaination of that heading. I am able to show the Heading and Explaination Randomly and now I want if the Text is shown once should not be shown again means it will be removed. This is the point where I stuck. I am not able to remove the texts. Any help will be appreciated. I am posting my code here.
MainActivity.java
TextView text_heading,text_explain;
Button click;
Random random;
Integer [] array_heading ,array_explain ;
Integer int_text;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
text_heading = (TextView) findViewById(R.id.text_heading);
text_explain = (TextView) findViewById(R.id.text_explain);
click = (Button) findViewById(R.id.click);
click.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
text_heading.setText(array_heading.get(int_text)); //getting error
text_explain(array_explain.get(int_text)); //getting error
array_heading.remove(int_text); //getting error
array_explain.remove(int_text); //getting error
}
});
random = new Random();
array_heading = new Integer []{R.string.source_text1, R.string.source_text2, R.string.source_text3,
R.string.source_text6, R.string.source_text5, R.string.source_text4, R.string.source_text7,
R.string.source_text8, R.string.source_text9};
array_explain = new Integer []{R.string.source_text1_explain, R.string.source_text2_explain,
R.string.source_text3_explain,
R.string.source_text4_explain, R.string.source_text5_explain, R.string.source_text6_explain,
R.string.source_text7_explain,
R.string.source_text8_explain, R.string.source_text9_explain};
ArrayList<Integer> array_headingList = new ArrayList<Integer>(Arrays.asList(array_heading));
ArrayList<Integer>array_explainList = new ArrayList<Integer>(Arrays.asList(array_explain));
int_text = random.nextInt(array_headingList.size() - 1);
}
}
I am not able to remove the texts. Any help will be appreciated. I am
posting my code here.
To clean the content of the TextView you could pass null to setText. E.g
text_heading.setText(null);
If you want to change the content every time you click on the button, you have to move
int_text = random.nextInt(array_heading.length);
your onClick callback,
You should be aware of the fact that next int returns an int between [0, n). array_heading.length -1 is necessary only if you want to exclude R.string.source_text9_explain from the possible texts you want to show. Keep also in mind that if array_heading contains more items than array_explain you could get ArrayIndexOutBoundException
I would keep the strings together in an object:
public class Item {
private final int textId;
private final int textExplanationId;
public class Item(int textId, int textExplanationId){
this.textId = textId;
this.textExplanationId = textExplanationId;
}
public int getTextId(){return textId;}
public int getTextExplanationId(){return textExplanationId;}
}
Then I would store those in an ArrayList:
List<Item> items = new ArrayList<Item>(new Item[]{
new Item(R.string.source_text1, R.string.source_text1_explain),
new Item(R.string.source_text2, R.string.source_text2_explain),
//etc
});
Then I would shuffle that array once:
Collections.shuffle(items);
And read from it in order:
Item current = items.get(currentIndex++);
text_heading.setText(current.getTextId());
text_explain.setText(current.getTextExplanationId());
TextView text_heading,text_explain;
Button click;
Random random;
Integer [] array_heading ,array_explain ;
Integer int_text;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
text_heading = (TextView) findViewById(R.id.text_heading);
text_explain = (TextView) findViewById(R.id.text_explain);
click = (Button) findViewById(R.id.click);
random = new Random();
array_heading = new Integer []{R.string.source_text1, R.string.source_text2, R.string.source_text3,
R.string.source_text6, R.string.source_text5, R.string.source_text4, R.string.source_text7,
R.string.source_text8, R.string.source_text9};
array_explain = new Integer []{R.string.source_text1_explain, R.string.source_text2_explain,
R.string.source_text3_explain,
R.string.source_text4_explain, R.string.source_text5_explain, R.string.source_text6_explain,
R.string.source_text7_explain,
R.string.source_text8_explain, R.string.source_text9_explain};
ArrayList<Integer> array_headingList = new ArrayList<Integer>(Arrays.asList(array_heading));
ArrayList<Integer> array_explainList = new ArrayList<Integer>(Arrays.asList(array_explain));
int_text = random.nextInt(array_headingList.size() - 1);
click.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
text_heading.setText(array_headingList.get(int_text)); //getting error
text_explain.setText(array_explainList.get(int_text)); //getting error
array_headingList.remove(int_text); //getting error
array_explainList.remove(int_text); //getting error
}
});
}
}
You must use ArrayList for it.
ArrayList<Integer> heading = Arrays.asList(array_heading);
ArrayList<Integer> explain = Arrays.asList(array_explain);
Now set text from this arraylists. And when its set once remove it from the arraylist so it cannot be shown again.
Use like this
random = new Random();
array_heading = new Integer []{R.string.source_text1, R.string.source_text2, R.string.source_text3,
R.string.source_text6, R.string.source_text5, R.string.source_text4, R.string.source_text7,
R.string.source_text8, R.string.source_text9};
array_explain = new Integer []{R.string.source_text1_explain, R.string.source_text2_explain,
R.string.source_text3_explain,
R.string.source_text4_explain, R.string.source_text5_explain, R.string.source_text6_explain,
R.string.source_text7_explain,
R.string.source_text8_explain, R.string.source_text9_explain};
ArrayList<Integer> array_headingList = new ArrayList<Integer>(Arrays.asList(array_heading));
ArrayList<Integer> array_explainList = new ArrayList<Integer>(Arrays.asList(array_explain));
int_text = random.nextInt(array_headingList.size());
click.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
text_heading.setText(array_headingList.get(int_text));
text_explain.setText(array_explainList.get(int_text));
array_headingList.remove(int_text);
array_explainList.remove(int_text);
if(array_headingList.size() == 0){
click.setEnabled(false);
Toast.makeText(getApplicationContext(),"All text finished",Toast.LENGTH_SHORT).show();
} else if(array_headingList.size() == 1){
int_text = 0;
} else {
int_text = random.nextInt(array_headingList.size());
}
}
});
Every time an user click on the button it has to show "John - Sue" or "Sue - John".
I tried with this code:
public class MyActivity extends Activity {
ArrayList<String> names = new ArrayList<String>();
int p1, p2;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.myactivity);
names.add("John");
names.add("Sue");
Button b = (Button) findViewById(R.id.mybutton);
b.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
p1 = (int)Math.random();
if (p1 == 0)
p2 = 1;
else
p2 = 0;
String msg = names.get(p1) + " - " + names.get(p2);
AlertDialog msgbox = new AlertDialog.Builder(About.this).setTitle("Click here").setMessage(msg).create();
//msgbox.setPositiveButton("OK", null);
msgbox.setCancelable(true);
msgbox.show();
TextView textView = (TextView) msgbox.findViewById(android.R.id.message);
textView.setTextSize(16);
}
});
}
}
But i get always the same order, even i close and run again the app. How to do that?
If you want shuffle list:
Collections.shuffle(names)
If you want random int between 0 or 1 (nextInt(int) javadoc):
Random random = new Random();
int randomInt = random.nextInt(2);
Math.random() returns a number between 0 and 1. So when you cast it to int it will always be 0.
Try this:
p1 = (int)(Math.random()*2);
It happens because
p1 = (int)Math.random();
always gives you zero.
I am doing an application in which I have to display the numbers on TextView randomly and automatically with the help of Timer. I am able to get the random Numbers in the log without repeating, but I am not able to print the same on device please help me...
Regards,
Akki
Source:
//RandomNumber.java
public class RandomNumber extends Activity{
static Random randGen = new Random();
int tambolanum,count=0;
private Button previousbutton;
private Button startbutton;
private Button nextbutton;
int bingonum[]=new int[90];
boolean fill;
#Override public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.numbers);
LinearLayout number=(LinearLayout)findViewById(R.id.numbersview);
final TextView randomnum=(TextView)findViewById(R.id.numberstext);
previousbutton=(Button)findViewById(R.id.previous);
nextbutton=(Button)findViewById(R.id.next);
startbutton=(Button)findViewById(R.id.start);
startbutton.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
// Perform action on click
//--- Initialize the array to the ints 0-90
do{
fill = true;
//Get new random number
tambolanum = randGen.nextInt(90) + 1;
//If the number exists in the array already, don't add it again
for(int i = 0; i < bingonum.length; i++)
{
if(bingonum == tambolanum)
{
fill = false;
}
}
//If the number didn't already exist, put it in the array and move
//To the next position
if(fill == true)
{
bingonum[count] = tambolanum;
count++;
}
} while(count < 90);
for(i=0;i
{
randomnum.setText(Integer.toString(bingonum[i]);
}
}
setText(CharSequence text)
The problem you're having is that you're overwriting your text in every itteration of this loop:
for(i=0;i
{
randomnum.setText(Integer.toString(bingonum[i]);
}
You need to build your string first then set it. Something like:
StringBuilder sb = new StringBuilder();
for(i=0;i /* where's the rest of this for-statement? */
{
sb.append(Integer.toString(bingonum[i]);
}
randomnum.setText(sb.toString());