在Android中从一个活动转移到另一个活动

Question

I want to move from one activity to another (using virtual device). When I click on button to move, My emulator ones a dialog box showing unfortunately SMS1 has stopped working (SMS1 is my app name).

Can anybody help me in correcting my code?

MainActivity.java:

package com.example.sms1;

 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.TextView;

 public class MainActivity extends Activity implements OnClickListener
 {

Button b1;
TextView tv1;
 @Override
 protected void onCreate(Bundle savedInstanceState)
 {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    b1 = (Button) findViewById(R.id.button1);
    tv1 = (TextView) findViewById(R.id.textView1);

    b1.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;
}

@Override
public void onClick(View v)
{
    // TODO Auto-generated method stub
    Intent i = new Intent(getApplicationContext(),NextActivity.class);
    startActivity(i);
    setContentView(R.layout.avtivity_next);
}



}

Here is the NextActivity

package com.example.sms1;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.widget.TextView;

public class NextActivity extends Activity {

TextView tv1;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.avtivity_next);
    tv1 = (TextView) findViewById(R.id.textView1);
}


@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;
}

}

Manifest.XML

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.sms1"
android:versionCode="1"
android:versionName="1.0" >

<uses-sdk
    android:minSdkVersion="8"
    android:targetSdkVersion="17" />

<application
    android:allowBackup="true"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >
    <activity
        android:name="com.example.sms1.MainActivity"
        android:label="@string/app_name" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
</application>

</manifest>

NextActivityLayout

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".NextActivity" >

<TextView
    android:id="@+id/textView1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="next activity" />



</RelativeLayout>

MainActivity Layout

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >

<TextView
    android:id="@+id/textView1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/hello_world" />

<Button
    android:id="@+id/button1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_below="@+id/textView1"
    android:layout_marginTop="80dp"
    android:layout_toRightOf="@+id/textView1"
    android:text="Button" />

</RelativeLayout>

Answer 1

First You have to use this code in MainActivity.java class

@Override
public void onClick(View v)
{
    // TODO Auto-generated method stub
    Intent i = new Intent(getApplicationContext(),NextActivity.class);
    startActivity(i);

}

You can pass intent this way.

Second

add proper entry into manifest.xml file.

<activity android:name=".NextActivity" />

Now see what happens.

Answer 2

You haven't defined NextActivity in the AndroidManifest.xml file.

Add these lines in android manifest after </activity> tag. It should work.

<activity
    android:name=".NextActivity" >
</activity>

final code will be

<application
    android:allowBackup="true"
    android:icon="@drawable/app_icon"
    android:label="@string/app_name" >
    <activity
        android:name=".MainActivity"
        android:label="Main Activity" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity
        android:name=".NextActivity" >
    </activity>
</application>

Answer 3

Simply add your NextActivity in the Manifest.XML file

<activity
            android:name="com.example.sms1.NextActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
            </intent-filter>
        </activity>

Answer 4

button1 in activity2

code written in activity 2

button1.setOnClickListener(new View.OnClickListener() {         
        public void onClick(View v)
        {
            // starting background task to update product               
            Intent fp=new Intent(getApplicationContext(),activity1.class);              
            startActivity(fp);              
        }
    });

This might help

Answer 5

1) place setContentView(R.layout.avtivity_next); to the next-activity's onCreate() method just like this (main) activity's onCreate()

2) if you have not defined the next-activity in your-apps manifest file then do this also, like:

<application
        android:allowBackup="true"
        android:icon="@drawable/app_icon"
        android:label="@string/app_name" >
        <activity
            android:name=".MainActivity"
            android:label="Main Activity" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name=".NextActivity"
            android:label="Next Activity" >
        </activity>
    </application>

You must have to perform the 2nd step every time you create a new activity, otherwise your app will crash

Answer 6

When you have to go from one page to another page in android changes made in 2 files

Intent intentSignUP = new Intent(this,SignUpActivity.class);
   startActivity(intentSignUP);

add activity in androidManifest file also like

 <activity android:name=".SignUpActivity"></activity>

Answer 7

setContentView(R.layout.avtivity_next);

I think this line of code should be moved to the next activity...

Answer 8

public void onClick(View v)
{
 startActivity(new Intent(getApplicationContext(), Next.class));

}

it is direct way to move second activity and there is no need for call intent

Answer 9

Below code is working fine with Android 4.3:

Intent i = new Intent(this,MainActivity2.class);
startActivity(i);

Answer 10

It is mainly due to unregistered activity in manifest file as "NextActivity" Firstly register NextActivity in Manifest like

<activity android:name=".NextActivity">

then use the code in the where you want

Intent intent=new Intent(MainActivity.this,NextActivity.class);
startActivity(intent);

where you have to call the NextActivity..

Answer 11

First you have to declare the activity in Manifest. It is important. You can add this inside application like this.

Answer 12

Register your java class on Android manifest file

After that write this code on button click

startActivity(new intent(MainActivity.this,NextActivity.class));

Answer 13

@Override
public void onClick(View v)
{
    // TODO Auto-generated method stub
    Intent intent = new Intent(Activity1.this,Activity2.class);
    startActivity(intent);

}

Answer 14

You can do

Intent i = new Intent(classname.this , targetclass.class);
startActivity(i);