如何在Android我的应用程序中显示吐司正确？

Question

我正在使用Android Studio。 我想在应用程序中使用Toast显示“正确”或“不正确”的答案。 如何显示Toast消息？ 以下是我的代码：

public class LayarKuisUmumNo1 extends Activity {

Button bt;
TextView tv;
RadioGroup rg;
RadioButton rbu1, rbu2, rbu3, rbu4;

public static String question[] = { "Negara terluas keempat di dunia"};
String answer[] = { "Amerika"};
String opts[] = {   "Rusia", "Australia", "Amerika", "Indonesia" };
int position = 0;
public static int correct;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_layar_kuis_umum_no1);

    bt = (Button) findViewById(R.id.btnextu1);
    tv = (TextView) findViewById(R.id.pertanyaanu1);
    rg = (RadioGroup) findViewById(R.id.radioGroup2);
    rbu1 = (RadioButton) findViewById(R.id.rbu1a);
    rbu2 = (RadioButton) findViewById(R.id.rbu1b);
    rbu3 = (RadioButton) findViewById(R.id.rbu1c);
    rbu4 = (RadioButton) findViewById(R.id.rbu1d);

    tv.setText(question[position]);
    rbu1.setText(opts[position]);
    rbu2.setText(opts[position + 1]);
    rbu3.setText(opts[position + 2]);
    rbu4.setText(opts[position + 3]);

    bt.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            RadioButton selectedans = (RadioButton) findViewById(rg.getCheckedRadioButtonId());
            String selectedanstext = selectedans.getText().toString();

            if (selectedanstext == answer[position]) {
                correct++;
            }
            position++;
            if (position < question.length) {
                tv.setText(question[position]);
                rbu1.setText(opts[position * 4]);
                rbu2.setText(opts[position * 4 + 1]);
                rbu3.setText(opts[position * 4 + 2]);
                rbu4.setText(opts[position * 4 + 3]);
            } else {
                Intent in = new Intent(getApplicationContext(), LayarNilaiUmum1.class);
                startActivity(in);
            }
        }
    });
}
}

Answer 1

添加Toast消息的代码是这样，

    Toast.makeText(this, "ZOOM Or use Landscape mode",
            Toast.LENGTH_SHORT).show();

基本上，第一个参数是上下文，第二个参数是包含要显示的消息的字符串，最后一个参数是希望显示消息的持续时间。

Answer 2

这是我的代码：

public class MainActivity extends Activity {

    RadioGroup rg;
    RadioButton rbut1;
    Button bt;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        rg = (RadioGroup) findViewById(R.id.radioGroup1);

        bt = (Button) findViewById(R.id.button1);

        bt.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                int selectedId = rg.getCheckedRadioButtonId();
                rbut1 = (RadioButton) findViewById(selectedId);
                Toast.makeText(MainActivity.this, rbut1.getText().toString(),
                        Toast.LENGTH_SHORT).show();
            }
        });

    }
}