Question

基本上我想要一个按钮来登录后开始新的活动。我发现我无法像登录页面中那样调用StartActivity（）。请指导

这是登录页面，我使用StartActivity（this，sth.class）成功

public class Login extends Activity
{

/** Called when the activity is first created. */


Button login;
String name="",pass="";
EditText username,password;
TextView tv;
byte[] data;
HttpPost httppost;
StringBuffer buffer;
HttpResponse response;
HttpClient httpclient;
InputStream inputStream;
SharedPreferences app_preferences ;
List<NameValuePair> nameValuePairs;
CheckBox check;


public void onCreate(Bundle savedInstanceState)

{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    app_preferences = PreferenceManager.getDefaultSharedPreferences(this);

    username = (EditText) findViewById(R.id.username);
    password = (EditText) findViewById(R.id.password);
    login = (Button) findViewById(R.id.login);
    check = (CheckBox) findViewById(R.id.check);

     String Str_user = app_preferences.getString("username","0" );
    String Str_pass = app_preferences.getString("password", "0");

    String Str_check = app_preferences.getString("checked", "no");
    if(Str_check.equals("yes"))

    {
            username.setText(Str_user);
            password.setText(Str_pass);
            check.setChecked(true);
    }

    login.setOnClickListener(new View.OnClickListener()
    {
        public void onClick(View v)

        {

            name = username.getText().toString();

            pass = password.getText().toString();

            String Str_check2 = app_preferences.getString("checked", "no");

            if(Str_check2.equals("yes"))

            {

                SharedPreferences.Editor editor = app_preferences.edit();

                editor.putString("username", name);

                editor.putString("password", pass);

                 editor.commit();

            }

            if(name.equals("") || pass.equals(""))

            {

                 Toast.makeText(Login.this, "Blank Field..Please Enter", Toast.LENGTH_LONG).show();

            }

            else

            {



            try {

                httpclient = new DefaultHttpClient();

                httppost = new HttpPost("http://fyptest.comyr.com/main.php");

                // Add your data

                nameValuePairs = new ArrayList<NameValuePair>(2);

               nameValuePairs.add(new BasicNameValuePair("UserEmail", name.trim()));

                nameValuePairs.add(new BasicNameValuePair("Password", pass.trim()));

                httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));



                // Execute HTTP Post Request

                response = httpclient.execute(httppost);

                inputStream = response.getEntity().getContent();



                data = new byte[256];



                buffer = new StringBuffer();

                int len = 0;

                while (-1 != (len = inputStream.read(data)) )

                {

                    buffer.append(new String(data, 0, len));

                }


                inputStream.close();

            }



            catch (Exception e)

            {

                Toast.makeText(Login.this, "error"+e.toString(), Toast.LENGTH_LONG).show();

            }

            if(buffer.charAt(0)=='Y')

            {

                Toast.makeText(Login.this, "login successfull", Toast.LENGTH_LONG).show();
                Move_to_next();

            }

            else
        {

                Toast.makeText(Login.this, "Invalid Username or password", Toast.LENGTH_LONG).show();

            }

            }

        }

    });

    check.setOnClickListener(new View.OnClickListener()

    {

        public void onClick(View v)

        {

            // Perform action on clicks, depending on whether it's now checked

            SharedPreferences.Editor editor = app_preferences.edit();

            if (((CheckBox) v).isChecked())

            {



                 editor.putString("checked", "yes");

                 editor.commit();

            }

            else

            {

                 editor.putString("checked", "no");

                 editor.commit();

            }

        }

    });

}



public void Move_to_next()

    {

     //may perform checking based on ID

      startActivity(new Intent(this, MainMenu.class));

    }

但是，我的startActivity用红色加下划线

public class MainMenu extends Activity{

@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main_menu);

    Button new_folder = (Button)findViewById(R.id.new_folder);
    new_folder.setOnClickListener(new View.OnClickListener(){

        @Override
        public void onClick(View v) {
            // show another class 
            startActivity(new Intent(this,Folder_Details.class));

        }

    });
}

}

它显示“构造函数Intent（new View.OnClickListener（）{}，Class）未定义”和“删除参数以匹配Intent（）”选项

我已将<Activity></Activity>包含在Manifest中。上面的代码显示，导入被截断

Answer 1

将其修改为

startActivity(new Intent(MainMenu.this,Folder_Details.class));

您正在使用View.OnClickListener而不是Context实例。

Answer 2

是的，这是因为，您尝试使用“this”来引用您的按钮而不是您的活动。你必须像这样替换它，

而不是startActivity(new Intent(this, Folder_Details.class));

这样做，

startActivity(new Intent(MainMenu.this, Folder_Details.class));

Answer 3

startActivity（new Intent（MainMenu.this，Folder_Details.class））;

突出显示StartActivity（）红色

3 个答案: