Но когда я запускаю код ниже, после нажатия кнопки появляется ошибка «К сожалению, приложение было остановлено»
Ниже мой 1-й файл Activity.xml:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".MainActivity">
<EditText
android:id="@+id/editText"
android:layout_width="wrap_content"
android:layout_height="36dp"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true"
android:layout_marginTop="22dp"
android:layout_weight="1"
android:ems="10"
android:hint="Name:"
android:inputType="textPersonName"
android:layout_alignParentLeft="true" />
<RadioGroup
android:layout_width="279dp"
android:layout_height="76dp"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true"
android:layout_marginTop="87dp"
android:layout_alignParentLeft="true">
<RadioButton
android:id="@+id/radioButton3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Male" />
<RadioButton
android:id="@+id/radioButton4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Female" />
</RadioGroup>
<EditText
android:id="@+id/editText3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true"
android:layout_marginTop="186dp"
android:ems="10"
android:hint="Address:"
android:inputType="textPersonName"
android:layout_alignParentLeft="true" />
<EditText
android:id="@+id/editText4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentStart="true"
android:layout_marginBottom="217dp"
android:ems="10"
android:hint="Contact no:"
android:inputType="textPersonName"
android:layout_alignParentLeft="true" />
<EditText
android:id="@+id/editText5"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentStart="true"
android:layout_marginBottom="156dp"
android:ems="10"
android:hint="E-mail ID"
android:inputType="textEmailAddress"
android:layout_alignParentLeft="true" />
<CheckBox
android:id="@+id/checkBox"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentStart="true"
android:layout_alignTop="@+id/checkBox2"
android:layout_marginStart="130dp"
android:text="Dancing"
android:layout_alignParentLeft="true"
android:layout_marginLeft="130dp" />
<CheckBox
android:id="@+id/checkBox3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentEnd="true"
android:layout_alignTop="@+id/checkBox"
android:layout_marginEnd="51dp"
android:text="Reading"
android:layout_alignParentRight="true"
android:layout_marginRight="51dp" />
<CheckBox
android:id="@+id/checkBox4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentStart="true"
android:layout_marginBottom="66dp"
android:layout_marginStart="70dp"
android:text="Singing"
android:layout_alignParentLeft="true"
android:layout_marginLeft="70dp" />
<CheckBox
android:id="@+id/checkBox2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentStart="true"
android:layout_marginBottom="115dp"
android:text="Playing"
android:layout_alignParentLeft="true" />
<Button
android:id="@+id/button"
android:layout_width="178dp"
android:layout_height="wrap_content"
android:layout_below="@+id/checkBox4"
android:layout_marginTop="-66dp"
android:layout_toEndOf="@+id/checkBox2"
android:text="Submit"
android:layout_toRightOf="@+id/checkBox2" />
</RelativeLayout>
Ниже мой java-файл 1-го занятия
package com.example.mypc.practical1;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.*;
public class MainActivity extends AppCompatActivity {
Button btn;
EditText name,add,cont,email;
CheckBox cb1,cb2,cb3,cb4;
Intent intent=new Intent(this,Activity2.class);
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn=(Button)findViewById(R.id.button);
name=(EditText)findViewById(R.id.editText);
add=(EditText)findViewById(R.id.editText3);
cont=(EditText)findViewById(R.id.editText4);
email=(EditText)findViewById(R.id.editText5);
cb1=(CheckBox)findViewById(R.id.checkBox);
cb2=(CheckBox)findViewById(R.id.checkBox2);
cb3=(CheckBox)findViewById(R.id.checkBox3);
cb4=(CheckBox)findViewById(R.id.checkBox4);
btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String nm=name.getText().toString();
String a=add.getText().toString();
String c=cont.getText().toString();
String em=email.getText().toString();
String cvalue="";
if (cb1.isChecked()==true)
{
cvalue+="Playing";
}
else if(cb2.isChecked()==true)
{
cvalue+="Dancing";
}
else if(cb3.isChecked()==true)
{
cvalue+="Reading";
}
else if(cb4.isChecked()==true)
{
cvalue+="Singing";
}
intent.putExtra("this_name", nm);
intent.putExtra("this_add", a);
intent.putExtra("this_cont", c);
intent.putExtra("this_email", em);
intent.putExtra("this_chechbox", cvalue);
startActivity(intent);
}
});
}
}
ниже мой 2-й файл активности .java
package com.example.mypc.practical1;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.*;
public class Activity2 extends AppCompatActivity {
EditText ed;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_2);
Intent i=getIntent();
Bundle b=getIntent().getExtras();
String name=i.getExtras().getString("this_name");
String add=i.getExtras().getString("this_add");
String cont=i.getExtras().getString("this_cont");
String email=i.getExtras().getString("this_email");
String check=i.getExtras().getString("this_chechbox");
ed.setText(name+add+cont+email+check);
}
}
ниже моя вторая активность.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".Activity2">
<EditText
android:id="@+id/editText2"
android:layout_width="301dp"
android:layout_height="396dp"
android:ems="10"
android:inputType="textMultiLine"
tools:layout_editor_absoluteX="33dp"
tools:layout_editor_absoluteY="30dp" />
</RelativeLayout>
Ниже моя трассировка стека:
E/AndroidRuntime: FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.mypc.practical1/com.example.mypc.practical1.MainActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1983)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
at android.app.ActivityThread.access$600(ActivityThread.java:130)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4745)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at android.content.ContextWrapper.getPackageName(ContextWrapper.java:127)
at android.content.ComponentName.<init>(ComponentName.java:75)
at android.content.Intent.<init>(Intent.java:3301)
at com.example.mypc.practical1.MainActivity.<init>(MainActivity.java:13)
at java.lang.Class.newInstanceImpl(Native Method)
at java.lang.Class.newInstance(Class.java:1319)
at android.app.Instrumentation.newActivity(Instrumentation.java:1053)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1974)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
at android.app.ActivityThread.access$600(ActivityThread.java:130)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4745)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
Application terminated.
Пожалуйста, помогите мне решить ошибку
Заранее спасибо.