如何禁用来自其他活动的按钮

Question

我有一个小登录程序，可以将数据保存到共享首选项中。主要活动具有">登录"和"帐户">按钮。我想在共享首选项为空时禁用登录按钮，并为用户启用"帐户"按钮以注册我的第二个活动。如果共享首选项为空，如何启用/禁用 2 个按钮？

1. 活动1

   protected void onCreate(Bundle savedInstanceState) {
   super.onCreate(savedInstanceState);
   setContentView(R.layout.main_interface);
   final Button login = (Button)findViewById(R.id.Login);
   final Button account = (Button)findViewById(R.id.Account);
   login.setEnabled(false);
   login.setOnClickListener(new OnClickListener() {
   public void onClick(View arg0) {
   startActivity(new Intent(MainActivity.this, Summation.class));
   }
   });
   
   account.setOnClickListener(new OnClickListener() {
   public void onClick(View arg0) {
   startActivity(new Intent(MainActivity.this, Append.class));
   }
   });
   Button exit = (Button)findViewById(R.id.Exit);
   exit.setOnClickListener(new OnClickListener() {
   public void onClick(View arg0) {
   finish();
   System.exit(0);
   }
   });
   

2. 活动2

   protected void onCreate(Bundle savedInstanceState){
   super.onCreate(savedInstanceState);
   Stetho.initializeWithDefaults(this);
   setContentView(R.layout.append_interface);
   
   final EditText usernameAppend = (EditText)findViewById(R.id.usernameAppend);
   final EditText passwordAppend = (EditText)findViewById(R.id.passwordAppend);
   //this buttons appends the username and password to the SharedPreferences
   Button append = (Button)findViewById(R.id.Append);
   append.setOnClickListener(new View.OnClickListener() {
   public void onClick(View arg0) {
   final SharedPreferences mySharedPref = getSharedPreferences(PREF_NAME, MODE_PRIVATE);
   final SharedPreferences.Editor editor = mySharedPref.edit();
   //Append get data
   final String un = usernameAppend.getText().toString();
   editor.putString(editorUsername,un);
   editor.commit();
   final String pw = passwordAppend.getText().toString();
   editor.putString(editorPassword, pw);
   editor.commit();
   if(mySharedPref != null){
   Toast.makeText(Append.this,"Account saved",Toast.LENGTH_LONG).show();
   startActivity(new Intent(Append.this, MainActivity.class));
   }else{
   Toast.makeText(Append.this,"Please enter again",Toast.LENGTH_LONG).show();
   }
   }
   }
   );
   //Exit button,, exits the app
   Button exit = (Button)findViewById(R.id.Exit);
   exit.setOnClickListener(new View.OnClickListener() {
   public void onClick(View arg0) {
   finish();
   System.exit(0);
   }
   });
   }
   

Answer 1

在第一个活动中，检查您的共享首选项是否存在。 第一次将为空。

btnLogin.setEnabled(false);
btnAccount.setEnabled(false);
SharedPreferences mPrefs=this.getSharedPreferences(Your_Preference_Name,Context.MODE_PRIVATE);
if(mPrefs==null)
{
btnAccount.setEnabled(true);
}
btnAccount.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
}
});
btnLogin.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
}
});