Question

我想打印A，B，C .....系列，但是当我点击按钮时，很遗憾就停止了，

public class MainActivity extends ActionBarActivity {

    protected void onCreate(Bundle savedInstanceState) {
                  super.onCreate(savedInstanceState);
                  setContentView(R.layout.activity_main);
    final TextView alphabets = (TextView) findViewById(R.id.alphabet);
    Button next = (Button) findViewById(R.id.button);
    View.OnClickListener listener = new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            String[] alpha= {"A","B","C" ,"D" ,"E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"};
            int alp = alpha.length;
            for (int i=0;i<=alpha.length;i++)
            alphabets.setText(alpha[i]);
            }
    };

    next.setOnClickListener(listener);

Answer 1

原因是IndexOutOfBoundException：

 for (int i=0;i<=alpha.length;i++)
    alphabets.setText(alpha[i]);
 }

将其更改为

for (int i=0;i<alpha.length;i++)
    alphabets.setText(alpha[i]);
}

使用您的代码尝试输入最后一个元素+1并且该元素不存在。

顺便说一句。您的textview只会显示最后一个元素！

编辑：

String[] alpha= {"A","B","C" ,"D" ,"E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"};
int alp = alpha.length;
StringBuffer alphabet = new StringBuffer();
for (int i=0;i<alpha.length;i++){
  alphabet.append(alpha[i]);
}
alphabets.setText(alphabet.toString());

Answer 2

试试这个

String alpha[30];    
alpha= {"A","B","C" ,"D" ,"E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"};

Android程序...编码错误

2 个答案: