So heres my problem. I set up a button that when clicked should open a new activity but when it is clicked I receive an error: Unfortunately "app_name" has stopped working my logcat says :Fatal Exception Main
So heres my xml:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_marginLeft="30dp"
android:layout_marginTop="58dp"
android:text="Monday"
android:textSize="20sp"/>
<TextView
android:id="@+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/textView1"
android:layout_below="@+id/textView1"
android:layout_marginTop="30dp"
android:textSize="20sp"
android:text="Tuesday" />
<TextView
android:id="@+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/textView2"
android:layout_below="@+id/textView2"
android:layout_marginTop="30dp"
android:textSize="20sp"
android:text="Wednesday" />
<TextView
android:id="@+id/textView4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/textView3"
android:layout_below="@+id/textView3"
android:layout_marginTop="30dp"
android:textSize="20sp"
android:text="Thursday" />
<TextView
android:id="@+id/textView5"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/textView4"
android:layout_below="@+id/textView4"
android:layout_marginTop="30dp"
android:textSize="20sp"
android:text="Friday" />
<TextView
android:id="@+id/textView6"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/textView5"
android:layout_below="@+id/textView5"
android:layout_marginTop="30dp"
android:textSize="20sp"
android:text="Saturday" />
<TextView
android:id="@+id/textView7"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/textView6"
android:layout_below="@+id/textView6"
android:layout_marginTop="30dp"
android:textSize="20sp"
android:text="Sunday" />
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/textView1"
android:layout_alignBottom="@+id/textView1"
android:layout_alignParentRight="true"
android:layout_marginRight="46dp"
android:text="Edit"
android:onClick="mondayintent" />
<Button
android:id="@+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/textView2"
android:layout_alignBottom="@+id/textView2"
android:layout_alignLeft="@+id/button1"
android:text="Edit" />
<Button
android:id="@+id/button3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/textView3"
android:layout_alignBottom="@+id/textView3"
android:layout_alignLeft="@+id/button2"
android:text="Edit" />
<Button
android:id="@+id/button4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/textView4"
android:layout_alignBottom="@+id/textView4"
android:layout_alignLeft="@+id/button3"
android:text="Edit" />
<Button
android:id="@+id/button5"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/textView5"
android:layout_alignBottom="@+id/textView5"
android:layout_alignLeft="@+id/button4"
android:text="Edit" />
<Button
android:id="@+id/button6"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/textView6"
android:layout_alignBottom="@+id/textView6"
android:layout_alignLeft="@+id/button5"
android:text="Edit" />
<Button
android:id="@+id/button7"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/textView7"
android:layout_alignBottom="@+id/textView7"
android:layout_alignLeft="@+id/button6"
android:text="Edit" />
</RelativeLayout>
and the second Xml to which im trying to reach in another activity:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="20dp"
android:textSize="40sp"
android:text="Monday" />
<EditText
android:id="@+id/editText1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/textView1"
android:layout_marginTop="36dp"
android:layout_toLeftOf="@+id/textView1"
android:ems="3"
android:inputType="time" />
<EditText
android:id="@+id/editText2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/editText1"
android:layout_alignBottom="@+id/editText1"
android:layout_centerHorizontal="true"
android:ems="3"
android:inputType="time" >
<requestFocus />
</EditText>
<Spinner
android:id="@+id/profileSelector"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/editText2"
android:layout_toRightOf="@+id/textView1"
android:ems="3"
android:prompt="@string/profile"
android:entries="@array/profileSelector"/>
</RelativeLayout>
Finally the code that supports both:
package com.example.hush;
import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.widget.Button;
import android.view.View.OnClickListener;
public class MainActivity extends Activity {
Intent clickedDay;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.mainlayout);
Button mondayEdit=(Button)findViewById(R.id.button1);
}
public void mondayintent()
{
clickedDay= new Intent(this,Monday.class);
startActivity(clickedDay);
}
@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;
}
}
second activity code:
package com.example.hush;
import android.app.Activity;
import android.os.Bundle;
import android.widget.Button;
public class Monday extends Activity{
@Override
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.monday);
}
}
Below I have added my android-manifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.hush"
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.hush.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>
<activity
android:name="com.example.hush.Monday"
android:label="@string/app_name" >
<intent-filter>
<action android:name="com.example.hush.Monday" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
</application>
</manifest>
You need to call another activity like this inside the OnClickListener() of button
Button mondayEdit= (Button)findViewById(R.id.button1);
mondayEdit.setOnClickListener(new OnClickListener()
{ public void onClick(View v)
{
Intent intent = new Intent(main.this, secondActivity.class);
startActivity(intent);
finish();
}
});
Probably your code is showing error due to Android manifest file, Try adding proper class in manifest file. Making first activity as main , and other as default.Others part of code is exactly fine.
来源：https://stackoverflow.com/questions/18550205/start-another-activity-by-clicking-a-button