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

    TextView tv = (TextView) findViewById(R.id.tv);
    Uri contentUri = ContactsContract.CommonDataKinds.Phone.CONTENT_URI;

    ContentResolver resolver = getContentResolver();
    Cursor cursor = resolver.query(contentUri
 
, null, null, null, null);
    while(cursor.moveToNext()){
        String name = cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME));
        String num = cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));
        System.out
 
.println(num);
        a+=name+num+"\n";
    }
    tv.setText(a);
}

注意獲取電話號碼的方法一定是getString   。。。。用getLong  如果你寫入的電話號碼格式不同獲取不到