Question

import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends Activity implements OnClickListener {
    EditText username;
    EditText password;
    Button login;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        username = (EditText) findViewById(R.id.editTextpaswrd);
        password = (EditText) findViewById(R.id.editTextpssd);
        Button login = (Button) findViewById(R.id.buttonlgin);

        login.setOnClickListener(this);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    public void onClick(View v) {
        String name=username.getText().toString();
        String pwd=password.getText().toString();

        switch(v.getId()) {
        case R.id.buttonlgin;
            break;

            if (name.equals("nana") && pwd.equals("12345")) {
                Intent i=new Intent(this, Qrcodescreen.class);
                startActivity(i);
                Toast.makeText(getBaseContext(),  "Success!", 
Toast.LENGTH_SHORT).show();
            } else Toast.makeText(getBaseContext(), "Invalid Login Details", Toast.LENGTH_SHORT).show();
        break;
        }
        displayNextAlert();
    }

    private void displayNextAlert() {
        // Get what the user entered
        EditText username = (EditText) findViewById(R.id.editTextpaswrd);
        //Puts out an error message (!)
        if ( username.getText().toString().length() == 0)
            username.setError( "Username required");
        EditText password = (EditText) findViewById(R.id.editTextpssd);
        if ( password.getText().toString().length() == 0)
            password.setError( "Password required");
    }   
}

我在'case R.id.buttonlgn;'上遇到错误。请帮忙。感谢

Answer 1

替换案例R.id.buttonlgin;与

case R.id.buttonlgin:

注意'：'

Answer 2

在case R.id.buttonlgin之后一定不能有半结肠，它必须是冒号。即用case R.id.buttonlgin;替换case R.id.buttonlgin:并删除第一次出现的断裂;在您的代码中使代码工作

Answer 3

 switch(v.getId()) {
    case R.id.buttonlgin:
    break;
}

Answer 4

你必须把＆＃34;：＆＃34;而不是＆＃34;;＆＃34;在R.id.buttonlgin之后。

switch(v.getId()) {
  case R.id.buttonlgin:
  break;
}

语法错误，插入“：”以完成SwitchLabel

4 个答案: