问题
what am doing is that am initializing a layout on the start of my activity. Whenever a button on that layout is clicked am initializing another layout in the same activity. Whenever i click the am doing some working regarding insertion of a database record. even on ignoring the database part am getting java null pointer exception in logcat. Kindly have a look and guide me
package com.example.emp_management;
import android.app.Activity;
import android.content.ContentValues;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.provider.SyncStateContract.Columns;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import com.example.emp_management.DatabaseHelper;
public class Administrator_Work extends Activity{
@Override
protected void onCreate(Bundle adminkakaam) {
// TODO Auto-generated method stub
super.onCreate(adminkakaam);
setContentView(R.layout.administrator);
Toast.makeText(this, "Logged in as Administrator!",Toast.LENGTH_LONG).show();
final EditText new_user = (EditText) findViewById(R.id.editText1);
final EditText new_pass = (EditText) findViewById(R.id.textView2);
Button add_emp = (Button)findViewById(R.id.addemployee);
final Button create_acc = (Button) findViewById(R.id.creat_acc);
add_emp.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
setContentView(R.layout.add_employee);
create_acc.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
//DatabaseHelper accessing_db = new DatabaseHelper(Administrator_Work.this);
//accessing_db.insert_new_user(new_user.getText().toString(), new_pass.getText().toString());
//Toast.makeText(getApplicationContext(), "New User Has Been Created!!", Toast.LENGTH_SHORT).show();
}
});
}
});
}
}
回答1:
Calling setContentView multiple times is not recommended. I would advise you to use different fragments for your application, or at least have the first layout contain all the views you need and hide/show them according to your needs. If you insist on using different layouts for the same activity then you could have a look here.
来源：https://stackoverflow.com/questions/14943862/calling-multiple-layouts-in-one-activity-on-2-different-call-backs