如何通过单击Android中的按钮来更改布局中的视图？

Question

I'm taking Questions and Answers in String[] .The TextView has questions and RadioButton has corresponding answers. If Start Button is clicked, first set of question and answers is displayed in Linear Layout1 . If Next Button is clicked LinearLayout1 is replaced by next set of question with answers and again if Next Button is clicked next set of question has to be replaced and vice versa. Help me in writing code for Next Button

Note : Only LinearLayout 1 should be changed when clicking Next Button

code:

TextView tv;
RadioButton rb1, rb2;
Button bStart, bNext;
String question[] = { "Key Lime Pie is upcoming version",
        "Android is Middleware", "Which is latest Android version?" };
String answerA[] = { "True", "False" };
String answerB[] = { "True", "False" };
String answerC[] = { "Android 4.2", "Android 5" };

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.ques);
    tv = (TextView) findViewById(R.id.textView111);
    rb1 = (RadioButton) findViewById(R.id.radioButton1);
    rb2 = (RadioButton) findViewById(R.id.radioButton2);

    bStart = (Button) findViewById(R.id.startExam);
    bNext = (Button) findViewById(R.id.bNext);
    bStart.setOnClickListener(new View.OnClickListener() {

        public void onClick(View v) {
            // TODO Auto-generated method stub
            tv.setText(question[0]);
            rb1.setText(answerA[0]);
            rb2.setText(answerA[1]);
        }
    });
    bNext.setOnClickListener(new View.OnClickListener() {

        public void onClick(View v) {
            // TODO Auto-generated method stub
            tv.setText(question[1]);
            rb1.setText(answerB[0]);
            rb2.setText(answerB[1]);

        }
    });
}

Answer 1

Create a single array for answers. And declare tracking variables for questions and answers as:

  String answer[] = {"True", "False" , "True", "False", 
                     "Android 4.2", "Android 5" };
  int current = 0; // this is your new variable
  int ans = 1;     // this is initialized to 1, because 
                   // I assumed your first question and answer
                   // is displayed with the press of start button

Change your next button listener to this

public void onClick(View v) {
        current ++;
        if(current < question.length){
            tv.setText(question[current]);
            rb1.setText(answer[ans+=1]);
            rb2.setText(answer[ans+=1]);
        }

    }

Answer 2

This is a logic problem.

1. Merge all the answers into a multidimensional array.
2. Keep track of the current question.
3. Use the tracking variable to get the question title in question .
4. Use the tracking variable to get the answers in the multidimensional array of answers. This is the first dimension of the array.
5. You read the answers in that dimension and display them in rb1 and rb2 .

By using what you have there you will have problems extending that code. After all, are you really going to create a new variable for each different set of answers? It does not make any sense. A multidimensional array works.

However... although you can improve your arrays structure and use an int to keep track of the current displayed question (and thus increment it to get the next question after pressing the bNext ), I suggest you try to create more meaningful objects, like a Question class, with relevant members ( title , optionA , optionB , whatever...), especially because it looks like you're using this code to learn how to program a quiz-styled application.

Then you can create various questions and iterate through then.

But is that the issue there? No. The problem is keeping track of questions and answers. Use a multidimensional array with a tracking variable.

// edited: OK, I'm going to suggest something very quick for you:

static String[] questions = new String[] { "Question 1", "Question 2", "Question 3" };
static String[][] answers = new String[][] {
        {"Answer 1.a", "Answer 1.b"},
        {"Answer 2.a", "Answer 2.b"},
        {"Answer 3.a", "Answer 3.b"},
    };
int pos = -1;

void showNextAnswer() {
    pos++;
    tv.setText(questions[pos]);
    rb1.setText(answers[pos][0]);
    rb2.setText(answers[pos][1]);
}

bStart.setOnClickListener(new View.OnClickListener() {
    public void onClick(View v) {
        showNextAnswer();
    }
});

bNext.setOnClickListener(new View.OnClickListener() {
    public void onClick(View v) {
        showNextAnswer();
    }
});

As you can, both buttons do the same thing, so it's probably better to only use a next button.