无法使用意图启动活动

Question

I have a button initialized

button1= (Button)findViewById(R.id.button1);

Tn the OnClick() function I have

public void onClick(View arg0) {
        // TODO Auto-generated method stub
        Intent intent = new Intent(this, MainActivity2.class);
        startActivity(intent);

    }

My New Activity's name is MainActivity2 in the Manifest file

  <activity
            android:name="com.example.intent.MainActivity2"
            android:label="@string/title_activity_main_activity2" >
        </activity>

But the 2nd activity never launches

Please help.

Activity 1

public class MainActivity extends Activity implements OnClickListener {

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

    }


    public void onClick(View arg0) {
        // TODO Auto-generated method stub
        Intent intent = new Intent(this, MainActivity2.class);
        startActivity(intent);

    }


}

XML LAYOUT

<activity
            android:name="com.example.intent.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.intent.MainActivity2"
            android:label="@string/title_activity_main_activity2" >
        </activity>
    </application>

Answer 1

You did not register the onClick event to the button.

From:

public class MainActivity extends Activity implements OnClickListener {

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

    }
    public void onClick(View arg0) {
        // TODO Auto-generated method stub
        Intent intent = new Intent(this, MainActivity2.class);
        startActivity(intent);
    }
}

To:

public class MainActivity extends Activity implements OnClickListener {

    Button button1;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        button1= (Button)findViewById(R.id.button1);
        button1.setOnClickListener(this);
    }
    public void onClick(View arg0) {
        // TODO Auto-generated method stub
        Intent intent = new Intent(this, MainActivity2.class);
        startActivity(intent);
    }
}

Answer 2

change

public void onClick(View arg0) {
    // TODO Auto-generated method stub
    Intent intent = new Intent(this, MainActivity2.class);
    startActivity(intent);

}

to

button1.setOnClickListener(new OnClickListener(){
public void onClick(View arg0) {
    // TODO Auto-generated method stub
    Intent intent = new Intent(this, MainActivity2.class);
    startActivity(intent);
   }
};

You should set the onClicklistener to the button

Answer 3

buddy you just need to chage one word from your code..

public class MainActivity extends Activity implements OnClickListener {

Button button1;

public void onClick(View arg0) {
    // TODO Auto-generated method stub
    if (R.id.button1) {
    Intent intent = new Intent(MainActivity.this, MainActivity2.class);
    startActivity(intent);
    }
}

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    button1= (Button)findViewById(R.id.button1);
    button1.setOnClickListener(this);
}

this will deeinitely work....