安卓开发期末复习之SharedPreferences文件存储+file的文件存储+SQLite数据库使用

弄了 好半天 

你要先配置一下环境 path  找到sdk 

忘记装哪里 你就看这儿 tools 下面的 sdk 管理器

看完之后找到位置

找到之后 配置到电脑path 里

我之后运行还是不行  adb root 就是不行 差了一下午 感觉是版本太高了 重弄了 一个模拟器 是安卓6.0版本的 就能root了 希望大佬给谁会能给俺说说

授权之后  又一个问题 我竟然找不到 ddms 没办法 就是 一顿找 找到view 里面 的terminal输入 monitor  结果端口占用 但是好歹能用 问问老师咋回事儿 

贴一下今天的布局  是 登录 的账号 和密码

看看 activity  怎么使用的sharedpreference

public class SharedPreferences1Activity extends AppCompatActivity {
    EditText txtName,txtPassword;
    Button btnOk;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_shared_preferences1);
        txtName=(EditText)findViewById(R.id.txtName);
        txtPassword=(EditText)findViewById(R.id.txtPassword);
        btnOk=(Button)findViewById(R.id.btnOk);
        SharedPreferences sharedPreferences=getSharedPreferences("user", Context.MODE_PRIVATE);
        //user是文件名，即user.xml,保存在/data/data/weili.org.myapplication/shared_prefs/user.xml

        String userName=sharedPreferences.getString("userName","");
        String userPassword=sharedPreferences.getString("userPassword","");

        if(!userName.equals(""))
            txtName.setText(userName);
        if(!userPassword.equals(""))
            txtPassword.setText(userPassword);

        btnOk.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                SharedPreferences sharedPreferences=getSharedPreferences("user", Context.MODE_PRIVATE);
                SharedPreferences.Editor editor=sharedPreferences.edit();
                editor.putString("userName",txtName.getText().toString());
                editor.putString("userPassword",txtPassword.getText().toString());
                editor.commit();
            }
        });
    }

刚才是sharedpreferences写入文件 的 程序 现在是file的

效果：

他放下这个默认的file的下面

fileactivity

public class FileActivity extends AppCompatActivity {
    EditText txtFileName,txtFileContent1,txtFileContent2;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_file);
        txtFileName=(EditText)findViewById(R.id.txtFileName);
        txtFileContent1=(EditText)findViewById(R.id.txtFileContent1);
        txtFileContent2=(EditText)findViewById(R.id.txtFileContent2);
    }
    public void btnWriteClick(View v){
        String fileName=txtFileName.getText().toString().trim();
        if(fileName.equals(""))
            return;
        FileOutputStream fout=null;
        try {
            fout=openFileOutput(fileName, Context.MODE_APPEND);//写入文件名字
            String fileContent=txtFileContent1.getText().toString();//写入文件文字
            fout.write(fileContent.getBytes());
        } catch (FileNotFoundException e) {
            System.out.println(fileName+" 不存在");
        } catch (IOException e) {
            System.out.println("写入数据到文件 "+fileName+" 失败:"+e.getMessage());
        }
    }
    public void btnReadClick(View v){
        String fileName=txtFileName.getText().toString().trim();
        byte[] buffer=new byte[1024];
        int count=0;
        StringBuffer sb=new StringBuffer();
        if(fileName.equals(""))
            return;
        FileInputStream fin=null;
        try {
            fin=this.openFileInput(fileName);
            String fileContent=txtFileContent1.getText().toString();

        while((count=fin.read(buffer))!=-1){
            sb.append(new String(buffer,0,count));
        }
        txtFileContent2.setText(sb.toString());
            } catch (FileNotFoundException e) {
                 System.out.println(fileName+" 不存在");
            } catch (IOException e) {
                    System.out.println("从"+"fileName+" +"读入数据失败:"+e.getMessage());
                                    }
            }

}

sql 建一个 老师的数据库来增删改

效果图如下

要先写 sqliteopenhelper类

创建数据库

public class MyDatabaseHelper extends SQLiteOpenHelper {
    public MyDatabaseHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) {
        super(context, name, factory, version);
    }
    public MyDatabaseHelper(Context context, String name, int version) {
        super(context, name, null, version);
    }
    public MyDatabaseHelper(Context context,String name){
        super(context,name,null,1);
    }
    public MyDatabaseHelper(Context context){
        super(context,"teacherDB",null,1);
    }

//第一次被
    @Override
    public void onCreate(SQLiteDatabase db) {
        String sqlCreateTableTeacher="create table teacher(teacherid text primary key,teachername text,sex text,money integer)";
        db.execSQL(sqlCreateTableTeacher);

    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    }
}
然后写控制数据库的

public class TeacherActivity extends AppCompatActivity {
    EditText teacherId,teacherName,teacherSex,teacherMoney;
    MyDatabaseHelper dbHelper;
    TextView txtResult;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_teacher);
        teacherId=(EditText) findViewById(R.id.teacherId);
        teacherName=(EditText) findViewById(R.id.name);
        teacherSex=(EditText) findViewById(R.id.sex);
        teacherMoney=(EditText) findViewById(R.id.money);
        txtResult=(TextView)findViewById(R.id.txtResult) ;
        dbHelper=new MyDatabaseHelper(TeacherActivity.this,"teacherDB",1);
    }
    public void btnAddClick(View view){

        String id=teacherId.getText().toString().trim();
        String name=teacherName.getText().toString().trim();
        String sex=teacherSex.getText().toString().trim();
        String money=teacherMoney.getText().toString().trim();
        String insertSql="insert into teacher(teacherid,teachername,sex,money) values(?,?,?,?)";
        SQLiteDatabase db=dbHelper.getReadableDatabase();
        db.execSQL(insertSql,new String[]{id,name,sex,money});

        btnQueryClick(view);
        //System.out.println("插入成功");

    }
    public void btnUpdateClick(View view){
        String id=teacherId.getText().toString().trim();
        String name=teacherName.getText().toString().trim();
        String sex=teacherSex.getText().toString().trim();
        String money=teacherMoney.getText().toString().trim();
        String updateSql="update teacher set teachername=?,sex=?,money=? where teacherid=?";
        SQLiteDatabase db=dbHelper.getReadableDatabase();
        db.execSQL(updateSql,new Object[]{name,sex,money,id});

        btnQueryClick(view);
    }
    public void btnDeleteClick(View view){
        String id=teacherId.getText().toString().trim();
        if(id.length()==0)
            return;
        SQLiteDatabase db=dbHelper.getReadableDatabase();
        String sqlDelete="delete from teacher where teacherid=?";
        db.execSQL(sqlDelete,new String[]{id});
        btnQueryClick(view);
    }
    public void btnQueryClick(View view){

        String sqlSelect="select * from teacher";
        SQLiteDatabase db=dbHelper.getReadableDatabase();
        Cursor cursor=db.rawQuery(sqlSelect,null);//Cursor相当于jdbc的ResultSet
        txtResult.setText("");
        while(cursor.moveToNext()){
            String id=cursor.getString(0);
            String name=cursor.getString(1);
            String sex=cursor.getString(2);
            String money=cursor.getString(3);
            txtResult.append("\t\t\t\t\t\t"+id+"\t\t\t\t\t"+name+"\t\t\t\t"+sex+"\t\t\t\t"+money+"\n");
        }
    }


}