要求：

• 英文大寫字元（A~Z）
• 英文小寫字元（a~z）
• 數字（0~9）
• 除了英文句號特殊符號“.”，其他的不能使用

效果圖：

MainActivity程式碼：

 1 public class Test05Activity extends AppCompatActivity {
 2 
 3     @Override
 4     protected void onCreate(Bundle savedInstanceState) {
 5         super.onCreate(savedInstanceState);
 6         setContentView(R.layout.activity_test05);
 
 7         initView();
 8     }
 9 
10     private void initView(){
11         EditText passwordEdit = findViewById(R.id.passwordEdit);
12         Button btnClean = findViewById(R.id.btnClean);
13         LinearLayout passLayout = findViewById(R.id.passwordLayout);
14         View passView1 = findViewById(R.id.passwordView1);
 
15         View passView2 = findViewById(R.id.passwordView2);
16         btnClean.setOnClickListener(new View.OnClickListener() {
17             @Override
18             public void onClick(View v) {
19                 passwordEdit.setText(null);
20             }
21         });
22         passwordEdit.addTextChangedListener(new
 
 TextWatcher() {
23             @Override
24             public void beforeTextChanged(CharSequence s, int start, int count, int after) {
25 
26             }
27 
28             @Override
29             public void onTextChanged(CharSequence s, int start, int before, int count) {
30 
31             }
32 
33             @Override
34             public void afterTextChanged(Editable s) {
35                 if(s.toString().length() > 0){
36                     if(s.toString().length() == 1)
37                         passLayout.setVisibility(View.VISIBLE);
38                     switch (checkPassWord(s.toString())){
39                         case 1:
40                             passView1.setVisibility(View.GONE);
41                             passView2.setVisibility(View.GONE);
42                             break;
43                         case 2:
44                             passView1.setVisibility(View.VISIBLE);
45                             passView2.setVisibility(View.GONE);
46                             break;
47                         case 3:
48                             passView2.setVisibility(View.VISIBLE);
49                             break;
50                     }
51                 }else{
52                     passLayout.setVisibility(View.GONE);
53                 }
54             }
55         });
56     }
57 
58     private int checkPassWord(String passwordStr){
59         String regexZ = "\\d*";
60         String regexS = "[a-zA-Z]+";
61         String regexT = "\\W+$";
62         String regexZT = "\\D*";
63         String regexST = "[\\d\\W]*";
64         String regexZS = "\\w*";
65         String regexZST = "[\\w\\W]*";
66 
67         int pass = 0;
68         if (passwordStr.matches(regexZ)) {
69             return 1;
70         }
71         if (passwordStr.matches(regexS)) {
72             return 1;
73         }
74         if (passwordStr.matches(regexT)) {
75             return 1;
76         }
77         if (passwordStr.matches(regexZT)) {
78             return 2;
79         }
80         if (passwordStr.matches(regexST)) {
81             return 2;
82         }
83         if (passwordStr.matches(regexZS)) {
84             return 2;
85         }
86         if (passwordStr.matches(regexZST)) {
87             return 3;
88         }
89         return pass;
90     }
91 }

activity_test05.xml程式碼：

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 3     xmlns:app="http://schemas.android.com/apk/res-auto"
 4     xmlns:tools="http://schemas.android.com/tools"
 5     android:orientation="vertical"
 6     android:layout_width="match_parent"
 7     android:layout_height="match_parent"
 8     tools:context=".test02.Test05Activity">
 9     <LinearLayout
10         android:layout_marginLeft="10dp"
11         android:layout_marginRight="10dp"
12         android:orientation="horizontal"
13         android:layout_width="match_parent"
14         android:layout_height="45dp">
15         <EditText
16             android:id="@+id/passwordEdit"
17             android:hint="請輸入密碼"
18             android:singleLine="true"
19             android:maxLength="16"
20             android:digits="0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ."
21             android:layout_weight="1"
22             android:layout_width="0dp"
23             android:layout_marginRight="@dimen/dp_10"
24             android:layout_height="match_parent"/>
25         <Button
26             android:id="@+id/btnClean"
27             android:text="清除"
28             android:layout_width="80dp"
29             android:layout_height="match_parent"/>
30     </LinearLayout>
31     <LinearLayout
32         android:visibility="gone"
33         android:id="@+id/passwordLayout"
34         android:layout_marginRight="10dp"
35         android:layout_marginLeft="10dp"
36         android:gravity="center_vertical"
37         android:orientation="horizontal"
38         android:layout_width="match_parent"
39         android:layout_height="45dp">
40         <TextView
41             android:text="密碼強度："
42             android:textColor="#333"
43             android:textSize="16sp"
44             android:layout_width="wrap_content"
45             android:layout_height="wrap_content"/>
46         <View
47             android:background="#E03D06"
48             android:layout_width="40dp"
49             android:layout_height="15dp"/>
50         <View
51             android:visibility="gone"
52             android:id="@+id/passwordView1"
53             android:layout_marginLeft="5dp"
54             android:background="#F2831A"
55             android:layout_width="40dp"
56             android:layout_height="15dp"/>
57         <View
58             android:visibility="gone"
59             android:id="@+id/passwordView2"
60             android:layout_marginLeft="5dp"
61             android:background="#6A9F09"
62             android:layout_width="40dp"
63             android:layout_height="15dp"/>
64     </LinearLayout>
65 </LinearLayout>