Android仿微信或支付宝方块密码输入框

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"   android:layout_width="fill_parent"   android:layout_height="wrap_content"   android:background="#ffffff"   android:paddingBottom="20dp"   android:paddingTop="30dp" >    <TextView     android:id="@+id/txtTitle"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:layout_centerHorizontal="true"     android:text="请输入验证码"     android:textStyle="bold"     android:textSize="22sp" />  <LinearLayout   android:id="@+id/layout"   android:layout_width="wrap_content"   android:layout_height="wrap_content"   android:layout_below="@+id/txtTitle"   android:layout_centerHorizontal="true"   android:layout_marginTop="10dp"   android:orientation="horizontal" >    <TextView     android:id="@+id/t1"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:background="@drawable/i1"     android:gravity="center"     android:inputType="number"     android:lines="1"     android:maxLines="1" />    <TextView     android:id="@+id/t2"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:background="@drawable/i1"     android:gravity="center"     android:inputType="number"     android:lines="1"     android:maxLines="1" />   <TextView     android:id="@+id/t3"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:background="@drawable/i1"     android:gravity="center"     android:inputType="number"     android:lines="1"     android:maxLines="1" />    <TextView     android:id="@+id/t4"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:background="@drawable/i2"     android:gravity="center"     android:inputType="number"     android:lines="1"     android:maxLines="1" />  </LinearLayout>  <EditText   android:id="@+id/editHide"   android:layout_width="wrap_content"   android:layout_height="wrap_content"   android:layout_alignBottom="@+id/layout"   android:layout_alignLeft="@+id/layout"   android:layout_alignRight="@+id/layout"   android:layout_alignTop="@+id/layout"   android:layout_weight="1"   android:background="#00000000"   android:cursorVisible="false"   android:ems="10"   android:inputType="number"   android:maxLength="4"   android:textColor="#00000000" />  <LinearLayout   android:layout_width="wrap_content"   android:layout_height="wrap_content"   android:layout_below="@+id/layout"   android:layout_centerHorizontal="true"   android:layout_marginTop="20dp" >    <Button     android:id="@+id/verifycode_ok"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:background="#fa8d70"     android:layout_marginRight="30dp"     android:textColor="#ffffff"     android:text="确定" />    <Button     android:id="@+id/verifycode_cancel"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:layout_marginLeft="30dp"      android:background="@color/index_time_but"     android:textColor="#ffffff"     android:text="取消" />  </LinearLayout>  </RelativeLayout> 

import android.app.Activity; import android.os.Bundle; import android.text.Editable; import android.text.TextWatcher; import android.widget.EditText; import android.widget.TextView;  public class MainActivity extends Activity {    TextView t1, t2, t3, t4, et;    String key = "";    @Override   protected void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     setContentView(R.layout.verifycode);     t1 = (TextView) findViewById(R.id.t1);     t2 = (TextView) findViewById(R.id.t2);     t3 = (TextView) findViewById(R.id.t3);     t4 = (TextView) findViewById(R.id.t4);     et = (EditText) findViewById(R.id.editText1);     et.addTextChangedListener(tw);   }    void setKey() {     char[] arr = key.toCharArray();     t1.setText("");     t2.setText("");     t3.setText("");     t4.setText("");     for (int i = 0; i < arr.length; i++) {       if (i == 0) {         t1.setText(String.valueOf(arr[0]));       } else if (i == 1) {         t2.setText(String.valueOf(arr[1]));       } else if (i == 2) {         t3.setText(String.valueOf(arr[2]));       } else if (i == 3) {         t4.setText(String.valueOf(arr[3]));       }     }   }    TextWatcher tw = new TextWatcher() {     @Override     public void onTextChanged(CharSequence s, int start, int before,         int count) {      }      @Override     public void beforeTextChanged(CharSequence s, int start, int count,         int after) {      }      @Override     public void afterTextChanged(Editable s) {       key = s.toString();       setKey();     }   }; } 

final AlertDialog dialog = new AlertDialog.Builder(mContext).create();    dialog.show();    dialog.getWindow().setContentView(R.layout.verifycode);t1 = (TextView) dialog.findViewById(R.id.t1);    t2 = (TextView) dialog.findViewById(R.id.t2);    t3 = (TextView) dialog.findViewById(R.id.t3);    t4 = (TextView) dialog.findViewById(R.id.t4);