Android实现记住账号密码功能

 public class MainActivity extends AppCompatActivity implements View.OnClickListener{ private CheckBox checkBox; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); checkBox = findViewById(R.id.checkbox); SharedPreferences sp = getSharedPreferences("items",MODE_PRIVATE); /** * getBoolean(name,defaultValue) 若没有name,则返回defaultValue * 获取标志位，若flag为true，则有数据 */ if( sp.getBoolean("flag",false)==true ){ getData(); //模拟点击 checkBox.performClick(); } //设置checkbox的监听事件 checkBox.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() { @Override public void onCheckedChanged(CompoundButton compoundButton, boolean isCheck) { //若选中，则保存数据，否则，清除数据 if(isCheck){ saveData(); Toast.makeText(MainActivity.this,"已保存",Toast.LENGTH_LONG).show(); } else{ clearData(); } } }); } /** * SharedPreferences为轻量级的存储方式 * Context.MODE_PRIVATE:为默认操作模式,代表该文件是私有数据,只能被应用本身访问。 * 在该模式下,写入的内容会覆盖原文件的内容 * 存储位置:Device File Explorer（idea 或Android studio右下角） * data/data/项目的包名/shared_prefs */ //清除数据 private void clearData() { SharedPreferences sp = getSharedPreferences("items",MODE_PRIVATE); SharedPreferences.Editor editor = sp.edit(); editor.clear(); editor.commit(); et1.setText(""); et2.setText(""); } /** * 获取SharedPreferences数据 */ private void getData(){ SharedPreferences sp = getSharedPreferences("items", Context.MODE_PRIVATE); String username = sp.getString("username",""); String password = sp.getString("password",""); et1.setText(username); //密文设置 TransformationMethod method = PasswordTransformationMethod.getInstance(); et2.setText(password); et2.setTransformationMethod(method); } /** *保存数据 * android:onClick响应的方法 只能用修饰符public */ public void saveData(){ SharedPreferences sharedPreferences = getSharedPreferences("items", Context.MODE_PRIVATE); SharedPreferences.Editor editor = sharedPreferences.edit(); String username = et1.getText().toString(); String password = et2.getText().toString(); if(!username.equals("") && !password.equals("")) { editor.putString("username", username); editor.putString("password", password); editor.putBoolean("flag", true); //标志位 editor.commit(); } } }