android课程设计问题简介

Posted 2020-11-06 李刚blog

以下是从零开始一步一步幸苦摸索得来的一些经验和方法，虽然看不懂但还是坚持看坚持改，所以贵在坚持

1，第一个界面写入sp始终虚拟即出现错误，后来再lab3上面修改

lab3原来是登陆界面并把用户和密码写入sp中。

只是把写sp改为注册，并消除界面信息

loginBt.setOnClickListener(new OnClickListener(){
                  public void onClick(View v){
                        if(qqNo.getText().toString().equals("")||qqPsw.getText().toString().equals("")){
                              Toast toast = Toast.makeText(getApplicationContext(), "请输入学号，姓名", Toast.LENGTH_SHORT);
                              toast.show();
                        }                 
                        else{
                              //通过Editor对象存储key-value键值对数据
                                                            edit.putString("qqno",qqNo.getText().toString());
                                                            edit.putString("qqpwd",qqPsw.getText().toString());
                                                            //edit.putString("班级",banji.getText().toString());
                                                            //通过commit()方法提交数据
                                                            edit.commit(); 
                                                            Toast toast = Toast.makeText(getApplicationContext(),
                                                                        "注册成功", Toast.LENGTH_SHORT);
                                                            toast.show();
                                                            qqNo.setText("");
                                                            qqPsw.setText("");
                        }
                  }
            });

登陆按钮。比较登陆的用户密码与sp做比较，然后跳转.跳转是一个麻烦事

Rdsp.setOnClickListener(new OnClickListener(){
                  public void onClick(View v){
                        /*if(null!=sp.getString("qqno",""))
                        {
                              qqNo.setText(sp.getString("qqno",""));
                        }
                        if(null!=sp.getString("qqpwd",""))
                        {
                              qqPsw.setText(sp.getString("qqpwd",""));
                        }*/
                        
                        if(qqNo.getText().toString().equals(sp.getString("qqno",""))&
                                    qqPsw.getText().toString().equals(sp.getString("qqpwd","")))
                        {
                              Toast toast = Toast.makeText(getApplicationContext(),
                                    "登陆成功", Toast.LENGTH_SHORT);
                              toast.show();
                              Intent intent = new Intent (MainActivity.this,addressbook.class);                
                              startActivity(intent);              
                              MainActivity.this.finish();
                              
                        }
                        else
                        {
                              Toast toast = Toast.makeText(getApplicationContext(),
                                          "登陆失败", Toast.LENGTH_SHORT);
                              toast.show();
                        }
                  }
            });

 

2，界面跳转问题

新建.java文件，选择父类Oncreate方法

Intent intent = new Intent (MainActivity.this,addressbook.class);                
                              startActivity(intent);              
                              MainActivity.this.finish();

 跳转后的界面

protected void onCreate(Bundle savedInstanceState) {
            // TODO Auto-generated method stub        
            super.onCreate(savedInstanceState);       
            this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN); 
            requestWindowFeature(Window.FEATURE_NO_TITLE); 
            setContentView(R.layout.addressbook);
      }

在androidManifest.xml文件中注册活动

<application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.dxxy.lab3.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
       
        <activity
            android:name=".addressbook"
            android:label="@string/app_name" >
           
        </activity>

3，添加朋友，加入朋友表，并根据weichat判断是否重复添加（借鉴 第十四章 EasyNotepad）

建表  但自己不懂这种方法的详细操作步骤只会判断是否添加重复，不会查找里面数据（在后面提到用另外的一种建表方法解决）

public class SqlHelp extends SQLiteOpenHelper {
      static int Ver = 1;// 数据库的版本号
      public static String TableUser = "User";// 用户表
      public static String TableNote = "Note";// 日记表
      public static String DBName = "Np.db";// 数据库名字
      // 多态构造函数
      public SqlHelp(Context context, String name, CursorFactory factory,
                  int version) {
            super(context, name, factory, version);
            // TODO 自动生成的构造函数存根
      }
      // 多态构造函数
      public SqlHelp(Context context, String name, int version) {
            this(context, name, null, version);
            // TODO 自动生成的构造函数存根
      }
      // 多态构造函数
      public SqlHelp(Context context, String name) {
            this(context, name, Ver);
            // TODO 自动生成的构造函数存根
      }
      // 创建数据库
      @Override
      public void onCreate(SQLiteDatabase db) {
            // TODO 自动生成的方法存根
            String sql = "Create Table "
                        + TableUser
                        + "(password long primary key ,username varchar(100))";
            db.execSQL(sql);
            sql = "Create Table "
                        + TableNote
                        + "(id integer primary key autoincrement,title varchar(100),plain varchar(100),date varchar(100))";
            db.execSQL(sql);
      }
      // 更新数据库
      @Override
      public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
            // TODO 自动生成的方法存根
      }
}

 判断

public class friendadd extends Activity {
      
      Button regButton;
      EditText usernameEditText;
      EditText passwordEditText;
      // 2 数据库操作变量
      SQLiteDatabase db;
      SqlHelp dbhelp;
//    @Override
      protected void onCreate(Bundle savedInstanceState) {
            // TODO Auto-generated method stub
            super.onCreate(savedInstanceState);
             this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
         requestWindowFeature(Window.FEATURE_NO_TITLE);
         setContentView(R.layout.friendadd);
        
        usernameEditText = (EditText) findViewById(R.id.friend_user);
        passwordEditText = (EditText) findViewById(R.id.friend_weichat);
            
            regButton = (Button) findViewById(R.id.tianjia);
      // 3 用户注册功能
                  regButton.setOnClickListener(new OnClickListener() {
                        @Override
                        public void onClick(View v) {
                              // TODO 自动生成的方法存根
                              dbhelp = new SqlHelp(friendadd.this, SqlHelp.DBName);
                              db = dbhelp.getReadableDatabase();
                              Cursor cursor = db.query(SqlHelp.TableUser, null, "password=?",
                                          new String[] { passwordEditText.getText().toString()
                                                      .trim() }, null, null, null);
                              int a = cursor.getCount();
                              db.close();
                              cursor.close();
                              if (usernameEditText.getText().toString().trim().equals("")
                                          || passwordEditText.getText().toString().trim()
                                                      .equals("")) {
                                    Toast.makeText(friendadd.this, "用户名或密码不能为空!",
                                                Toast.LENGTH_LONG).show();
                              } else if (a == 0) {
                                    db = dbhelp.getWritableDatabase();
                                    ContentValues values = new ContentValues();
                                    values.put("username", usernameEditText.getText()
                                                .toString().trim());
                                    values.put("password", passwordEditText.getText()
                                                .toString().trim());
                                    db.insert(SqlHelp.TableUser, null, values);
                                    Toast.makeText(friendadd.this, "添加朋友成功!",
                                                Toast.LENGTH_LONG).show();
                              } else {
                                    Toast.makeText(friendadd.this, "微信号重复!",
                                                Toast.LENGTH_LONG).show();
                              }
                        }
                  });
      
      }

 

4，今天解决的问题，界面跳转问题·，并带上数据

  Intent intent = new Intent();
  intent.putExtra("name",usernameEditText.getText().toString() );
  intent.putExtra("weichat",passwordEditText.getText().toString());
  intent.setClass(friendadd.this,addressbook.class);
  friendadd.this.startActivity(intent);

跳转后的页面取出数据

Intent intent = getIntent();
        String tnNumber = intent.getStringExtra("name");
        String payMode = intent.getStringExtra("weichat");
       
        ll = (ListView) findViewById(R.id.listView1);             
            ArrayList<HashMap<String,Object>> users = new ArrayList<HashMap<String, Object>>();
            
            HashMap<String, Object> user = new HashMap<String, Object>();
            user.put("pic",tnNumber);                 
            user.put("small", payMode);   
            users.add(user);
            
                  
            SimpleAdapter adapter = new SimpleAdapter(this, users, R.layout.detail, new String[]{"pic","small",},
                              new int[]{R.id.text1,R.id.text2});
                  
            ll.setAdapter(adapter);

 5，单击一个listview，跳转到另外一个activity

private ListView ll;
ll = (ListView) findViewById(R.id.listView1)
ll.setOnItemClickListener(new AdapterView.OnItemClickListener() {
    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
        //position 点击的Item位置，从0开始算
        Intent intent=new Intent(addressbook.this,friendadd.class);
        intent.putExtra("xx","");//传递给下一个Activity的值
        startActivity(intent);//启动Activity
    }
});

 

6，qq的聊天功能 三大程序

ChatActivity.java ,ChatMsgViewAdapter.java ,ChatMsgEntity.java

public class ChatActivity extends Activity implements OnClickListener{
      
      private Button mBtnSend;
      private Button mBtnBack;
      private EditText mEditTextContent;
      private ListView mListView;
      private ChatMsgViewAdapter mAdapter;
      private List<ChatMsgEntity> mDataArrays = new ArrayList<ChatMsgEntity>();
      
      private  String value;
      protected void onCreate(Bundle savedInstanceState) {
            // TODO Auto-generated method stub
            super.onCreate(savedInstanceState);
            setContentView(R.layout.chat_friend);
        //启动activity时不自动弹出软键盘
        getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_HIDDEN);
       
        Intent intent = getIntent();
        value =intent.getStringExtra("name");
        initView();
        initData();
    }
      public void initView()
    {
      mListView = (ListView) findViewById(R.id.listview);
      mBtnSend = (Button) findViewById(R.id.btn_send);
      mBtnSend.setOnClickListener(this);
      mBtnBack = (Button) findViewById(R.id.btn_back);
      mBtnBack.setOnClickListener(this);
      mBtnBack = (Button) findViewById(R.id.btn_qury);
      mBtnBack.setOnClickListener(this);
      
      mEditTextContent = (EditText) findViewById(R.id.et_sendmessage);
    }
   
  
 
    public void initData()
    {
      
            ChatMsgEntity entity = new ChatMsgEntity();
            entity.setDate(getDate());
            entity.setName(value);
            entity.setMsgType(true);
            mDataArrays.add(entity);
              mAdapter = new ChatMsgViewAdapter(this, mDataArrays);
            mListView.setAdapter(mAdapter);
            
    }
   
      @Override
      public void onClick(View v) {
            // TODO Auto-generated method stub
            switch(v.getId())
            {
            case R.id.btn_send:
                  send();
                  break;
            case R.id.btn_back:
                  Intent intent1 = new Intent (ChatActivity.this,addressbook.class);                
                  startActivity(intent1); 
                  break;
            case R.id.btn_qury:
                  Intent intent2 = new Intent (ChatActivity.this,qury.class);                 
                  startActivity(intent2); 
                  break;
            }
      
      }
      
      private void send()
      {
            String contString = mEditTextContent.getText().toString();
            if (contString.length() > 0)
            {
                  //发送方
                  ChatMsgEntity entity = new ChatMsgEntity();
                  entity.setDate(getDate());
                  entity.setName("李刚");
                  entity.setMsgType(false);
                  entity.setText(contString);
                  
                  mDataArrays.add(entity);
                  mAdapter.notifyDataSetChanged();
                  
                  mEditTextContent.setText("");
                  
                  mListView.setSelection(mListView.getCount() - 1);
                  
                  //接收方
                  ChatMsgEntity entity2 = new ChatMsgEntity();
                  entity2.setName(value);
                  entity2.setMsgType(true);
                  entity2.setText(value+"朋友收到的信息是："+contString);
                  
                  mDataArrays.add(entity2);
                  mAdapter.notifyDataSetChanged();
                  
                  mEditTextContent.setText("");
                  
                  mListView.setSelection(mListView.getCount() - 1);
                  
            }
      }
      
    private String getDate() {
        Calendar c = Calendar.getInstance();
        String year = String.valueOf(c.get(Calendar.YEAR));
        String month = String.valueOf(c.get(Calendar.MONTH));
        String day = String.valueOf(c.get(Calendar.DAY_OF_MONTH) + 1);
        String hour = String.valueOf(c.get(Calendar.HOUR_OF_DAY));
        String mins = String.valueOf(c.get(Calendar.MINUTE));
       
       
        StringBuffer sbBuffer = new StringBuffer();
        sbBuffer.append(year + "-" + month + "-" + day + " " + hour + ":" + mins);
                                          
                                          
        return sbBuffer.toString();
    }
   
    public void head_xiaohei(View v) {     //标题栏 返回按钮
      //Intent intent = new Intent (ChatActivity.this,InfoXiaohei.class);                
            //startActivity(intent);      
      }