code improvements

app/src/androidTest/java/com/example/Cat/ExampleInstrumentedTest.java

@@ -22,6 +22,6 @@ public class ExampleInstrumentedTest {
         // Context of the app under test.
         Context appContext = InstrumentationRegistry.getInstrumentation().getTargetContext();
 
-        assertEquals("com.example.orangesale_01", appContext.getPackageName());
+        assertEquals("com.example.Cat", appContext.getPackageName());
     }
 }

app/src/main/AndroidManifest.xml

@@ -10,18 +10,18 @@
         android:supportsRtl="true"
         android:theme="@style/AppTheme">
         <activity
-            android:name=".activity.activity.GoodsActivity"
+            android:name=".activity.GoodsActivity"
             android:exported="false" />
-        <activity android:name=".activity.activity.MainActivity">
+        <activity android:name=".activity.MainActivity">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
 
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
         </activity>
-        <activity android:name=".activity.activity.RegisterActivity" />
+        <activity android:name=".activity.RegisterActivity" />
-        <activity android:name=".activity.activity.UserActivity" />
+        <activity android:name=".activity.UserActivity" />
-        <activity android:name=".activity.activity.UserMessageActivity" />
+        <activity android:name=".activity.UserMessageActivity" />
     </application>
 
 </manifest>

app/src/main/java/com/example/Cat/activity/GoodsActivity.java

@@ -1,15 +1,14 @@
-package com.example.Cat.activity.activity;
+package com.example.Cat.activity;
 
-import androidx.appcompat.app.AppCompatActivity;
-import androidx.fragment.app.Fragment;
 import androidx.fragment.app.FragmentActivity;
 import androidx.fragment.app.FragmentManager;
 import androidx.fragment.app.FragmentTransaction;
 
 import android.os.Bundle;
-import android.view.View;
 
 import com.example.Cat.R;
+import com.example.Cat.fragment.ContentFragment;
+import com.example.Cat.fragment.TitleFragment;
 
 public class GoodsActivity extends FragmentActivity {
 

app/src/main/java/com/example/Cat/activity/MainActivity.java

@@ -1,4 +1,4 @@
-package com.example.Cat.activity.activity;
+package com.example.Cat.activity;
 
 import androidx.appcompat.app.AppCompatActivity;
 
@@ -8,12 +8,12 @@ import android.os.Bundle;
 import android.view.View;
 import android.widget.Button;
 import android.widget.EditText;
-import android.widget.ImageView;
 import android.widget.Toast;
 
 import com.example.Cat.R;
+import com.example.Cat.databaseoperation.User_Database;
+import com.example.Cat.entity.UserInfo;
 
-import java.util.ArrayList;
 import java.util.List;
 
 public class MainActivity extends AppCompatActivity implements View.OnClickListener {
@@ -58,16 +58,22 @@ public class MainActivity extends AppCompatActivity implements View.OnClickListe
     public void Verification(){
         //UserInfo info;
         Intent intent = new Intent(MainActivity.this, UserActivity.class);
-        intent.putExtra("username",usernameText.getText().toString());
+        //intent.putExtra("username",usernameText.getText().toString());
         User_Database user=new User_Database(MainActivity.this);
         SQLiteDatabase sqLiteDatabase=user.getReadableDatabase();
-        list=user.queryByName(sqLiteDatabase,usernameText.getText().toString());
+        UserInfo info=user.queryByName(sqLiteDatabase,usernameText.getText().toString());
         //info=list.get(0);
-        if(paswdEdit.getText().toString().equals(list.get(0).paswd)){
+        if(info!=null){
+            intent.putExtra("username",usernameText.getText().toString());
+            if(paswdEdit.getText().toString().equals(info.getPaswd())){
                 startActivity(intent);
             }
             else{
                 Toast.makeText(this, "密码错误！", Toast.LENGTH_SHORT).show();
             }
         }
+        else{
+            Toast.makeText(this, "用户不存在！", Toast.LENGTH_SHORT).show();
+        }
+    }
 }

app/src/main/java/com/example/Cat/activity/RegisterActivity.java

@@ -1,12 +1,10 @@
-package com.example.Cat.activity.activity;
+package com.example.Cat.activity;
 
 import android.content.Intent;
 import android.database.sqlite.SQLiteDatabase;
 import android.graphics.Color;
 import android.os.Bundle;
-import android.util.Log;
 import android.view.View;
-import android.view.Window;
 import android.widget.Button;
 import android.widget.EditText;
 import android.widget.RadioGroup;
@@ -17,6 +15,7 @@ import androidx.annotation.Nullable;
 import androidx.appcompat.app.AppCompatActivity;
 
 import com.example.Cat.R;
+import com.example.Cat.databaseoperation.User_Database;
 import com.lljjcoder.citypickerview.widget.CityPicker;
 
 public class RegisterActivity extends AppCompatActivity implements View.OnClickListener,RadioGroup.OnCheckedChangeListener {

app/src/main/java/com/example/Cat/activity/UserActivity.java

@@ -1,9 +1,10 @@
-package com.example.Cat.activity.activity;
+package com.example.Cat.activity;
 
 import android.app.Activity;
 import android.content.Intent;
 import android.os.Bundle;
 import android.view.View;
+import android.widget.Button;
 import android.widget.ImageView;
 import android.widget.LinearLayout;
 import android.widget.TextView;
@@ -15,6 +16,7 @@ import com.example.Cat.R;
 public class UserActivity extends Activity implements View.OnClickListener{
     private ImageView userIconImage;
     public String username;
+    Button button;
     private TextView usernameText;
     private LinearLayout usernameLine, userSettingLine,userProductLine;
 
@@ -36,6 +38,8 @@ public class UserActivity extends Activity implements View.OnClickListener{
         userProductLine = findViewById(R.id.user_product);
         userProductLine.setOnClickListener(this);
         userSettingLine.setOnClickListener(this);
+        button=findViewById(R.id.exit);
+        button.setOnClickListener(this);
         setData();
     }
 
@@ -51,14 +55,17 @@ public class UserActivity extends Activity implements View.OnClickListener{
     public void onClick(View v) {
         switch (v.getId()) {
             case R.id.user_product:
-                Intent intent2 = new Intent(this,GoodsActivity.class);
+                Intent intent2 = new Intent(this, GoodsActivity.class);
                 startActivity(intent2);
                 break;
             case R.id.user_setting:
-                Intent intent3 = new Intent(this,UserMessageActivity.class);
+                Intent intent3 = new Intent(this, UserMessageActivity.class);
                 intent3.putExtra("username",username);
                 startActivity(intent3);
                 break;
+            case R.id.exit:
+                Intent intent4 = new Intent(this, MainActivity.class);
+                startActivity(intent4);
         }
     }
 }

app/src/main/java/com/example/Cat/activity/UserMessageActivity.java

@@ -1,4 +1,4 @@
-package com.example.Cat.activity.activity;
+package com.example.Cat.activity;
 
 import androidx.appcompat.app.AppCompatActivity;
 
@@ -9,6 +9,8 @@ import android.view.View;
 import android.widget.TextView;
 
 import com.example.Cat.R;
+import com.example.Cat.databaseoperation.User_Database;
+import com.example.Cat.entity.UserInfo;
 
 import java.util.List;
 
@@ -29,11 +31,11 @@ public class UserMessageActivity extends AppCompatActivity implements View.OnCli
         username = intent.getStringExtra("username");
         User_Database user=new User_Database(UserMessageActivity.this);
         SQLiteDatabase sqLiteDatabase=user.getReadableDatabase();
-        list=user.queryByName(sqLiteDatabase,username);
+        UserInfo info=user.queryByName(sqLiteDatabase,username);
         user.close();
-        usernameText.setText(String.format("%s", list.get(0).username));
+        usernameText.setText(String.format("%s", info.getUsername()));
-        sexText.setText(String.format("%s",list.get(0).sex));
+        sexText.setText(String.format("%s",info.getSex()));
-        addressText.setText(String.format("%s", list.get(0).city));
+        addressText.setText(String.format("%s", info.getCity()));
     }
     private void init() {
         usernameText = findViewById(R.id.username);

app/src/main/java/com/example/Cat/databaseoperation/User_Database.java

@@ -1,4 +1,4 @@
-package com.example.Cat.activity.activity;
+package com.example.Cat.databaseoperation;
 
 import android.content.ContentValues;
 import android.content.Context;
@@ -7,7 +7,7 @@ import android.database.sqlite.SQLiteDatabase;
 import android.database.sqlite.SQLiteOpenHelper;
 import android.util.Log;
 
-import androidx.annotation.NonNull;
+import com.example.Cat.entity.UserInfo;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -46,9 +46,9 @@ public class User_Database extends SQLiteOpenHelper {
         values.put("sex", sex);
         values.put("city", city);
         //验证用户名是否存在
-        List<UserInfo> userListByName=queryByName(sqLiteDatabase,username);
+        UserInfo userListByName=queryByName(sqLiteDatabase,username);
         //存在返回“repeat”,不存在则继续添加
-        if(!userListByName.isEmpty()) return"repeat";
+        if(userListByName!=null) return"repeat";
         long res=sqLiteDatabase.insert("user", null, values);
         sqLiteDatabase.close();
         if(res==-1) return"false";
@@ -81,7 +81,7 @@ public class User_Database extends SQLiteOpenHelper {
     public List<UserInfo> queryData(SQLiteDatabase sqLiteDatabase) {
         Cursor cursor = sqLiteDatabase.query("user", null, null, null, null, null, "id ASC");
         List<UserInfo> list = new ArrayList<UserInfo>();
-        while (cursor.moveToNext()) {
+        while (cursor.moveToNext()&&cursor!=null) {
             int id = cursor.getInt(cursor.getColumnIndex("id"));
             Log.i("SQLite","id="+id);
             String username = cursor.getString(1);
@@ -100,16 +100,17 @@ public class User_Database extends SQLiteOpenHelper {
     }
 
     //根据传入用户名查询记录
-    public List<UserInfo> queryByName(SQLiteDatabase sqLiteDatabase,String name) {
+    public UserInfo queryByName(SQLiteDatabase sqLiteDatabase,String name) {
         Cursor cursor = sqLiteDatabase.query("user", null, "username=?", new String[]{name}, null, null, "id ASC");
-        List<UserInfo> list = new ArrayList<UserInfo>();
+        UserInfo list=null;
-        while (cursor.moveToNext()) {
+        //List<UserInfo> list = new ArrayList<UserInfo>();
+        while (cursor.moveToNext()&&cursor!=null) {
             int id = cursor.getInt(cursor.getColumnIndex("id"));
             String username = cursor.getString(1);
             String paswd = cursor.getString(2);
             String sex = cursor.getString(3);
             String city = cursor.getString(4);
-            list.add(new UserInfo(id, username, paswd, sex, city));
+            list=new UserInfo(id, username, paswd, sex, city);
         }
         cursor.close();
 //        sqLiteDatabase.close();

app/src/main/java/com/example/Cat/entity/UserInfo.java

@@ -1,4 +1,4 @@
-package com.example.Cat.activity.activity;
+package com.example.Cat.entity;
 
 public class UserInfo {
     int id;

app/src/main/java/com/example/Cat/fragment/ContentFragment.java

@@ -1,4 +1,4 @@
-package com.example.Cat.activity.activity;
+package com.example.Cat.fragment;
 
 import android.os.Bundle;
 
@@ -12,7 +12,7 @@ import android.widget.ImageView;
 import android.widget.TextView;
 
 import com.example.Cat.R;
-import com.example.Cat.activity.activity.MainActivity;
+import com.example.Cat.activity.GoodsActivity;
 
 
 public class ContentFragment extends Fragment {

app/src/main/java/com/example/Cat/fragment/TitleFragment.java

@@ -1,4 +1,4 @@
-package com.example.Cat.activity.activity;
+package com.example.Cat.fragment;
 import android.os.Bundle;
 
 import androidx.fragment.app.Fragment;
@@ -11,6 +11,7 @@ import android.widget.ListView;
 import android.widget.TextView;
 
 import com.example.Cat.R;
+import com.example.Cat.activity.GoodsActivity;
 
 
 public class TitleFragment extends Fragment {
@@ -42,7 +43,7 @@ public class TitleFragment extends Fragment {
             @Override
             public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
                 //通过activity实例获取另一个Fragment对象
-                com.example.Cat.activity.activity.ContentFragment content=(com.example.Cat.activity.activity.ContentFragment)((GoodsActivity)getActivity())
+                ContentFragment content=(ContentFragment)((GoodsActivity)getActivity())
                         .getSupportFragmentManager().findFragmentById(R.id.setcontent);
                 content.setText(contents[i]);
                 content.imageView.findViewById(R.id.icon11);

app/src/main/res/layout/activity_main.xml

@@ -5,7 +5,7 @@
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:orientation="horizontal"
-    tools:context=".activity.activity.GoodsActivity">
+    tools:context=".activity.GoodsActivity">
 
     <!--标题-->
     <!--内容-->

app/src/main/res/layout/content_user.xml

@@ -105,7 +105,6 @@
 
     <Button
         android:id="@+id/exit"
-        android:onClick="click"
         android:layout_width="fill_parent"
         android:layout_height="40dp"
         android:layout_gravity="center"