Android -- 获取汉字的首字母

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity" >

    <EditText
        android:id="@+id/edit"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:hint="输入汉字" >
    </EditText>

    <Button
        android:id="@+id/button"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="button" >
    </Button>

    <TextView
        android:id="@+id/textView"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" >
    </TextView>

</LinearLayout>

public class MainActivity extends Activity {
    static final int GB_SP_DIFF = 160;
    // 存放国标一级汉字不同读音的起始区位码
    static final int[] secPosValueList = { 1601, 1637, 1833, 2078, 2274, 2302,
            2433, 2594, 2787, 3106, 3212, 3472, 3635, 3722, 3730, 3858, 4027,
            4086, 4390, 4558, 4684, 4925, 5249, 5600 };
    // 存放国标一级汉字不同读音的起始区位码对应读音
    static final char[] firstLetter = { 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h',
            'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'w', 'x',
            'y', 'z' };
    private EditText edit;
    private TextView text;
    private Button button;

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

        edit = (EditText) this.findViewById(R.id.edit);
        text = (TextView) this.findViewById(R.id.textView);
        button = (Button) this.findViewById(R.id.button);
        button.setOnClickListener(buttonListener);
        text.setText("拼音");
    }

    private View.OnClickListener buttonListener = new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            if (v == button) {
                String characters = edit.getText().toString();
                String spells = getSpells(characters);
                text.setText(spells);
            }
        }
    };

    public static String getSpells(String characters) {
        StringBuffer buffer = new StringBuffer();
        for (int i = 0; i < characters.length(); i++) {

            char ch = characters.charAt(i);
            if ((ch >> 7) == 0) {
                // 判断是否为汉字，如果左移7为为0就不是汉字，否则是汉字
            } else {
                char spell = getFirstLetter(ch);
                buffer.append(String.valueOf(spell));
            }
        }
        return buffer.toString();
    }

    // 获取一个汉字的首字母
    public static Character getFirstLetter(char ch) {

        byte[] uniCode = null;
        try {
            uniCode = String.valueOf(ch).getBytes("GBK");
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
            return null;
        }
        if (uniCode[0] < 128 && uniCode[0] > 0) { // 非汉字
            return null;
        } else {
            return convert(uniCode);
        }
    }

    /**
     * 获取一个汉字的拼音首字母。 GB码两个字节分别减去160，转换成10进制码组合就可以得到区位码
     * 例如汉字“你”的GB码是0xC4/0xE3，分别减去0xA0（160）就是0x24/0x43
     * 0x24转成10进制就是36，0x43是67，那么它的区位码就是3667，在对照表中读音为‘n’
     */
    static char convert(byte[] bytes) {
        char result = '-';
        int secPosValue = 0;
        int i;
        for (i = 0; i < bytes.length; i++) {
            bytes[i] -= GB_SP_DIFF;
        }
        secPosValue = bytes[0] * 100 + bytes[1];
        for (i = 0; i < 23; i++) {
            if (secPosValue >= secPosValueList[i]
                    && secPosValue < secPosValueList[i + 1]) {
                result = firstLetter[i];
                break;
            }
        }
        return result;
    }

}